buffer.c 23.1 KB
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Vicent Marti committed
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/*
Edward Thomson committed
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 * Copyright (C) the libgit2 contributors. All rights reserved.
Vicent Marti committed
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 *
 * This file is part of libgit2, distributed under the GNU GPL v2 with
 * a Linking Exception. For full terms see the included COPYING file.
 */
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#include "buffer.h"
#include "posix.h"
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#include "git2/buffer.h"
joshaber committed
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#include "buf_text.h"
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#include <ctype.h>
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/* Used as default value for git_buf->ptr so that people can always
 * assume ptr is non-NULL and zero terminated even for new git_bufs.
 */
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char git_buf__initbuf[1];
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char git_buf__oom[1];
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#define ENSURE_SIZE(b, d) \
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	if ((d) > (b)->asize && git_buf_grow((b), (d)) < 0)\
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		return -1;
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int git_buf_init(git_buf *buf, size_t initial_size)
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{
	buf->asize = 0;
	buf->size = 0;
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	buf->ptr = git_buf__initbuf;
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	ENSURE_SIZE(buf, initial_size);

	return 0;
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}

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int git_buf_try_grow(
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	git_buf *buf, size_t target_size, bool mark_oom)
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{
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	char *new_ptr;
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	size_t new_size;
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	if (buf->ptr == git_buf__oom)
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		return -1;
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	if (buf->asize == 0 && buf->size != 0) {
		giterr_set(GITERR_INVALID, "cannot grow a borrowed buffer");
		return GIT_EINVALID;
	}
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	if (!target_size)
		target_size = buf->size;

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	if (target_size <= buf->asize)
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		return 0;
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	if (buf->asize == 0) {
		new_size = target_size;
		new_ptr = NULL;
	} else {
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		new_size = buf->asize;
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		new_ptr = buf->ptr;
	}
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	/* grow the buffer size by 1.5, until it's big enough
	 * to fit our target size */
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	while (new_size < target_size)
		new_size = (new_size << 1) - (new_size >> 1);
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	/* round allocation up to multiple of 8 */
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	new_size = (new_size + 7) & ~7;
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	if (new_size < buf->size) {
		if (mark_oom)
			buf->ptr = git_buf__oom;

		giterr_set_oom();
		return -1;
	}

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	new_ptr = git__realloc(new_ptr, new_size);
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	if (!new_ptr) {
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		if (mark_oom) {
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			if (buf->ptr && (buf->ptr != git_buf__initbuf))
				git__free(buf->ptr);
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			buf->ptr = git_buf__oom;
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		}
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		return -1;
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	}
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	buf->asize = new_size;
	buf->ptr   = new_ptr;

	/* truncate the existing buffer size if necessary */
	if (buf->size >= buf->asize)
		buf->size = buf->asize - 1;
	buf->ptr[buf->size] = '\0';

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	return 0;
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}

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int git_buf_grow(git_buf *buffer, size_t target_size)
{
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	return git_buf_try_grow(buffer, target_size, true);
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}

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int git_buf_grow_by(git_buf *buffer, size_t additional_size)
{
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	size_t newsize;

	if (GIT_ADD_SIZET_OVERFLOW(&newsize, buffer->size, additional_size)) {
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		buffer->ptr = git_buf__oom;
		return -1;
	}

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	return git_buf_try_grow(buffer, newsize, true);
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}

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void git_buf_free(git_buf *buf)
{
	if (!buf) return;

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	if (buf->asize > 0 && buf->ptr != NULL && buf->ptr != git_buf__oom)
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		git__free(buf->ptr);

	git_buf_init(buf, 0);
}

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void git_buf_sanitize(git_buf *buf)
{
	if (buf->ptr == NULL) {
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		assert(buf->size == 0 && buf->asize == 0);
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		buf->ptr = git_buf__initbuf;
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	} else if (buf->asize > buf->size)
		buf->ptr[buf->size] = '\0';
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}

