CbC/CbC_gcc: zlib/crc32.c comparison

comparison zlib/crc32.c @ 111:04ced10e8804

gcc 7

author	kono
date	Fri, 27 Oct 2017 22:46:09 +0900
parents	ae3a4bfb450b
children

comparison

equal deleted inserted replaced

-:561a7518be6b
+:04ced10e8804
 /* crc32.c -- compute the CRC-32 of a data stream
-* Copyright (C) 1995-2005 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
 * 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
 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
 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.
 */
 #ifdef MAKECRCH
 #  include <stdio.h>
 #  ifndef DYNAMIC_CRC_TABLE
 #  endif /* !DYNAMIC_CRC_TABLE */
 #endif /* MAKECRCH */
 #include "zutil.h"      /* for STDC and FAR definitions */
-#define local static
-/* Find a four-byte integer type for crc32_little() and crc32_big(). */
-#ifndef NOBYFOUR
-#  ifdef STDC           /* need ANSI C limits.h to determine sizes */
-#    include <limits.h>
-#    define BYFOUR
-#    if (UINT_MAX == 0xffffffffUL)
-typedef unsigned int u4;
-#    else
-#      if (ULONG_MAX == 0xffffffffUL)
-typedef unsigned long u4;
-#      else
-#        if (USHRT_MAX == 0xffffffffUL)
-typedef unsigned short u4;
-#        else
-#          undef BYFOUR     /* can't find a four-byte integer type! */
-#        endif
-#      endif
-#    endif
-#  endif /* STDC */
-#endif /* !NOBYFOUR */
 /* Definitions for doing the crc four data bytes at a time. */
+#if !defined(NOBYFOUR) && defined(Z_U4)
+#  define BYFOUR
+#endif
 #ifdef BYFOUR
-#  define REV(w) (((w)>>24)+(((w)>>8)&0xff00)+ \
-(((w)&0xff00)<<8)+(((w)&0xff)<<24))
 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
 #endif /* BYFOUR */
 /* 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));
 #ifdef DYNAMIC_CRC_TABLE
 local volatile int crc_table_empty = 1;
-local unsigned long FAR crc_table[TBLS][256];
+local z_crc_t FAR crc_table[TBLS][256];
 local void make_crc_table OF((void));
 #ifdef MAKECRCH
-local void write_table OF((FILE *, const unsigned long FAR *));
+local void write_table OF((FILE *, const z_crc_t FAR *));
 #endif /* MAKECRCH */
 /*
 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.
 allow for word-at-a-time CRC calculation for both big-endian and little-
 endian machines, where a word is four bytes.
 */
 local void make_crc_table()
 {
-unsigned long c;
+z_crc_t c;
 int n, k;
-unsigned long poly;                 /* polynomial exclusive-or pattern */
+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
 case the advice about DYNAMIC_CRC_TABLE is ignored) */
 if (first) {
 first = 0;
 /* make exclusive-or pattern from polynomial (0xedb88320UL) */
-poly = 0UL;
+poly = 0;
-for (n = 0; n < sizeof(p)/sizeof(unsigned char); n++)
+for (n = 0; n < (int)(sizeof(p)/sizeof(unsigned char)); n++)
-poly |= 1UL << (31 - p[n]);
+poly |= (z_crc_t)1 << (31 - p[n]);
 /* generate a crc for every 8-bit value */
 for (n = 0; n < 256; n++) {
-c = (unsigned long)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;
 }
 #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] = REV(c);
+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] = REV(c);
+crc_table[k + 4][n] = ZSWAP32(c);
 }
 }
 #endif /* BYFOUR */
 crc_table_empty = 0;
 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 unsigned long FAR ");
+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++) {
 }
 #ifdef MAKECRCH
 local void write_table(out, table)
 FILE *out;
-const unsigned long FAR *table;
+const z_crc_t FAR *table;
 {
 int n;
 for (n = 0; n < 256; n++)
-fprintf(out, "%s0x%08lxUL%s", n % 5 ? "" : "    ", table[n],
+fprintf(out, "%s0x%08lxUL%s", n % 5 ? "" : "    ",
+(unsigned long)(table[n]),
 n == 255 ? "\n" : (n % 5 == 4 ? ",\n" : ", "));
 }
 #endif /* MAKECRCH */
 #else /* !DYNAMIC_CRC_TABLE */
 #endif /* DYNAMIC_CRC_TABLE */
 /* =========================================================================
 * This function can be used by asm versions of crc32()
 */
-const unsigned long FAR * ZEXPORT get_crc_table()
+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 unsigned long FAR *)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
 /* ========================================================================= */
-unsigned long ZEXPORT crc32(crc, buf, len)
+unsigned long ZEXPORT crc32_z(crc, buf, len)
 unsigned long crc;
 const unsigned char FAR *buf;
-unsigned len;
+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)) {
-u4 endian;
+z_crc_t endian;
 endian = 1;
 if (*((unsigned char *)(&endian)))
 return crc32_little(crc, buf, len);
 else
 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);
+}
 #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] ^ \
 crc_table[1][(c >> 16) & 0xff] ^ crc_table[0][c >> 24]
 /* ========================================================================= */
 local unsigned long crc32_little(crc, buf, len)
 unsigned long crc;
 const unsigned char FAR *buf;
-unsigned len;
+z_size_t len;
 {
-register u4 c;
+register z_crc_t c;
-register const u4 FAR *buf4;
+register const z_crc_t FAR *buf4;
-c = (u4)crc;
+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 u4 FAR *)(const void FAR *)buf;
+buf4 = (const z_crc_t FAR *)(const void FAR *)buf;
 while (len >= 32) {
 DOLIT32;
 len -= 32;
 }
 while (len >= 4) {
 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;
+z_size_t len;
 {
-register u4 c;
+register z_crc_t c;
-register const u4 FAR *buf4;
+register const z_crc_t FAR *buf4;
-c = REV((u4)crc);
+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 u4 FAR *)(const void FAR *)buf;
+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)(REV(c));
+return (unsigned long)(ZSWAP32(c));
 }
 #endif /* BYFOUR */
 #define GF2_DIM 32      /* dimension of GF(2) vectors (length of CRC) */
 for (n = 0; n < GF2_DIM; n++)
 square[n] = gf2_matrix_times(mat, mat[n]);
 }
 /* ========================================================================= */
-uLong ZEXPORT crc32_combine(crc1, crc2, len2)
+local uLong crc32_combine_(crc1, crc2, len2)
 uLong crc1;
 uLong crc2;
-z_off_t 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 */
+/* degenerate case (also disallow negative lengths) */
-if (len2 == 0)
+if (len2 <= 0)
 return crc1;
 /* put operator for one zero bit in odd */
-odd[0] = 0xedb88320L;           /* CRC-32 polynomial */
+odd[0] = 0xedb88320UL;          /* CRC-32 polynomial */
 row = 1;
 for (n = 1; n < GF2_DIM; n++) {
 odd[n] = row;
 row <<= 1;
 }
 /* return combined crc */
 crc1 ^= crc2;
 return crc1;
 }
+/* ========================================================================= */
+uLong ZEXPORT crc32_combine(crc1, crc2, len2)
+uLong crc1;
+uLong crc2;
+z_off_t len2;
+{
+return crc32_combine_(crc1, crc2, len2);
+}
+uLong ZEXPORT crc32_combine64(crc1, crc2, len2)
+uLong crc1;
+uLong crc2;
+z_off64_t len2;
+{
+return crc32_combine_(crc1, crc2, len2);
+}

Mercurial > hg > CbC > CbC_gcc

comparison zlib/crc32.c @ 111:04ced10e8804