database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-07-30 11:03:19 +03:00
Code Activity

Add routines for text trimming on both ends, substring, and string position.

Browse Source 
Used to support SQL92 compatibility.
This commit is contained in:
Thomas G. Lockhart
1997-07-29 16:12:07 +00:00
parent d95c93bf99
commit bf138e2139
2 changed files with 147 additions and 39 deletions
Download Patch File Download Diff File Expand all files Collapse all files

89
src/backend/utils/adt/varlena.c
View File

@ -7,7 +7,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/utils/adt/varlena.c,v 1.16 1997/06/11 05:18:02 vadim Exp $
* $Header: /cvsroot/pgsql/src/backend/utils/adt/varlena.c,v 1.17 1997/07/29 16:12:07 thomas Exp $
*
*-------------------------------------------------------------------------
*/
@ -216,40 +216,81 @@ int textlen (text* t)
/*
* textcat -
* takes two text* and returns a text* that is the concatentation of
* the two
*/
/*
* Rewrited by Sapa, sapa@hq.icb.chel.su. 8-Jul-96.
* the two.
*
* Rewritten by Sapa, sapa@hq.icb.chel.su. 8-Jul-96.
* Updated by Thomas, Thomas.Lockhart@jpl.nasa.gov 1997-07-10.
* Allocate space for output in all cases.
* XXX - thomas 1997-07-10
* As in previous code, allow concatenation when one string is NULL.
* Is this OK?
*/
text*
textcat(text* t1, text* t2)
{
int len1, len2, newlen;
int len1, len2, len;
char *ptr;
text* result;
/* Check for NULL strings... */
if (t1 == NULL) return t2;
if (t2 == NULL) return t1;
if (!PointerIsValid(t1) && !PointerIsValid(t2))
return(NULL);
/* Check for ZERO-LENGTH strings... */
/* I use <= instead of == , I know - it's paranoia, but... */
if((len1 = VARSIZE(t1) - VARHDRSZ) <= 0) return t2;
if((len2 = VARSIZE(t2) - VARHDRSZ) <= 0) return t1;
len1 = (PointerIsValid(t1)? (VARSIZE(t1) - VARHDRSZ): 0);
if (len1 < 0) len1 = 0;
len2 = (PointerIsValid(t2)? (VARSIZE(t2) - VARHDRSZ): 0);
if (len2 < 0) len2 = 0;
result = (text *)palloc(newlen = len1 + len2 + VARHDRSZ);
result = PALLOC(len = len1 + len2 + VARHDRSZ);
/* Fill data field of result string... */
memcpy(ptr = VARDATA(result), VARDATA(t1), len1);
memcpy(ptr + len1, VARDATA(t2), len2);
ptr = VARDATA(result);
if (PointerIsValid(t1)) memcpy(ptr, VARDATA(t1), len1);
if (PointerIsValid(t2)) memcpy(ptr + len1, VARDATA(t2), len2);
/* Set size of result string... */
VARSIZE(result) = newlen;
VARSIZE(result) = len;
return result;
}
return(result);
} /* textcat() */
/*
* textpos -
* Return the position of the specified substring.
* Implements the SQL92 POSITION() function.
* Ref: A Guide To The SQL Standard, Date & Darwen, 1997
* - thomas 1997-07-27
*/
int32
textpos(text* t1, text* t2)
{
int pos;
int px, p;
int len1, len2;
char *p1, *p2;
if (!PointerIsValid(t1) || !PointerIsValid(t2))
return(0);
if (VARSIZE(t2) <= 0)
return(1);
len1 = (VARSIZE(t1) - VARHDRSZ);
len2 = (VARSIZE(t2) - VARHDRSZ);
p1 = VARDATA(t1);
p2 = VARDATA(t2);
pos = 0;
px = (len1 - len2);
for (p = 0; p <= px; p++) {
if ((*p2 == *p1) && (strncmp(p1, p2, len2) == 0)) {
pos = p + 1;
break;
};
p1++;
};
return(pos);
} /* textpos() */
/*
* texteq - returns 1 iff arguments are equal
@ -269,15 +310,15 @@ texteq(struct varlena *arg1, struct varlena *arg2)
a2p = arg2->vl_dat;
/*
* Varlenas are stored as the total size (data + size variable)
* followed by the data. The size variable is an int32 so the
* length of the data is the total length less sizeof(int32)
* followed by the data.
* Use VARHDRSZ instead of explicit sizeof() - thomas 1997-07-10
*/
len -= sizeof(int32);
len -= VARHDRSZ;
while (len-- != 0)
if (*a1p++ != *a2p++)
return((bool) 0);
return((bool) 1);
}
} /* texteq() */
bool
textne(struct varlena *arg1, struct varlena *arg2)