zlib: updated bundled zlib to v1.2.12

deps/zlib/adler32.c

@@ -177,3 +177,10 @@ uLong ZEXPORT adler32_combine(adler1, adler2, len2)
     return adler32_combine_(adler1, adler2, len2);
 }
 
+uLong ZEXPORT adler32_combine64(adler1, adler2, len2)
+    uLong adler1;
+    uLong adler2;
+    z_off64_t len2;
+{
+    return adler32_combine_(adler1, adler2, len2);
+}

deps/zlib/crc32.c

 /* crc32.c -- compute the CRC-32 of a data stream
- * Copyright (C) 1995-2006, 2010, 2011, 2012, 2016 Mark Adler
+ * Copyright (C) 1995-2022 Mark Adler
  * For conditions of distribution and use, see copyright notice in zlib.h
  *
- * Thanks to Rodney Brown <rbrown64@csc.com.au> for his contribution of faster
- * CRC methods: exclusive-oring 32 bits of data at a time, and pre-computing
- * tables for updating the shift register in one step with three exclusive-ors
- * instead of four steps with four exclusive-ors.  This results in about a
- * factor of two increase in speed on a Power PC G4 (PPC7455) using gcc -O3.
+ * This interleaved implementation of a CRC makes use of pipelined multiple
+ * arithmetic-logic units, commonly found in modern CPU cores. It is due to
+ * Kadatch and Jenkins (2010). See doc/crc-doc.1.0.pdf in this distribution.
  */
 
 /* @(#) $Id$ */
@@ -14,11 +12,12 @@
 /*
   Note on the use of DYNAMIC_CRC_TABLE: there is no mutex or semaphore
   protection on the static variables used to control the first-use generation
-  of the crc tables.  Therefore, if you #define DYNAMIC_CRC_TABLE, you should
+  of the crc tables. Therefore, if you #define DYNAMIC_CRC_TABLE, you should
   first call get_crc_table() to initialize the tables before allowing more than
   one thread to use crc32().
 
-  DYNAMIC_CRC_TABLE and MAKECRCH can be #defined to write out crc32.h.
+  MAKECRCH can be #defined to write out crc32.h. A main() routine is also
+  produced, so that this one source file can be compiled to an executable.
  */
 
 #ifdef MAKECRCH
@@ -28,408 +27,1090 @@
 #  endif /* !DYNAMIC_CRC_TABLE */
 #endif /* MAKECRCH */
 
-#include "zutil.h"      /* for STDC and FAR definitions */
+#include "zutil.h"      /* for Z_U4, Z_U8, z_crc_t, and FAR definitions */
 
-/* Definitions for doing the crc four data bytes at a time. */
-#if !defined(NOBYFOUR) && defined(Z_U4)
-#  define BYFOUR
+ /*
+  A CRC of a message is computed on N braids of words in the message, where
+  each word consists of W bytes (4 or 8). If N is 3, for example, then three
+  running sparse CRCs are calculated respectively on each braid, at these
+  indices in the array of words: 0, 3, 6, ..., 1, 4, 7, ..., and 2, 5, 8, ...
+  This is done starting at a word boundary, and continues until as many blocks
+  of N * W bytes as are available have been processed. The results are combined
+  into a single CRC at the end. For this code, N must be in the range 1..6 and
+  W must be 4 or 8. The upper limit on N can be increased if desired by adding
+  more #if blocks, extending the patterns apparent in the code. In addition,
+  crc32.h would need to be regenerated, if the maximum N value is increased.
+
+  N and W are chosen empirically by benchmarking the execution time on a given
+  processor. The choices for N and W below were based on testing on Intel Kaby
+  Lake i7, AMD Ryzen 7, ARM Cortex-A57, Sparc64-VII, PowerPC POWER9, and MIPS64
+  Octeon II processors. The Intel, AMD, and ARM processors were all fastest
+  with N=5, W=8. The Sparc, PowerPC, and MIPS64 were all fastest at N=5, W=4.
+  They were all tested with either gcc or clang, all using the -O3 optimization
+  level. Your mileage may vary.
+ */
+
+/* Define N */
+#ifdef Z_TESTN
+#  define N Z_TESTN
+#else
+#  define N 5
+#endif
+#if N < 1 || N > 6
+#  error N must be in 1..6
 #endif
-#ifdef BYFOUR
-   local unsigned long crc32_little OF((unsigned long,
-                        const unsigned char FAR *, z_size_t));
-   local unsigned long crc32_big OF((unsigned long,
-                        const unsigned char FAR *, z_size_t));
-#  define TBLS 8
+
+/*
+  z_crc_t must be at least 32 bits. z_word_t must be at least as long as
+  z_crc_t. It is assumed here that z_word_t is either 32 bits or 64 bits, and
+  that bytes are eight bits.
+ */
+
+/*
+  Define W and the associated z_word_t type. If W is not defined, then a
+  braided calculation is not used, and the associated tables and code are not
+  compiled.
+ */
+#ifdef Z_TESTW
+#  if Z_TESTW-1 != -1
+#    define W Z_TESTW
+#  endif
 #else
-#  define TBLS 1
-#endif /* BYFOUR */
+#  ifdef MAKECRCH
+#    define W 8         /* required for MAKECRCH */
+#  else
+#    if defined(__x86_64__) || defined(__aarch64__)
+#      define W 8
+#    else
+#      define W 4
+#    endif
+#  endif
+#endif
+#ifdef W
+#  if W == 8 && defined(Z_U8)
+     typedef Z_U8 z_word_t;
+#  elif defined(Z_U4)
+#    undef W
+#    define W 4
+     typedef Z_U4 z_word_t;
+#  else
+#    undef W
+#  endif
+#endif
 
-/* Local functions for crc concatenation */
-local unsigned long gf2_matrix_times OF((unsigned long *mat,
-                                         unsigned long vec));
-local void gf2_matrix_square OF((unsigned long *square, unsigned long *mat));
-local uLong crc32_combine_ OF((uLong crc1, uLong crc2, z_off64_t len2));
+/* Local functions. */
+local z_crc_t multmodp OF((z_crc_t a, z_crc_t b));
+local z_crc_t x2nmodp OF((z_off64_t n, unsigned k));
 
+/* If available, use the ARM processor CRC32 instruction. */
+#if defined(__aarch64__) && defined(__ARM_FEATURE_CRC32) && W == 8
+#  define ARMCRC32
+#endif
+
+#if defined(W) && (!defined(ARMCRC32) || defined(DYNAMIC_CRC_TABLE))
+/*
+  Swap the bytes in a z_word_t to convert between little and big endian. Any
+  self-respecting compiler will optimize this to a single machine byte-swap
+  instruction, if one is available. This assumes that word_t is either 32 bits
+  or 64 bits.
+ */
+local z_word_t byte_swap(word)
+    z_word_t word;
+{
+#  if W == 8
+    return
+        (word & 0xff00000000000000) >> 56 |
+        (word & 0xff000000000000) >> 40 |
+        (word & 0xff0000000000) >> 24 |
+        (word & 0xff00000000) >> 8 |
+        (word & 0xff000000) << 8 |
+        (word & 0xff0000) << 24 |
+        (word & 0xff00) << 40 |
+        (word & 0xff) << 56;
+#  else   /* W == 4 */
+    return
+        (word & 0xff000000) >> 24 |
+        (word & 0xff0000) >> 8 |
+        (word & 0xff00) << 8 |
+        (word & 0xff) << 24;
+#  endif
+}
+#endif
+
+/* CRC polynomial. */
+#define POLY 0xedb88320         /* p(x) reflected, with x^32 implied */
 
 #ifdef DYNAMIC_CRC_TABLE
 
-local volatile int crc_table_empty = 1;
-local z_crc_t FAR crc_table[TBLS][256];
+local z_crc_t FAR crc_table[256];
+local z_crc_t FAR x2n_table[32];
 local void make_crc_table OF((void));
+#ifdef W
+   local z_word_t FAR crc_big_table[256];
+   local z_crc_t FAR crc_braid_table[W][256];
+   local z_word_t FAR crc_braid_big_table[W][256];
+   local void braid OF((z_crc_t [][256], z_word_t [][256], int, int));
+#endif
 #ifdef MAKECRCH
-   local void write_table OF((FILE *, const z_crc_t FAR *));
+   local void write_table OF((FILE *, const z_crc_t FAR *, int));
+   local void write_table32hi OF((FILE *, const z_word_t FAR *, int));
+   local void write_table64 OF((FILE *, const z_word_t FAR *, int));
 #endif /* MAKECRCH */
+
+/*
+  Define a once() function depending on the availability of atomics. If this is
+  compiled with DYNAMIC_CRC_TABLE defined, and if CRCs will be computed in
+  multiple threads, and if atomics are not available, then get_crc_table() must
+  be called to initialize the tables and must return before any threads are
+  allowed to compute or combine CRCs.
+ */
+
+/* Definition of once functionality. */
+typedef struct once_s once_t;
+local void once OF((once_t *, void (*)(void)));
+
+/* Check for the availability of atomics. */
+#if defined(__STDC__) && __STDC_VERSION__ >= 201112L && \
+    !defined(__STDC_NO_ATOMICS__)
+
+#include <stdatomic.h>
+
+/* Structure for once(), which must be initialized with ONCE_INIT. */
+struct once_s {
+    atomic_flag begun;
+    atomic_int done;
+};
+#define ONCE_INIT {ATOMIC_FLAG_INIT, 0}
+
+/*
+  Run the provided init() function exactly once, even if multiple threads
+  invoke once() at the same time. The state must be a once_t initialized with
+  ONCE_INIT.
+ */
+local void once(state, init)
+    once_t *state;
+    void (*init)(void);
+{
+    if (!atomic_load(&state->done)) {
+        if (atomic_flag_test_and_set(&state->begun))
+            while (!atomic_load(&state->done))
+                ;
+        else {
+            init();
+            atomic_store(&state->done, 1);
+        }
+    }
+}
+
+#else   /* no atomics */
+
+/* Structure for once(), which must be initialized with ONCE_INIT. */
+struct once_s {
+    volatile int begun;
+    volatile int done;
+};
+#define ONCE_INIT {0, 0}
+
+/* Test and set. Alas, not atomic, but tries to minimize the period of
+   vulnerability. */
+local int test_and_set OF((int volatile *));
+local int test_and_set(flag)
+    int volatile *flag;
+{
+    int was;
+
+    was = *flag;
+    *flag = 1;
+    return was;
+}
+
+/* Run the provided init() function once. This is not thread-safe. */
+local void once(state, init)
+    once_t *state;
+    void (*init)(void);
+{
+    if (!state->done) {
+        if (test_and_set(&state->begun))
+            while (!state->done)
+                ;
+        else {
+            init();
+            state->done = 1;
+        }
+    }
+}
+
+#endif
+
+/* State for once(). */
+local once_t made = ONCE_INIT;
+
 /*
   Generate tables for a byte-wise 32-bit CRC calculation on the polynomial:
   x^32+x^26+x^23+x^22+x^16+x^12+x^11+x^10+x^8+x^7+x^5+x^4+x^2+x+1.
 
   Polynomials over GF(2) are represented in binary, one bit per coefficient,
-  with the lowest powers in the most significant bit.  Then adding polynomials
+  with the lowest powers in the most significant bit. Then adding polynomials
   is just exclusive-or, and multiplying a polynomial by x is a right shift by
-  one.  If we call the above polynomial p, and represent a byte as the
+  one. If we call the above polynomial p, and represent a byte as the
   polynomial q, also with the lowest power in the most significant bit (so the
-  byte 0xb1 is the polynomial x^7+x^3+x+1), then the CRC is (q*x^32) mod p,
+  byte 0xb1 is the polynomial x^7+x^3+x^2+1), then the CRC is (q*x^32) mod p,
   where a mod b means the remainder after dividing a by b.
 
   This calculation is done using the shift-register method of multiplying and
-  taking the remainder.  The register is initialized to zero, and for each
+  taking the remainder. The register is initialized to zero, and for each
   incoming bit, x^32 is added mod p to the register if the bit is a one (where
-  x^32 mod p is p+x^32 = x^26+...+1), and the register is multiplied mod p by
-  x (which is shifting right by one and adding x^32 mod p if the bit shifted
-  out is a one).  We start with the highest power (least significant bit) of
-  q and repeat for all eight bits of q.
-
-  The first table is simply the CRC of all possible eight bit values.  This is
-  all the information needed to generate CRCs on data a byte at a time for all
-  combinations of CRC register values and incoming bytes.  The remaining tables
-  allow for word-at-a-time CRC calculation for both big-endian and little-
-  endian machines, where a word is four bytes.
-*/
+  x^32 mod p is p+x^32 = x^26+...+1), and the register is multiplied mod p by x
+  (which is shifting right by one and adding x^32 mod p if the bit shifted out
+  is a one). We start with the highest power (least significant bit) of q and
+  repeat for all eight bits of q.
+
+  The table is simply the CRC of all possible eight bit values. This is all the
+  information needed to generate CRCs on data a byte at a time for all
+  combinations of CRC register values and incoming bytes.
+ */
+
 local void make_crc_table()
 {
-    z_crc_t c;
-    int n, k;
-    z_crc_t poly;                       /* polynomial exclusive-or pattern */
-    /* terms of polynomial defining this crc (except x^32): */
-    static volatile int first = 1;      /* flag to limit concurrent making */
-    static const unsigned char p[] = {0,1,2,4,5,7,8,10,11,12,16,22,23,26};
-
-    /* See if another task is already doing this (not thread-safe, but better
-       than nothing -- significantly reduces duration of vulnerability in
-       case the advice about DYNAMIC_CRC_TABLE is ignored) */
-    if (first) {
-        first = 0;
-
-        /* make exclusive-or pattern from polynomial (0xedb88320UL) */
-        poly = 0;
-        for (n = 0; n < (int)(sizeof(p)/sizeof(unsigned char)); n++)
-            poly |= (z_crc_t)1 << (31 - p[n]);
-
-        /* generate a crc for every 8-bit value */
-        for (n = 0; n < 256; n++) {
-            c = (z_crc_t)n;
-            for (k = 0; k < 8; k++)
-                c = c & 1 ? poly ^ (c >> 1) : c >> 1;
-            crc_table[0][n] = c;
-        }
+    unsigned i, j, n;
+    z_crc_t p;
 
-#ifdef BYFOUR
-        /* generate crc for each value followed by one, two, and three zeros,
-           and then the byte reversal of those as well as the first table */
-        for (n = 0; n < 256; n++) {
-            c = crc_table[0][n];
-            crc_table[4][n] = ZSWAP32(c);
-            for (k = 1; k < 4; k++) {
-                c = crc_table[0][c & 0xff] ^ (c >> 8);
-                crc_table[k][n] = c;
-                crc_table[k + 4][n] = ZSWAP32(c);
-            }
-        }
-#endif /* BYFOUR */
-
-        crc_table_empty = 0;
-    }
-    else {      /* not first */
-        /* wait for the other guy to finish (not efficient, but rare) */
-        while (crc_table_empty)
-            ;
+    /* initialize the CRC of bytes tables */
+    for (i = 0; i < 256; i++) {
+        p = i;
+        for (j = 0; j < 8; j++)
+            p = p & 1 ? (p >> 1) ^ POLY : p >> 1;
+        crc_table[i] = p;
+#ifdef W
+        crc_big_table[i] = byte_swap(p);
+#endif
     }
 
