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
  11 #define USE_HOSTCC
  12
  13 #ifndef USE_HOSTCC      /* Shut down "ANSI does not permit..." warnings */
  14 #include <common.h>     /* to get command definitions like CFG_CMD_JFFS2 */
  15 #endif
  16
  17 #include "zlib.h"
  18
  19 #define local static
  20 #define ZEXPORT /* empty */
  21 unsigned long crc32 (unsigned long, const unsigned char *, unsigned int);
  22
  23 #ifdef DYNAMIC_CRC_TABLE
  24
  25 local int crc_table_empty = 1;
  26 local uLongf crc_table[256];
  27 local void make_crc_table OF((void));
  28
  29 /*
  30   Generate a table for a byte-wise 32-bit CRC calculation on the polynomial:
  31   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.
  32
  33   Polynomials over GF(2) are represented in binary, one bit per coefficient,
  34   with the lowest powers in the most significant bit.  Then adding polynomials
  35   is just exclusive-or, and multiplying a polynomial by x is a right shift by
  36   one.  If we call the above polynomial p, and represent a byte as the
  37   polynomial q, also with the lowest power in the most significant bit (so the
  38   byte 0xb1 is the polynomial x^7+x^3+x+1), then the CRC is (q*x^32) mod p,
  39   where a mod b means the remainder after dividing a by b.
  40
  41   This calculation is done using the shift-register method of multiplying and
  42   taking the remainder.  The register is initialized to zero, and for each
  43   incoming bit, x^32 is added mod p to the register if the bit is a one (where
  44   x^32 mod p is p+x^32 = x^26+...+1), and the register is multiplied mod p by
  45   x (which is shifting right by one and adding x^32 mod p if the bit shifted
  46   out is a one).  We start with the highest power (least significant bit) of
  47   q and repeat for all eight bits of q.
  48
  49   The table is simply the CRC of all possible eight bit values.  This is all
  50   the information needed to generate CRC's on data a byte at a time for all
  51   combinations of CRC register values and incoming bytes.
  52 */
  53 local void make_crc_table()
  54 {
  55   uLong c;
  56   int n, k;
  57   uLong poly;            /* polynomial exclusive-or pattern */
  58   /* terms of polynomial defining this crc (except x^32): */
  59   static const Byte p[] = {0,1,2,4,5,7,8,10,11,12,16,22,23,26};
  60
  61   /* make exclusive-or pattern from polynomial (0xedb88320L) */
  62   poly = 0L;
  63   for (n = 0; n < sizeof(p)/sizeof(Byte); n++)
  64     poly |= 1L << (31 - p[n]);
  65
  66   for (n = 0; n < 256; n++)
  67   {
  68     c = (uLong)n;
  69     for (k = 0; k < 8; k++)
  70       c = c & 1 ? poly ^ (c >> 1) : c >> 1;
  71     crc_table[n] = c;
  72   }
  73   crc_table_empty = 0;
  74 }
  75 #else
  76 /* ========================================================================
