tools/mkimage/src/crc32.c

   1 /*
   2  * This file is derived from crc32.c from the zlib-1.1.3 distribution
   3  * by Jean-loup Gailly and Mark Adler.
   4  */
   5
   6 /* crc32.c -- compute the CRC-32 of a data stream
   7  * Copyright (C) 1995-1998 Mark Adler
   8  * For conditions of distribution and use, see copyright notice in zlib.h
   9  */
  10 #define USE_HOSTCC
  11 #ifndef USE_HOSTCC      /* Shut down "ANSI does not permit..." warnings */
  12 #include <common.h>     /* to get command definitions like CFG_CMD_JFFS2 */
  13 #endif
  14
  15 #include "zlib.h"
  16
  17 #define local static
  18 #define ZEXPORT /* empty */
  19 unsigned long crc32 (unsigned long, const unsigned char *, unsigned int);
  20
  21 #ifdef DYNAMIC_CRC_TABLE
  22
  23 local int crc_table_empty = 1;
  24 local uLongf crc_table[256];
  25 local void make_crc_table OF((void));
  26
  27 /*
  28   Generate a table for a byte-wise 32-bit CRC calculation on the polynomial:
  29   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.
  30
  31   Polynomials over GF(2) are represented in binary, one bit per coefficient,
  32   with the lowest powers in the most significant bit.  Then adding polynomials
  33   is just exclusive-or, and multiplying a polynomial by x is a right shift by
  34   one.  If we call the above polynomial p, and represent a byte as the
  35   polynomial q, also with the lowest power in the most significant bit (so the
  36   byte 0xb1 is the polynomial x^7+x^3+x+1), then the CRC is (q*x^32) mod p,
  37   where a mod b means the remainder after dividing a by b.
  38
  39   This calculation is done using the shift-register method of multiplying and
  40   taking the remainder.  The register is initialized to zero, and for each
  41   incoming bit, x^32 is added mod p to the register if the bit is a one (where
  42   x^32 mod p is p+x^32 = x^26+...+1), and the register is multiplied mod p by
  43   x (which is shifting right by one and adding x^32 mod p if the bit shifted
  44   out is a one).  We start with the highest power (least significant bit) of
  45   q and repeat for all eight bits of q.
  46
  47   The table is simply the CRC of all possible eight bit values.  This is all
  48   the information needed to generate CRC's on data a byte at a time for all
  49   combinations of CRC register values and incoming bytes.
  50 */
  51 local void make_crc_table()
  52 {
  53   uLong c;
  54   int n, k;
  55   uLong poly;            /* polynomial exclusive-or pattern */
  56   /* terms of polynomial defining this crc (except x^32): */
  57   static const Byte p[] = {0,1,2,4,5,7,8,10,11,12,16,22,23,26};
  58
  59   /* make exclusive-or pattern from polynomial (0xedb88320L) */
  60   poly = 0L;
  61   for (n = 0; n < sizeof(p)/sizeof(Byte); n++)
  62     poly |= 1L << (31 - p[n]);
  63
  64   for (n = 0; n < 256; n++)
  65   {
  66     c = (uLong)n;
  67     for (k = 0; k < 8; k++)