+    /* initialize the x^2^n mod p(x) table */
+    p = (z_crc_t)1 << 30;         /* x^1 */
+    x2n_table[0] = p;
+    for (n = 1; n < 32; n++)
+        x2n_table[n] = p = multmodp(p, p);
+
+#ifdef W
+    /* initialize the braiding tables -- needs x2n_table[] */
+    braid(crc_braid_table, crc_braid_big_table, N, W);
+#endif
+
 #ifdef MAKECRCH
-    /* write out CRC tables to crc32.h */
     {
+        /*
+          The crc32.h header file contains tables for both 32-bit and 64-bit
+          z_word_t's, and so requires a 64-bit type be available. In that case,
+          z_word_t must be defined to be 64-bits. This code then also generates
+          and writes out the tables for the case that z_word_t is 32 bits.
+         */
+#if !defined(W) || W != 8
+#  error Need a 64-bit integer type in order to generate crc32.h.
+#endif
         FILE *out;
+        int k, n;
+        z_crc_t ltl[8][256];
+        z_word_t big[8][256];
 
         out = fopen("crc32.h", "w");
         if (out == NULL) return;
-        fprintf(out, "/* crc32.h -- tables for rapid CRC calculation\n");
-        fprintf(out, " * Generated automatically by crc32.c\n */\n\n");
-        fprintf(out, "local const z_crc_t FAR ");
-        fprintf(out, "crc_table[TBLS][256] =\n{\n  {\n");
-        write_table(out, crc_table[0]);
-#  ifdef BYFOUR
-        fprintf(out, "#ifdef BYFOUR\n");
-        for (k = 1; k < 8; k++) {
-            fprintf(out, "  },\n  {\n");
-            write_table(out, crc_table[k]);
+
+        /* write out little-endian CRC table to crc32.h */
+        fprintf(out,
+            "/* crc32.h -- tables for rapid CRC calculation\n"
+            " * Generated automatically by crc32.c\n */\n"
+            "\n"
+            "local const z_crc_t FAR crc_table[] = {\n"
+            "    ");
+        write_table(out, crc_table, 256);
+        fprintf(out,
+            "};\n");
+
+        /* write out big-endian CRC table for 64-bit z_word_t to crc32.h */
+        fprintf(out,
+            "\n"
+            "#ifdef W\n"
+            "\n"
+            "#if W == 8\n"
+            "\n"
+            "local const z_word_t FAR crc_big_table[] = {\n"
+            "    ");
+        write_table64(out, crc_big_table, 256);
+        fprintf(out,
+            "};\n");
+
+        /* write out big-endian CRC table for 32-bit z_word_t to crc32.h */
+        fprintf(out,
+            "\n"
+            "#else /* W == 4 */\n"
+            "\n"
+            "local const z_word_t FAR crc_big_table[] = {\n"
+            "    ");
+        write_table32hi(out, crc_big_table, 256);
+        fprintf(out,
+            "};\n"
+            "\n"
+            "#endif\n");
+
+        /* write out braid tables for each value of N */
+        for (n = 1; n <= 6; n++) {
+            fprintf(out,
+            "\n"
+            "#if N == %d\n", n);
+
+            /* compute braid tables for this N and 64-bit word_t */
+            braid(ltl, big, n, 8);
+
+            /* write out braid tables for 64-bit z_word_t to crc32.h */
+            fprintf(out,
+            "\n"
+            "#if W == 8\n"
+            "\n"
+            "local const z_crc_t FAR crc_braid_table[][256] = {\n");
+            for (k = 0; k < 8; k++) {
+                fprintf(out, "   {");
+                write_table(out, ltl[k], 256);
+                fprintf(out, "}%s", k < 7 ? ",\n" : "");
+            }
+            fprintf(out,
+            "};\n"
+            "\n"
+            "local const z_word_t FAR crc_braid_big_table[][256] = {\n");
+            for (k = 0; k < 8; k++) {
+                fprintf(out, "   {");
+                write_table64(out, big[k], 256);
+                fprintf(out, "}%s", k < 7 ? ",\n" : "");
+            }
+            fprintf(out,
+            "};\n");
+
+            /* compute braid tables for this N and 32-bit word_t */
+            braid(ltl, big, n, 4);
+
+            /* write out braid tables for 32-bit z_word_t to crc32.h */
+            fprintf(out,
+            "\n"
+            "#else /* W == 4 */\n"
+            "\n"
+            "local const z_crc_t FAR crc_braid_table[][256] = {\n");
+            for (k = 0; k < 4; k++) {
+                fprintf(out, "   {");
+                write_table(out, ltl[k], 256);
+                fprintf(out, "}%s", k < 3 ? ",\n" : "");
+            }
+            fprintf(out,
+            "};\n"
+            "\n"
+            "local const z_word_t FAR crc_braid_big_table[][256] = {\n");
+            for (k = 0; k < 4; k++) {
+                fprintf(out, "   {");
+                write_table32hi(out, big[k], 256);
+                fprintf(out, "}%s", k < 3 ? ",\n" : "");
+            }
+            fprintf(out,
+            "};\n"
+            "\n"
+            "#endif\n"
+            "\n"
+            "#endif\n");
         }
-        fprintf(out, "#endif\n");
-#  endif /* BYFOUR */
-        fprintf(out, "  }\n};\n");
+        fprintf(out,
+            "\n"
+            "#endif\n");
+
+        /* write out zeros operator table to crc32.h */
+        fprintf(out,
+            "\n"
+            "local const z_crc_t FAR x2n_table[] = {\n"
+            "    ");
+        write_table(out, x2n_table, 32);
+        fprintf(out,
+            "};\n");
         fclose(out);
     }
 #endif /* MAKECRCH */
 }
 
 #ifdef MAKECRCH
-local void write_table(out, table)
+
+/*
+   Write the 32-bit values in table[0..k-1] to out, five per line in
+   hexadecimal separated by commas.
+ */
+local void write_table(out, table, k)
     FILE *out;
     const z_crc_t FAR *table;
+    int k;
 {
     int n;
 
-    for (n = 0; n < 256; n++)
-        fprintf(out, "%s0x%08lxUL%s", n % 5 ? "" : "    ",
+    for (n = 0; n < k; n++)
+        fprintf(out, "%s0x%08lx%s", n == 0 || n % 5 ? "" : "    ",
                 (unsigned long)(table[n]),
-                n == 255 ? "\n" : (n % 5 == 4 ? ",\n" : ", "));
+                n == k - 1 ? "" : (n % 5 == 4 ? ",\n" : ", "));
 }
+
+/*
+   Write the high 32-bits of each value in table[0..k-1] to out, five per line
+   in hexadecimal separated by commas.
+ */
+local void write_table32hi(out, table, k)
+FILE *out;
+const z_word_t FAR *table;
+int k;
+{
+    int n;
+
+    for (n = 0; n < k; n++)
+        fprintf(out, "%s0x%08lx%s", n == 0 || n % 5 ? "" : "    ",
+                (unsigned long)(table[n] >> 32),
+                n == k - 1 ? "" : (n % 5 == 4 ? ",\n" : ", "));
+}
+
+/*
+  Write the 64-bit values in table[0..k-1] to out, three per line in
+  hexadecimal separated by commas. This assumes that if there is a 64-bit
+  type, then there is also a long long integer type, and it is at least 64
+  bits. If not, then the type cast and format string can be adjusted
+  accordingly.
+ */
+local void write_table64(out, table, k)
+    FILE *out;
+    const z_word_t FAR *table;
+    int k;
+{
+    int n;
+
+    for (n = 0; n < k; n++)
+        fprintf(out, "%s0x%016llx%s", n == 0 || n % 3 ? "" : "    ",
+                (unsigned long long)(table[n]),
+                n == k - 1 ? "" : (n % 3 == 2 ? ",\n" : ", "));
+}
+
+/* Actually do the deed. */
+int main()
+{
+    make_crc_table();
+    return 0;
+}
+
 #endif /* MAKECRCH */
 
+#ifdef W
+/*
+  Generate the little and big-endian braid tables for the given n and z_word_t
+  size w. Each array must have room for w blocks of 256 elements.
+ */
+local void braid(ltl, big, n, w)
+    z_crc_t ltl[][256];
+    z_word_t big[][256];
+    int n;
+    int w;
+{
+    int k;
+    z_crc_t i, p, q;
+    for (k = 0; k < w; k++) {
+        p = x2nmodp((n * w + 3 - k) << 3, 0);
+        ltl[k][0] = 0;
+        big[w - 1 - k][0] = 0;
+        for (i = 1; i < 256; i++) {
+            ltl[k][i] = q = multmodp(i << 24, p);
+            big[w - 1 - k][i] = byte_swap(q);
+        }
+    }
+}
+#endif
+
 #else /* !DYNAMIC_CRC_TABLE */
 /* ========================================================================
- * Tables of CRC-32s of all single-byte values, made by make_crc_table().
+ * Tables for byte-wise and braided CRC-32 calculations, and a table of powers
+ * of x for combining CRC-32s, all made by make_crc_table().
  */
 #include "crc32.h"
 #endif /* DYNAMIC_CRC_TABLE */
 
+/* ========================================================================
+ * Routines used for CRC calculation. Some are also required for the table
+ * generation above.
+ */
+
+/*
+  Return a(x) multiplied by b(x) modulo p(x), where p(x) is the CRC polynomial,
+  reflected. For speed, this requires that a not be zero.
+ */
+local z_crc_t multmodp(a, b)
+    z_crc_t a;
+    z_crc_t b;
+{
+    z_crc_t m, p;
+
+    m = (z_crc_t)1 << 31;
+    p = 0;
+    for (;;) {
+        if (a & m) {
+            p ^= b;
+            if ((a & (m - 1)) == 0)
+                break;
+        }
+        m >>= 1;
+        b = b & 1 ? (b >> 1) ^ POLY : b >> 1;
+    }
+    return p;
+}
+
+/*
+  Return x^(n * 2^k) modulo p(x). Requires that x2n_table[] has been
+  initialized.
+ */
+local z_crc_t x2nmodp(n, k)
+    z_off64_t n;
+    unsigned k;
+{
+    z_crc_t p;
+
+    p = (z_crc_t)1 << 31;           /* x^0 == 1 */
+    while (n) {
+        if (n & 1)
+            p = multmodp(x2n_table[k & 31], p);
+        n >>= 1;
+        k++;
+    }
+    return p;
+}
+
 /* =========================================================================
- * This function can be used by asm versions of crc32()
+ * This function can be used by asm versions of crc32(), and to force the
+ * generation of the CRC tables in a threaded application.
  */
 const z_crc_t FAR * ZEXPORT get_crc_table()
 {
 #ifdef DYNAMIC_CRC_TABLE
-    if (crc_table_empty)
-        make_crc_table();
+    once(&made, make_crc_table);
 #endif /* DYNAMIC_CRC_TABLE */
     return (const z_crc_t FAR *)crc_table;
 }
 
-/* ========================================================================= */
-#define DO1 crc = crc_table[0][((int)crc ^ (*buf++)) & 0xff] ^ (crc >> 8)
-#define DO8 DO1; DO1; DO1; DO1; DO1; DO1; DO1; DO1
+/* =========================================================================
+ * Use ARM machine instructions if available. This will compute the CRC about
+ * ten times faster than the braided calculation. This code does not check for
+ * the presence of the CRC instruction at run time. __ARM_FEATURE_CRC32 will
+ * only be defined if the compilation specifies an ARM processor architecture
+ * that has the instructions. For example, compiling with -march=armv8.1-a or
+ * -march=armv8-a+crc, or -march=native if the compile machine has the crc32
+ * instructions.
+ */
+#ifdef ARMCRC32
+
+/*
+   Constants empirically determined to maximize speed. These values are from
+   measurements on a Cortex-A57. Your mileage may vary.
+ */
+#define Z_BATCH 3990                /* number of words in a batch */
+#define Z_BATCH_ZEROS 0xa10d3d0c    /* computed from Z_BATCH = 3990 */
+#define Z_BATCH_MIN 800             /* fewest words in a final batch */
 
-/* ========================================================================= */
 unsigned long ZEXPORT crc32_z(crc, buf, len)
     unsigned long crc;
     const unsigned char FAR *buf;
     z_size_t len;
 {
-    if (buf == Z_NULL) return 0UL;
+    z_crc_t val;
+    z_word_t crc1, crc2;
+    const z_word_t *word;
+    z_word_t val0, val1, val2;
+    z_size_t last, last2, i;
+    z_size_t num;
+
+    /* Return initial CRC, if requested. */
+    if (buf == Z_NULL) return 0;
 
 #ifdef DYNAMIC_CRC_TABLE
-    if (crc_table_empty)
-        make_crc_table();
+    once(&made, make_crc_table);
 #endif /* DYNAMIC_CRC_TABLE */
 
-#ifdef BYFOUR
-    if (sizeof(void *) == sizeof(ptrdiff_t)) {
-        z_crc_t endian;
+    /* Pre-condition the CRC */
+    crc ^= 0xffffffff;
 
-        endian = 1;
-        if (*((unsigned char *)(&endian)))
-            return crc32_little(crc, buf, len);
-        else
-            return crc32_big(crc, buf, len);
+    /* Compute the CRC up to a word boundary. */
+    while (len && ((z_size_t)buf & 7) != 0) {
+        len--;
+        val = *buf++;
+        __asm__ volatile("crc32b %w0, %w0, %w1" : "+r"(crc) : "r"(val));
     }
-#endif /* BYFOUR */
-    crc = crc ^ 0xffffffffUL;
-    while (len >= 8) {
-        DO8;
-        len -= 8;
+
+    /* Prepare to compute the CRC on full 64-bit words word[0..num-1]. */
+    word = (z_word_t const *)buf;
+    num = len >> 3;
+    len &= 7;
+
+    /* Do three interleaved CRCs to realize the throughput of one crc32x
+       instruction per cycle. Each CRC is calcuated on Z_BATCH words. The three
+       CRCs are combined into a single CRC after each set of batches. */
+    while (num >= 3 * Z_BATCH) {
+        crc1 = 0;
+        crc2 = 0;
+        for (i = 0; i < Z_BATCH; i++) {
+            val0 = word[i];
+            val1 = word[i + Z_BATCH];
+            val2 = word[i + 2 * Z_BATCH];
+            __asm__ volatile("crc32x %w0, %w0, %x1" : "+r"(crc) : "r"(val0));
+            __asm__ volatile("crc32x %w0, %w0, %x1" : "+r"(crc1) : "r"(val1));
+            __asm__ volatile("crc32x %w0, %w0, %x1" : "+r"(crc2) : "r"(val2));
+        }
+        word += 3 * Z_BATCH;
+        num -= 3 * Z_BATCH;
+        crc = multmodp(Z_BATCH_ZEROS, crc) ^ crc1;
+        crc = multmodp(Z_BATCH_ZEROS, crc) ^ crc2;
     }
-    if (len) do {
-        DO1;
-    } while (--len);
-    return crc ^ 0xffffffffUL;
-}
 