  77  * Table of CRC-32's of all single-byte values (made by make_crc_table)
  78  */
  79 local const uLongf crc_table[256] = {
  80   0x00000000L, 0x77073096L, 0xee0e612cL, 0x990951baL, 0x076dc419L,
  81   0x706af48fL, 0xe963a535L, 0x9e6495a3L, 0x0edb8832L, 0x79dcb8a4L,
  82   0xe0d5e91eL, 0x97d2d988L, 0x09b64c2bL, 0x7eb17cbdL, 0xe7b82d07L,
  83   0x90bf1d91L, 0x1db71064L, 0x6ab020f2L, 0xf3b97148L, 0x84be41deL,
  84   0x1adad47dL, 0x6ddde4ebL, 0xf4d4b551L, 0x83d385c7L, 0x136c9856L,
  85   0x646ba8c0L, 0xfd62f97aL, 0x8a65c9ecL, 0x14015c4fL, 0x63066cd9L,
  86   0xfa0f3d63L, 0x8d080df5L, 0x3b6e20c8L, 0x4c69105eL, 0xd56041e4L,
  87   0xa2677172L, 0x3c03e4d1L, 0x4b04d447L, 0xd20d85fdL, 0xa50ab56bL,
  88   0x35b5a8faL, 0x42b2986cL, 0xdbbbc9d6L, 0xacbcf940L, 0x32d86ce3L,
  89   0x45df5c75L, 0xdcd60dcfL, 0xabd13d59L, 0x26d930acL, 0x51de003aL,
  90   0xc8d75180L, 0xbfd06116L, 0x21b4f4b5L, 0x56b3c423L, 0xcfba9599L,
  91   0xb8bda50fL, 0x2802b89eL, 0x5f058808L, 0xc60cd9b2L, 0xb10be924L,
  92   0x2f6f7c87L, 0x58684c11L, 0xc1611dabL, 0xb6662d3dL, 0x76dc4190L,
  93   0x01db7106L, 0x98d220bcL, 0xefd5102aL, 0x71b18589L, 0x06b6b51fL,
  94   0x9fbfe4a5L, 0xe8b8d433L, 0x7807c9a2L, 0x0f00f934L, 0x9609a88eL,
  95   0xe10e9818L, 0x7f6a0dbbL, 0x086d3d2dL, 0x91646c97L, 0xe6635c01L,
  96   0x6b6b51f4L, 0x1c6c6162L, 0x856530d8L, 0xf262004eL, 0x6c0695edL,
  97   0x1b01a57bL, 0x8208f4c1L, 0xf50fc457L, 0x65b0d9c6L, 0x12b7e950L,
  98   0x8bbeb8eaL, 0xfcb9887cL, 0x62dd1ddfL, 0x15da2d49L, 0x8cd37cf3L,
  99   0xfbd44c65L, 0x4db26158L, 0x3ab551ceL, 0xa3bc0074L, 0xd4bb30e2L,
 100   0x4adfa541L, 0x3dd895d7L, 0xa4d1c46dL, 0xd3d6f4fbL, 0x4369e96aL,
 101   0x346ed9fcL, 0xad678846L, 0xda60b8d0L, 0x44042d73L, 0x33031de5L,
 102   0xaa0a4c5fL, 0xdd0d7cc9L, 0x5005713cL, 0x270241aaL, 0xbe0b1010L,
 103   0xc90c2086L, 0x5768b525L, 0x206f85b3L, 0xb966d409L, 0xce61e49fL,
 104   0x5edef90eL, 0x29d9c998L, 0xb0d09822L, 0xc7d7a8b4L, 0x59b33d17L,
 105   0x2eb40d81L, 0xb7bd5c3bL, 0xc0ba6cadL, 0xedb88320L, 0x9abfb3b6L,
 106   0x03b6e20cL, 0x74b1d29aL, 0xead54739L, 0x9dd277afL, 0x04db2615L,
 107   0x73dc1683L, 0xe3630b12L, 0x94643b84L, 0x0d6d6a3eL, 0x7a6a5aa8L,
 108   0xe40ecf0bL, 0x9309ff9dL, 0x0a00ae27L, 0x7d079eb1L, 0xf00f9344L,
 109   0x8708a3d2L, 0x1e01f268L, 0x6906c2feL, 0xf762575dL, 0x806567cbL,
 110   0x196c3671L, 0x6e6b06e7L, 0xfed41b76L, 0x89d32be0L, 0x10da7a5aL,
 111   0x67dd4accL, 0xf9b9df6fL, 0x8ebeeff9L, 0x17b7be43L, 0x60b08ed5L,
 112   0xd6d6a3e8L, 0xa1d1937eL, 0x38d8c2c4L, 0x4fdff252L, 0xd1bb67f1L,
 113   0xa6bc5767L, 0x3fb506ddL, 0x48b2364bL, 0xd80d2bdaL, 0xaf0a1b4cL,
 114   0x36034af6L, 0x41047a60L, 0xdf60efc3L, 0xa867df55L, 0x316e8eefL,
 115   0x4669be79L, 0xcb61b38cL, 0xbc66831aL, 0x256fd2a0L, 0x5268e236L,
 116   0xcc0c7795L, 0xbb0b4703L, 0x220216b9L, 0x5505262fL, 0xc5ba3bbeL,
 117   0xb2bd0b28L, 0x2bb45a92L, 0x5cb36a04L, 0xc2d7ffa7L, 0xb5d0cf31L,