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void git_buf_clear(git_buf *buf)
{
	buf->size = 0;
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	if (!buf->ptr) {
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		buf->ptr = git_buf__initbuf;
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		buf->asize = 0;
	}
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	if (buf->asize > 0)
		buf->ptr[0] = '\0';
}

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int git_buf_set(git_buf *buf, const void *data, size_t len)
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{
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	size_t alloclen;

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	if (len == 0 || data == NULL) {
		git_buf_clear(buf);
	} else {
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		if (data != buf->ptr) {
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			GITERR_CHECK_ALLOC_ADD(&alloclen, len, 1);
			ENSURE_SIZE(buf, alloclen);
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			memmove(buf->ptr, data, len);
		}
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		buf->size = len;
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		if (buf->asize > buf->size)
			buf->ptr[buf->size] = '\0';

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	}
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	return 0;
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}

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int git_buf_is_binary(const git_buf *buf)
{
	return git_buf_text_is_binary(buf);
}

int git_buf_contains_nul(const git_buf *buf)
{
	return git_buf_text_contains_nul(buf);
}

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int git_buf_sets(git_buf *buf, const char *string)
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{
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	return git_buf_set(buf, string, string ? strlen(string) : 0);
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}

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int git_buf_putc(git_buf *buf, char c)
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{
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	size_t new_size;
	GITERR_CHECK_ALLOC_ADD(&new_size, buf->size, 2);
	ENSURE_SIZE(buf, new_size);
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	buf->ptr[buf->size++] = c;
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	buf->ptr[buf->size] = '\0';
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	return 0;
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}

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int git_buf_putcn(git_buf *buf, char c, size_t len)
{
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	size_t new_size;
	GITERR_CHECK_ALLOC_ADD(&new_size, buf->size, len);
	GITERR_CHECK_ALLOC_ADD(&new_size, new_size, 1);
	ENSURE_SIZE(buf, new_size);
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	memset(buf->ptr + buf->size, c, len);
	buf->size += len;
	buf->ptr[buf->size] = '\0';
	return 0;
}

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int git_buf_put(git_buf *buf, const char *data, size_t len)
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{
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	if (len) {
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		size_t new_size;

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		assert(data);
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		GITERR_CHECK_ALLOC_ADD(&new_size, buf->size, len);
		GITERR_CHECK_ALLOC_ADD(&new_size, new_size, 1);
		ENSURE_SIZE(buf, new_size);
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		memmove(buf->ptr + buf->size, data, len);
		buf->size += len;
		buf->ptr[buf->size] = '\0';
	}
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	return 0;
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}

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int git_buf_puts(git_buf *buf, const char *string)
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{
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	assert(string);
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	return git_buf_put(buf, string, strlen(string));
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}

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static const char base64_encode[] =
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	"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

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int git_buf_encode_base64(git_buf *buf, const char *data, size_t len)
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{
	size_t extra = len % 3;
	uint8_t *write, a, b, c;
	const uint8_t *read = (const uint8_t *)data;
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	size_t blocks = (len / 3) + !!extra, alloclen;

	GITERR_CHECK_ALLOC_ADD(&blocks, blocks, 1);
	GITERR_CHECK_ALLOC_MULTIPLY(&alloclen, blocks, 4);
	GITERR_CHECK_ALLOC_ADD(&alloclen, alloclen, buf->size);
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	ENSURE_SIZE(buf, alloclen);
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	write = (uint8_t *)&buf->ptr[buf->size];

	/* convert each run of 3 bytes into 4 output bytes */
	for (len -= extra; len > 0; len -= 3) {
		a = *read++;
		b = *read++;
		c = *read++;

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		*write++ = base64_encode[a >> 2];
		*write++ = base64_encode[(a & 0x03) << 4 | b >> 4];
		*write++ = base64_encode[(b & 0x0f) << 2 | c >> 6];
		*write++ = base64_encode[c & 0x3f];
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	}

	if (extra > 0) {
		a = *read++;
		b = (extra > 1) ? *read++ : 0;

