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Diffstat (limited to 'libs/zlib/src/crc32.c')
-rw-r--r--libs/zlib/src/crc32.c377
1 files changed, 197 insertions, 180 deletions
diff --git a/libs/zlib/src/crc32.c b/libs/zlib/src/crc32.c
index a7da8f56fb..9580440c0e 100644
--- a/libs/zlib/src/crc32.c
+++ b/libs/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
@@ -184,16 +182,16 @@ local void write_table(out, table)
#include "crc32.h"
#endif /* DYNAMIC_CRC_TABLE */
- /* =========================================================================
- * This function can be used by asm versions of crc32()
- */
+/* =========================================================================
+ * This function can be used by asm versions of crc32()
+ */
const z_crc_t FAR * ZEXPORT get_crc_table()
{
- #ifdef DYNAMIC_CRC_TABLE
- if (crc_table_empty)
- make_crc_table();
- #endif /* DYNAMIC_CRC_TABLE */
- return (const z_crc_t FAR *)crc_table;
+#ifdef DYNAMIC_CRC_TABLE
+ if (crc_table_empty)
+ make_crc_table();
+#endif /* DYNAMIC_CRC_TABLE */
+ return (const z_crc_t FAR *)crc_table;
}
/* ========================================================================= */
@@ -201,42 +199,63 @@ const z_crc_t FAR * ZEXPORT get_crc_table()
#define DO8 DO1; DO1; DO1; DO1; DO1; DO1; DO1; DO1
/* ========================================================================= */
+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;
+
+#ifdef DYNAMIC_CRC_TABLE
+ if (crc_table_empty)
+ make_crc_table();
+#endif /* DYNAMIC_CRC_TABLE */
+
+#ifdef BYFOUR
+ if (sizeof(void *) == sizeof(ptrdiff_t)) {
+ z_crc_t endian;
+
+ endian = 1;
+ if (*((unsigned char *)(&endian)))
+ return crc32_little(crc, buf, len);
+ else
+ return crc32_big(crc, buf, len);
+ }
+#endif /* BYFOUR */
+ crc = crc ^ 0xffffffffUL;
+ while (len >= 8) {
+ DO8;
+ len -= 8;
+ }
+ 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;
+ unsigned long crc;
+ const unsigned char FAR *buf;
+ uInt len;
{
- if (buf == Z_NULL) return 0UL;
-
- #ifdef DYNAMIC_CRC_TABLE
- if (crc_table_empty)
- make_crc_table();
- #endif /* DYNAMIC_CRC_TABLE */
-
- #ifdef BYFOUR
- if (sizeof(void *) == sizeof(ptrdiff_t)) {
- z_crc_t endian;
-
- endian = 1;
- if (*((unsigned char *)(&endian)))
- return crc32_little(crc, buf, len);
- else
- return crc32_big(crc, buf, len);
- }
- #endif /* BYFOUR */
- crc = crc ^ 0xffffffffUL;
- while (len >= 8) {
- DO8;
- len -= 8;
- }
- if (len) do {
- DO1;
- } while (--len);
- return crc ^ 0xffffffffUL;
+ 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] ^ \
@@ -245,78 +264,76 @@ uInt len;
/* ========================================================================= */
local unsigned long crc32_little(crc, buf, len)
-unsigned long crc;
-const unsigned char FAR *buf;
-unsigned 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;
-
- c = (z_crc_t)crc;
- c = ~c;
- while (len && ((ptrdiff_t)buf & 3)) {
- c = crc_table[0][(c ^ *buf++) & 0xff] ^ (c >> 8);
- len--;
- }
-
- 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;
-
- if (len) do {
- c = crc_table[0][(c ^ *buf++) & 0xff] ^ (c >> 8);
- } while (--len);
- c = ~c;
- return (unsigned long)c;
+ register z_crc_t c;
+ register const z_crc_t FAR *buf4;
+
+ c = (z_crc_t)crc;
+ c = ~c;
+ while (len && ((ptrdiff_t)buf & 3)) {