-/* ========================================================================= */
-unsigned long ZEXPORT crc32(crc, buf, len)
-    unsigned long crc;
-    const unsigned char FAR *buf;
-    uInt len;
-{
-    return crc32_z(crc, buf, len);
+    /* Do one last smaller batch with the remaining words, if there are enough
+       to pay for the combination of CRCs. */
+    last = num / 3;
+    if (last >= Z_BATCH_MIN) {
+        last2 = last << 1;
+        crc1 = 0;
+        crc2 = 0;
+        for (i = 0; i < last; i++) {
+            val0 = word[i];
+            val1 = word[i + last];
+            val2 = word[i + last2];
+            __asm__ volatile("crc32x %w0, %w0, %x1" : "+r"(crc) : "r"(val0));
+            __asm__ volatile("crc32x %w0, %w0, %x1" : "+r"(crc1) : "r"(val1));
+            __asm__ volatile("crc32x %w0, %w0, %x1" : "+r"(crc2) : "r"(val2));
+        }
+        word += 3 * last;
+        num -= 3 * last;
+        val = x2nmodp(last, 6);
+        crc = multmodp(val, crc) ^ crc1;
+        crc = multmodp(val, crc) ^ crc2;
+    }
+
+    /* Compute the CRC on any remaining words. */
+    for (i = 0; i < num; i++) {
+        val0 = word[i];
+        __asm__ volatile("crc32x %w0, %w0, %x1" : "+r"(crc) : "r"(val0));
+    }
+    word += num;
+
+    /* Complete the CRC on any remaining bytes. */
+    buf = (const unsigned char FAR *)word;
+    while (len) {
+        len--;
+        val = *buf++;
+        __asm__ volatile("crc32b %w0, %w0, %w1" : "+r"(crc) : "r"(val));
+    }
+
+    /* Return the CRC, post-conditioned. */
+    return crc ^ 0xffffffff;
 }
 
-#ifdef BYFOUR
+#else
+
+#ifdef W
 
 /*
-   This BYFOUR code accesses the passed unsigned char * buffer with a 32-bit
-   integer pointer type. This violates the strict aliasing rule, where a
-   compiler can assume, for optimization purposes, that two pointers to
-   fundamentally different types won't ever point to the same memory. This can
-   manifest as a problem only if one of the pointers is written to. This code
-   only reads from those pointers. So long as this code remains isolated in
-   this compilation unit, there won't be a problem. For this reason, this code
-   should not be copied and pasted into a compilation unit in which other code
-   writes to the buffer that is passed to these routines.
+  Return the CRC of the W bytes in the word_t data, taking the
+  least-significant byte of the word as the first byte of data, without any pre
+  or post conditioning. This is used to combine the CRCs of each braid.
  */
+local z_crc_t crc_word(data)
+    z_word_t data;
+{
+    int k;
+    for (k = 0; k < W; k++)
+        data = (data >> 8) ^ crc_table[data & 0xff];
+    return (z_crc_t)data;
+}
 
-/* ========================================================================= */
-#define DOLIT4 c ^= *buf4++; \
-        c = crc_table[3][c & 0xff] ^ crc_table[2][(c >> 8) & 0xff] ^ \
-            crc_table[1][(c >> 16) & 0xff] ^ crc_table[0][c >> 24]
-#define DOLIT32 DOLIT4; DOLIT4; DOLIT4; DOLIT4; DOLIT4; DOLIT4; DOLIT4; DOLIT4
+local z_word_t crc_word_big(data)
+    z_word_t data;
+{
+    int k;
+    for (k = 0; k < W; k++)
+        data = (data << 8) ^
+            crc_big_table[(data >> ((W - 1) << 3)) & 0xff];
+    return data;
+}
+
+#endif
 
 /* ========================================================================= */
-local unsigned long crc32_little(crc, buf, len)
+unsigned long ZEXPORT crc32_z(crc, buf, len)
     unsigned long crc;
     const unsigned char FAR *buf;
     z_size_t len;
 {
-    register z_crc_t c;
-    register const z_crc_t FAR *buf4;
+    /* Return initial CRC, if requested. */
+    if (buf == Z_NULL) return 0;
 
-    c = (z_crc_t)crc;
-    c = ~c;
-    while (len && ((ptrdiff_t)buf & 3)) {
-        c = crc_table[0][(c ^ *buf++) & 0xff] ^ (c >> 8);
-        len--;
-    }
+#ifdef DYNAMIC_CRC_TABLE
+    once(&made, make_crc_table);
+#endif /* DYNAMIC_CRC_TABLE */
 
-    buf4 = (const z_crc_t FAR *)(const void FAR *)buf;
-    while (len >= 32) {
-        DOLIT32;
-        len -= 32;
-    }
-    while (len >= 4) {
-        DOLIT4;
-        len -= 4;
-    }
-    buf = (const unsigned char FAR *)buf4;
+    /* Pre-condition the CRC */
+    crc ^= 0xffffffff;
 
-    if (len) do {
-        c = crc_table[0][(c ^ *buf++) & 0xff] ^ (c >> 8);
-    } while (--len);
-    c = ~c;
-    return (unsigned long)c;
-}
+#ifdef W
 
-/* ========================================================================= */
-#define DOBIG4 c ^= *buf4++; \
-        c = crc_table[4][c & 0xff] ^ crc_table[5][(c >> 8) & 0xff] ^ \
-            crc_table[6][(c >> 16) & 0xff] ^ crc_table[7][c >> 24]
-#define DOBIG32 DOBIG4; DOBIG4; DOBIG4; DOBIG4; DOBIG4; DOBIG4; DOBIG4; DOBIG4
+    /* If provided enough bytes, do a braided CRC calculation. */
+    if (len >= N * W + W - 1) {
+        z_size_t blks;
+        z_word_t const *words;
+        unsigned endian;
+        int k;
 
-/* ========================================================================= */
-local unsigned long crc32_big(crc, buf, len)
-    unsigned long crc;
-    const unsigned char FAR *buf;
-    z_size_t len;
-{
-    register z_crc_t c;
-    register const z_crc_t FAR *buf4;
+        /* Compute the CRC up to a z_word_t boundary. */
+        while (len && ((z_size_t)buf & (W - 1)) != 0) {
+            len--;
+            crc = (crc >> 8) ^ crc_table[(crc ^ *buf++) & 0xff];
+        }
 
-    c = ZSWAP32((z_crc_t)crc);
-    c = ~c;
-    while (len && ((ptrdiff_t)buf & 3)) {
-        c = crc_table[4][(c >> 24) ^ *buf++] ^ (c << 8);
-        len--;
+        /* Compute the CRC on as many N z_word_t blocks as are available. */
+        blks = len / (N * W);
+        len -= blks * N * W;
+        words = (z_word_t const *)buf;
+
+        /* Do endian check at execution time instead of compile time, since ARM
+           processors can change the endianess at execution time. If the
+           compiler knows what the endianess will be, it can optimize out the
+           check and the unused branch. */
+        endian = 1;
+        if (*(unsigned char *)&endian) {
+            /* Little endian. */
+
+            z_crc_t crc0;
+            z_word_t word0;
+#if N > 1
+            z_crc_t crc1;
+            z_word_t word1;
+#if N > 2
+            z_crc_t crc2;
+            z_word_t word2;
+#if N > 3
+            z_crc_t crc3;
+            z_word_t word3;
+#if N > 4
+            z_crc_t crc4;
+            z_word_t word4;
+#if N > 5
+            z_crc_t crc5;
+            z_word_t word5;
+#endif
+#endif
+#endif
+#endif
+#endif
+
+            /* Initialize the CRC for each braid. */
+            crc0 = crc;
+#if N > 1
+            crc1 = 0;
+#if N > 2
+            crc2 = 0;
+#if N > 3
+            crc3 = 0;
+#if N > 4
+            crc4 = 0;
+#if N > 5
+            crc5 = 0;
+#endif
+#endif
+#endif
+#endif
+#endif
+
+            /*
+              Process the first blks-1 blocks, computing the CRCs on each braid
+              independently.
+             */
+            while (--blks) {
+                /* Load the word for each braid into registers. */
+                word0 = crc0 ^ words[0];
+#if N > 1
+                word1 = crc1 ^ words[1];
+#if N > 2
+                word2 = crc2 ^ words[2];
+#if N > 3
+                word3 = crc3 ^ words[3];
+#if N > 4
+                word4 = crc4 ^ words[4];
+#if N > 5
+                word5 = crc5 ^ words[5];
+#endif
+#endif
+#endif
+#endif
+#endif
+                words += N;
+
+                /* Compute and update the CRC for each word. The loop should
+                   get unrolled. */
+                crc0 = crc_braid_table[0][word0 & 0xff];
+#if N > 1
+                crc1 = crc_braid_table[0][word1 & 0xff];
+#if N > 2
+                crc2 = crc_braid_table[0][word2 & 0xff];
+#if N > 3
+                crc3 = crc_braid_table[0][word3 & 0xff];
+#if N > 4
+                crc4 = crc_braid_table[0][word4 & 0xff];
+#if N > 5
+                crc5 = crc_braid_table[0][word5 & 0xff];
+#endif
+#endif
+#endif
+#endif
+#endif
+                for (k = 1; k < W; k++) {
+                    crc0 ^= crc_braid_table[k][(word0 >> (k << 3)) & 0xff];
+#if N > 1
+                    crc1 ^= crc_braid_table[k][(word1 >> (k << 3)) & 0xff];
+#if N > 2
+                    crc2 ^= crc_braid_table[k][(word2 >> (k << 3)) & 0xff];
+#if N > 3
+                    crc3 ^= crc_braid_table[k][(word3 >> (k << 3)) & 0xff];
+#if N > 4
+                    crc4 ^= crc_braid_table[k][(word4 >> (k << 3)) & 0xff];
+#if N > 5
+                    crc5 ^= crc_braid_table[k][(word5 >> (k << 3)) & 0xff];
+#endif
+#endif
+#endif
+#endif
+#endif
+                }
+            }
+
+            /*
+              Process the last block, combining the CRCs of the N braids at the
+              same time.
+             */
+            crc = crc_word(crc0 ^ words[0]);
+#if N > 1
+            crc = crc_word(crc1 ^ words[1] ^ crc);
+#if N > 2
+            crc = crc_word(crc2 ^ words[2] ^ crc);
+#if N > 3
+            crc = crc_word(crc3 ^ words[3] ^ crc);
+#if N > 4
+            crc = crc_word(crc4 ^ words[4] ^ crc);
+#if N > 5
+            crc = crc_word(crc5 ^ words[5] ^ crc);
+#endif
+#endif
+#endif
+#endif
+#endif
+            words += N;
+        }
+        else {
+            /* Big endian. */
+
+            z_word_t crc0, word0, comb;
+#if N > 1
+            z_word_t crc1, word1;
+#if N > 2
+            z_word_t crc2, word2;
+#if N > 3
+            z_word_t crc3, word3;
+#if N > 4
+            z_word_t crc4, word4;
+#if N > 5
+            z_word_t crc5, word5;
+#endif
+#endif
+#endif
+#endif
+#endif
+
+            /* Initialize the CRC for each braid. */
+            crc0 = byte_swap(crc);
+#if N > 1
+            crc1 = 0;
+#if N > 2
+            crc2 = 0;
+#if N > 3
+            crc3 = 0;
+#if N > 4
+            crc4 = 0;
+#if N > 5
+            crc5 = 0;
+#endif
+#endif
+#endif
+#endif
+#endif
+
+            /*
+              Process the first blks-1 blocks, computing the CRCs on each braid
+              independently.
+             */
+            while (--blks) {
+                /* Load the word for each braid into registers. */
+                word0 = crc0 ^ words[0];
+#if N > 1
+                word1 = crc1 ^ words[1];
+#if N > 2
+                word2 = crc2 ^ words[2];
+#if N > 3
+                word3 = crc3 ^ words[3];
+#if N > 4
+                word4 = crc4 ^ words[4];
+#if N > 5
+                word5 = crc5 ^ words[5];
+#endif
+#endif
+#endif
+#endif
+#endif
+                words += N;
+
+                /* Compute and update the CRC for each word. The loop should
+                   get unrolled. */
+                crc0 = crc_braid_big_table[0][word0 & 0xff];
+#if N > 1
+                crc1 = crc_braid_big_table[0][word1 & 0xff];
+#if N > 2
+                crc2 = crc_braid_big_table[0][word2 & 0xff];
+#if N > 3
+                crc3 = crc_braid_big_table[0][word3 & 0xff];
+#if N > 4
+                crc4 = crc_braid_big_table[0][word4 & 0xff];
+#if N > 5
+                crc5 = crc_braid_big_table[0][word5 & 0xff];
+#endif
+#endif
+#endif
+#endif
+#endif
+                for (k = 1; k < W; k++) {
+                    crc0 ^= crc_braid_big_table[k][(word0 >> (k << 3)) & 0xff];
+#if N > 1
+                    crc1 ^= crc_braid_big_table[k][(word1 >> (k << 3)) & 0xff];
+#if N > 2
+                    crc2 ^= crc_braid_big_table[k][(word2 >> (k << 3)) & 0xff];
+#if N > 3
+                    crc3 ^= crc_braid_big_table[k][(word3 >> (k << 3)) & 0xff];
+#if N > 4
+                    crc4 ^= crc_braid_big_table[k][(word4 >> (k << 3)) & 0xff];
+#if N > 5
+                    crc5 ^= crc_braid_big_table[k][(word5 >> (k << 3)) & 0xff];
+#endif
+#endif
+#endif
+#endif
+#endif
+                }
+            }
+
+            /*
+              Process the last block, combining the CRCs of the N braids at the
+              same time.
+             */
+            comb = crc_word_big(crc0 ^ words[0]);
+#if N > 1
+            comb = crc_word_big(crc1 ^ words[1] ^ comb);
+#if N > 2
+            comb = crc_word_big(crc2 ^ words[2] ^ comb);
+#if N > 3
+            comb = crc_word_big(crc3 ^ words[3] ^ comb);
+#if N > 4
+            comb = crc_word_big(crc4 ^ words[4] ^ comb);
+#if N > 5
+            comb = crc_word_big(crc5 ^ words[5] ^ comb);
+#endif
+#endif
+#endif
+#endif
+#endif
+            words += N;
+            crc = byte_swap(comb);
+        }
+
+        /*
+          Update the pointer to the remaining bytes to process.
+         */
+        buf = (unsigned char const *)words;
     }
 