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		*write++ = base64_encode[a >> 2];
		*write++ = base64_encode[(a & 0x03) << 4 | b >> 4];
		*write++ = (extra > 1) ? base64_encode[(b & 0x0f) << 2] : '=';
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		*write++ = '=';
	}

	buf->size = ((char *)write) - buf->ptr;
	buf->ptr[buf->size] = '\0';

	return 0;
}

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/* The inverse of base64_encode */
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static const int8_t base64_decode[] = {
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	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63,
	52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1,  0, -1, -1,
	-1,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
	15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1,
	-1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
	41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1,
	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1
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};

int git_buf_decode_base64(git_buf *buf, const char *base64, size_t len)
{
	size_t i;
	int8_t a, b, c, d;
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	size_t orig_size = buf->size, new_size;
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	if (len % 4) {
		giterr_set(GITERR_INVALID, "invalid base64 input");
		return -1;
	}

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	assert(len % 4 == 0);
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	GITERR_CHECK_ALLOC_ADD(&new_size, (len / 4 * 3), buf->size);
	GITERR_CHECK_ALLOC_ADD(&new_size, new_size, 1);
	ENSURE_SIZE(buf, new_size);
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	for (i = 0; i < len; i += 4) {
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		if ((a = base64_decode[(unsigned char)base64[i]]) < 0 ||
			(b = base64_decode[(unsigned char)base64[i+1]]) < 0 ||
			(c = base64_decode[(unsigned char)base64[i+2]]) < 0 ||
			(d = base64_decode[(unsigned char)base64[i+3]]) < 0) {
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			buf->size = orig_size;
			buf->ptr[buf->size] = '\0';

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			giterr_set(GITERR_INVALID, "invalid base64 input");
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			return -1;
		}

		buf->ptr[buf->size++] = ((a << 2) | (b & 0x30) >> 4);
		buf->ptr[buf->size++] = ((b & 0x0f) << 4) | ((c & 0x3c) >> 2);
		buf->ptr[buf->size++] = (c & 0x03) << 6 | (d & 0x3f);
	}

	buf->ptr[buf->size] = '\0';
	return 0;
}

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static const char base85_encode[] =
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	"0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz!#$%&()*+-;<=>?@^_`{|}~";

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int git_buf_encode_base85(git_buf *buf, const char *data, size_t len)
338
{
339
	size_t blocks = (len / 4) + !!(len % 4), alloclen;
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	GITERR_CHECK_ALLOC_MULTIPLY(&alloclen, blocks, 5);
	GITERR_CHECK_ALLOC_ADD(&alloclen, alloclen, buf->size);
	GITERR_CHECK_ALLOC_ADD(&alloclen, alloclen, 1);

	ENSURE_SIZE(buf, alloclen);
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	while (len) {
		uint32_t acc = 0;
		char b85[5];
		int i;

		for (i = 24; i >= 0; i -= 8) {
			uint8_t ch = *data++;
			acc |= ch << i;

			if (--len == 0)
				break;
		}

		for (i = 4; i >= 0; i--) {
			int val = acc % 85;
			acc /= 85;

364
			b85[i] = base85_encode[val];
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		}

		for (i = 0; i < 5; i++)
			buf->ptr[buf->size++] = b85[i];
	}

	buf->ptr[buf->size] = '\0';

	return 0;
}

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/* The inverse of base85_encode */
static const int8_t base85_decode[] = {
	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
	-1, 63, -1, 64, 65, 66, 67, -1, 68, 69, 70, 71, -1, 72, -1, -1,
	 1,  2,  3,  4,  5,  6,  7,  8,  9, 10, -1, 73, 74, 75, 76, 77,
	78, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25,
	26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, -1, -1, -1, 79, 80,
	81, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51,
	52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 82, 83, 84, 85, -1,
	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1
};

int git_buf_decode_base85(
	git_buf *buf,
	const char *base85,
	size_t base85_len,
	size_t output_len)
{
	size_t orig_size = buf->size, new_size;

	if (base85_len % 5 ||
		output_len > base85_len * 4 / 5) {
		giterr_set(GITERR_INVALID, "invalid base85 input");
		return -1;
	}

