346 lines
6.8 KiB
C
346 lines
6.8 KiB
C
/*-------------------------------------------------------------------------
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*
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* nbtcompare.c
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* Comparison functions for btree access method.
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*
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* Portions Copyright (c) 1996-2014, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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*
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* IDENTIFICATION
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* src/backend/access/nbtree/nbtcompare.c
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*
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* NOTES
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*
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* These functions are stored in pg_amproc. For each operator class
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* defined on btrees, they compute
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*
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* compare(a, b):
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* < 0 if a < b,
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* = 0 if a == b,
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* > 0 if a > b.
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*
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* The result is always an int32 regardless of the input datatype.
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*
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* Although any negative int32 (except INT_MIN) is acceptable for reporting
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* "<", and any positive int32 is acceptable for reporting ">", routines
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* that work on 32-bit or wider datatypes can't just return "a - b".
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* That could overflow and give the wrong answer. Also, one must not
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* return INT_MIN to report "<", since some callers will negate the result.
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*
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* NOTE: it is critical that the comparison function impose a total order
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* on all non-NULL values of the data type, and that the datatype's
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* boolean comparison operators (= < >= etc) yield results consistent
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* with the comparison routine. Otherwise bad behavior may ensue.
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* (For example, the comparison operators must NOT punt when faced with
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* NAN or other funny values; you must devise some collation sequence for
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* all such values.) If the datatype is not trivial, this is most
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* reliably done by having the boolean operators invoke the same
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* three-way comparison code that the btree function does. Therefore,
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* this file contains only btree support for "trivial" datatypes ---
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* all others are in the /utils/adt/ files that implement their datatypes.
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*
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* NOTE: these routines must not leak memory, since memory allocated
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* during an index access won't be recovered till end of query. This
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* primarily affects comparison routines for toastable datatypes;
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* they have to be careful to free any detoasted copy of an input datum.
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*-------------------------------------------------------------------------
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*/
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#include "postgres.h"
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#include "utils/builtins.h"
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#include "utils/sortsupport.h"
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Datum
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btboolcmp(PG_FUNCTION_ARGS)
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{
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bool a = PG_GETARG_BOOL(0);
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bool b = PG_GETARG_BOOL(1);
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PG_RETURN_INT32((int32) a - (int32) b);
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}
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Datum
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btint2cmp(PG_FUNCTION_ARGS)
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{
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int16 a = PG_GETARG_INT16(0);
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int16 b = PG_GETARG_INT16(1);
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PG_RETURN_INT32((int32) a - (int32) b);
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}
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static int
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btint2fastcmp(Datum x, Datum y, SortSupport ssup)
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{
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int16 a = DatumGetInt16(x);
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int16 b = DatumGetInt16(y);
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return (int) a - (int) b;
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}
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Datum
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btint2sortsupport(PG_FUNCTION_ARGS)
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{
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SortSupport ssup = (SortSupport) PG_GETARG_POINTER(0);
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ssup->comparator = btint2fastcmp;
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PG_RETURN_VOID();
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}
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Datum
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btint4cmp(PG_FUNCTION_ARGS)
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{
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int32 a = PG_GETARG_INT32(0);
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int32 b = PG_GETARG_INT32(1);
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if (a > b)
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PG_RETURN_INT32(1);
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else if (a == b)
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PG_RETURN_INT32(0);
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else
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PG_RETURN_INT32(-1);
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}
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static int
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btint4fastcmp(Datum x, Datum y, SortSupport ssup)
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{
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int32 a = DatumGetInt32(x);
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int32 b = DatumGetInt32(y);
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if (a > b)
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return 1;
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else if (a == b)
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return 0;
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else
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return -1;
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}
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Datum
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btint4sortsupport(PG_FUNCTION_ARGS)
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{
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SortSupport ssup = (SortSupport) PG_GETARG_POINTER(0);
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ssup->comparator = btint4fastcmp;
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PG_RETURN_VOID();
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}
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Datum
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btint8cmp(PG_FUNCTION_ARGS)
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{
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int64 a = PG_GETARG_INT64(0);
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int64 b = PG_GETARG_INT64(1);
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if (a > b)
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PG_RETURN_INT32(1);
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else if (a == b)
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PG_RETURN_INT32(0);
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else
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PG_RETURN_INT32(-1);
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}
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static int
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btint8fastcmp(Datum x, Datum y, SortSupport ssup)
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{
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int64 a = DatumGetInt64(x);
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int64 b = DatumGetInt64(y);
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if (a > b)
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return 1;
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else if (a == b)
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return 0;
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else
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return -1;
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}
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Datum
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btint8sortsupport(PG_FUNCTION_ARGS)
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{
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SortSupport ssup = (SortSupport) PG_GETARG_POINTER(0);
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ssup->comparator = btint8fastcmp;
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PG_RETURN_VOID();
