diff options
Diffstat (limited to 'zlib/crc32.c')
| -rw-r--r-- | zlib/crc32.c | 357 |
1 files changed, 253 insertions, 104 deletions
diff --git a/zlib/crc32.c b/zlib/crc32.c index 60deca2ddf4..689b2883b43 100644 --- a/zlib/crc32.c +++ b/zlib/crc32.c @@ -1,22 +1,72 @@ /* crc32.c -- compute the CRC-32 of a data stream - * Copyright (C) 1995-2002 Mark Adler - * For conditions of distribution and use, see copyright notice in zlib.h + * Copyright (C) 1995-2003 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 + * instead of four steps with four exclusive-ors. This results about a factor + * of two increase in speed on a Power PC G4 (PPC7455) using gcc -O3. */ /* @(#) $Id$ */ -#include "zlib.h" +#ifdef MAKECRCH +# include <stdio.h> +# ifndef DYNAMIC_CRC_TABLE +# define 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. */ +#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)); + local unsigned long crc32_big OF((unsigned long, + const unsigned char FAR *, unsigned)); +# define TBLS 8 +#else +# define TBLS 1 +#endif /* BYFOUR */ + #ifdef DYNAMIC_CRC_TABLE local int crc_table_empty = 1; -local uLongf crc_table[256]; +local unsigned long FAR crc_table[TBLS][256]; local void make_crc_table OF((void)); +#ifdef MAKECRCH + local void write_table OF((FILE *, const unsigned long FAR *)); +#endif /* MAKECRCH */ /* - Generate a table for a byte-wise 32-bit CRC calculation on the polynomial: + 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. Polynomials over GF(2) are represented in binary, one bit per coefficient, @@ -35,128 +85,227 @@ local void make_crc_table OF((void)); out is a one). We start with the highest power (least significant bit) of q and repeat for all eight bits of q. - The table is simply the CRC of all possible eight bit values. This is all - the information needed to generate CRC's on data a byte at a time for all - combinations of CRC register values and incoming bytes. + The first table is simply the CRC of all possible eight bit values. This is + all the information needed to generate CRCs on data a byte at a time for all + combinations of CRC register values and incoming bytes. The remaining tables + 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() { - uLong c; - int n, k; - uLong poly; /* polynomial exclusive-or pattern */ - /* terms of polynomial defining this crc (except x^32): */ - static const Byte p[] = {0,1,2,4,5,7,8,10,11,12,16,22,23,26}; - - /* make exclusive-or pattern from polynomial (0xedb88320L) */ - poly = 0L; - for (n = 0; n < sizeof(p)/sizeof(Byte); n++) - poly |= 1L << (31 - p[n]); - - for (n = 0; n < 256; n++) - { - c = (uLong)n; - for (k = 0; k < 8; k++) - c = c & 1 ? poly ^ (c >> 1) : c >> 1; - crc_table[n] = c; - } + unsigned long c; + int n, k; + unsigned long poly; /* polynomial exclusive-or pattern */ + /* terms of polynomial defining this crc (except x^32): */ + static const unsigned char p[] = {0,1,2,4,5,7,8,10,11,12,16,22,23,26}; + + /* make exclusive-or pattern from polynomial (0xedb88320UL) */ + poly = 0UL; + for (n = 0; n < sizeof(p)/sizeof(unsigned char); n++) + poly |= 1UL << (31 - p[n]); + + /* generate a crc for every 8-bit value */ + for (n = 0; n < 256; n++) { + c = (unsigned long)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); + 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); + } + } +#endif /* BYFOUR */ + crc_table_empty = 0; + +#ifdef MAKECRCH + /* write out CRC tables to crc32.h */ + { + FILE *out; + + 