	GITERR_CHECK_ALLOC_ADD(&new_size, output_len, buf->size);
	GITERR_CHECK_ALLOC_ADD(&new_size, new_size, 1);
	ENSURE_SIZE(buf, new_size);

	while (output_len) {
		unsigned acc = 0;
		int de, cnt = 4;
		unsigned char ch;
		do {
			ch = *base85++;
			de = base85_decode[ch];
			if (--de < 0)
				goto on_error;

			acc = acc * 85 + de;
		} while (--cnt);
		ch = *base85++;
		de = base85_decode[ch];
		if (--de < 0)
			goto on_error;

		/* Detect overflow. */
		if (0xffffffff / 85 < acc ||
			0xffffffff - de < (acc *= 85))
			goto on_error;

		acc += de;

		cnt = (output_len < 4) ? output_len : 4;
		output_len -= cnt;
		do {
			acc = (acc << 8) | (acc >> 24);
			buf->ptr[buf->size++] = acc;
		} while (--cnt);
	}

	buf->ptr[buf->size] = 0;

	return 0;

on_error:
	buf->size = orig_size;
	buf->ptr[buf->size] = '\0';

	giterr_set(GITERR_INVALID, "invalid base85 input");
	return -1;
}

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#define HEX_DECODE(c) ((c | 32) % 39 - 9)

int git_buf_decode_percent(
	git_buf *buf,
	const char *str,
	size_t str_len)
{
	size_t str_pos, new_size;

	GITERR_CHECK_ALLOC_ADD(&new_size, buf->size, str_len);
	GITERR_CHECK_ALLOC_ADD(&new_size, new_size, 1);
	ENSURE_SIZE(buf, new_size);

	for (str_pos = 0; str_pos < str_len; buf->size++, str_pos++) {
		if (str[str_pos] == '%' &&
			str_len > str_pos + 2 &&
			isxdigit(str[str_pos + 1]) &&
			isxdigit(str[str_pos + 2])) {
			buf->ptr[buf->size] = (HEX_DECODE(str[str_pos + 1]) << 4) +
				HEX_DECODE(str[str_pos + 2]);
			str_pos += 2;
		} else {
			buf->ptr[buf->size] = str[str_pos];
		}
	}

	buf->ptr[buf->size] = '\0';
	return 0;
}

488
int git_buf_vprintf(git_buf *buf, const char *format, va_list ap)
489
{
490
	size_t expected_size, new_size;
491
	int len;
492

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	GITERR_CHECK_ALLOC_MULTIPLY(&expected_size, strlen(format), 2);
	GITERR_CHECK_ALLOC_ADD(&expected_size, expected_size, buf->size);
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	ENSURE_SIZE(buf, expected_size);
496 497

	while (1) {
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		va_list args;
		va_copy(args, ap);

		len = p_vsnprintf(
			buf->ptr + buf->size,
			buf->asize - buf->size,
			format, args
		);
506

507 508
		va_end(args);

509
		if (len < 0) {
510
			git__free(buf->ptr);
511
			buf->ptr = git_buf__oom;
512
			return -1;
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		}

515
		if ((size_t)len + 1 <= buf->asize - buf->size) {
516
			buf->size += len;
517
			break;
518 519
		}

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		GITERR_CHECK_ALLOC_ADD(&new_size, buf->size, len);
		GITERR_CHECK_ALLOC_ADD(&new_size, new_size, 1);
		ENSURE_SIZE(buf, new_size);
523
	}
524

525
	return 0;
526 527
}

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int git_buf_printf(git_buf *buf, const char *format, ...)
{
	int r;
	va_list ap;

	va_start(ap, format);
	r = git_buf_vprintf(buf, format, ap);
	va_end(ap);

	return r;
}

540
void git_buf_copy_cstr(char *data, size_t datasize, const git_buf *buf)
541 542 543
{
	size_t copylen;