+ c = crc_table[0][(c ^ *buf++) & 0xff] ^ (c >> 8);
+ len--;
+ }
+
+ 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;
+
+ if (len) do {
+ c = crc_table[0][(c ^ *buf++) & 0xff] ^ (c >> 8);
+ } while (--len);
+ c = ~c;
+ return (unsigned long)c;
}
/* ========================================================================= */
-#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
/* ========================================================================= */
local unsigned long crc32_big(crc, buf, len)
-unsigned long crc;
-const unsigned char FAR *buf;
-unsigned 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;
-
- c = ZSWAP32((z_crc_t)crc);
- c = ~c;
- while (len && ((ptrdiff_t)buf & 3)) {
- c = crc_table[4][(c >> 24) ^ *buf++] ^ (c << 8);
- len--;
- }
-
- buf4 = (const z_crc_t FAR *)(const void FAR *)buf;
- buf4--;
- while (len >= 32) {
- DOBIG32;
- len -= 32;
- }
- while (len >= 4) {
- DOBIG4;
- len -= 4;
- }
- buf4++;
- 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));
+ register z_crc_t c;
+ register const z_crc_t FAR *buf4;
+
+ c = ZSWAP32((z_crc_t)crc);
+ c = ~c;
+ while (len && ((ptrdiff_t)buf & 3)) {
+ c = crc_table[4][(c >> 24) ^ *buf++] ^ (c << 8);
+ len--;
+ }
+
+ buf4 = (const z_crc_t FAR *)(const void FAR *)buf;
+ while (len >= 32) {
+ DOBIG32;
+ len -= 32;
+ }
+ while (len >= 4) {
+ DOBIG4;
+ len -= 4;
+ }
+ 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));
}
#endif /* BYFOUR */
@@ -325,101 +342,101 @@ unsigned len;
/* ========================================================================= */
local unsigned long gf2_matrix_times(mat, vec)
-unsigned long *mat;
-unsigned long vec;
+ unsigned long *mat;
+ unsigned long vec;
{
- unsigned long sum;
-
- sum = 0;
- while (vec) {
- if (vec & 1)
- sum ^= *mat;
- vec >>= 1;
- mat++;
- }
- return sum;
+ unsigned long sum;
+
+ sum = 0;
+ while (vec) {
+ if (vec & 1)
+ sum ^= *mat;
+ vec >>= 1;
+ mat++;
+ }
+ return sum;
}
/* ========================================================================= */
local void gf2_matrix_square(square, mat)
-unsigned long *square;
-unsigned long *mat;
+ unsigned long *square;
+ unsigned long *mat;
{
- int n;
+ int n;
- for (n = 0; n < GF2_DIM; n++)
- square[n] = gf2_matrix_times(mat, mat[n]);
+ for (n = 0; n < GF2_DIM; n++)
+ square[n] = gf2_matrix_times(mat, mat[n]);
}
/* ========================================================================= */
local uLong crc32_combine_(crc1, crc2, len2)
-uLong crc1;
-uLong crc2;
-z_off64_t len2;
+ uLong crc1;
+ uLong crc2;
+ 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;
- }
-
- /* 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;
+ 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;
+ }
+
+ /* 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(crc1, crc2, len2)
-uLong crc1;
-uLong crc2;
-z_off_t len2;
+ uLong crc1;
+ uLong crc2;
+ z_off_t len2;
{
- return crc32_combine_(crc1, crc2, len2);
+ return crc32_combine_(crc1, crc2, len2);
}
uLong ZEXPORT crc32_combine64(crc1, crc2, len2)
-uLong crc1;
-uLong crc2;
-z_off64_t len2;
+ uLong crc1;
+ uLong crc2;
+ z_off64_t len2;
{
- return crc32_combine_(crc1, crc2, len2);
+ return crc32_combine_(crc1, crc2, len2);
}
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