hashfunc.c File Reference

#include "postgres.h"
#include "access/hash.h"
#include "catalog/pg_collation.h"
#include "common/hashfn.h"
#include "utils/builtins.h"
#include "utils/float.h"
#include "utils/pg_locale.h"
#include "varatt.h"

Include dependency graph for hashfunc.c:

Go to the source code of this file.

Functions
Datum	hashchar (PG_FUNCTION_ARGS)
Datum	hashcharextended (PG_FUNCTION_ARGS)
Datum	hashint2 (PG_FUNCTION_ARGS)
Datum	hashint2extended (PG_FUNCTION_ARGS)
Datum	hashint4 (PG_FUNCTION_ARGS)
Datum	hashint4extended (PG_FUNCTION_ARGS)
Datum	hashint8 (PG_FUNCTION_ARGS)
Datum	hashint8extended (PG_FUNCTION_ARGS)
Datum	hashoid (PG_FUNCTION_ARGS)
Datum	hashoidextended (PG_FUNCTION_ARGS)
Datum	hashenum (PG_FUNCTION_ARGS)
Datum	hashenumextended (PG_FUNCTION_ARGS)
Datum	hashfloat4 (PG_FUNCTION_ARGS)
Datum	hashfloat4extended (PG_FUNCTION_ARGS)
Datum	hashfloat8 (PG_FUNCTION_ARGS)
Datum	hashfloat8extended (PG_FUNCTION_ARGS)
Datum	hashoidvector (PG_FUNCTION_ARGS)
Datum	hashoidvectorextended (PG_FUNCTION_ARGS)
Datum	hashname (PG_FUNCTION_ARGS)
Datum	hashnameextended (PG_FUNCTION_ARGS)
Datum	hashtext (PG_FUNCTION_ARGS)
Datum	hashtextextended (PG_FUNCTION_ARGS)
Datum	hashvarlena (PG_FUNCTION_ARGS)
Datum	hashvarlenaextended (PG_FUNCTION_ARGS)

Function Documentation

hashchar()

Datum hashchar

(

PG_FUNCTION_ARGS

)

Definition at line 49 of file hashfunc.c.

{
    return hash_uint32((int32) PG_GETARG_CHAR(0));
}

References hash_uint32(), and PG_GETARG_CHAR.

hashcharextended()

Datum hashcharextended

(

PG_FUNCTION_ARGS

)

Definition at line 55 of file hashfunc.c.

{
    return hash_uint32_extended((int32) PG_GETARG_CHAR(0), PG_GETARG_INT64(1));
}

References hash_uint32_extended(), PG_GETARG_CHAR, and PG_GETARG_INT64.

Referenced by JsonbHashScalarValueExtended().

hashenum()

Datum hashenum

(

PG_FUNCTION_ARGS

)

Definition at line 130 of file hashfunc.c.

{
    return hash_uint32((uint32) PG_GETARG_OID(0));
}

References hash_uint32(), and PG_GETARG_OID.

hashenumextended()

Datum hashenumextended

(

PG_FUNCTION_ARGS

)

Definition at line 136 of file hashfunc.c.

{
    return hash_uint32_extended((uint32) PG_GETARG_OID(0), PG_GETARG_INT64(1));
}

References hash_uint32_extended(), PG_GETARG_INT64, and PG_GETARG_OID.

hashfloat4()

Datum hashfloat4

(

PG_FUNCTION_ARGS

)

Definition at line 142 of file hashfunc.c.

{
    float4      key = PG_GETARG_FLOAT4(0);
    float8      key8;
 
    /*
     * On IEEE-float machines, minus zero and zero have different bit patterns
     * but should compare as equal.  We must ensure that they have the same
     * hash value, which is most reliably done this way:
     */
    if (key == (float4) 0)
        PG_RETURN_UINT32(0);
 
    /*
     * To support cross-type hashing of float8 and float4, we want to return
     * the same hash value hashfloat8 would produce for an equal float8 value.
     * So, widen the value to float8 and hash that.  (We must do this rather
     * than have hashfloat8 try to narrow its value to float4; that could fail
     * on overflow.)
     */
    key8 = key;
 
    /*
     * Similarly, NaNs can have different bit patterns but they should all
     * compare as equal.  For backwards-compatibility reasons we force them to
     * have the hash value of a standard float8 NaN.  (You'd think we could
     * replace key with a float4 NaN and then widen it; but on some old
     * platforms, that way produces a different bit pattern.)
     */
    if (isnan(key8))
        key8 = get_float8_nan();
 
    return hash_any((unsigned char *) &key8, sizeof(key8));
}

References get_float8_nan(), hash_any(), sort-test::key, PG_GETARG_FLOAT4, and PG_RETURN_UINT32.

hashfloat4extended()

Datum hashfloat4extended

(

PG_FUNCTION_ARGS

)

Definition at line 178 of file hashfunc.c.