544
	assert(data && datasize && buf);
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	data[0] = '\0';

	if (buf->size == 0 || buf->asize <= 0)
		return;

	copylen = buf->size;
	if (copylen > datasize - 1)
		copylen = datasize - 1;
	memmove(data, buf->ptr, copylen);
	data[copylen] = '\0';
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}

558 559
void git_buf_consume(git_buf *buf, const char *end)
{
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	if (end > buf->ptr && end <= buf->ptr + buf->size) {
		size_t consumed = end - buf->ptr;
		memmove(buf->ptr, end, buf->size - consumed);
		buf->size -= consumed;
564
		buf->ptr[buf->size] = '\0';
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	}
}

568
void git_buf_truncate(git_buf *buf, size_t len)
569
{
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	if (len >= buf->size)
		return;

	buf->size = len;
	if (buf->size < buf->asize)
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		buf->ptr[buf->size] = '\0';
}

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void git_buf_shorten(git_buf *buf, size_t amount)
{
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	if (buf->size > amount)
		git_buf_truncate(buf, buf->size - amount);
	else
		git_buf_clear(buf);
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}

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void git_buf_rtruncate_at_char(git_buf *buf, char separator)
{
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	ssize_t idx = git_buf_rfind_next(buf, separator);
	git_buf_truncate(buf, idx < 0 ? 0 : (size_t)idx);
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}

592 593 594 595 596
void git_buf_swap(git_buf *buf_a, git_buf *buf_b)
{
	git_buf t = *buf_a;
	*buf_a = *buf_b;
	*buf_b = t;
597
}
598

599
char *git_buf_detach(git_buf *buf)
600
{
601
	char *data = buf->ptr;
602

603
	if (buf->asize == 0 || buf->ptr == git_buf__oom)
604 605
		return NULL;

606
	git_buf_init(buf, 0);
607 608 609 610

	return data;
}

611
int git_buf_attach(git_buf *buf, char *ptr, size_t asize)
612
{
613 614 615 616 617 618 619 620 621 622
	git_buf_free(buf);

	if (ptr) {
		buf->ptr = ptr;
		buf->size = strlen(ptr);
		if (asize)
			buf->asize = (asize < buf->size) ? buf->size + 1 : asize;
		else /* pass 0 to fall back on strlen + 1 */
			buf->asize = buf->size + 1;
	}
623 624 625

	ENSURE_SIZE(buf, asize);
	return 0;
626
}
627

628 629 630 631 632 633 634 635 636 637 638 639 640 641
void git_buf_attach_notowned(git_buf *buf, const char *ptr, size_t size)
{
	if (git_buf_is_allocated(buf))
		git_buf_free(buf);

	if (!size) {
		git_buf_init(buf, 0);
	} else {
		buf->ptr = (char *)ptr;
		buf->asize = 0;
		buf->size = size;
	}
}

642 643
int git_buf_join_n(git_buf *buf, char separator, int nbuf, ...)
{
644
	va_list ap;
645
	int i;
646 647
	size_t total_size = 0, original_size = buf->size;
	char *out, *original = buf->ptr;
648 649 650 651

	if (buf->size > 0 && buf->ptr[buf->size - 1] != separator)
		++total_size; /* space for initial separator */

652 653
	/* Make two passes to avoid multiple reallocation */

654 655 656
	va_start(ap, nbuf);
	for (i = 0; i < nbuf; ++i) {
		const char* segment;
657
		size_t segment_len;
658 659 660 661 662 663

		segment = va_arg(ap, const char *);
		if (!segment)
			continue;

		segment_len = strlen(segment);
664 665 666

		GITERR_CHECK_ALLOC_ADD(&total_size, total_size, segment_len);

667
		if (segment_len == 0 || segment[segment_len - 1] != separator)
668
			GITERR_CHECK_ALLOC_ADD(&total_size, total_size, 1);
669 670 671
	}
	va_end(ap);

672
	/* expand buffer if needed */
673 674
	if (total_size == 0)
		return 0;
675

676 677
	GITERR_CHECK_ALLOC_ADD(&total_size, total_size, 1);
	if (git_buf_grow_by(buf, total_size) < 0)
678
		return -1;
679 680 681 682 683 684 685 686 687 688

	out = buf->ptr + buf->size;

