crc32.c

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/* contrib/ltree/crc32.c */
 
/*
 * Implements CRC-32, as used in ltree.
 *
 * Note that the CRC is used in the on-disk format of GiST indexes, so we
 * must stay backwards-compatible!
 */
 
#include "postgres.h"
#include "ltree.h"
 
#include "crc32.h"
#include "utils/pg_crc.h"
#ifdef LOWER_NODE
#include "utils/pg_locale.h"
#endif
 
#ifdef LOWER_NODE
 
unsigned int
ltree_crc32_sz(const char *buf, int size)
{
    pg_crc32    crc;
    const char *p = buf;
    const char *end = buf + size;
    static pg_locale_t locale = NULL;
 
    if (!locale)
        locale = pg_database_locale();
 
    INIT_TRADITIONAL_CRC32(crc);
    while (size > 0)
    {
        char        foldstr[UNICODE_CASEMAP_BUFSZ];
        int         srclen = pg_mblen_range(p, end);
        size_t      foldlen;
 
        /* fold one codepoint at a time */
        foldlen = pg_strfold(foldstr, UNICODE_CASEMAP_BUFSZ, p, srclen,
                             locale);
 
        COMP_TRADITIONAL_CRC32(crc, foldstr, foldlen);
 
        size -= srclen;
        p += srclen;
    }
    FIN_TRADITIONAL_CRC32(crc);
    return (unsigned int) crc;
}
 
#else
 
unsigned int
ltree_crc32_sz(const char *buf, int size)
{
    pg_crc32    crc;
    const char *p = buf;
 
    INIT_TRADITIONAL_CRC32(crc);
    while (size > 0)
    {
        COMP_TRADITIONAL_CRC32(crc, p, 1);
        size--;
        p++;
    }
    FIN_TRADITIONAL_CRC32(crc);
    return (unsigned int) crc;
}
 
#endif                          /* !LOWER_NODE */