{
    float4      key = PG_GETARG_FLOAT4(0);
    uint64      seed = PG_GETARG_INT64(1);
    float8      key8;
 
    /* Same approach as hashfloat4 */
    if (key == (float4) 0)
        PG_RETURN_UINT64(seed);
    key8 = key;
    if (isnan(key8))
        key8 = get_float8_nan();
 
    return hash_any_extended((unsigned char *) &key8, sizeof(key8), seed);
}

References get_float8_nan(), hash_any_extended(), sort-test::key, PG_GETARG_FLOAT4, PG_GETARG_INT64, and PG_RETURN_UINT64.

hashfloat8()

Datum hashfloat8

(

PG_FUNCTION_ARGS

)

Definition at line 195 of file hashfunc.c.

{
    float8      key = PG_GETARG_FLOAT8(0);
 
    /*
     * On IEEE-float machines, minus zero and zero have different bit patterns
     * but should compare as equal.  We must ensure that they have the same
     * hash value, which is most reliably done this way:
     */
    if (key == (float8) 0)
        PG_RETURN_UINT32(0);
 
    /*
     * Similarly, NaNs can have different bit patterns but they should all
     * compare as equal.  For backwards-compatibility reasons we force them to
     * have the hash value of a standard NaN.
     */
    if (isnan(key))
        key = get_float8_nan();
 
    return hash_any((unsigned char *) &key, sizeof(key));
}

References get_float8_nan(), hash_any(), sort-test::key, PG_GETARG_FLOAT8, and PG_RETURN_UINT32.

Referenced by tablesample_init().

hashfloat8extended()

Datum hashfloat8extended

(

PG_FUNCTION_ARGS

)

Definition at line 219 of file hashfunc.c.

{
    float8      key = PG_GETARG_FLOAT8(0);
    uint64      seed = PG_GETARG_INT64(1);
 
    /* Same approach as hashfloat8 */
    if (key == (float8) 0)
        PG_RETURN_UINT64(seed);
    if (isnan(key))
        key = get_float8_nan();
 
    return hash_any_extended((unsigned char *) &key, sizeof(key), seed);
}

References get_float8_nan(), hash_any_extended(), sort-test::key, PG_GETARG_FLOAT8, PG_GETARG_INT64, and PG_RETURN_UINT64.

hashint2()

Datum hashint2

(

PG_FUNCTION_ARGS

)

Definition at line 61 of file hashfunc.c.

{
    return hash_uint32((int32) PG_GETARG_INT16(0));
}

References hash_uint32(), and PG_GETARG_INT16.

hashint2extended()

Datum hashint2extended

(

PG_FUNCTION_ARGS

)

Definition at line 67 of file hashfunc.c.

{
    return hash_uint32_extended((int32) PG_GETARG_INT16(0), PG_GETARG_INT64(1));
}

References hash_uint32_extended(), PG_GETARG_INT16, and PG_GETARG_INT64.

hashint4()

Datum hashint4

(

PG_FUNCTION_ARGS

)

Definition at line 73 of file hashfunc.c.

{
    return hash_uint32(PG_GETARG_INT32(0));
}

References hash_uint32(), and PG_GETARG_INT32.

hashint4extended()

Datum hashint4extended

(

PG_FUNCTION_ARGS

)

Definition at line 79 of file hashfunc.c.

{
    return hash_uint32_extended(PG_GETARG_INT32(0), PG_GETARG_INT64(1));
}

References hash_uint32_extended(), PG_GETARG_INT32, and PG_GETARG_INT64.

hashint8()

Datum hashint8

(

PG_FUNCTION_ARGS

)

Definition at line 85 of file hashfunc.c.

{
    /*
     * The idea here is to produce a hash value compatible with the values
     * produced by hashint4 and hashint2 for logically equal inputs; this is
     * necessary to support cross-type hash joins across these input types.
     * Since all three types are signed, we can xor the high half of the int8
     * value if the sign is positive, or the complement of the high half when
     * the sign is negative.
     */
    int64       val = PG_GETARG_INT64(0);
    uint32      lohalf = (uint32) val;
    uint32      hihalf = (uint32) (val >> 32);
 
    lohalf ^= (val >= 0) ? hihalf : ~hihalf;
 
    return hash_uint32(lohalf);
}

References hash_uint32(), PG_GETARG_INT64, and val.

