Add auxiliary method git__hexdump

New function in util.c to do a dump of a buffer's contents in
hexadecimal to stdout.

Signed-off-by: Vicent Marti <tanoku@gmail.com>

src/util.c

@@ -121,3 +121,47 @@ int git__basename(char *base, size_t n, char *path)
 	return len;
 }
 
+void git__hexdump(const char *buffer, size_t len)
+{
+	static const size_t LINE_WIDTH = 16;
+
+	size_t line_count, last_line, i, j;
+	const char *line;
+
+	line_count = (len / LINE_WIDTH);
+	last_line = (len % LINE_WIDTH);
+
+	for (i = 0; i < line_count; ++i) {
+		line = buffer + (i * LINE_WIDTH);
+		for (j = 0; j < LINE_WIDTH; ++j, ++line)
+			printf("%02X ", (unsigned char)*line & 0xFF);
+
+		printf("| ");
+
+		line = buffer + (i * LINE_WIDTH);
+		for (j = 0; j < LINE_WIDTH; ++j, ++line)
+			printf("%c", (*line >= 32 && *line <= 126) ? *line : '.');
+
+		printf("\n");
+	}
+
+	if (last_line > 0) {
+
+		line = buffer + (line_count * LINE_WIDTH);
+		for (j = 0; j < last_line; ++j, ++line)
+			printf("%02X ", (unsigned char)*line & 0xFF);
+
+		for (j = 0; j < (LINE_WIDTH - last_line); ++j)
+			printf("   ");
+
+		printf("| ");
+
+		line = buffer + (line_count * LINE_WIDTH);
+		for (j = 0; j < last_line; ++j, ++line)
+			printf("%c", (*line >= 32 && *line <= 126) ? *line : '.');
+
+		printf("\n");
+	}
+
+	printf("\n");
+}

src/util.h

@@ -34,6 +34,8 @@ extern int git__suffixcmp(const char *str, const char *suffix);
 extern int git__dirname(char *dir, size_t n, char *path);
 extern int git__basename(char *base, size_t n, char *path);
 
+extern void git__hexdump(const char *buffer, size_t n);
+
 /** @return true if p fits into the range of a size_t */
 GIT_INLINE(int) git__is_sizet(off_t p)
 {