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-rw-r--r--modules/zlib/src/crc32.c41
1 files changed, 29 insertions, 12 deletions
diff --git a/modules/zlib/src/crc32.c b/modules/zlib/src/crc32.c
index 979a7190a..9580440c0 100644
--- a/modules/zlib/src/crc32.c
+++ b/modules/zlib/src/crc32.c
@@ -1,5 +1,5 @@
/* crc32.c -- compute the CRC-32 of a data stream
- * Copyright (C) 1995-2006, 2010, 2011, 2012 Mark Adler
+ * Copyright (C) 1995-2006, 2010, 2011, 2012, 2016 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
@@ -30,17 +30,15 @@
#include "zutil.h" /* for STDC and FAR definitions */
-#define local static
-
/* Definitions for doing the crc four data bytes at a time. */
#if !defined(NOBYFOUR) && defined(Z_U4)
# define BYFOUR
#endif
#ifdef BYFOUR
local unsigned long crc32_little OF((unsigned long,
- const unsigned char FAR *, unsigned));
+ const unsigned char FAR *, z_size_t));
local unsigned long crc32_big OF((unsigned long,
- const unsigned char FAR *, unsigned));
+ const unsigned char FAR *, z_size_t));
# define TBLS 8
#else
# define TBLS 1
@@ -201,10 +199,10 @@ const z_crc_t FAR * ZEXPORT get_crc_table()
#define DO8 DO1; DO1; DO1; DO1; DO1; DO1; DO1; DO1
/* ========================================================================= */
-unsigned long ZEXPORT crc32(crc, buf, len)
+unsigned long ZEXPORT crc32_z(crc, buf, len)
unsigned long crc;
const unsigned char FAR *buf;
- uInt len;
+ z_size_t len;
{
if (buf == Z_NULL) return 0UL;
@@ -235,8 +233,29 @@ unsigned long ZEXPORT crc32(crc, buf, 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);
+}
+
#ifdef BYFOUR
+/*
+ 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.
+ */
+
/* ========================================================================= */
#define DOLIT4 c ^= *buf4++; \
c = crc_table[3][c & 0xff] ^ crc_table[2][(c >> 8) & 0xff] ^ \
@@ -247,7 +266,7 @@ unsigned long ZEXPORT crc32(crc, buf, len)
local unsigned long crc32_little(crc, buf, len)
unsigned long crc;
const unsigned char FAR *buf;
- unsigned len;
+ z_size_t len;
{
register z_crc_t c;
register const z_crc_t FAR *buf4;
@@ -278,7 +297,7 @@ local unsigned long crc32_little(crc, buf, len)
}
/* ========================================================================= */
-#define DOBIG4 c ^= *++buf4; \
+#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
@@ -287,7 +306,7 @@ local unsigned long crc32_little(crc, buf, len)
local unsigned long crc32_big(crc, buf, len)
unsigned long crc;
const unsigned char FAR *buf;
- unsigned len;
+ z_size_t len;
{
register z_crc_t c;
register const z_crc_t FAR *buf4;
@@ -300,7 +319,6 @@ local unsigned long crc32_big(crc, buf, len)
}
buf4 = (const z_crc_t FAR *)(const void FAR *)buf;
- buf4--;
while (len >= 32) {
DOBIG32;
len -= 32;
@@ -309,7 +327,6 @@ local unsigned long crc32_big(crc, buf, len)
DOBIG4;
len -= 4;
}
- buf4++;
buf = (const unsigned char FAR *)buf4;
if (len) do {