 118   0x2cd99e8bL, 0x5bdeae1dL, 0x9b64c2b0L, 0xec63f226L, 0x756aa39cL,
 119   0x026d930aL, 0x9c0906a9L, 0xeb0e363fL, 0x72076785L, 0x05005713L,
 120   0x95bf4a82L, 0xe2b87a14L, 0x7bb12baeL, 0x0cb61b38L, 0x92d28e9bL,
 121   0xe5d5be0dL, 0x7cdcefb7L, 0x0bdbdf21L, 0x86d3d2d4L, 0xf1d4e242L,
 122   0x68ddb3f8L, 0x1fda836eL, 0x81be16cdL, 0xf6b9265bL, 0x6fb077e1L,
 123   0x18b74777L, 0x88085ae6L, 0xff0f6a70L, 0x66063bcaL, 0x11010b5cL,
 124   0x8f659effL, 0xf862ae69L, 0x616bffd3L, 0x166ccf45L, 0xa00ae278L,
 125   0xd70dd2eeL, 0x4e048354L, 0x3903b3c2L, 0xa7672661L, 0xd06016f7L,
 126   0x4969474dL, 0x3e6e77dbL, 0xaed16a4aL, 0xd9d65adcL, 0x40df0b66L,
 127   0x37d83bf0L, 0xa9bcae53L, 0xdebb9ec5L, 0x47b2cf7fL, 0x30b5ffe9L,
 128   0xbdbdf21cL, 0xcabac28aL, 0x53b39330L, 0x24b4a3a6L, 0xbad03605L,
 129   0xcdd70693L, 0x54de5729L, 0x23d967bfL, 0xb3667a2eL, 0xc4614ab8L,
 130   0x5d681b02L, 0x2a6f2b94L, 0xb40bbe37L, 0xc30c8ea1L, 0x5a05df1bL,
 131   0x2d02ef8dL
 132 };
 133 #endif
 134
 135 #if 0
 136 /* =========================================================================
 137  * This function can be used by asm versions of crc32()
 138  */
 139 const uLongf * ZEXPORT get_crc_table()
 140 {
 141 #ifdef DYNAMIC_CRC_TABLE
 142   if (crc_table_empty) make_crc_table();
 143 #endif
 144   return (const uLongf *)crc_table;
 145 }
 146 #endif
 147
 148 /* ========================================================================= */
 149 #define DO1(buf) crc = crc_table[((int)crc ^ (*buf++)) & 0xff] ^ (crc >> 8);
 150 #define DO2(buf)  DO1(buf); DO1(buf);
 151 #define DO4(buf)  DO2(buf); DO2(buf);
 152 #define DO8(buf)  DO4(buf); DO4(buf);
 153
 154 /* ========================================================================= */
 155 uLong ZEXPORT crc32(crc, buf, len)
 156     uLong crc;
 157     const Bytef *buf;
 158     uInt len;
 159 {
 160 #ifdef DYNAMIC_CRC_TABLE
 161     if (crc_table_empty)
 162       make_crc_table();
 163 #endif
 164     crc = crc ^ 0xffffffffL;
 165     while (len >= 8)
 166     {
 167       DO8(buf);
 168       len -= 8;
 169     }
 170     if (len) do {
 171       DO1(buf);
 172     } while (--len);
 173     return crc ^ 0xffffffffL;
 174 }
 175
 176 #if (CONFIG_COMMANDS & CFG_CMD_JFFS2) || \
 177         ((CONFIG_COMMANDS & CFG_CMD_NAND) && !defined(CFG_NAND_LEGACY))
 178
 179 /* No ones complement version. JFFS2 (and other things ?)
 180  * don't use ones compliment in their CRC calculations.
 181  */
 182 uLong ZEXPORT crc32_no_comp(uLong crc, const Bytef *buf, uInt len)
 183 {
 184 #ifdef DYNAMIC_CRC_TABLE
 185     if (crc_table_empty)
 186       make_crc_table();
 187 #endif
 188     while (len >= 8)
 189     {
 190       DO8(buf);
 191       len -= 8;
 192     }
 193     if (len) do {
 194       DO1(buf);
 195     } while (--len);
 196
 197     return crc;
 198 }
 199
 200 #endif  /* CFG_CMD_JFFS2 */