  68       c = c & 1 ? poly ^ (c >> 1) : c >> 1;
  69     crc_table[n] = c;
  70   }
  71   crc_table_empty = 0;
  72 }
  73 #else
  74 /* ========================================================================
  75  * Table of CRC-32's of all single-byte values (made by make_crc_table)
  76  */
  77 local const uLongf crc_table[256] = {
  78   0x00000000L, 0x77073096L, 0xee0e612cL, 0x990951baL, 0x076dc419L,
  79   0x706af48fL, 0xe963a535L, 0x9e6495a3L, 0x0edb8832L, 0x79dcb8a4L,
  80   0xe0d5e91eL, 0x97d2d988L, 0x09b64c2bL, 0x7eb17cbdL, 0xe7b82d07L,
  81   0x90bf1d91L, 0x1db71064L, 0x6ab020f2L, 0xf3b97148L, 0x84be41deL,
  82   0x1adad47dL, 0x6ddde4ebL, 0xf4d4b551L, 0x83d385c7L, 0x136c9856L,
  83   0x646ba8c0L, 0xfd62f97aL, 0x8a65c9ecL, 0x14015c4fL, 0x63066cd9L,
  84   0xfa0f3d63L, 0x8d080df5L, 0x3b6e20c8L, 0x4c69105eL, 0xd56041e4L,
  85   0xa2677172L, 0x3c03e4d1L, 0x4b04d447L, 0xd20d85fdL, 0xa50ab56bL,
  86   0x35b5a8faL, 0x42b2986cL, 0xdbbbc9d6L, 0xacbcf940L, 0x32d86ce3L,
  87   0x45df5c75L, 0xdcd60dcfL, 0xabd13d59L, 0x26d930acL, 0x51de003aL,
  88   0xc8d75180L, 0xbfd06116L, 0x21b4f4b5L, 0x56b3c423L, 0xcfba9599L,
  89   0xb8bda50fL, 0x2802b89eL, 0x5f058808L, 0xc60cd9b2L, 0xb10be924L,
  90   0x2f6f7c87L, 0x58684c11L, 0xc1611dabL, 0xb6662d3dL, 0x76dc4190L,
  91   0x01db7106L, 0x98d220bcL, 0xefd5102aL, 0x71b18589L, 0x06b6b51fL,
  92   0x9fbfe4a5L, 0xe8b8d433L, 0x7807c9a2L, 0x0f00f934L, 0x9609a88eL,
  93   0xe10e9818L, 0x7f6a0dbbL, 0x086d3d2dL, 0x91646c97L, 0xe6635c01L,
  94   0x6b6b51f4L, 0x1c6c6162L, 0x856530d8L, 0xf262004eL, 0x6c0695edL,
  95   0x1b01a57bL, 0x8208f4c1L, 0xf50fc457L, 0x65b0d9c6L, 0x12b7e950L,
  96   0x8bbeb8eaL, 0xfcb9887cL, 0x62dd1ddfL, 0x15da2d49L, 0x8cd37cf3L,
  97   0xfbd44c65L, 0x4db26158L, 0x3ab551ceL, 0xa3bc0074L, 0xd4bb30e2L,
  98   0x4adfa541L, 0x3dd895d7L, 0xa4d1c46dL, 0xd3d6f4fbL, 0x4369e96aL,
  99   0x346ed9fcL, 0xad678846L, 0xda60b8d0L, 0x44042d73L, 0x33031de5L,
 100   0xaa0a4c5fL, 0xdd0d7cc9L, 0x5005713cL, 0x270241aaL, 0xbe0b1010L,
 101   0xc90c2086L, 0x5768b525L, 0x206f85b3L, 0xb966d409L, 0xce61e49fL,
 102   0x5edef90eL, 0x29d9c998L, 0xb0d09822L, 0xc7d7a8b4L, 0x59b33d17L,
 103   0x2eb40d81L, 0xb7bd5c3bL, 0xc0ba6cadL, 0xedb88320L, 0x9abfb3b6L,
 104   0x03b6e20cL, 0x74b1d29aL, 0xead54739L, 0x9dd277afL, 0x04db2615L,
 105   0x73dc1683L, 0xe3630b12L, 0x94643b84L, 0x0d6d6a3eL, 0x7a6a5aa8L,
 106   0xe40ecf0bL, 0x9309ff9dL, 0x0a00ae27L, 0x7d079eb1L, 0xf00f9344L,
 107   0x8708a3d2L, 0x1e01f268L, 0x6906c2feL, 0xf762575dL, 0x806567cbL,
 108   0x196c3671L, 0x6e6b06e7L, 0xfed41b76L, 0x89d32be0L, 0x10da7a5aL,
 109   0x67dd4accL, 0xf9b9df6fL, 0x8ebeeff9L, 0x17b7be43L, 0x60b08ed5L,
 110   0xd6d6a3e8L, 0xa1d1937eL, 0x38d8c2c4L, 0x4fdff252L, 0xd1bb67f1L,
 111   0xa6bc5767L, 0x3fb506ddL, 0x48b2364bL, 0xd80d2bdaL, 0xaf0a1b4cL,
 112   0x36034af6L, 0x41047a60L, 0xdf60efc3L, 0xa867df55L, 0x316e8eefL,
 113   0x4669be79L, 0xcb61b38cL, 0xbc66831aL, 0x256fd2a0L, 0x5268e236L,