	/* append separator to existing buf if needed */
	if (buf->size > 0 && out[-1] != separator)
		*out++ = separator;

	va_start(ap, nbuf);
	for (i = 0; i < nbuf; ++i) {
		const char* segment;
689
		size_t segment_len;
690 691 692 693 694

		segment = va_arg(ap, const char *);
		if (!segment)
			continue;

695 696 697 698 699 700 701 702 703
		/* deal with join that references buffer's original content */
		if (segment >= original && segment < original + original_size) {
			size_t offset = (segment - original);
			segment = buf->ptr + offset;
			segment_len = original_size - offset;
		} else {
			segment_len = strlen(segment);
		}

704 705
		/* skip leading separators */
		if (out > buf->ptr && out[-1] == separator)
706 707 708 709
			while (segment_len > 0 && *segment == separator) {
				segment++;
				segment_len--;
			}
710 711 712 713 714 715 716 717 718 719 720 721 722 723 724

		/* copy over next buffer */
		if (segment_len > 0) {
			memmove(out, segment, segment_len);
			out += segment_len;
		}

		/* append trailing separator (except for last item) */
		if (i < nbuf - 1 && out > buf->ptr && out[-1] != separator)
			*out++ = separator;
	}
	va_end(ap);

	/* set size based on num characters actually written */
	buf->size = out - buf->ptr;
725
	buf->ptr[buf->size] = '\0';
726

727
	return 0;
728 729
}

730
int git_buf_join(
731 732 733 734 735
	git_buf *buf,
	char separator,
	const char *str_a,
	const char *str_b)
{
736
	size_t strlen_a = str_a ? strlen(str_a) : 0;
737
	size_t strlen_b = strlen(str_b);
738
	size_t alloc_len;
739
	int need_sep = 0;
740 741 742
	ssize_t offset_a = -1;

	/* not safe to have str_b point internally to the buffer */
743
	assert(str_b < buf->ptr || str_b >= buf->ptr + buf->size);
744 745 746 747 748 749

	/* figure out if we need to insert a separator */
	if (separator && strlen_a) {
		while (*str_b == separator) { str_b++; strlen_b--; }
		if (str_a[strlen_a - 1] != separator)
			need_sep = 1;
750 751
	}

752 753 754 755
	/* str_a could be part of the buffer */
	if (str_a >= buf->ptr && str_a < buf->ptr + buf->size)
		offset_a = str_a - buf->ptr;

756 757 758
	GITERR_CHECK_ALLOC_ADD(&alloc_len, strlen_a, strlen_b);
	GITERR_CHECK_ALLOC_ADD(&alloc_len, alloc_len, need_sep);
	GITERR_CHECK_ALLOC_ADD(&alloc_len, alloc_len, 1);
759
	ENSURE_SIZE(buf, alloc_len);
760

761 762 763 764 765
	/* fix up internal pointers */
	if (offset_a >= 0)
		str_a = buf->ptr + offset_a;

	/* do the actual copying */
766
	if (offset_a != 0 && str_a)
767
		memmove(buf->ptr, str_a, strlen_a);
768 769
	if (need_sep)
		buf->ptr[strlen_a] = separator;
770
	memcpy(buf->ptr + strlen_a + need_sep, str_b, strlen_b);
771

772
	buf->size = strlen_a + strlen_b + need_sep;
773
	buf->ptr[buf->size] = '\0';
774

775
	return 0;
776
}
777

778 779 780 781 782 783 784
int git_buf_join3(
	git_buf *buf,
	char separator,
	const char *str_a,
	const char *str_b,
	const char *str_c)
{
785 786 787 788
	size_t len_a = strlen(str_a),
		len_b = strlen(str_b),
		len_c = strlen(str_c),
		len_total;
789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807
	int sep_a = 0, sep_b = 0;
	char *tgt;