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}
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Datum
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btint48cmp(PG_FUNCTION_ARGS)
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{
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int32 a = PG_GETARG_INT32(0);
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int64 b = PG_GETARG_INT64(1);
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if (a > b)
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PG_RETURN_INT32(1);
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else if (a == b)
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PG_RETURN_INT32(0);
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else
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PG_RETURN_INT32(-1);
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}
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Datum
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btint84cmp(PG_FUNCTION_ARGS)
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{
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int64 a = PG_GETARG_INT64(0);
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int32 b = PG_GETARG_INT32(1);
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if (a > b)
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PG_RETURN_INT32(1);
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else if (a == b)
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PG_RETURN_INT32(0);
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else
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PG_RETURN_INT32(-1);
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}
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Datum
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btint24cmp(PG_FUNCTION_ARGS)
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{
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int16 a = PG_GETARG_INT16(0);
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int32 b = PG_GETARG_INT32(1);
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if (a > b)
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PG_RETURN_INT32(1);
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else if (a == b)
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PG_RETURN_INT32(0);
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else
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PG_RETURN_INT32(-1);
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}
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Datum
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btint42cmp(PG_FUNCTION_ARGS)
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{
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int32 a = PG_GETARG_INT32(0);
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int16 b = PG_GETARG_INT16(1);
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if (a > b)
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PG_RETURN_INT32(1);
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else if (a == b)
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PG_RETURN_INT32(0);
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else
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PG_RETURN_INT32(-1);
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}
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Datum
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btint28cmp(PG_FUNCTION_ARGS)
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{
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int16 a = PG_GETARG_INT16(0);
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int64 b = PG_GETARG_INT64(1);
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if (a > b)
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PG_RETURN_INT32(1);
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else if (a == b)
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PG_RETURN_INT32(0);
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else
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PG_RETURN_INT32(-1);
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}
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Datum
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btint82cmp(PG_FUNCTION_ARGS)
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{
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int64 a = PG_GETARG_INT64(0);
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int16 b = PG_GETARG_INT16(1);
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if (a > b)
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PG_RETURN_INT32(1);
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else if (a == b)
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PG_RETURN_INT32(0);
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else
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PG_RETURN_INT32(-1);
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}
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Datum
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btoidcmp(PG_FUNCTION_ARGS)
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{
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Oid a = PG_GETARG_OID(0);
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Oid b = PG_GETARG_OID(1);
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if (a > b)
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PG_RETURN_INT32(1);
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else if (a == b)
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PG_RETURN_INT32(0);
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else
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PG_RETURN_INT32(-1);
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}
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static int
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btoidfastcmp(Datum x, Datum y, SortSupport ssup)
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{
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Oid a = DatumGetObjectId(x);
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Oid b = DatumGetObjectId(y);
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if (a > b)
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return 1;
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else if (a == b)
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return 0;
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else
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return -1;
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}
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Datum
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btoidsortsupport(PG_FUNCTION_ARGS)
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{
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SortSupport ssup = (SortSupport) PG_GETARG_POINTER(0);
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ssup->comparator = btoidfastcmp;
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PG_RETURN_VOID();
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}
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Datum
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btoidvectorcmp(PG_FUNCTION_ARGS)
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{
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oidvector *a = (oidvector *) PG_GETARG_POINTER(0);
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oidvector *b = (oidvector *) PG_GETARG_POINTER(1);
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int i;
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/* We arbitrarily choose to sort first by vector length */
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if (a->dim1 != b->dim1)
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PG_RETURN_INT32(a->dim1 - b->dim1);
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for (i = 0; i < a->dim1; i++)
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{
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if (a->values[i] != b->values[i])
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{
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if (a->values[i] > b->values[i])
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PG_RETURN_INT32(1);
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else
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PG_RETURN_INT32(-1);
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}
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}
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PG_RETURN_INT32(0);
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}
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Datum
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btcharcmp(PG_FUNCTION_ARGS)
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{
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char a = PG_GETARG_CHAR(0);
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char b = PG_GETARG_CHAR(1);
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/* Be careful to compare chars as unsigned */
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PG_RETURN_INT32((int32) ((uint8) a) - (int32) ((uint8) b));
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}
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Datum
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btnamecmp(PG_FUNCTION_ARGS)
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{
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Name a = PG_GETARG_NAME(0);
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Name b = PG_GETARG_NAME(1);
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PG_RETURN_INT32(strncmp(NameStr(*a), NameStr(*b), NAMEDATALEN));
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}
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static int
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btnamefastcmp(Datum x, Datum y, SortSupport ssup)
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{
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Name a = DatumGetName(x);
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Name b = DatumGetName(y);
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return strncmp(NameStr(*a), NameStr(*b), NAMEDATALEN);
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}
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Datum
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btnamesortsupport(PG_FUNCTION_ARGS)
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{
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SortSupport ssup = (SortSupport) PG_GETARG_POINTER(0);
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ssup->comparator = btnamefastcmp;
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PG_RETURN_VOID();
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}
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