-    buf4 = (const z_crc_t FAR *)(const void FAR *)buf;
-    while (len >= 32) {
-        DOBIG32;
-        len -= 32;
+#endif /* W */
+
+    /* Complete the computation of the CRC on any remaining bytes. */
+    while (len >= 8) {
+        len -= 8;
+        crc = (crc >> 8) ^ crc_table[(crc ^ *buf++) & 0xff];
+        crc = (crc >> 8) ^ crc_table[(crc ^ *buf++) & 0xff];
+        crc = (crc >> 8) ^ crc_table[(crc ^ *buf++) & 0xff];
+        crc = (crc >> 8) ^ crc_table[(crc ^ *buf++) & 0xff];
+        crc = (crc >> 8) ^ crc_table[(crc ^ *buf++) & 0xff];
+        crc = (crc >> 8) ^ crc_table[(crc ^ *buf++) & 0xff];
+        crc = (crc >> 8) ^ crc_table[(crc ^ *buf++) & 0xff];
+        crc = (crc >> 8) ^ crc_table[(crc ^ *buf++) & 0xff];
     }
-    while (len >= 4) {
-        DOBIG4;
-        len -= 4;
+    while (len) {
+        len--;
+        crc = (crc >> 8) ^ crc_table[(crc ^ *buf++) & 0xff];
     }
-    buf = (const unsigned char FAR *)buf4;
 
-    if (len) do {
-        c = crc_table[4][(c >> 24) ^ *buf++] ^ (c << 8);
-    } while (--len);
-    c = ~c;
-    return (unsigned long)(ZSWAP32(c));
+    /* Return the CRC, post-conditioned. */
+    return crc ^ 0xffffffff;
 }
 
-#endif /* BYFOUR */
-
-#define GF2_DIM 32      /* dimension of GF(2) vectors (length of CRC) */
+#endif
 
 /* ========================================================================= */
-local unsigned long gf2_matrix_times(mat, vec)
-    unsigned long *mat;
-    unsigned long vec;
+unsigned long ZEXPORT crc32(crc, buf, len)
+    unsigned long crc;
+    const unsigned char FAR *buf;
+    uInt len;
 {
-    unsigned long sum;
-
-    sum = 0;
-    while (vec) {
-        if (vec & 1)
-            sum ^= *mat;
-        vec >>= 1;
-        mat++;
-    }
-    return sum;
+    return crc32_z(crc, buf, len);
 }
 
 /* ========================================================================= */
-local void gf2_matrix_square(square, mat)
-    unsigned long *square;
-    unsigned long *mat;
+uLong ZEXPORT crc32_combine64(crc1, crc2, len2)
+    uLong crc1;
+    uLong crc2;
+    z_off64_t len2;
 {
-    int n;
-
-    for (n = 0; n < GF2_DIM; n++)
-        square[n] = gf2_matrix_times(mat, mat[n]);
+#ifdef DYNAMIC_CRC_TABLE
+    once(&made, make_crc_table);
+#endif /* DYNAMIC_CRC_TABLE */
+    return multmodp(x2nmodp(len2, 3), crc1) ^ crc2;
 }
 
 /* ========================================================================= */
-local uLong crc32_combine_(crc1, crc2, len2)
+uLong ZEXPORT crc32_combine(crc1, crc2, len2)
     uLong crc1;
     uLong crc2;
+    z_off_t len2;
+{
+    return crc32_combine64(crc1, crc2, len2);
+}
+
+/* ========================================================================= */
+uLong ZEXPORT crc32_combine_gen64(len2)
     z_off64_t len2;
 {
-    int n;
-    unsigned long row;
-    unsigned long even[GF2_DIM];    /* even-power-of-two zeros operator */
-    unsigned long odd[GF2_DIM];     /* odd-power-of-two zeros operator */
-
-    /* degenerate case (also disallow negative lengths) */
-    if (len2 <= 0)
-        return crc1;
-
-    /* put operator for one zero bit in odd */
-    odd[0] = 0xedb88320UL;          /* CRC-32 polynomial */
-    row = 1;
-    for (n = 1; n < GF2_DIM; n++) {
-        odd[n] = row;
-        row <<= 1;
-    }
+#ifdef DYNAMIC_CRC_TABLE
+    once(&made, make_crc_table);
+#endif /* DYNAMIC_CRC_TABLE */
+    return x2nmodp(len2, 3);
+}
 
-    /* put operator for two zero bits in even */
-    gf2_matrix_square(even, odd);
-
-    /* put operator for four zero bits in odd */
-    gf2_matrix_square(odd, even);
-
-    /* apply len2 zeros to crc1 (first square will put the operator for one
-       zero byte, eight zero bits, in even) */
-    do {
-        /* apply zeros operator for this bit of len2 */
-        gf2_matrix_square(even, odd);
-        if (len2 & 1)
-            crc1 = gf2_matrix_times(even, crc1);
-        len2 >>= 1;
-
-        /* if no more bits set, then done */
-        if (len2 == 0)
-            break;
-
-        /* another iteration of the loop with odd and even swapped */
-        gf2_matrix_square(odd, even);
-        if (len2 & 1)
-            crc1 = gf2_matrix_times(odd, crc1);
-        len2 >>= 1;
-
-        /* if no more bits set, then done */
-    } while (len2 != 0);
-
-    /* return combined crc */
-    crc1 ^= crc2;
-    return crc1;
+/* ========================================================================= */
+uLong ZEXPORT crc32_combine_gen(len2)
+    z_off_t len2;
+{
+    return crc32_combine_gen64(len2);
 }
 
 /* ========================================================================= */
-uLong ZEXPORT crc32_combine(crc1, crc2, len2)
+uLong crc32_combine_op(crc1, crc2, op)
     uLong crc1;
     uLong crc2;
-    z_off_t len2;
+    uLong op;
 {
-    return crc32_combine_(crc1, crc2, len2);
+    return multmodp(op, crc1) ^ crc2;
 }
-

deps/zlib/deflate.c

 /* deflate.c -- compress data using the deflation algorithm
- * Copyright (C) 1995-2017 Jean-loup Gailly and Mark Adler
+ * Copyright (C) 1995-2022 Jean-loup Gailly and Mark Adler
  * For conditions of distribution and use, see copyright notice in zlib.h
  */
 
@@ -52,7 +52,7 @@
 #include "deflate.h"
 
 const char deflate_copyright[] =
-   " deflate 1.2.11 Copyright 1995-2017 Jean-loup Gailly and Mark Adler ";
+   " deflate 1.2.12 Copyright 1995-2022 Jean-loup Gailly and Mark Adler ";
 /*
   If you use the zlib library in a product, an acknowledgment is welcome
   in the documentation of your product. If for some reason you cannot
@@ -190,8 +190,11 @@ local const config configuration_table[10] = {
  * prev[] will be initialized on the fly.
  */
 #define CLEAR_HASH(s) \
-    s->head[s->hash_size-1] = NIL; \
-    zmemzero((Bytef *)s->head, (unsigned)(s->hash_size-1)*sizeof(*s->head));
+    do { \
+        s->head[s->hash_size-1] = NIL; \
+        zmemzero((Bytef *)s->head, \
+                 (unsigned)(s->hash_size-1)*sizeof(*s->head)); \
+    } while (0)
 
 /* ===========================================================================
  * Slide the hash table when sliding the window down (could be avoided with 32
@@ -252,11 +255,6 @@ int ZEXPORT deflateInit2_(strm, level, method, windowBits, memLevel, strategy,
     int wrap = 1;
     static const char my_version[] = ZLIB_VERSION;
 
-    ushf *overlay;
-    /* We overlay pending_buf and d_buf+l_buf. This works since the average
-     * output size for (length,distance) codes is <= 24 bits.
-     */
-
     if (version == Z_NULL || version[0] != my_version[0] ||
         stream_size != sizeof(z_stream)) {
         return Z_VERSION_ERROR;
@@ -320,16 +318,53 @@ int ZEXPORT deflateInit2_(strm, level, method, windowBits, memLevel, strategy,
 
     s->window = (Bytef *) ZALLOC(strm, s->w_size, 2*sizeof(Byte));
     s->prev   = (Posf *)  ZALLOC(strm, s->w_size, sizeof(Pos));
-    memset(s->prev, 0, s->w_size * sizeof(Pos));
     s->head   = (Posf *)  ZALLOC(strm, s->hash_size, sizeof(Pos));
 
     s->high_water = 0;      /* nothing written to s->window yet */
 
     s->lit_bufsize = 1 << (memLevel + 6); /* 16K elements by default */
 
-    overlay = (ushf *) ZALLOC(strm, s->lit_bufsize, sizeof(ush)+2);
-    s->pending_buf = (uchf *) overlay;
-    s->pending_buf_size = (ulg)s->lit_bufsize * (sizeof(ush)+2L);
+    /* We overlay pending_buf and sym_buf. This works since the average size
+     * for length/distance pairs over any compressed block is assured to be 31
+     * bits or less.
+     *
+     * Analysis: The longest fixed codes are a length code of 8 bits plus 5
+     * extra bits, for lengths 131 to 257. The longest fixed distance codes are
+     * 5 bits plus 13 extra bits, for distances 16385 to 32768. The longest
+     * possible fixed-codes length/distance pair is then 31 bits total.
+     *
+     * sym_buf starts one-fourth of the way into pending_buf. So there are
+     * three bytes in sym_buf for every four bytes in pending_buf. Each symbol
+     * in sym_buf is three bytes -- two for the distance and one for the
+     * literal/length. As each symbol is consumed, the pointer to the next
+     * sym_buf value to read moves forward three bytes. From that symbol, up to
+     * 31 bits are written to pending_buf. The closest the written pending_buf
+     * bits gets to the next sym_buf symbol to read is just before the last
+     * code is written. At that time, 31*(n-2) bits have been written, just
+     * after 24*(n-2) bits have been consumed from sym_buf. sym_buf starts at
+     * 8*n bits into pending_buf. (Note that the symbol buffer fills when n-1
+     * symbols are written.) The closest the writing gets to what is unread is
+     * then n+14 bits. Here n is lit_bufsize, which is 16384 by default, and
+     * can range from 128 to 32768.
+     *
+     * Therefore, at a minimum, there are 142 bits of space between what is
+     * written and what is read in the overlain buffers, so the symbols cannot
+     * be overwritten by the compressed data. That space is actually 139 bits,
+     * due to the three-bit fixed-code block header.
+     *
+     * That covers the case where either Z_FIXED is specified, forcing fixed
+     * codes, or when the use of fixed codes is chosen, because that choice
+     * results in a smaller compressed block than dynamic codes. That latter
+     * condition then assures that the above analysis also covers all dynamic
+     * blocks. A dynamic-code block will only be chosen to be emitted if it has
+     * fewer bits than a fixed-code block would for the same set of symbols.
+     * Therefore its average symbol length is assured to be less than 31. So
+     * the compressed data for a dynamic block also cannot overwrite the
+     * symbols from which it is being constructed.
+     */
+
+    s->pending_buf = (uchf *) ZALLOC(strm, s->lit_bufsize, 4);
+    s->pending_buf_size = (ulg)s->lit_bufsize * 4;
 
     if (s->window == Z_NULL || s->prev == Z_NULL || s->head == Z_NULL ||
         s->pending_buf == Z_NULL) {
@@ -338,8 +373,12 @@ int ZEXPORT deflateInit2_(strm, level, method, windowBits, memLevel, strategy,
         deflateEnd (strm);
         return Z_MEM_ERROR;
     }
-    s->d_buf = overlay + s->lit_bufsize/sizeof(ush);
-    s->l_buf = s->pending_buf + (1+sizeof(ush))*s->lit_bufsize;
+    s->sym_buf = s->pending_buf + s->lit_bufsize;
+    s->sym_end = (s->lit_bufsize - 1) * 3;
+    /* We avoid equality with lit_bufsize*3 because of wraparound at 64K
+     * on 16 bit machines and because stored blocks are restricted to
+     * 64K-1 bytes.
+     */
 
     s->level = level;
     s->strategy = strategy;
@@ -489,13 +528,13 @@ int ZEXPORT deflateResetKeep (strm)
 #ifdef GZIP
         s->wrap == 2 ? GZIP_STATE :
 #endif
-        s->wrap ? INIT_STATE : BUSY_STATE;
+        INIT_STATE;
     strm->adler =
 #ifdef GZIP
         s->wrap == 2 ? crc32(0L, Z_NULL, 0) :
 #endif
         adler32(0L, Z_NULL, 0);
-    s->last_flush = Z_NO_FLUSH;
+    s->last_flush = -2;
 
     _tr_init(s);
 
@@ -550,7 +589,8 @@ int ZEXPORT deflatePrime (strm, bits, value)
 
     if (deflateStateCheck(strm)) return Z_STREAM_ERROR;
     s = strm->state;
-    if ((Bytef *)(s->d_buf) < s->pending_out + ((Buf_size + 7) >> 3))
+    if (bits < 0 || bits > 16 ||
+        s->sym_buf < s->pending_out + ((Buf_size + 7) >> 3))
         return Z_BUF_ERROR;
     do {
         put = Buf_size - s->bi_valid;
@@ -588,12 +628,12 @@ int ZEXPORT deflateParams(strm, level, strategy)
     func = configuration_table[s->level].func;
 
     if ((strategy != s->strategy || func != configuration_table[level].func) &&
-        s->high_water) {
+        s->last_flush != -2) {
         /* Flush the last buffer: */
         int err = deflate(strm, Z_BLOCK);
         if (err == Z_STREAM_ERROR)
             return err;
-        if (strm->avail_out == 0)
+        if (strm->avail_in || (s->strstart - s->block_start) + s->lookahead)
             return Z_BUF_ERROR;
     }
     if (s->level != level) {
@@ -812,6 +852,8 @@ int ZEXPORT deflate (strm, flush)
     }
 