	/* for this function, disallow pointers into the existing buffer */
	assert(str_a < buf->ptr || str_a >= buf->ptr + buf->size);
	assert(str_b < buf->ptr || str_b >= buf->ptr + buf->size);
	assert(str_c < buf->ptr || str_c >= buf->ptr + buf->size);

	if (separator) {
		if (len_a > 0) {
			while (*str_b == separator) { str_b++; len_b--; }
			sep_a = (str_a[len_a - 1] != separator);
		}
		if (len_a > 0 || len_b > 0)
			while (*str_c == separator) { str_c++; len_c--; }
		if (len_b > 0)
			sep_b = (str_b[len_b - 1] != separator);
	}

808 809 810 811 812
	GITERR_CHECK_ALLOC_ADD(&len_total, len_a, sep_a);
	GITERR_CHECK_ALLOC_ADD(&len_total, len_total, len_b);
	GITERR_CHECK_ALLOC_ADD(&len_total, len_total, sep_b);
	GITERR_CHECK_ALLOC_ADD(&len_total, len_total, len_c);
	GITERR_CHECK_ALLOC_ADD(&len_total, len_total, 1);
813
	ENSURE_SIZE(buf, len_total);
814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837

	tgt = buf->ptr;

	if (len_a) {
		memcpy(tgt, str_a, len_a);
		tgt += len_a;
	}
	if (sep_a)
		*tgt++ = separator;
	if (len_b) {
		memcpy(tgt, str_b, len_b);
		tgt += len_b;
	}
	if (sep_b)
		*tgt++ = separator;
	if (len_c)
		memcpy(tgt, str_c, len_c);

	buf->size = len_a + sep_a + len_b + sep_b + len_c;
	buf->ptr[buf->size] = '\0';

	return 0;
}

838 839 840
void git_buf_rtrim(git_buf *buf)
{
	while (buf->size > 0) {
841
		if (!git__isspace(buf->ptr[buf->size - 1]))
842 843 844 845
			break;

		buf->size--;
	}
846

847 848
	if (buf->asize > buf->size)
		buf->ptr[buf->size] = '\0';
849
}
850 851 852 853 854 855 856

int git_buf_cmp(const git_buf *a, const git_buf *b)
{
	int result = memcmp(a->ptr, b->ptr, min(a->size, b->size));
	return (result != 0) ? result :
		(a->size < b->size) ? -1 : (a->size > b->size) ? 1 : 0;
}
857

858 859 860 861 862 863 864
int git_buf_splice(
	git_buf *buf,
	size_t where,
	size_t nb_to_remove,
	const char *data,
	size_t nb_to_insert)
{
865 866
	char *splice_loc;
	size_t new_size, alloc_size;
867

868 869 870
	assert(buf && where <= buf->size && nb_to_remove <= buf->size - where);

	splice_loc = buf->ptr + where;
871 872 873 874

	/* Ported from git.git
	 * https://github.com/git/git/blob/16eed7c/strbuf.c#L159-176
	 */
875 876 877
	GITERR_CHECK_ALLOC_ADD(&new_size, (buf->size - nb_to_remove), nb_to_insert);
	GITERR_CHECK_ALLOC_ADD(&alloc_size, new_size, 1);
	ENSURE_SIZE(buf, alloc_size);
878

879 880 881
	memmove(splice_loc + nb_to_insert,
		splice_loc + nb_to_remove,
		buf->size - where - nb_to_remove);
882

883
	memcpy(splice_loc, data, nb_to_insert);
884

885
	buf->size = new_size;
886 887 888
	buf->ptr[buf->size] = '\0';
	return 0;
}
889

890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932
/* Quote per http://marc.info/?l=git&m=112927316408690&w=2 */
int git_buf_quote(git_buf *buf)
{
	const char whitespace[] = { 'a', 'b', 't', 'n', 'v', 'f', 'r' };
	git_buf quoted = GIT_BUF_INIT;
	size_t i = 0;
	bool quote = false;
	int error = 0;