 114   0xcc0c7795L, 0xbb0b4703L, 0x220216b9L, 0x5505262fL, 0xc5ba3bbeL,
 115   0xb2bd0b28L, 0x2bb45a92L, 0x5cb36a04L, 0xc2d7ffa7L, 0xb5d0cf31L,
 116   0x2cd99e8bL, 0x5bdeae1dL, 0x9b64c2b0L, 0xec63f226L, 0x756aa39cL,
 117   0x026d930aL, 0x9c0906a9L, 0xeb0e363fL, 0x72076785L, 0x05005713L,
 118   0x95bf4a82L, 0xe2b87a14L, 0x7bb12baeL, 0x0cb61b38L, 0x92d28e9bL,
 119   0xe5d5be0dL, 0x7cdcefb7L, 0x0bdbdf21L, 0x86d3d2d4L, 0xf1d4e242L,
 120   0x68ddb3f8L, 0x1fda836eL, 0x81be16cdL, 0xf6b9265bL, 0x6fb077e1L,
 121   0x18b74777L, 0x88085ae6L, 0xff0f6a70L, 0x66063bcaL, 0x11010b5cL,
 122   0x8f659effL, 0xf862ae69L, 0x616bffd3L, 0x166ccf45L, 0xa00ae278L,
 123   0xd70dd2eeL, 0x4e048354L, 0x3903b3c2L, 0xa7672661L, 0xd06016f7L,
 124   0x4969474dL, 0x3e6e77dbL, 0xaed16a4aL, 0xd9d65adcL, 0x40df0b66L,
 125   0x37d83bf0L, 0xa9bcae53L, 0xdebb9ec5L, 0x47b2cf7fL, 0x30b5ffe9L,
 126   0xbdbdf21cL, 0xcabac28aL, 0x53b39330L, 0x24b4a3a6L, 0xbad03605L,
 127   0xcdd70693L, 0x54de5729L, 0x23d967bfL, 0xb3667a2eL, 0xc4614ab8L,
 128   0x5d681b02L, 0x2a6f2b94L, 0xb40bbe37L, 0xc30c8ea1L, 0x5a05df1bL,
 129   0x2d02ef8dL
 130 };
 131 #endif
 132
 133 #if 0
 134 /* =========================================================================
 135  * This function can be used by asm versions of crc32()
 136  */
 137 const uLongf * ZEXPORT get_crc_table()
 138 {
 139 #ifdef DYNAMIC_CRC_TABLE
 140   if (crc_table_empty) make_crc_table();
 141 #endif
 142   return (const uLongf *)crc_table;
 143 }
 144 #endif
 145
 146 /* ========================================================================= */
 147 #define DO1(buf) crc = crc_table[((int)crc ^ (*buf++)) & 0xff] ^ (crc >> 8);
 148 #define DO2(buf)  DO1(buf); DO1(buf);
 149 #define DO4(buf)  DO2(buf); DO2(buf);
 150 #define DO8(buf)  DO4(buf); DO4(buf);
 151
 152 /* ========================================================================= */
 153 uLong ZEXPORT crc32(crc, buf, len)
 154     uLong crc;
 155     const Bytef *buf;
 156     uInt len;
 157 {
 158 #ifdef DYNAMIC_CRC_TABLE
 159     if (crc_table_empty)
 160       make_crc_table();
 161 #endif
 162     crc = crc ^ 0xffffffffL;
 163     while (len >= 8)
 164     {
 165       DO8(buf);
 166       len -= 8;
 167     }
 168     if (len) do {
 169       DO1(buf);
 170     } while (--len);
 171     return crc ^ 0xffffffffL;
 172 }
 173
 174 #if (CONFIG_COMMANDS & CFG_CMD_JFFS2)
 175
 176 /* No ones complement version. JFFS2 (and other things ?)
 177  * don't use ones compliment in their CRC calculations.
 178  */
 179 uLong ZEXPORT crc32_no_comp(uLong crc, const Bytef *buf, uInt len)
 180 {
 181 #ifdef DYNAMIC_CRC_TABLE
 182     if (crc_table_empty)
 183       make_crc_table();
 184 #endif
 185     while (len >= 8)
 186     {
 187       DO8(buf);
 188       len -= 8;
 189     }
 190     if (len) do {
 191       DO1(buf);
 192     } while (--len);
 193
 194     return crc;
 195 }
 196
 197 #endif  /* CFG_CMD_JFFS2 */