     /* Write the header */
+    if (s->status == INIT_STATE && s->wrap == 0)
+        s->status = BUSY_STATE;
     if (s->status == INIT_STATE) {
         /* zlib header */
         uInt header = (Z_DEFLATED + ((s->w_bits-8)<<4)) << 8;
@@ -1109,7 +1151,6 @@ int ZEXPORT deflateCopy (dest, source)
 #else
     deflate_state *ds;
     deflate_state *ss;
-    ushf *overlay;
 
 
     if (deflateStateCheck(source) || dest == Z_NULL) {
@@ -1129,8 +1170,7 @@ int ZEXPORT deflateCopy (dest, source)
     ds->window = (Bytef *) ZALLOC(dest, ds->w_size, 2*sizeof(Byte));
     ds->prev   = (Posf *)  ZALLOC(dest, ds->w_size, sizeof(Pos));
     ds->head   = (Posf *)  ZALLOC(dest, ds->hash_size, sizeof(Pos));
-    overlay = (ushf *) ZALLOC(dest, ds->lit_bufsize, sizeof(ush)+2);
-    ds->pending_buf = (uchf *) overlay;
+    ds->pending_buf = (uchf *) ZALLOC(dest, ds->lit_bufsize, 4);
 
     if (ds->window == Z_NULL || ds->prev == Z_NULL || ds->head == Z_NULL ||
         ds->pending_buf == Z_NULL) {
@@ -1144,8 +1184,7 @@ int ZEXPORT deflateCopy (dest, source)
     zmemcpy(ds->pending_buf, ss->pending_buf, (uInt)ds->pending_buf_size);
 
     ds->pending_out = ds->pending_buf + (ss->pending_out - ss->pending_buf);
-    ds->d_buf = overlay + ds->lit_bufsize/sizeof(ush);
-    ds->l_buf = ds->pending_buf + (1+sizeof(ush))*ds->lit_bufsize;
+    ds->sym_buf = ds->pending_buf + ds->lit_bufsize;
 
     ds->l_desc.dyn_tree = ds->dyn_ltree;
     ds->d_desc.dyn_tree = ds->dyn_dtree;
@@ -1514,6 +1553,8 @@ local void fill_window(s)
             s->match_start -= wsize;
             s->strstart    -= wsize; /* we now have strstart >= MAX_DIST */
             s->block_start -= (long) wsize;
+            if (s->insert > s->strstart)
+                s->insert = s->strstart;
             slide_hash(s);
             more += wsize;
         }
@@ -1743,6 +1784,7 @@ local block_state deflate_stored(s, flush)
             s->matches = 2;         /* clear hash */
             zmemcpy(s->window, s->strm->next_in - s->w_size, s->w_size);
             s->strstart = s->w_size;
+            s->insert = s->strstart;
         }
         else {
             if (s->window_size - s->strstart <= used) {
@@ -1751,12 +1793,14 @@ local block_state deflate_stored(s, flush)
                 zmemcpy(s->window, s->window + s->w_size, s->strstart);
                 if (s->matches < 2)
                     s->matches++;   /* add a pending slide_hash() */
+                if (s->insert > s->strstart)
+                    s->insert = s->strstart;
             }
             zmemcpy(s->window + s->strstart, s->strm->next_in - used, used);
             s->strstart += used;
+            s->insert += MIN(used, s->w_size - s->insert);
         }
         s->block_start = s->strstart;
-        s->insert += MIN(used, s->w_size - s->insert);
     }
     if (s->high_water < s->strstart)
         s->high_water = s->strstart;
@@ -1771,7 +1815,7 @@ local block_state deflate_stored(s, flush)
         return block_done;
 
     /* Fill the window with any remaining input. */
-    have = s->window_size - s->strstart - 1;
+    have = s->window_size - s->strstart;
     if (s->strm->avail_in > have && s->block_start >= (long)s->w_size) {
         /* Slide the window down. */
         s->block_start -= s->w_size;
@@ -1780,12 +1824,15 @@ local block_state deflate_stored(s, flush)
         if (s->matches < 2)
             s->matches++;           /* add a pending slide_hash() */
         have += s->w_size;          /* more space now */
+        if (s->insert > s->strstart)
+            s->insert = s->strstart;
     }
     if (have > s->strm->avail_in)
         have = s->strm->avail_in;
     if (have) {
         read_buf(s->strm, s->window + s->strstart, have);
         s->strstart += have;
+        s->insert += MIN(have, s->w_size - s->insert);
     }
     if (s->high_water < s->strstart)
         s->high_water = s->strstart;
@@ -1913,7 +1960,7 @@ local block_state deflate_fast(s, flush)
         FLUSH_BLOCK(s, 1);
         return finish_done;
     }
-    if (s->last_lit)
+    if (s->sym_next)
         FLUSH_BLOCK(s, 0);
     return block_done;
 }
@@ -2044,7 +2091,7 @@ local block_state deflate_slow(s, flush)
         FLUSH_BLOCK(s, 1);
         return finish_done;
     }
-    if (s->last_lit)
+    if (s->sym_next)
         FLUSH_BLOCK(s, 0);
     return block_done;
 }
@@ -2119,7 +2166,7 @@ local block_state deflate_rle(s, flush)
         FLUSH_BLOCK(s, 1);
         return finish_done;
     }
-    if (s->last_lit)
+    if (s->sym_next)
         FLUSH_BLOCK(s, 0);
     return block_done;
 }
@@ -2158,7 +2205,7 @@ local block_state deflate_huff(s, flush)
         FLUSH_BLOCK(s, 1);
         return finish_done;
     }
-    if (s->last_lit)
+    if (s->sym_next)
         FLUSH_BLOCK(s, 0);
     return block_done;
 }

deps/zlib/deflate.h

 /* deflate.h -- internal compression state
- * Copyright (C) 1995-2016 Jean-loup Gailly
+ * Copyright (C) 1995-2018 Jean-loup Gailly
  * For conditions of distribution and use, see copyright notice in zlib.h
  */
 
@@ -217,7 +217,7 @@ typedef struct internal_state {
     /* Depth of each subtree used as tie breaker for trees of equal frequency
      */
 
-    uchf *l_buf;          /* buffer for literals or lengths */
+    uchf *sym_buf;        /* buffer for distances and literals/lengths */
 
     uInt  lit_bufsize;
     /* Size of match buffer for literals/lengths.  There are 4 reasons for
@@ -239,13 +239,8 @@ typedef struct internal_state {
      *   - I can't count above 4
      */
 
-    uInt last_lit;      /* running index in l_buf */
-
-    ushf *d_buf;
-    /* Buffer for distances. To simplify the code, d_buf and l_buf have
-     * the same number of elements. To use different lengths, an extra flag
-     * array would be necessary.
-     */
+    uInt sym_next;      /* running index in sym_buf */
+    uInt sym_end;       /* symbol table full when sym_next reaches this */
 
     ulg opt_len;        /* bit length of current block with optimal trees */
     ulg static_len;     /* bit length of current block with static trees */
@@ -325,20 +320,22 @@ void ZLIB_INTERNAL _tr_stored_block OF((deflate_state *s, charf *buf,
 
 # define _tr_tally_lit(s, c, flush) \
   { uch cc = (c); \
-    s->d_buf[s->last_lit] = 0; \
-    s->l_buf[s->last_lit++] = cc; \
+    s->sym_buf[s->sym_next++] = 0; \
+    s->sym_buf[s->sym_next++] = 0; \
+    s->sym_buf[s->sym_next++] = cc; \
     s->dyn_ltree[cc].Freq++; \
-    flush = (s->last_lit == s->lit_bufsize-1); \
+    flush = (s->sym_next == s->sym_end); \
    }
 # define _tr_tally_dist(s, distance, length, flush) \
   { uch len = (uch)(length); \
     ush dist = (ush)(distance); \
-    s->d_buf[s->last_lit] = dist; \
-    s->l_buf[s->last_lit++] = len; \
+    s->sym_buf[s->sym_next++] = dist; \
+    s->sym_buf[s->sym_next++] = dist >> 8; \
+    s->sym_buf[s->sym_next++] = len; \
     dist--; \
     s->dyn_ltree[_length_code[len]+LITERALS+1].Freq++; \
     s->dyn_dtree[d_code(dist)].Freq++; \
-    flush = (s->last_lit == s->lit_bufsize-1); \
+    flush = (s->sym_next == s->sym_end); \
   }
 #else
 # define _tr_tally_lit(s, c, flush) flush = _tr_tally(s, 0, c)

deps/zlib/gzguts.h

 /* gzguts.h -- zlib internal header definitions for gz* operations
- * Copyright (C) 2004, 2005, 2010, 2011, 2012, 2013, 2016 Mark Adler
+ * Copyright (C) 2004-2019 Mark Adler
  * For conditions of distribution and use, see copyright notice in zlib.h
  */
 
@@ -39,7 +39,7 @@
 #  include <io.h>
 #endif
 
-#if defined(_WIN32) || defined(__CYGWIN__)
+#if defined(_WIN32)
 #  define WIDECHAR
 #endif
 
@@ -190,6 +190,7 @@ typedef struct {
         /* just for writing */
     int level;              /* compression level */
     int strategy;           /* compression strategy */
+    int reset;              /* true if a reset is pending after a Z_FINISH */
         /* seek request */
     z_off64_t skip;         /* amount to skip (already rewound if backwards) */
     int seek;               /* true if seek request pending */

deps/zlib/infback.c

 /* infback.c -- inflate using a call-back interface
- * Copyright (C) 1995-2016 Mark Adler
+ * Copyright (C) 1995-2022 Mark Adler
  * For conditions of distribution and use, see copyright notice in zlib.h
  */
 
@@ -477,6 +477,7 @@ void FAR *out_desc;
             }
             Tracev((stderr, "inflate:       codes ok\n"));
             state->mode = LEN;
+                /* fallthrough */
 
         case LEN:
             /* use inflate_fast() if we have enough input and output */

deps/zlib/inffast.c

@@ -70,7 +70,7 @@ unsigned start;         /* inflate()'s starting value for strm->avail_out */
     code const FAR *dcode;      /* local strm->distcode */
     unsigned lmask;             /* mask for first level of length codes */
     unsigned dmask;             /* mask for first level of distance codes */
-    code here;                  /* retrieved table entry */
+    code const *here;           /* retrieved table entry */
     unsigned op;                /* code bits, operation, extra bits, or */
                                 /*  window position, window bytes to copy */
     unsigned len;               /* match length, unused bytes */
@@ -107,20 +107,20 @@ unsigned start;         /* inflate()'s starting value for strm->avail_out */
             hold += (unsigned long)(*in++) << bits;
             bits += 8;
         }
-        here = lcode[hold & lmask];
+        here = lcode + (hold & lmask);
       dolen:
-        op = (unsigned)(here.bits);
+        op = (unsigned)(here->bits);
         hold >>= op;
         bits -= op;
-        op = (unsigned)(here.op);
+        op = (unsigned)(here->op);
         if (op == 0) {                          /* literal */
-            Tracevv((stderr, here.val >= 0x20 && here.val < 0x7f ?
+            Tracevv((stderr, here->val >= 0x20 && here->val < 0x7f ?
                     "inflate:         literal '%c'\n" :
-                    "inflate:         literal 0x%02x\n", here.val));
-            *out++ = (unsigned char)(here.val);
+                    "inflate:         literal 0x%02x\n", here->val));
+            *out++ = (unsigned char)(here->val);
         }
         else if (op & 16) {                     /* length base */
-            len = (unsigned)(here.val);
+            len = (unsigned)(here->val);
             op &= 15;                           /* number of extra bits */
             if (op) {
                 if (bits < op) {
@@ -138,14 +138,14 @@ unsigned start;         /* inflate()'s starting value for strm->avail_out */
                 hold += (unsigned long)(*in++) << bits;
                 bits += 8;
             }
-            here = dcode[hold & dmask];
+            here = dcode + (hold & dmask);
           dodist:
-            op = (unsigned)(here.bits);
+            op = (unsigned)(here->bits);
             hold >>= op;
             bits -= op;
-            op = (unsigned)(here.op);
+            op = (unsigned)(here->op);
             if (op & 16) {                      /* distance base */
-                dist = (unsigned)(here.val);
+                dist = (unsigned)(here->val);
                 op &= 15;                       /* number of extra bits */
                 if (bits < op) {
                     hold += (unsigned long)(*in++) << bits;
@@ -264,7 +264,7 @@ unsigned start;         /* inflate()'s starting value for strm->avail_out */
                 }
             }
             else if ((op & 64) == 0) {          /* 2nd level distance code */
-                here = dcode[here.val + (hold & ((1U << op) - 1))];
+                here = dcode + here->val + (hold & ((1U << op) - 1));
                 goto dodist;
             }
             else {
@@ -274,7 +274,7 @@ unsigned start;         /* inflate()'s starting value for strm->avail_out */
             }
         }
         else if ((op & 64) == 0) {              /* 2nd level length code */
-            here = lcode[here.val + (hold & ((1U << op) - 1))];
+            here = lcode + here->val + (hold & ((1U << op) - 1));
             goto dolen;
         }
         else if (op & 32) {                     /* end-of-block */

deps/zlib/inflate.c

 /* inflate.c -- zlib decompression
- * Copyright (C) 1995-2016 Mark Adler
+ * Copyright (C) 1995-2022 Mark Adler
  * For conditions of distribution and use, see copyright notice in zlib.h
  */
 
@@ -130,6 +130,7 @@ z_streamp strm;
     state->mode = HEAD;
     state->last = 0;
     state->havedict = 0;
+    state->flags = -1;
     state->dmax = 32768U;
     state->head = Z_NULL;
     state->hold = 0;
@@ -447,10 +448,10 @@ unsigned copy;
 
 /* check function to use adler32() for zlib or crc32() for gzip */
 #ifdef GUNZIP
-#  define UPDATE(check, buf, len) \
+#  define UPDATE_CHECK(check, buf, len) \
     (state->flags ? crc32(check, buf, len) : adler32(check, buf, len))
 #else
-#  define UPDATE(check, buf, len) adler32(check, buf, len)
+#  define UPDATE_CHECK(check, buf, len) adler32(check, buf, len)
 #endif
 