Referenced by interval_hash(), pg_lsn_hash(), time_hash(), timestamp_hash(), and timetz_hash().

hashint8extended()

Datum hashint8extended

(

PG_FUNCTION_ARGS

)

Definition at line 105 of file hashfunc.c.

{
    /* Same approach as hashint8 */
    int64       val = PG_GETARG_INT64(0);
    uint32      lohalf = (uint32) val;
    uint32      hihalf = (uint32) (val >> 32);
 
    lohalf ^= (val >= 0) ? hihalf : ~hihalf;
 
    return hash_uint32_extended(lohalf, PG_GETARG_INT64(1));
}

References hash_uint32_extended(), PG_GETARG_INT64, and val.

Referenced by interval_hash_extended(), pg_lsn_hash_extended(), time_hash_extended(), timestamp_hash_extended(), and timetz_hash_extended().

hashname()

Datum hashname

(

PG_FUNCTION_ARGS

)

Definition at line 252 of file hashfunc.c.

{
    char       *key = NameStr(*PG_GETARG_NAME(0));
 
    return hash_any((unsigned char *) key, strlen(key));
}

References hash_any(), sort-test::key, NameStr, and PG_GETARG_NAME.

hashnameextended()

Datum hashnameextended

(

PG_FUNCTION_ARGS

)

Definition at line 260 of file hashfunc.c.

{
    char       *key = NameStr(*PG_GETARG_NAME(0));
 
    return hash_any_extended((unsigned char *) key, strlen(key),
                             PG_GETARG_INT64(1));
}

References hash_any_extended(), sort-test::key, NameStr, PG_GETARG_INT64, and PG_GETARG_NAME.

hashoid()

Datum hashoid

(

PG_FUNCTION_ARGS

)

Definition at line 118 of file hashfunc.c.

{
    return hash_uint32((uint32) PG_GETARG_OID(0));
}

References hash_uint32(), and PG_GETARG_OID.

hashoidextended()

Datum hashoidextended

(

PG_FUNCTION_ARGS

)

Definition at line 124 of file hashfunc.c.

{
    return hash_uint32_extended((uint32) PG_GETARG_OID(0), PG_GETARG_INT64(1));
}

References hash_uint32_extended(), PG_GETARG_INT64, and PG_GETARG_OID.

hashoidvector()

Datum hashoidvector

(

PG_FUNCTION_ARGS

)

Definition at line 234 of file hashfunc.c.

{
    oidvector  *key = (oidvector *) PG_GETARG_POINTER(0);
 
    return hash_any((unsigned char *) key->values, key->dim1 * sizeof(Oid));
}

References hash_any(), sort-test::key, and PG_GETARG_POINTER.

Referenced by oidvectorhashfast().

hashoidvectorextended()

Datum hashoidvectorextended

(

PG_FUNCTION_ARGS

)

Definition at line 242 of file hashfunc.c.

{
    oidvector  *key = (oidvector *) PG_GETARG_POINTER(0);
 
    return hash_any_extended((unsigned char *) key->values,
                             key->dim1 * sizeof(Oid),
                             PG_GETARG_INT64(1));
}

References hash_any_extended(), sort-test::key, PG_GETARG_INT64, and PG_GETARG_POINTER.

hashtext()

Datum hashtext

(

PG_FUNCTION_ARGS

)

Definition at line 269 of file hashfunc.c.

{
    text       *key = PG_GETARG_TEXT_PP(0);
    Oid         collid = PG_GET_COLLATION();
    pg_locale_t mylocale = 0;
    Datum       result;
 
    if (!collid)
        ereport(ERROR,
                (errcode(ERRCODE_INDETERMINATE_COLLATION),
                 errmsg("could not determine which collation to use for string hashing"),
                 errhint("Use the COLLATE clause to set the collation explicitly.")));
 
    if (!lc_collate_is_c(collid))
        mylocale = pg_newlocale_from_collation(collid);
 
    if (pg_locale_deterministic(mylocale))
    {
        result = hash_any((unsigned char *) VARDATA_ANY(key),
                          VARSIZE_ANY_EXHDR(key));
    }
    else
    {
        Size        bsize, rsize;
        char       *buf;
        const char *keydata = VARDATA_ANY(key);
        size_t      keylen = VARSIZE_ANY_EXHDR(key);
 
 
        bsize = pg_strnxfrm(NULL, 0, keydata, keylen, mylocale);
        buf = palloc(bsize + 1);
 
        rsize = pg_strnxfrm(buf, bsize + 1, keydata, keylen, mylocale);
        if (rsize != bsize)
            elog(ERROR, "pg_strnxfrm() returned unexpected result");
 