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, "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++) { + fprintf(out, " },\n {\n"); + write_table(out, crc_table[k]); + } + fprintf(out, "#endif\n"); +# endif /* BYFOUR */ + fprintf(out, " }\n};\n"); + fclose(out); + } +#endif /* MAKECRCH */ } -#else + +#ifdef MAKECRCH +local void write_table(out, table) + FILE *out; + const unsigned long FAR *table; +{ + int n; + + for (n = 0; n < 256; n++) + fprintf(out, "%s0x%08lxUL%s", n % 5 ? "" : " ", table[n], + n == 255 ? "\n" : (n % 5 == 4 ? ",\n" : ", ")); +} +#endif /* MAKECRCH */ + +#else /* !DYNAMIC_CRC_TABLE */ /* ======================================================================== - * Table of CRC-32's of all single-byte values (made by make_crc_table) + * Tables of CRC-32s of all single-byte values, made by make_crc_table(). */ -local const uLongf crc_table[256] = { - 0x00000000L, 0x77073096L, 0xee0e612cL, 0x990951baL, 0x076dc419L, - 0x706af48fL, 0xe963a535L, 0x9e6495a3L, 0x0edb8832L, 0x79dcb8a4L, - 0xe0d5e91eL, 0x97d2d988L, 0x09b64c2bL, 0x7eb17cbdL, 0xe7b82d07L, - 0x90bf1d91L, 0x1db71064L, 0x6ab020f2L, 0xf3b97148L, 0x84be41deL, - 0x1adad47dL, 0x6ddde4ebL, 0xf4d4b551L, 0x83d385c7L, 0x136c9856L, - 0x646ba8c0L, 0xfd62f97aL, 0x8a65c9ecL, 0x14015c4fL, 0x63066cd9L, - 0xfa0f3d63L, 0x8d080df5L, 0x3b6e20c8L, 0x4c69105eL, 0xd56041e4L, - 0xa2677172L, 0x3c03e4d1L, 0x4b04d447L, 0xd20d85fdL, 0xa50ab56bL, - 0x35b5a8faL, 0x42b2986cL, 0xdbbbc9d6L, 0xacbcf940L, 0x32d86ce3L, - 0x45df5c75L, 0xdcd60dcfL, 0xabd13d59L, 0x26d930acL, 0x51de003aL, - 0xc8d75180L, 0xbfd06116L, 0x21b4f4b5L, 0x56b3c423L, 0xcfba9599L, - 0xb8bda50fL, 0x2802b89eL, 0x5f058808L, 0xc60cd9b2L, 0xb10be924L, - 0x2f6f7c87L, 0x58684c11L, 0xc1611dabL, 0xb6662d3dL, 0x76dc4190L, - 0x01db7106L, 0x98d220bcL, 0xefd5102aL, 0x71b18589L, 0x06b6b51fL, - 0x9fbfe4a5L, 0xe8b8d433L, 0x7807c9a2L, 0x0f00f934L, 0x9609a88eL, - 0xe10e9818L, 0x7f6a0dbbL, 0x086d3d2dL, 0x91646c97L, 0xe6635c01L, - 0x6b6b51f4L, 0x1c6c6162L, 0x856530d8L, 0xf262004eL, 0x6c0695edL, - 0x1b01a57bL, 0x8208f4c1L, 0xf50fc457L, 0x65b0d9c6L, 0x12b7e950L, - 0x8bbeb8eaL, 0xfcb9887cL, 0x62dd1ddfL, 0x15da2d49L, 0x8cd37cf3L, - 0xfbd44c65L, 0x4db26158L, 0x3ab551ceL, 0xa3bc0074L, 0xd4bb30e2L, - 0x4adfa541L, 0x3dd895d7L, 0xa4d1c46dL, 0xd3d6f4fbL, 0x4369e96aL, - 0x346ed9fcL, 0xad678846L, 0xda60b8d0L, 0x44042d73L, 0x33031de5L, - 0xaa0a4c5fL, 0xdd0d7cc9L, 0x5005713cL, 0x270241aaL, 0xbe0b1010L, - 0xc90c2086L, 0x5768b525L, 0x206f85b3L, 0xb966d409L, 0xce61e49fL, - 0x5edef90eL, 0x29d9c998L, 0xb0d09822L, 0xc7d7a8b4L, 0x59b33d17L, - 0x2eb40d81L, 0xb7bd5c3bL, 0xc0ba6cadL, 0xedb88320L, 0x9abfb3b6L, - 0x03b6e20cL, 0x74b1d29aL, 0xead54739L, 0x9dd277afL, 0x04db2615L, - 0x73dc1683L, 0xe3630b12L, 0x94643b84L, 0x0d6d6a3eL, 0x7a6a5aa8L, - 0xe40ecf0bL, 0x9309ff9dL, 0x0a00ae27L, 0x7d079eb1L, 0xf00f9344L, - 0x8708a3d2L, 0x1e01f268L, 0x6906c2feL, 0xf762575dL, 0x806567cbL, - 0x196c3671L, 0x6e6b06e7L, 0xfed41b76L, 0x89d32be0L, 0x10da7a5aL, - 0x67dd4accL, 0xf9b9df6fL, 0x8ebeeff9L, 0x17b7be43L, 0x60b08ed5L, - 0xd6d6a3e8L, 0xa1d1937eL, 0x38d8c2c4L, 0x4fdff252L, 0xd1bb67f1L, - 0xa6bc5767L, 0x3fb506ddL, 0x48b2364bL, 0xd80d2bdaL, 0xaf0a1b4cL, - 0x36034af6L, 0x41047a60L, 0xdf60efc3L, 0xa867df55L, 0x316e8eefL, - 0x4669be79L, 0xcb61b38cL, 0xbc66831aL, 0x256fd2a0L, 0x5268e236L, - 0xcc0c7795L, 0xbb0b4703L, 0x220216b9L, 0x5505262fL, 0xc5ba3bbeL, - 0xb2bd0b28L, 0x2bb45a92L, 0x5cb36a04L, 0xc2d7ffa7L, 0xb5d0cf31L, - 0x2cd99e8bL, 0x5bdeae1dL, 0x9b64c2b0L, 0xec63f226L, 0x756aa39cL, - 0x026d930aL, 