 /* check macros for header crc */
@@ -670,7 +671,6 @@ int flush;
                 state->mode = FLAGS;
                 break;
             }
-            state->flags = 0;           /* expect zlib header */
             if (state->head != Z_NULL)
                 state->head->done = -1;
             if (!(state->wrap & 1) ||   /* check if zlib header allowed */
@@ -697,6 +697,7 @@ int flush;
                 break;
             }
             state->dmax = 1U << len;
+            state->flags = 0;               /* indicate zlib header */
             Tracev((stderr, "inflate:   zlib header ok\n"));
             strm->adler = state->check = adler32(0L, Z_NULL, 0);
             state->mode = hold & 0x200 ? DICTID : TYPE;
@@ -722,6 +723,7 @@ int flush;
                 CRC2(state->check, hold);
             INITBITS();
             state->mode = TIME;
+                /* fallthrough */
         case TIME:
             NEEDBITS(32);
             if (state->head != Z_NULL)
@@ -730,6 +732,7 @@ int flush;
                 CRC4(state->check, hold);
             INITBITS();
             state->mode = OS;
+                /* fallthrough */
         case OS:
             NEEDBITS(16);
             if (state->head != Z_NULL) {
@@ -740,6 +743,7 @@ int flush;
                 CRC2(state->check, hold);
             INITBITS();
             state->mode = EXLEN;
+                /* fallthrough */
         case EXLEN:
             if (state->flags & 0x0400) {
                 NEEDBITS(16);
@@ -753,6 +757,7 @@ int flush;
             else if (state->head != Z_NULL)
                 state->head->extra = Z_NULL;
             state->mode = EXTRA;
+                /* fallthrough */
         case EXTRA:
             if (state->flags & 0x0400) {
                 copy = state->length;
@@ -775,6 +780,7 @@ int flush;
             }
             state->length = 0;
             state->mode = NAME;
+                /* fallthrough */
         case NAME:
             if (state->flags & 0x0800) {
                 if (have == 0) goto inf_leave;
@@ -796,6 +802,7 @@ int flush;
                 state->head->name = Z_NULL;
             state->length = 0;
             state->mode = COMMENT;
+                /* fallthrough */
         case COMMENT:
             if (state->flags & 0x1000) {
                 if (have == 0) goto inf_leave;
@@ -816,6 +823,7 @@ int flush;
             else if (state->head != Z_NULL)
                 state->head->comment = Z_NULL;
             state->mode = HCRC;
+                /* fallthrough */
         case HCRC:
             if (state->flags & 0x0200) {
                 NEEDBITS(16);
@@ -839,6 +847,7 @@ int flush;
             strm->adler = state->check = ZSWAP32(hold);
             INITBITS();
             state->mode = DICT;
+                /* fallthrough */
         case DICT:
             if (state->havedict == 0) {
                 RESTORE();
@@ -846,8 +855,10 @@ int flush;
             }
             strm->adler = state->check = adler32(0L, Z_NULL, 0);
             state->mode = TYPE;
+                /* fallthrough */
         case TYPE:
             if (flush == Z_BLOCK || flush == Z_TREES) goto inf_leave;
+                /* fallthrough */
         case TYPEDO:
             if (state->last) {
                 BYTEBITS();
@@ -898,8 +909,10 @@ int flush;
             INITBITS();
             state->mode = COPY_;
             if (flush == Z_TREES) goto inf_leave;
+                /* fallthrough */
         case COPY_:
             state->mode = COPY;
+                /* fallthrough */
         case COPY:
             copy = state->length;
             if (copy) {
@@ -935,6 +948,7 @@ int flush;
             Tracev((stderr, "inflate:       table sizes ok\n"));
             state->have = 0;
             state->mode = LENLENS;
+                /* fallthrough */
         case LENLENS:
             while (state->have < state->ncode) {
                 NEEDBITS(3);
@@ -956,6 +970,7 @@ int flush;
             Tracev((stderr, "inflate:       code lengths ok\n"));
             state->have = 0;
             state->mode = CODELENS;
+                /* fallthrough */
         case CODELENS:
             while (state->have < state->nlen + state->ndist) {
                 for (;;) {
@@ -1039,8 +1054,10 @@ int flush;
             Tracev((stderr, "inflate:       codes ok\n"));
             state->mode = LEN_;
             if (flush == Z_TREES) goto inf_leave;
+                /* fallthrough */
         case LEN_:
             state->mode = LEN;
+                /* fallthrough */
         case LEN:
             if (have >= 6 && left >= 258) {
                 RESTORE();
@@ -1090,6 +1107,7 @@ int flush;
             }
             state->extra = (unsigned)(here.op) & 15;
             state->mode = LENEXT;
+                /* fallthrough */
         case LENEXT:
             if (state->extra) {
                 NEEDBITS(state->extra);
@@ -1100,6 +1118,7 @@ int flush;
             Tracevv((stderr, "inflate:         length %u\n", state->length));
             state->was = state->length;
             state->mode = DIST;
+                /* fallthrough */
         case DIST:
             for (;;) {
                 here = state->distcode[BITS(state->distbits)];
@@ -1127,6 +1146,7 @@ int flush;
             state->offset = (unsigned)here.val;
             state->extra = (unsigned)(here.op) & 15;
             state->mode = DISTEXT;
+                /* fallthrough */
         case DISTEXT:
             if (state->extra) {
                 NEEDBITS(state->extra);
@@ -1143,6 +1163,7 @@ int flush;
 #endif
             Tracevv((stderr, "inflate:         distance %u\n", state->offset));
             state->mode = MATCH;
+                /* fallthrough */
         case MATCH:
             if (left == 0) goto inf_leave;
             copy = out - left;
@@ -1202,7 +1223,7 @@ int flush;
                 state->total += out;
                 if ((state->wrap & 4) && out)
                     strm->adler = state->check =
-                        UPDATE(state->check, put - out, out);
+                        UPDATE_CHECK(state->check, put - out, out);
                 out = left;
                 if ((state->wrap & 4) && (
 #ifdef GUNZIP
@@ -1218,10 +1239,11 @@ int flush;
             }
 #ifdef GUNZIP
             state->mode = LENGTH;
+                /* fallthrough */
         case LENGTH:
             if (state->wrap && state->flags) {
                 NEEDBITS(32);
-                if (hold != (state->total & 0xffffffffUL)) {
+                if ((state->wrap & 4) && hold != (state->total & 0xffffffff)) {
                     strm->msg = (char *)"incorrect length check";
                     state->mode = BAD;
                     break;
@@ -1231,6 +1253,7 @@ int flush;
             }
 #endif
             state->mode = DONE;
+                /* fallthrough */
         case DONE:
             ret = Z_STREAM_END;
             goto inf_leave;
@@ -1240,6 +1263,7 @@ int flush;
         case MEM:
             return Z_MEM_ERROR;
         case SYNC:
+                /* fallthrough */
         default:
             return Z_STREAM_ERROR;
         }
@@ -1265,7 +1289,7 @@ int flush;
     state->total += out;
     if ((state->wrap & 4) && out)
         strm->adler = state->check =
-            UPDATE(state->check, strm->next_out - out, out);
+            UPDATE_CHECK(state->check, strm->next_out - out, out);
     strm->data_type = (int)state->bits + (state->last ? 64 : 0) +
                       (state->mode == TYPE ? 128 : 0) +
                       (state->mode == LEN_ || state->mode == COPY_ ? 256 : 0);
@@ -1401,6 +1425,7 @@ int ZEXPORT inflateSync(strm)
 z_streamp strm;
 {
     unsigned len;               /* number of bytes to look at or looked at */
+    int flags;                  /* temporary to save header status */
     unsigned long in, out;      /* temporary to save total_in and total_out */
     unsigned char buf[4];       /* to restore bit buffer to byte string */
     struct inflate_state FAR *state;
@@ -1433,9 +1458,15 @@ z_streamp strm;
 
     /* return no joy or set up to restart inflate() on a new block */
     if (state->have != 4) return Z_DATA_ERROR;
+    if (state->flags == -1)
+        state->wrap = 0;    /* if no header yet, treat as raw */
+    else
+        state->wrap &= ~4;  /* no point in computing a check value now */
+    flags = state->flags;
     in = strm->total_in;  out = strm->total_out;
     inflateReset(strm);
     strm->total_in = in;  strm->total_out = out;
+    state->flags = flags;
     state->mode = TYPE;
     return Z_OK;
 }
@@ -1531,7 +1562,7 @@ int check;
 
     if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
     state = (struct inflate_state FAR *)strm->state;
-    if (check)
+    if (check && state->wrap)
         state->wrap |= 4;
     else
         state->wrap &= ~4;

deps/zlib/inflate.h

 /* inflate.h -- internal inflate state definition
- * Copyright (C) 1995-2016 Mark Adler
+ * Copyright (C) 1995-2019 Mark Adler
  * For conditions of distribution and use, see copyright notice in zlib.h
  */
 
@@ -86,7 +86,8 @@ struct inflate_state {
     int wrap;                   /* bit 0 true for zlib, bit 1 true for gzip,
                                    bit 2 true to validate check value */
     int havedict;               /* true if dictionary provided */
-    int flags;                  /* gzip header method and flags (0 if zlib) */
+    int flags;                  /* gzip header method and flags, 0 if zlib, or
+                                   -1 if raw or no header yet */
     unsigned dmax;              /* zlib header max distance (INFLATE_STRICT) */
     unsigned long check;        /* protected copy of check value */
     unsigned long total;        /* protected copy of output count */

deps/zlib/inftrees.c

 /* inftrees.c -- generate Huffman trees for efficient decoding
- * Copyright (C) 1995-2017 Mark Adler
+ * Copyright (C) 1995-2022 Mark Adler
  * For conditions of distribution and use, see copyright notice in zlib.h
  */
 
@@ -9,7 +9,7 @@
 #define MAXBITS 15
 
 const char inflate_copyright[] =
-   " inflate 1.2.11 Copyright 1995-2017 Mark Adler ";
+   " inflate 1.2.12 Copyright 1995-2022 Mark Adler ";
 /*
   If you use the zlib library in a product, an acknowledgment is welcome
   in the documentation of your product. If for some reason you cannot
@@ -62,7 +62,7 @@ unsigned short FAR *work;
         35, 43, 51, 59, 67, 83, 99, 115, 131, 163, 195, 227, 258, 0, 0};
     static const unsigned short lext[31] = { /* Length codes 257..285 extra */
         16, 16, 16, 16, 16, 16, 16, 16, 17, 17, 17, 17, 18, 18, 18, 18,
-        19, 19, 19, 19, 20, 20, 20, 20, 21, 21, 21, 21, 16, 77, 202};
+        19, 19, 19, 19, 20, 20, 20, 20, 21, 21, 21, 21, 16, 199, 202};
     static const unsigned short dbase[32] = { /* Distance codes 0..29 base */
         1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193,
         257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145,

deps/zlib/trees.c

 /* trees.c -- output deflated data using Huffman coding
- * Copyright (C) 1995-2017 Jean-loup Gailly
+ * Copyright (C) 1995-2021 Jean-loup Gailly
  * detect_data_type() function provided freely by Cosmin Truta, 2006
  * For conditions of distribution and use, see copyright notice in zlib.h
  */
@@ -149,7 +149,7 @@ local void send_all_trees OF((deflate_state *s, int lcodes, int dcodes,
 local void compress_block OF((deflate_state *s, const ct_data *ltree,
                               const ct_data *dtree));
 local int  detect_data_type OF((deflate_state *s));
-local unsigned bi_reverse OF((unsigned value, int length));
+local unsigned bi_reverse OF((unsigned code, int len));
 local void bi_windup      OF((deflate_state *s));
 local void bi_flush       OF((deflate_state *s));
 
@@ -416,7 +416,7 @@ local void init_block(s)
 
     s->dyn_ltree[END_BLOCK].Freq = 1;
     s->opt_len = s->static_len = 0L;
-    s->last_lit = s->matches = 0;
+    s->sym_next = s->matches = 0;
 }
 
 #define SMALLEST 1
@@ -870,7 +870,8 @@ void ZLIB_INTERNAL _tr_stored_block(s, buf, stored_len, last)
     bi_windup(s);        /* align on byte boundary */
     put_short(s, (ush)stored_len);
     put_short(s, (ush)~stored_len);
-    zmemcpy(s->pending_buf + s->pending, (Bytef *)buf, stored_len);
+    if (stored_len)
+        zmemcpy(s->pending_buf + s->pending, (Bytef *)buf, stored_len);
     s->pending += stored_len;
 #ifdef ZLIB_DEBUG
     s->compressed_len = (s->compressed_len + 3 + 7) & (ulg)~7L;
@@ -947,7 +948,7 @@ void ZLIB_INTERNAL _tr_flush_block(s, buf, stored_len, last)
 
         Tracev((stderr, "\nopt %lu(%lu) stat %lu(%lu) stored %lu lit %u ",
                 opt_lenb, s->opt_len, static_lenb, s->static_len, stored_len,
-                s->last_lit));
+                s->sym_next / 3));
 
         if (static_lenb <= opt_lenb) opt_lenb = static_lenb;
 
@@ -1016,8 +1017,9 @@ int ZLIB_INTERNAL _tr_tally (s, dist, lc)
     unsigned dist;  /* distance of matched string */
     unsigned lc;    /* match length-MIN_MATCH or unmatched char (if dist==0) */
 {
-    s->d_buf[s->last_lit] = (ush)dist;
-    s->l_buf[s->last_lit++] = (uch)lc;
+    s->sym_buf[s->sym_next++] = dist;
+    s->sym_buf[s->sym_next++] = dist >> 8;
+    s->sym_buf[s->sym_next++] = lc;
     if (dist == 0) {
         /* lc is the unmatched char */
         s->dyn_ltree[lc].Freq++;
@@ -1032,30 +1034,7 @@ int ZLIB_INTERNAL _tr_tally (s, dist, lc)
         s->dyn_ltree[_length_code[lc]+LITERALS+1].Freq++;
         s->dyn_dtree[d_code(dist)].Freq++;
     }
-
-#ifdef TRUNCATE_BLOCK
-    /* Try to guess if it is profitable to stop the current block here */
-    if ((s->last_lit & 0x1fff) == 0 && s->level > 2) {
-        /* Compute an upper bound for the compressed length */
-        ulg out_length = (ulg)s->last_lit*8L;
-        ulg in_length = (ulg)((long)s->strstart - s->block_start);
-        int dcode;
-        for (dcode = 0; dcode < D_CODES; dcode++) {
-            out_length += (ulg)s->dyn_dtree[dcode].Freq *
-                (5L+extra_dbits[dcode]);
-        }
-        out_length >>= 3;
-        Tracev((stderr,"\nlast_lit %u, in %ld, out ~%ld(%ld%%) ",
-               s->last_lit, in_length, out_length,
-               100L - out_length*100L/in_length));
-        if (s->matches < s->last_lit/2 && out_length < in_length/2) return 1;
-    }
-#endif
-    return (s->last_lit == s->lit_bufsize-1);
-    /* We avoid equality with lit_bufsize because of wraparound at 64K
-     * on 16 bit machines and because stored blocks are restricted to
-     * 64K-1 bytes.
-     */
+    return (s->sym_next == s->sym_end);
 }
 
 /* ===========================================================================
@@ -1068,13 +1047,14 @@ local void compress_block(s, ltree, dtree)
 {
     unsigned dist;      /* distance of matched string */
     int lc;             /* match length or unmatched char (if dist == 0) */
-    unsigned lx = 0;    /* running index in l_buf */
+    unsigned sx = 0;    /* running index in sym_buf */
     unsigned code;      /* the code to send */
     int extra;          /* number of extra bits to send */
 
-    if (s->last_lit != 0) do {
-        dist = s->d_buf[lx];
-        lc = s->l_buf[lx++];
+    if (s->sym_next != 0) do {
+        dist = s->sym_buf[sx++] & 0xff;
+        dist += (unsigned)(s->sym_buf[sx++] & 0xff) << 8;
+        lc = s->sym_buf[sx++];
         if (dist == 0) {
             send_code(s, lc, ltree); /* send a literal byte */
             Tracecv(isgraph(lc), (stderr," '%c' ", lc));
@@ -1099,11 +1079,10 @@ local void compress_block(s, ltree, dtree)
             }
         } /* literal or match pair ? */
 
-        /* Check that the overlay between pending_buf and d_buf+l_buf is ok: */
-        Assert((uInt)(s->pending) < s->lit_bufsize + 2*lx,
-               "pendingBuf overflow");
+        /* Check that the overlay between pending_buf and sym_buf is ok: */
+        Assert(s->pending < s->lit_bufsize + sx, "pendingBuf overflow");
 
