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/*-------------------------------------------------------------------------
*
* nbtcompare.c--
* Comparison functions for btree access method.
*
* Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/access/nbtree/nbtcompare.c,v 1.4 1996/11/03 22:57:48 scrappy Exp $
*
* NOTES
* These functions are stored in pg_amproc. For each operator class
* defined on btrees, they compute
*
* compare(a, b):
* < 0 if a < b,
* = 0 if a == b,
* > 0 if a > b.
*-------------------------------------------------------------------------
*/
#include <string.h>
#include "postgres.h"
#include "utils/nabstime.h"
int32
btint2cmp(int16 a, int16 b)
{
return ((int32) (a - b));
}
int32
btint4cmp(int32 a, int32 b)
{
return (a - b);
}
int32
btint24cmp(int16 a, int32 b)
{
return (((int32) a) - b);
}
int32
btint42cmp(int32 a, int16 b)
{
return (a - ((int32) b));
}
int32
btfloat4cmp(float32 a, float32 b)
{
if (*a > *b)
return (1);
else if (*a == *b)
return (0);
else
return (-1);
}
int32
btfloat8cmp(float64 a, float64 b)
{
if (*a > *b)
return (1);
else if (*a == *b)
return (0);
else
return (-1);
}
int32
btoidcmp(Oid a, Oid b)
{
if (a > b)
return (1);
else if (a == b)
return (0);
else
return (-1);
}
int32
btabstimecmp(AbsoluteTime a, AbsoluteTime b)
{
if (AbsoluteTimeIsBefore(a, b))
return (1);
else if (AbsoluteTimeIsBefore(b, a))
return (-1);
else
return (0);
}
int32
btcharcmp(char a, char b)
{
return ((int32) (a - b));
}
int32
btchar2cmp(uint16 a, uint16 b)
{
return (strncmp((char *) &a, (char *) &b, 2));
}
int32
btchar4cmp(uint32 a, uint32 b)
{
return (strncmp((char *) &a, (char *) &b, 4));
}
int32
btchar8cmp(char *a, char *b)
{
return (strncmp(a, b, 8));
}
int32
btchar16cmp(char *a, char *b)
{
return (strncmp(a, b, 16));
}
int32
btnamecmp(NameData *a, NameData *b)
{
return (strncmp(a->data, b->data, NAMEDATALEN));
}
int32
bttextcmp(struct varlena *a, struct varlena *b)
{
char *ap, *bp;
int len;
int res;
ap = VARDATA(a);
bp = VARDATA(b);
/* len is the length of the shorter of the two strings */
if ((len = VARSIZE(a)) > VARSIZE(b))
len = VARSIZE(b);
/* len includes the four bytes in which string length is stored */
len -= sizeof(VARSIZE(a));
/*
* If the two strings differ in the first len bytes, or if they're
* the same in the first len bytes and they're both len bytes long,
* we're done.
*/
res = 0;
if (len > 0) {
do {
res = (int) (*ap++ - *bp++);
len--;
} while (res == 0 && len != 0);
}
if (res != 0 || VARSIZE(a) == VARSIZE(b))
return (res);
/*
* The two strings are the same in the first len bytes, and they
* are of different lengths.
*/
if (VARSIZE(a) < VARSIZE(b))
return (-1);
else
return (1);
}
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