citext.c

Go to the documentation of this file.

/*
 * contrib/citext/citext.c
 */
#include "postgres.h"
 
#include "catalog/pg_collation.h"
#include "common/hashfn.h"
#include "fmgr.h"
#include "utils/formatting.h"
#include "utils/varlena.h"
#include "varatt.h"
 
PG_MODULE_MAGIC_EXT(
                    .name = "citext",
                    .version = PG_VERSION
);
 
/*
 *      ====================
 *      FORWARD DECLARATIONS
 *      ====================
 */
 
static int32 citextcmp(text *left, text *right, Oid collid);
static int32 internal_citext_pattern_cmp(text *left, text *right, Oid collid);
 
/*
 *      =================
 *      UTILITY FUNCTIONS
 *      =================
 */
 
/*
 * citextcmp()
 * Internal comparison function for citext strings.
 * Returns int32 negative, zero, or positive.
 */
static int32
citextcmp(text *left, text *right, Oid collid)
{
    char       *lcstr,
               *rcstr;
    int32       result;
 
    /*
     * We must do our str_tolower calls with DEFAULT_COLLATION_OID, not the
     * input collation as you might expect.  This is so that the behavior of
     * citext's equality and hashing functions is not collation-dependent.  We
     * should change this once the core infrastructure is able to cope with
     * collation-dependent equality and hashing functions.
     */
 
    lcstr = str_tolower(VARDATA_ANY(left), VARSIZE_ANY_EXHDR(left), DEFAULT_COLLATION_OID);
    rcstr = str_tolower(VARDATA_ANY(right), VARSIZE_ANY_EXHDR(right), DEFAULT_COLLATION_OID);
 
    result = varstr_cmp(lcstr, strlen(lcstr),
                        rcstr, strlen(rcstr),
                        collid);
 
    pfree(lcstr);
    pfree(rcstr);
 
    return result;
}
 
/*
 * citext_pattern_cmp()
 * Internal character-by-character comparison function for citext strings.
 * Returns int32 negative, zero, or positive.
 */
static int32
internal_citext_pattern_cmp(text *left, text *right, Oid collid)
{
    char       *lcstr,
               *rcstr;
    int         llen,
                rlen;
    int32       result;
 
    lcstr = str_tolower(VARDATA_ANY(left), VARSIZE_ANY_EXHDR(left), DEFAULT_COLLATION_OID);
    rcstr = str_tolower(VARDATA_ANY(right), VARSIZE_ANY_EXHDR(right), DEFAULT_COLLATION_OID);
 
    llen = strlen(lcstr);
    rlen = strlen(rcstr);
 
    result = memcmp(lcstr, rcstr, Min(llen, rlen));
    if (result == 0)
    {
        if (llen < rlen)
            result = -1;
        else if (llen > rlen)
            result = 1;
    }
 
    pfree(lcstr);
    pfree(rcstr);
 
    return result;
}
 
/*
 *      ==================
 *      INDEXING FUNCTIONS
 *      ==================
 */
 
PG_FUNCTION_INFO_V1(citext_cmp);
 
Datum
citext_cmp(PG_FUNCTION_ARGS)
{
    text       *left = PG_GETARG_TEXT_PP(0);
    text       *right = PG_GETARG_TEXT_PP(1);
    int32       result;
 
    result = citextcmp(left, right, PG_GET_COLLATION());
 
    PG_FREE_IF_COPY(left, 0);
    PG_FREE_IF_COPY(right, 1);
 
    PG_RETURN_INT32(result);
}
 
PG_FUNCTION_INFO_V1(citext_pattern_cmp);
 
Datum
citext_pattern_cmp(PG_FUNCTION_ARGS)
{
    text       *left = PG_GETARG_TEXT_PP(0);
    text       *right = PG_GETARG_TEXT_PP(1);
    int32       result;
 
    result = internal_citext_pattern_cmp(left, right, PG_GET_COLLATION());
 
    PG_FREE_IF_COPY(left, 0);
    PG_FREE_IF_COPY(right, 1);
 
    PG_RETURN_INT32(result);
}
 
PG_FUNCTION_INFO_V1(citext_hash);
 
Datum
citext_hash(PG_FUNCTION_ARGS)
{
    text       *txt = PG_GETARG_TEXT_PP(0);
    char       *str;
    Datum       result;
 
    str = str_tolower(VARDATA_ANY(txt), VARSIZE_ANY_EXHDR(txt), DEFAULT_COLLATION_OID);
    result = hash_any((unsigned char *) str, strlen(str));
    pfree(str);
 