-    } while (lx < s->last_lit);
+    } while (sx < s->sym_next);
 
     send_code(s, END_BLOCK, ltree);
 }
@@ -1112,9 +1091,9 @@ local void compress_block(s, ltree, dtree)
  * Check if the data type is TEXT or BINARY, using the following algorithm:
  * - TEXT if the two conditions below are satisfied:
  *    a) There are no non-portable control characters belonging to the
- *       "black list" (0..6, 14..25, 28..31).
+ *       "block list" (0..6, 14..25, 28..31).
  *    b) There is at least one printable character belonging to the
- *       "white list" (9 {TAB}, 10 {LF}, 13 {CR}, 32..255).
+ *       "allow list" (9 {TAB}, 10 {LF}, 13 {CR}, 32..255).
  * - BINARY otherwise.
  * - The following partially-portable control characters form a
  *   "gray list" that is ignored in this detection algorithm:
@@ -1124,19 +1103,19 @@ local void compress_block(s, ltree, dtree)
 local int detect_data_type(s)
     deflate_state *s;
 {
-    /* black_mask is the bit mask of black-listed bytes
+    /* block_mask is the bit mask of block-listed bytes
      * set bits 0..6, 14..25, and 28..31
      * 0xf3ffc07f = binary 11110011111111111100000001111111
      */
-    unsigned long black_mask = 0xf3ffc07fUL;
+    unsigned long block_mask = 0xf3ffc07fUL;
     int n;
 
-    /* Check for non-textual ("black-listed") bytes. */
-    for (n = 0; n <= 31; n++, black_mask >>= 1)
-        if ((black_mask & 1) && (s->dyn_ltree[n].Freq != 0))
+    /* Check for non-textual ("block-listed") bytes. */
+    for (n = 0; n <= 31; n++, block_mask >>= 1)
+        if ((block_mask & 1) && (s->dyn_ltree[n].Freq != 0))
             return Z_BINARY;
 
-    /* Check for textual ("white-listed") bytes. */
+    /* Check for textual ("allow-listed") bytes. */
     if (s->dyn_ltree[9].Freq != 0 || s->dyn_ltree[10].Freq != 0
             || s->dyn_ltree[13].Freq != 0)
         return Z_TEXT;
@@ -1144,7 +1123,7 @@ local int detect_data_type(s)
         if (s->dyn_ltree[n].Freq != 0)
             return Z_TEXT;
 
-    /* There are no "black-listed" or "white-listed" bytes:
+    /* There are no "block-listed" or "allow-listed" bytes:
      * this stream either is empty or has tolerated ("gray-listed") bytes only.
      */
     return Z_BINARY;

deps/zlib/zlib.h

 /* zlib.h -- interface of the 'zlib' general purpose compression library
-  version 1.2.11, January 15th, 2017
+  version 1.2.12, March 11th, 2022
 
-  Copyright (C) 1995-2017 Jean-loup Gailly and Mark Adler
+  Copyright (C) 1995-2022 Jean-loup Gailly and Mark Adler
 
   This software is provided 'as-is', without any express or implied
   warranty.  In no event will the authors be held liable for any damages
@@ -37,11 +37,11 @@
 extern "C" {
 #endif
 
-#define ZLIB_VERSION "1.2.11"
-#define ZLIB_VERNUM 0x12b0
+#define ZLIB_VERSION "1.2.12"
+#define ZLIB_VERNUM 0x12c0
 #define ZLIB_VER_MAJOR 1
 #define ZLIB_VER_MINOR 2
-#define ZLIB_VER_REVISION 11
+#define ZLIB_VER_REVISION 12
 #define ZLIB_VER_SUBREVISION 0
 
 /*
@@ -543,8 +543,7 @@ ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm,
                                      int  strategy));
 
      This is another version of deflateInit with more compression options.  The
-   fields next_in, zalloc, zfree and opaque must be initialized before by the
-   caller.
+   fields zalloc, zfree and opaque must be initialized before by the caller.
 
      The method parameter is the compression method.  It must be Z_DEFLATED in
    this version of the library.
@@ -712,11 +711,12 @@ ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm,
    used to switch between compression and straight copy of the input data, or
    to switch to a different kind of input data requiring a different strategy.
    If the compression approach (which is a function of the level) or the
-   strategy is changed, and if any input has been consumed in a previous
-   deflate() call, then the input available so far is compressed with the old
-   level and strategy using deflate(strm, Z_BLOCK).  There are three approaches
-   for the compression levels 0, 1..3, and 4..9 respectively.  The new level
-   and strategy will take effect at the next call of deflate().
+   strategy is changed, and if there have been any deflate() calls since the
+   state was initialized or reset, then the input available so far is
+   compressed with the old level and strategy using deflate(strm, Z_BLOCK).
+   There are three approaches for the compression levels 0, 1..3, and 4..9
+   respectively.  The new level and strategy will take effect at the next call
+   of deflate().
 
      If a deflate(strm, Z_BLOCK) is performed by deflateParams(), and it does
    not have enough output space to complete, then the parameter change will not
@@ -865,9 +865,11 @@ ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm,
    detection, or add 16 to decode only the gzip format (the zlib format will
    return a Z_DATA_ERROR).  If a gzip stream is being decoded, strm->adler is a
    CRC-32 instead of an Adler-32.  Unlike the gunzip utility and gzread() (see
-   below), inflate() will not automatically decode concatenated gzip streams.
-   inflate() will return Z_STREAM_END at the end of the gzip stream.  The state
-   would need to be reset to continue decoding a subsequent gzip stream.
+   below), inflate() will *not* automatically decode concatenated gzip members.
+   inflate() will return Z_STREAM_END at the end of the gzip member.  The state
+   would need to be reset to continue decoding a subsequent gzip member.  This
+   *must* be done if there is more data after a gzip member, in order for the
+   decompression to be compliant with the gzip standard (RFC 1952).
 
      inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
    memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
@@ -1302,14 +1304,14 @@ typedef struct gzFile_s *gzFile;    /* semi-opaque gzip file descriptor */
 /*
 ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode));
 
-     Opens a gzip (.gz) file for reading or writing.  The mode parameter is as
-   in fopen ("rb" or "wb") but can also include a compression level ("wb9") or
-   a strategy: 'f' for filtered data as in "wb6f", 'h' for Huffman-only
-   compression as in "wb1h", 'R' for run-length encoding as in "wb1R", or 'F'
-   for fixed code compression as in "wb9F".  (See the description of
-   deflateInit2 for more information about the strategy parameter.)  'T' will
-   request transparent writing or appending with no compression and not using
-   the gzip format.
+     Open the gzip (.gz) file at path for reading and decompressing, or
+   compressing and writing.  The mode parameter is as in fopen ("rb" or "wb")
+   but can also include a compression level ("wb9") or a strategy: 'f' for
+   filtered data as in "wb6f", 'h' for Huffman-only compression as in "wb1h",
+   'R' for run-length encoding as in "wb1R", or 'F' for fixed code compression
+   as in "wb9F".  (See the description of deflateInit2 for more information
+   about the strategy parameter.)  'T' will request transparent writing or
+   appending with no compression and not using the gzip format.
 
      "a" can be used instead of "w" to request that the gzip stream that will
    be written be appended to the file.  "+" will result in an error, since
@@ -1339,9 +1341,9 @@ ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode));
 
 ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode));
 /*
-     gzdopen associates a gzFile with the file descriptor fd.  File descriptors
-   are obtained from calls like open, dup, creat, pipe or fileno (if the file
-   has been previously opened with fopen).  The mode parameter is as in gzopen.
+     Associate a gzFile with the file descriptor fd.  File descriptors are
+   obtained from calls like open, dup, creat, pipe or fileno (if the file has
+   been previously opened with fopen).  The mode parameter is as in gzopen.
 
      The next call of gzclose on the returned gzFile will also close the file
    descriptor fd, just like fclose(fdopen(fd, mode)) closes the file descriptor
@@ -1362,13 +1364,13 @@ ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode));
 
 ZEXTERN int ZEXPORT gzbuffer OF((gzFile file, unsigned size));
 /*
-     Set the internal buffer size used by this library's functions.  The
-   default buffer size is 8192 bytes.  This function must be called after
-   gzopen() or gzdopen(), and before any other calls that read or write the
-   file.  The buffer memory allocation is always deferred to the first read or
-   write.  Three times that size in buffer space is allocated.  A larger buffer
-   size of, for example, 64K or 128K bytes will noticeably increase the speed
-   of decompression (reading).
+     Set the internal buffer size used by this library's functions for file to
+   size.  The default buffer size is 8192 bytes.  This function must be called
+   after gzopen() or gzdopen(), and before any other calls that read or write
+   the file.  The buffer memory allocation is always deferred to the first read
+   or write.  Three times that size in buffer space is allocated.  A larger
+   buffer size of, for example, 64K or 128K bytes will noticeably increase the
+   speed of decompression (reading).
 
      The new buffer size also affects the maximum length for gzprintf().
 
@@ -1378,9 +1380,9 @@ ZEXTERN int ZEXPORT gzbuffer OF((gzFile file, unsigned size));
 
 ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy));
 /*
-     Dynamically update the compression level or strategy.  See the description
-   of deflateInit2 for the meaning of these parameters.  Previously provided
-   data is flushed before the parameter change.
+     Dynamically update the compression level and strategy for file.  See the
+   description of deflateInit2 for the meaning of these parameters. Previously
+   provided data is flushed before applying the parameter changes.
 
      gzsetparams returns Z_OK if success, Z_STREAM_ERROR if the file was not
    opened for writing, Z_ERRNO if there is an error writing the flushed data,
@@ -1389,7 +1391,7 @@ ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy));
 
 ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len));
 /*
-     Reads the given number of uncompressed bytes from the compressed file.  If
+     Read and decompress up to len uncompressed bytes from file into buf.  If
    the input file is not in gzip format, gzread copies the given number of
    bytes into the buffer directly from the file.
 
@@ -1420,11 +1422,11 @@ ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len));
 ZEXTERN z_size_t ZEXPORT gzfread OF((voidp buf, z_size_t size, z_size_t nitems,
                                      gzFile file));
 /*
-     Read up to nitems items of size size from file to buf, otherwise operating
-   as gzread() does.  This duplicates the interface of stdio's fread(), with
-   size_t request and return types.  If the library defines size_t, then
-   z_size_t is identical to size_t.  If not, then z_size_t is an unsigned
-   integer type that can contain a pointer.
+     Read and decompress up to nitems items of size size from file into buf,
+   otherwise operating as gzread() does.  This duplicates the interface of
+   stdio's fread(), with size_t request and return types.  If the library
+   defines size_t, then z_size_t is identical to size_t.  If not, then z_size_t
+   is an unsigned integer type that can contain a pointer.
 
      gzfread() returns the number of full items read of size size, or zero if
    the end of the file was reached and a full item could not be read, or if
@@ -1443,18 +1445,16 @@ ZEXTERN z_size_t ZEXPORT gzfread OF((voidp buf, z_size_t size, z_size_t nitems,
    file, reseting and retrying on end-of-file, when size is not 1.
 */
 
-ZEXTERN int ZEXPORT gzwrite OF((gzFile file,
-                                voidpc buf, unsigned len));
+ZEXTERN int ZEXPORT gzwrite OF((gzFile file, voidpc buf, unsigned len));
 /*
-     Writes the given number of uncompressed bytes into the compressed file.
-   gzwrite returns the number of uncompressed bytes written or 0 in case of
-   error.
+     Compress and write the len uncompressed bytes at buf to file. gzwrite
+   returns the number of uncompressed bytes written or 0 in case of error.
 */
 
 ZEXTERN z_size_t ZEXPORT gzfwrite OF((voidpc buf, z_size_t size,
                                       z_size_t nitems, gzFile file));
 /*
-     gzfwrite() writes nitems items of size size from buf to file, duplicating
+     Compress and write nitems items of size size from buf to file, duplicating
    the interface of stdio's fwrite(), with size_t request and return types.  If
    the library defines size_t, then z_size_t is identical to size_t.  If not,
    then z_size_t is an unsigned integer type that can contain a pointer.
@@ -1467,22 +1467,22 @@ ZEXTERN z_size_t ZEXPORT gzfwrite OF((voidpc buf, z_size_t size,
 
 ZEXTERN int ZEXPORTVA gzprintf Z_ARG((gzFile file, const char *format, ...));
 /*
-     Converts, formats, and writes the arguments to the compressed file under
-   control of the format string, as in fprintf.  gzprintf returns the number of
+     Convert, format, compress, and write the arguments (...) to file under
+   control of the string format, as in fprintf.  gzprintf returns the number of
    uncompressed bytes actually written, or a negative zlib error code in case
    of error.  The number of uncompressed bytes written is limited to 8191, or
    one less than the buffer size given to gzbuffer().  The caller should assure
    that this limit is not exceeded.  If it is exceeded, then gzprintf() will
    return an error (0) with nothing written.  In this case, there may also be a
    buffer overflow with unpredictable consequences, which is possible only if
-   zlib was compiled with the insecure functions sprintf() or vsprintf()
+   zlib was compiled with the insecure functions sprintf() or vsprintf(),
    because the secure snprintf() or vsnprintf() functions were not available.
    This can be determined using zlibCompileFlags().
 */
 
 ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s));
 /*
-     Writes the given null-terminated string to the compressed file, excluding
+     Compress and write the given null-terminated string s to file, excluding
    the terminating null character.
 
      gzputs returns the number of characters written, or -1 in case of error.
@@ -1490,11 +1490,12 @@ ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s));
 
 ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len));
 /*
-     Reads bytes from the compressed file until len-1 characters are read, or a
-   newline character is read and transferred to buf, or an end-of-file
-   condition is encountered.  If any characters are read or if len == 1, the
-   string is terminated with a null character.  If no characters are read due
-   to an end-of-file or len < 1, then the buffer is left untouched.
+     Read and decompress bytes from file into buf, until len-1 characters are
+   read, or until a newline character is read and transferred to buf, or an
+   end-of-file condition is encountered.  If any characters are read or if len
+   is one, the string is terminated with a null character.  If no characters
+   are read due to an end-of-file or len is less than one, then the buffer is
+   left untouched.
 
      gzgets returns buf which is a null-terminated string, or it returns NULL
    for end-of-file or in case of error.  If there was an error, the contents at
@@ -1503,13 +1504,13 @@ ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len));
 
 ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c));
 /*
-     Writes c, converted to an unsigned char, into the compressed file.  gzputc
+     Compress and write c, converted to an unsigned char, into file.  gzputc
    returns the value that was written, or -1 in case of error.
 */
 
 ZEXTERN int ZEXPORT gzgetc OF((gzFile file));
 /*
-     Reads one byte from the compressed file.  gzgetc returns this byte or -1
+     Read and decompress one byte from file.  gzgetc returns this byte or -1
    in case of end of file or error.  This is implemented as a macro for speed.
    As such, it does not do all of the checking the other functions do.  I.e.
    it does not check to see if file is NULL, nor whether the structure file
@@ -1518,8 +1519,8 @@ ZEXTERN int ZEXPORT gzgetc OF((gzFile file));
 
 ZEXTERN int ZEXPORT gzungetc OF((int c, gzFile file));
 /*
-     Push one character back onto the stream to be read as the first character
-   on the next read.  At least one character of push-back is allowed.
+     Push c back onto the stream for file to be read as the first character on
+   the next read.  At least one character of push-back is always allowed.
    gzungetc() returns the character pushed, or -1 on failure.  gzungetc() will
    fail if c is -1, and may fail if a character has been pushed but not read
    yet.  If gzungetc is used immediately after gzopen or gzdopen, at least the
@@ -1530,9 +1531,9 @@ ZEXTERN int ZEXPORT gzungetc OF((int c, gzFile file));
 
 ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush));
 /*
-     Flushes all pending output into the compressed file.  The parameter flush
-   is as in the deflate() function.  The return value is the zlib error number
-   (see function gzerror below).  gzflush is only permitted when writing.
+     Flush all pending output to file.  The parameter flush is as in the
+   deflate() function.  The return value is the zlib error number (see function
+   gzerror below).  gzflush is only permitted when writing.
 