0x9c0906a9L, 0xeb0e363fL, 0x72076785L, 0x05005713L, - 0x95bf4a82L, 0xe2b87a14L, 0x7bb12baeL, 0x0cb61b38L, 0x92d28e9bL, - 0xe5d5be0dL, 0x7cdcefb7L, 0x0bdbdf21L, 0x86d3d2d4L, 0xf1d4e242L, - 0x68ddb3f8L, 0x1fda836eL, 0x81be16cdL, 0xf6b9265bL, 0x6fb077e1L, - 0x18b74777L, 0x88085ae6L, 0xff0f6a70L, 0x66063bcaL, 0x11010b5cL, - 0x8f659effL, 0xf862ae69L, 0x616bffd3L, 0x166ccf45L, 0xa00ae278L, - 0xd70dd2eeL, 0x4e048354L, 0x3903b3c2L, 0xa7672661L, 0xd06016f7L, - 0x4969474dL, 0x3e6e77dbL, 0xaed16a4aL, 0xd9d65adcL, 0x40df0b66L, - 0x37d83bf0L, 0xa9bcae53L, 0xdebb9ec5L, 0x47b2cf7fL, 0x30b5ffe9L, - 0xbdbdf21cL, 0xcabac28aL, 0x53b39330L, 0x24b4a3a6L, 0xbad03605L, - 0xcdd70693L, 0x54de5729L, 0x23d967bfL, 0xb3667a2eL, 0xc4614ab8L, - 0x5d681b02L, 0x2a6f2b94L, 0xb40bbe37L, 0xc30c8ea1L, 0x5a05df1bL, - 0x2d02ef8dL -}; -#endif +#include "crc32.h" +#endif /* DYNAMIC_CRC_TABLE */ /* ========================================================================= * This function can be used by asm versions of crc32() */ -const uLongf * ZEXPORT get_crc_table() +const unsigned long FAR * ZEXPORT get_crc_table() { #ifdef DYNAMIC_CRC_TABLE if (crc_table_empty) make_crc_table(); -#endif - return (const uLongf *)crc_table; +#endif /* DYNAMIC_CRC_TABLE */ + return (const unsigned long FAR *)crc_table; } /* ========================================================================= */ -#define DO1(buf) crc = crc_table[((int)crc ^ (*buf++)) & 0xff] ^ (crc >> 8); -#define DO2(buf) DO1(buf); DO1(buf); -#define DO4(buf) DO2(buf); DO2(buf); -#define DO8(buf) DO4(buf); DO4(buf); +#define DO1 crc = crc_table[0][((int)crc ^ (*buf++)) & 0xff] ^ (crc >> 8) +#define DO8 DO1; DO1; DO1; DO1; DO1; DO1; DO1; DO1 /* ========================================================================= */ -uLong ZEXPORT crc32(crc, buf, len) - uLong crc; - const Bytef *buf; - uInt len; +unsigned long ZEXPORT crc32(crc, buf, len) + unsigned long crc; + const unsigned char FAR *buf; + unsigned len; { - if (buf == Z_NULL) return 0L; + if (buf == Z_NULL) return 0UL; + #ifdef DYNAMIC_CRC_TABLE if (crc_table_empty) - make_crc_table(); -#endif - crc = crc ^ 0xffffffffL; - while (len >= 8) - { - DO8(buf); - len -= 8; + make_crc_table(); +#endif /* DYNAMIC_CRC_TABLE */ + +#ifdef BYFOUR + if (sizeof(void *) == sizeof(ptrdiff_t)) { + u4 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(buf); + DO1; } while (--len); - return crc ^ 0xffffffffL; + return crc ^ 0xffffffffUL; } + +#ifdef BYFOUR + +/* ========================================================================= */ +#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] +#define DOLIT32 DOLIT4; DOLIT4; DOLIT4; DOLIT4; DOLIT4; DOLIT4; DOLIT4; DOLIT4 + +/* ========================================================================= */ +local unsigned long crc32_little(crc, buf, len) + unsigned long crc; + const unsigned char FAR *buf; + unsigned len; +{ + register u4 c; + register const u4 FAR *buf4; + + c = (u4)crc; + c = ~c; + while (len && ((ptrdiff_t)buf & 3)) { + c = crc_table[0][(c ^ *buf++) & 0xff] ^ (c >> 8); + len--; + } + + buf4 = (const u4 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; \ + 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; +{ + register u4 c; + register const u4 FAR *buf4; + + c = REV((u4)crc); + c = ~c; + while (len && ((ptrdiff_t)buf & 3)) { + c = crc_table[4][(c >> 24) ^ *buf++] ^ (c << 8); + len--; + } + + buf4 = (const u4 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)); +} + +#endif /* BYFOUR */ |