        /*
         * In principle, there's no reason to include the terminating NUL
         * character in the hash, but it was done before and the behavior
         * must be preserved.
         */
        result = hash_any((uint8_t *) buf, bsize + 1);
 
        pfree(buf);
    }
 
    /* Avoid leaking memory for toasted inputs */
    PG_FREE_IF_COPY(key, 0);
 
    return result;
}

References buf, collid, elog(), ereport, errcode(), errhint(), errmsg(), ERROR, hash_any(), sort-test::key, lc_collate_is_c(), palloc(), pfree(), PG_FREE_IF_COPY, PG_GET_COLLATION, PG_GETARG_TEXT_PP, pg_locale_deterministic(), pg_newlocale_from_collation(), pg_strnxfrm(), VARDATA_ANY, and VARSIZE_ANY_EXHDR.

Referenced by texthashfast().

hashtextextended()

Datum hashtextextended

(

PG_FUNCTION_ARGS

)

Definition at line 322 of file hashfunc.c.

{
    text       *key = PG_GETARG_TEXT_PP(0);
    Oid         collid = PG_GET_COLLATION();
    pg_locale_t mylocale = 0;
    Datum       result;
 
    if (!collid)
        ereport(ERROR,
                (errcode(ERRCODE_INDETERMINATE_COLLATION),
                 errmsg("could not determine which collation to use for string hashing"),
                 errhint("Use the COLLATE clause to set the collation explicitly.")));
 
    if (!lc_collate_is_c(collid))
        mylocale = pg_newlocale_from_collation(collid);
 
    if (pg_locale_deterministic(mylocale))
    {
        result = hash_any_extended((unsigned char *) VARDATA_ANY(key),
                                   VARSIZE_ANY_EXHDR(key),
                                   PG_GETARG_INT64(1));
    }
    else
    {
        Size        bsize, rsize;
        char       *buf;
        const char *keydata = VARDATA_ANY(key);
        size_t      keylen = VARSIZE_ANY_EXHDR(key);
 
        bsize = pg_strnxfrm(NULL, 0, keydata, keylen, mylocale);
        buf = palloc(bsize + 1);
 
        rsize = pg_strnxfrm(buf, bsize + 1, keydata, keylen, mylocale);
        if (rsize != bsize)
            elog(ERROR, "pg_strnxfrm() returned unexpected result");
 
        /*
         * In principle, there's no reason to include the terminating NUL
         * character in the hash, but it was done before and the behavior
         * must be preserved.
         */
        result = hash_any_extended((uint8_t *) buf, bsize + 1,
                                   PG_GETARG_INT64(1));
 
        pfree(buf);
    }
 
    PG_FREE_IF_COPY(key, 0);
 
    return result;
}

References buf, collid, elog(), ereport, errcode(), errhint(), errmsg(), ERROR, hash_any_extended(), sort-test::key, lc_collate_is_c(), palloc(), pfree(), PG_FREE_IF_COPY, PG_GET_COLLATION, PG_GETARG_INT64, PG_GETARG_TEXT_PP, pg_locale_deterministic(), pg_newlocale_from_collation(), pg_strnxfrm(), VARDATA_ANY, and VARSIZE_ANY_EXHDR.

hashvarlena()

Datum hashvarlena

(

PG_FUNCTION_ARGS

)

Definition at line 379 of file hashfunc.c.

{
    struct varlena *key = PG_GETARG_VARLENA_PP(0);
    Datum       result;
 
    result = hash_any((unsigned char *) VARDATA_ANY(key),
                      VARSIZE_ANY_EXHDR(key));
 
    /* Avoid leaking memory for toasted inputs */
    PG_FREE_IF_COPY(key, 0);
 
    return result;
}

References hash_any(), sort-test::key, PG_FREE_IF_COPY, PG_GETARG_VARLENA_PP, VARDATA_ANY, and VARSIZE_ANY_EXHDR.

hashvarlenaextended()

Datum hashvarlenaextended

(

PG_FUNCTION_ARGS

)

Definition at line 394 of file hashfunc.c.

{
    struct varlena *key = PG_GETARG_VARLENA_PP(0);
    Datum       result;
 
    result = hash_any_extended((unsigned char *) VARDATA_ANY(key),
                               VARSIZE_ANY_EXHDR(key),
                               PG_GETARG_INT64(1));
 
    PG_FREE_IF_COPY(key, 0);
 
    return result;
}

References hash_any_extended(), sort-test::key, PG_FREE_IF_COPY, PG_GETARG_INT64, PG_GETARG_VARLENA_PP, VARDATA_ANY, and VARSIZE_ANY_EXHDR.