    /* Avoid leaking memory for toasted inputs */
    PG_FREE_IF_COPY(txt, 0);
 
    PG_RETURN_DATUM(result);
}
 
PG_FUNCTION_INFO_V1(citext_hash_extended);
 
Datum
citext_hash_extended(PG_FUNCTION_ARGS)
{
    text       *txt = PG_GETARG_TEXT_PP(0);
    uint64      seed = PG_GETARG_INT64(1);
    char       *str;
    Datum       result;
 
    str = str_tolower(VARDATA_ANY(txt), VARSIZE_ANY_EXHDR(txt), DEFAULT_COLLATION_OID);
    result = hash_any_extended((unsigned char *) str, strlen(str), seed);
    pfree(str);
 
    /* Avoid leaking memory for toasted inputs */
    PG_FREE_IF_COPY(txt, 0);
 
    PG_RETURN_DATUM(result);
}
 
/*
 *      ==================
 *      OPERATOR FUNCTIONS
 *      ==================
 */
 
PG_FUNCTION_INFO_V1(citext_eq);
 
Datum
citext_eq(PG_FUNCTION_ARGS)
{
    text       *left = PG_GETARG_TEXT_PP(0);
    text       *right = PG_GETARG_TEXT_PP(1);
    char       *lcstr,
               *rcstr;
    bool        result;
 
    /* We can't compare lengths in advance of downcasing ... */
 
    lcstr = str_tolower(VARDATA_ANY(left), VARSIZE_ANY_EXHDR(left), DEFAULT_COLLATION_OID);
    rcstr = str_tolower(VARDATA_ANY(right), VARSIZE_ANY_EXHDR(right), DEFAULT_COLLATION_OID);
 
    /*
     * Since we only care about equality or not-equality, we can avoid all the
     * expense of strcoll() here, and just do bitwise comparison.
     */
    result = (strcmp(lcstr, rcstr) == 0);
 
    pfree(lcstr);
    pfree(rcstr);
    PG_FREE_IF_COPY(left, 0);
    PG_FREE_IF_COPY(right, 1);
 
    PG_RETURN_BOOL(result);
}
 
PG_FUNCTION_INFO_V1(citext_ne);
 
Datum
citext_ne(PG_FUNCTION_ARGS)
{
    text       *left = PG_GETARG_TEXT_PP(0);
    text       *right = PG_GETARG_TEXT_PP(1);
    char       *lcstr,
               *rcstr;
    bool        result;
 
    /* We can't compare lengths in advance of downcasing ... */
 
    lcstr = str_tolower(VARDATA_ANY(left), VARSIZE_ANY_EXHDR(left), DEFAULT_COLLATION_OID);
    rcstr = str_tolower(VARDATA_ANY(right), VARSIZE_ANY_EXHDR(right), DEFAULT_COLLATION_OID);
 
    /*
     * Since we only care about equality or not-equality, we can avoid all the
     * expense of strcoll() here, and just do bitwise comparison.
     */
    result = (strcmp(lcstr, rcstr) != 0);
 
    pfree(lcstr);
    pfree(rcstr);
    PG_FREE_IF_COPY(left, 0);
    PG_FREE_IF_COPY(right, 1);
 
    PG_RETURN_BOOL(result);
}
 
PG_FUNCTION_INFO_V1(citext_lt);
 
Datum
citext_lt(PG_FUNCTION_ARGS)
{
    text       *left = PG_GETARG_TEXT_PP(0);
    text       *right = PG_GETARG_TEXT_PP(1);
    bool        result;
 
    result = citextcmp(left, right, PG_GET_COLLATION()) < 0;
 
    PG_FREE_IF_COPY(left, 0);
    PG_FREE_IF_COPY(right, 1);
 
    PG_RETURN_BOOL(result);
}
 
PG_FUNCTION_INFO_V1(citext_le);
 
Datum
citext_le(PG_FUNCTION_ARGS)
{
    text       *left = PG_GETARG_TEXT_PP(0);
    text       *right = PG_GETARG_TEXT_PP(1);
    bool        result;
 
    result = citextcmp(left, right, PG_GET_COLLATION()) <= 0;
 
    PG_FREE_IF_COPY(left, 0);
    PG_FREE_IF_COPY(right, 1);
 
