contrib/ltree/crc32.c

   1 /* contrib/ltree/crc32.c */
   2
   3 /*
   4  * Implements CRC-32, as used in ltree.
   5  *
   6  * Note that the CRC is used in the on-disk format of GiST indexes, so we
   7  * must stay backwards-compatible!
   8  */
   9
  10 #include "postgres.h"
  11 #include "ltree.h"
  12
  13 #ifdef LOWER_NODE
  14 #include <ctype.h>
  15 #define TOLOWER(x)      tolower((unsigned char) (x))
  16 #else
  17 #define TOLOWER(x)      (x)
  18 #endif
  19
  20 #include "crc32.h"
  21 #include "utils/pg_crc.h"
  22
  23 unsigned int
  24 ltree_crc32_sz(const char *buf, int size)
  25 {
  26         pg_crc32        crc;
  27         const char *p = buf;
  28
  29         INIT_TRADITIONAL_CRC32(crc);
  30         while (size > 0)
  31         {
  32                 char            c = (char) TOLOWER(*p);
  33
  34                 COMP_TRADITIONAL_CRC32(crc, &c, 1);
  35                 size--;
  36                 p++;
  37         }
  38         FIN_TRADITIONAL_CRC32(crc);
  39         return (unsigned int) crc;
  40 }