	/* walk to the first char that needs quoting */
	if (buf->size && buf->ptr[0] == '!')
		quote = true;

	for (i = 0; !quote && i < buf->size; i++) {
		if (buf->ptr[i] == '"' || buf->ptr[i] == '\\' ||
			buf->ptr[i] < ' ' || buf->ptr[i] > '~') {
			quote = true;
			break;
		}
	}

	if (!quote)
		goto done;

	git_buf_putc(&quoted, '"');
	git_buf_put(&quoted, buf->ptr, i);

	for (; i < buf->size; i++) {
		/* whitespace - use the map above, which is ordered by ascii value */
		if (buf->ptr[i] >= '\a' && buf->ptr[i] <= '\r') {
			git_buf_putc(&quoted, '\\');
			git_buf_putc(&quoted, whitespace[buf->ptr[i] - '\a']);
		}

		/* double quote and backslash must be escaped */
		else if (buf->ptr[i] == '"' || buf->ptr[i] == '\\') {
			git_buf_putc(&quoted, '\\');
			git_buf_putc(&quoted, buf->ptr[i]);
		}

		/* escape anything unprintable as octal */
		else if (buf->ptr[i] != ' ' &&
				(buf->ptr[i] < '!' || buf->ptr[i] > '~')) {
933
			git_buf_printf(&quoted, "\\%03o", (unsigned char)buf->ptr[i]);
934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955
		}

		/* yay, printable! */
		else {
			git_buf_putc(&quoted, buf->ptr[i]);
		}
	}

	git_buf_putc(&quoted, '"');

	if (git_buf_oom(&quoted)) {
		error = -1;
		goto done;
	}

	git_buf_swap(&quoted, buf);

done:
	git_buf_free(&quoted);
	return error;
}

956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990
/* Unquote per http://marc.info/?l=git&m=112927316408690&w=2 */
int git_buf_unquote(git_buf *buf)
{
	size_t i, j;
	char ch;

	git_buf_rtrim(buf);

	if (buf->size < 2 || buf->ptr[0] != '"' || buf->ptr[buf->size-1] != '"')
		goto invalid;

	for (i = 0, j = 1; j < buf->size-1; i++, j++) {
		ch = buf->ptr[j];

		if (ch == '\\') {
			if (j == buf->size-2)
				goto invalid;

			ch = buf->ptr[++j];

			switch (ch) {
			/* \" or \\ simply copy the char in */
			case '"': case '\\':
				break;

			/* add the appropriate escaped char */
			case 'a': ch = '\a'; break;
			case 'b': ch = '\b'; break;
			case 'f': ch = '\f'; break;
			case 'n': ch = '\n'; break;
			case 'r': ch = '\r'; break;
			case 't': ch = '\t'; break;
			case 'v': ch = '\v'; break;

			/* \xyz digits convert to the char*/
991
			case '0': case '1': case '2': case '3':
992 993
				if (j == buf->size-3) {
					giterr_set(GITERR_INVALID,
994
						"truncated quoted character \\%c", ch);
995 996 997 998 999 1000
					return -1;
				}

				if (buf->ptr[j+1] < '0' || buf->ptr[j+1] > '7' ||
					buf->ptr[j+2] < '0' || buf->ptr[j+2] > '7') {
					giterr_set(GITERR_INVALID,
1001
						"truncated quoted character \\%c%c%c",
1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012
						buf->ptr[j], buf->ptr[j+1], buf->ptr[j+2]);
					return -1;
				}

				ch = ((buf->ptr[j] - '0') << 6) |
					((buf->ptr[j+1] - '0') << 3) |
					(buf->ptr[j+2] - '0');
				j += 2;
				break;

			default:
1013
				giterr_set(GITERR_INVALID, "invalid quoted character \\%c", ch);
1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026
				return -1;
			}
		}

		buf->ptr[i] = ch;
	}

	buf->ptr[i] = '\0';
	buf->size = i;

	return 0;

invalid:
1027
	giterr_set(GITERR_INVALID, "invalid quoted line");
1028 1029
	return -1;
}