    PG_RETURN_BOOL(result);
}
 
PG_FUNCTION_INFO_V1(citext_gt);
 
Datum
citext_gt(PG_FUNCTION_ARGS)
{
    text       *left = PG_GETARG_TEXT_PP(0);
    text       *right = PG_GETARG_TEXT_PP(1);
    bool        result;
 
    result = citextcmp(left, right, PG_GET_COLLATION()) > 0;
 
    PG_FREE_IF_COPY(left, 0);
    PG_FREE_IF_COPY(right, 1);
 
    PG_RETURN_BOOL(result);
}
 
PG_FUNCTION_INFO_V1(citext_ge);
 
Datum
citext_ge(PG_FUNCTION_ARGS)
{
    text       *left = PG_GETARG_TEXT_PP(0);
    text       *right = PG_GETARG_TEXT_PP(1);
    bool        result;
 
    result = citextcmp(left, right, PG_GET_COLLATION()) >= 0;
 
    PG_FREE_IF_COPY(left, 0);
    PG_FREE_IF_COPY(right, 1);
 
    PG_RETURN_BOOL(result);
}
 
PG_FUNCTION_INFO_V1(citext_pattern_lt);
 
Datum
citext_pattern_lt(PG_FUNCTION_ARGS)
{
    text       *left = PG_GETARG_TEXT_PP(0);
    text       *right = PG_GETARG_TEXT_PP(1);
    bool        result;
 
    result = internal_citext_pattern_cmp(left, right, PG_GET_COLLATION()) < 0;
 
    PG_FREE_IF_COPY(left, 0);
    PG_FREE_IF_COPY(right, 1);
 
    PG_RETURN_BOOL(result);
}
 
PG_FUNCTION_INFO_V1(citext_pattern_le);
 
Datum
citext_pattern_le(PG_FUNCTION_ARGS)
{
    text       *left = PG_GETARG_TEXT_PP(0);
    text       *right = PG_GETARG_TEXT_PP(1);
    bool        result;
 
    result = internal_citext_pattern_cmp(left, right, PG_GET_COLLATION()) <= 0;
 
    PG_FREE_IF_COPY(left, 0);
    PG_FREE_IF_COPY(right, 1);
 
    PG_RETURN_BOOL(result);
}
 
PG_FUNCTION_INFO_V1(citext_pattern_gt);
 
Datum
citext_pattern_gt(PG_FUNCTION_ARGS)
{
    text       *left = PG_GETARG_TEXT_PP(0);
    text       *right = PG_GETARG_TEXT_PP(1);
    bool        result;
 
    result = internal_citext_pattern_cmp(left, right, PG_GET_COLLATION()) > 0;
 
    PG_FREE_IF_COPY(left, 0);
    PG_FREE_IF_COPY(right, 1);
 
    PG_RETURN_BOOL(result);
}
 
PG_FUNCTION_INFO_V1(citext_pattern_ge);
 
Datum
citext_pattern_ge(PG_FUNCTION_ARGS)
{
    text       *left = PG_GETARG_TEXT_PP(0);
    text       *right = PG_GETARG_TEXT_PP(1);
    bool        result;
 
    result = internal_citext_pattern_cmp(left, right, PG_GET_COLLATION()) >= 0;
 
    PG_FREE_IF_COPY(left, 0);
    PG_FREE_IF_COPY(right, 1);
 
    PG_RETURN_BOOL(result);
}
 
/*
 *      ===================
 *      AGGREGATE FUNCTIONS
 *      ===================
 */
 
PG_FUNCTION_INFO_V1(citext_smaller);
 
Datum
citext_smaller(PG_FUNCTION_ARGS)
{
    text       *left = PG_GETARG_TEXT_PP(0);
    text       *right = PG_GETARG_TEXT_PP(1);
    text       *result;
 
    result = citextcmp(left, right, PG_GET_COLLATION()) < 0 ? left : right;
    PG_RETURN_TEXT_P(result);
}
 
PG_FUNCTION_INFO_V1(citext_larger);
 
Datum
citext_larger(PG_FUNCTION_ARGS)
{
    text       *left = PG_GETARG_TEXT_PP(0);
    text       *right = PG_GETARG_TEXT_PP(1);
    text       *result;
 
    result = citextcmp(left, right, PG_GET_COLLATION()) > 0 ? left : right;
    PG_RETURN_TEXT_P(result);
}