      If the flush parameter is Z_FINISH, the remaining data is written and the
    gzip stream is completed in the output.  If gzwrite() is called again, a new
@@ -1547,8 +1548,8 @@ ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush));
 ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file,
                                    z_off_t offset, int whence));
 
-     Sets the starting position for the next gzread or gzwrite on the given
-   compressed file.  The offset represents a number of bytes in the
+     Set the starting position to offset relative to whence for the next gzread
+   or gzwrite on file.  The offset represents a number of bytes in the
    uncompressed data stream.  The whence parameter is defined as in lseek(2);
    the value SEEK_END is not supported.
 
@@ -1565,18 +1566,18 @@ ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file,
 
 ZEXTERN int ZEXPORT    gzrewind OF((gzFile file));
 /*
-     Rewinds the given file. This function is supported only for reading.
+     Rewind file. This function is supported only for reading.
 
-     gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET)
+     gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET).
 */
 
 /*
 ZEXTERN z_off_t ZEXPORT    gztell OF((gzFile file));
 
-     Returns the starting position for the next gzread or gzwrite on the given
-   compressed file.  This position represents a number of bytes in the
-   uncompressed data stream, and is zero when starting, even if appending or
-   reading a gzip stream from the middle of a file using gzdopen().
+     Return the starting position for the next gzread or gzwrite on file.
+   This position represents a number of bytes in the uncompressed data stream,
+   and is zero when starting, even if appending or reading a gzip stream from
+   the middle of a file using gzdopen().
 
      gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR)
 */
@@ -1584,22 +1585,22 @@ ZEXTERN z_off_t ZEXPORT    gztell OF((gzFile file));
 /*
 ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile file));
 
-     Returns the current offset in the file being read or written.  This offset
-   includes the count of bytes that precede the gzip stream, for example when
-   appending or when using gzdopen() for reading.  When reading, the offset
-   does not include as yet unused buffered input.  This information can be used
-   for a progress indicator.  On error, gzoffset() returns -1.
+     Return the current compressed (actual) read or write offset of file.  This
+   offset includes the count of bytes that precede the gzip stream, for example
+   when appending or when using gzdopen() for reading.  When reading, the
+   offset does not include as yet unused buffered input.  This information can
+   be used for a progress indicator.  On error, gzoffset() returns -1.
 */
 
 ZEXTERN int ZEXPORT gzeof OF((gzFile file));
 /*
-     Returns true (1) if the end-of-file indicator has been set while reading,
-   false (0) otherwise.  Note that the end-of-file indicator is set only if the
-   read tried to go past the end of the input, but came up short.  Therefore,
-   just like feof(), gzeof() may return false even if there is no more data to
-   read, in the event that the last read request was for the exact number of
-   bytes remaining in the input file.  This will happen if the input file size
-   is an exact multiple of the buffer size.
+     Return true (1) if the end-of-file indicator for file has been set while
+   reading, false (0) otherwise.  Note that the end-of-file indicator is set
+   only if the read tried to go past the end of the input, but came up short.
+   Therefore, just like feof(), gzeof() may return false even if there is no
+   more data to read, in the event that the last read request was for the exact
+   number of bytes remaining in the input file.  This will happen if the input
+   file size is an exact multiple of the buffer size.
 
      If gzeof() returns true, then the read functions will return no more data,
    unless the end-of-file indicator is reset by gzclearerr() and the input file
@@ -1608,7 +1609,7 @@ ZEXTERN int ZEXPORT gzeof OF((gzFile file));
 
 ZEXTERN int ZEXPORT gzdirect OF((gzFile file));
 /*
-     Returns true (1) if file is being copied directly while reading, or false
+     Return true (1) if file is being copied directly while reading, or false
    (0) if file is a gzip stream being decompressed.
 
      If the input file is empty, gzdirect() will return true, since the input
@@ -1629,8 +1630,8 @@ ZEXTERN int ZEXPORT gzdirect OF((gzFile file));
 
 ZEXTERN int ZEXPORT    gzclose OF((gzFile file));
 /*
-     Flushes all pending output if necessary, closes the compressed file and
-   deallocates the (de)compression state.  Note that once file is closed, you
+     Flush all pending output for file, if necessary, close file and
+   deallocate the (de)compression state.  Note that once file is closed, you
    cannot call gzerror with file, since its structures have been deallocated.
    gzclose must not be called more than once on the same file, just as free
    must not be called more than once on the same allocation.
@@ -1654,10 +1655,10 @@ ZEXTERN int ZEXPORT gzclose_w OF((gzFile file));
 
 ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum));
 /*
-     Returns the error message for the last error which occurred on the given
-   compressed file.  errnum is set to zlib error number.  If an error occurred
-   in the file system and not in the compression library, errnum is set to
-   Z_ERRNO and the application may consult errno to get the exact error code.
+     Return the error message for the last error which occurred on file.
+   errnum is set to zlib error number.  If an error occurred in the file system
+   and not in the compression library, errnum is set to Z_ERRNO and the
+   application may consult errno to get the exact error code.
 
      The application must not modify the returned string.  Future calls to
    this function may invalidate the previously returned string.  If file is
@@ -1670,7 +1671,7 @@ ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum));
 
 ZEXTERN void ZEXPORT gzclearerr OF((gzFile file));
 /*
-     Clears the error and end-of-file flags for file.  This is analogous to the
+     Clear the error and end-of-file flags for file.  This is analogous to the
    clearerr() function in stdio.  This is useful for continuing to read a gzip
    file that is being written concurrently.
 */
@@ -1688,8 +1689,9 @@ ZEXTERN void ZEXPORT gzclearerr OF((gzFile file));
 ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len));
 /*
      Update a running Adler-32 checksum with the bytes buf[0..len-1] and
-   return the updated checksum.  If buf is Z_NULL, this function returns the
-   required initial value for the checksum.
+   return the updated checksum. An Adler-32 value is in the range of a 32-bit
+   unsigned integer. If buf is Z_NULL, this function returns the required
+   initial value for the checksum.
 
      An Adler-32 checksum is almost as reliable as a CRC-32 but can be computed
    much faster.
@@ -1722,12 +1724,13 @@ ZEXTERN uLong ZEXPORT adler32_combine OF((uLong adler1, uLong adler2,
    negative, the result has no meaning or utility.
 */
 
-ZEXTERN uLong ZEXPORT crc32   OF((uLong crc, const Bytef *buf, uInt len));
+ZEXTERN uLong ZEXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len));
 /*
      Update a running CRC-32 with the bytes buf[0..len-1] and return the
-   updated CRC-32.  If buf is Z_NULL, this function returns the required
-   initial value for the crc.  Pre- and post-conditioning (one's complement) is
-   performed within this function so it shouldn't be done by the application.
+   updated CRC-32. A CRC-32 value is in the range of a 32-bit unsigned integer.
+   If buf is Z_NULL, this function returns the required initial value for the
+   crc. Pre- and post-conditioning (one's complement) is performed within this
+   function so it shouldn't be done by the application.
 
    Usage example:
 
@@ -1739,7 +1742,7 @@ ZEXTERN uLong ZEXPORT crc32   OF((uLong crc, const Bytef *buf, uInt len));
      if (crc != original_crc) error();
 */
 
-ZEXTERN uLong ZEXPORT crc32_z OF((uLong adler, const Bytef *buf,
+ZEXTERN uLong ZEXPORT crc32_z OF((uLong crc, const Bytef *buf,
                                   z_size_t len));
 /*
      Same as crc32(), but with a size_t length.
@@ -1755,6 +1758,20 @@ ZEXTERN uLong ZEXPORT crc32_combine OF((uLong crc1, uLong crc2, z_off_t len2));
    len2.
 */
 
+/*
+ZEXTERN uLong ZEXPORT crc32_combine_gen OF((z_off_t len2));
+
+     Return the operator corresponding to length len2, to be used with
+   crc32_combine_op().
+*/
+
+ZEXTERN uLong ZEXPORT crc32_combine_op OF((uLong crc1, uLong crc2, uLong op));
+/*
+     Give the same result as crc32_combine(), using op in place of len2. op is
+   is generated from len2 by crc32_combine_gen(). This will be faster than
+   crc32_combine() if the generated op is used more than once.
+*/
+
 
                         /* various hacks, don't look :) */
 
@@ -1842,6 +1859,7 @@ ZEXTERN int ZEXPORT gzgetc_ OF((gzFile file));  /* backward compatibility */
    ZEXTERN z_off64_t ZEXPORT gzoffset64 OF((gzFile));
    ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off64_t));
    ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off64_t));
+   ZEXTERN uLong ZEXPORT crc32_combine_gen64 OF((z_off64_t));
 #endif
 
 #if !defined(ZLIB_INTERNAL) && defined(Z_WANT64)
@@ -1852,6 +1870,7 @@ ZEXTERN int ZEXPORT gzgetc_ OF((gzFile file));  /* backward compatibility */
 #    define z_gzoffset z_gzoffset64
 #    define z_adler32_combine z_adler32_combine64
 #    define z_crc32_combine z_crc32_combine64
+#    define z_crc32_combine_gen z_crc32_combine_gen64
 #  else
 #    define gzopen gzopen64
 #    define gzseek gzseek64
@@ -1859,6 +1878,7 @@ ZEXTERN int ZEXPORT gzgetc_ OF((gzFile file));  /* backward compatibility */
 #    define gzoffset gzoffset64
 #    define adler32_combine adler32_combine64
 #    define crc32_combine crc32_combine64
+#    define crc32_combine_gen crc32_combine_gen64
 #  endif
 #  ifndef Z_LARGE64
      ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *));
@@ -1867,6 +1887,7 @@ ZEXTERN int ZEXPORT gzgetc_ OF((gzFile file));  /* backward compatibility */
      ZEXTERN z_off_t ZEXPORT gzoffset64 OF((gzFile));
      ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off_t));
      ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off_t));
+     ZEXTERN uLong ZEXPORT crc32_combine_gen64 OF((z_off_t));
 #  endif
 #else
    ZEXTERN gzFile ZEXPORT gzopen OF((const char *, const char *));
@@ -1875,12 +1896,14 @@ ZEXTERN int ZEXPORT gzgetc_ OF((gzFile file));  /* backward compatibility */
    ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile));
    ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t));
    ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t));
+   ZEXTERN uLong ZEXPORT crc32_combine_gen OF((z_off_t));
 #endif
 
 #else /* Z_SOLO */
 
    ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t));
    ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t));
+   ZEXTERN uLong ZEXPORT crc32_combine_gen OF((z_off_t));
 
 #endif /* !Z_SOLO */
 
@@ -1893,7 +1916,7 @@ ZEXTERN int            ZEXPORT inflateValidate OF((z_streamp, int));
 ZEXTERN unsigned long  ZEXPORT inflateCodesUsed OF ((z_streamp));
 ZEXTERN int            ZEXPORT inflateResetKeep OF((z_streamp));
 ZEXTERN int            ZEXPORT deflateResetKeep OF((z_streamp));
-#if (defined(_WIN32) || defined(__CYGWIN__)) && !defined(Z_SOLO)
+#if defined(_WIN32) && !defined(Z_SOLO)
 ZEXTERN gzFile         ZEXPORT gzopen_w OF((const wchar_t *path,
                                             const char *mode));
 #endif

deps/zlib/zutil.c

@@ -136,8 +136,8 @@ const char * ZEXPORT zError(err)
     return ERR_MSG(err);
 }
 
-#if defined(_WIN32_WCE)
-    /* The Microsoft C Run-Time Library for Windows CE doesn't have
+#if defined(_WIN32_WCE) && _WIN32_WCE < 0x800
+    /* The older Microsoft C Run-Time Library for Windows CE doesn't have
      * errno.  We define it as a global variable to simplify porting.
      * Its value is always 0 and should not be used.
      */

deps/zlib/zutil.h

 /* zutil.h -- internal interface and configuration of the compression library
- * Copyright (C) 1995-2016 Jean-loup Gailly, Mark Adler
+ * Copyright (C) 1995-2022 Jean-loup Gailly, Mark Adler
  * For conditions of distribution and use, see copyright notice in zlib.h
  */
 
@@ -29,10 +29,6 @@
 #  include <stdlib.h>
 #endif
 
-#ifdef Z_SOLO
-   typedef long ptrdiff_t;  /* guess -- will be caught if guess is wrong */
-#endif
-
 #ifndef local
 #  define local static
 #endif
@@ -46,6 +42,17 @@ typedef unsigned short ush;
 typedef ush FAR ushf;
 typedef unsigned long  ulg;
 
+#if !defined(Z_U8) && !defined(Z_SOLO) && defined(STDC)
+#  include <limits.h>
+#  if (ULONG_MAX == 0xffffffffffffffff)
+#    define Z_U8 unsigned long
+#  elif (ULLONG_MAX == 0xffffffffffffffff)
+#    define Z_U8 unsigned long long
+#  elif (UINT_MAX == 0xffffffffffffffff)
+#    define Z_U8 unsigned
+#  endif
+#endif
+
 extern z_const char * const z_errmsg[10]; /* indexed by 2-zlib_error */
 /* (size given to avoid silly warnings with Visual C++) */
 
@@ -170,10 +177,6 @@ extern z_const char * const z_errmsg[10]; /* indexed by 2-zlib_error */
 #if (defined(_MSC_VER) && (_MSC_VER > 600)) && !defined __INTERIX
 #  if defined(_WIN32_WCE)
 #    define fdopen(fd,mode) NULL /* No fdopen() */
-#    ifndef _PTRDIFF_T_DEFINED
-       typedef int ptrdiff_t;
-#      define _PTRDIFF_T_DEFINED
-#    endif
 #  else
 #    define fdopen(fd,type)  _fdopen(fd,type)
 #  endif