diff options
Diffstat (limited to 'src/backend/utils/adt/varlena.c')
| -rw-r--r-- | src/backend/utils/adt/varlena.c | 89 |
1 files changed, 65 insertions, 24 deletions
diff --git a/src/backend/utils/adt/varlena.c b/src/backend/utils/adt/varlena.c index d33ea702bbb..91bfdfaca23 100644 --- a/src/backend/utils/adt/varlena.c +++ b/src/backend/utils/adt/varlena.c @@ -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) |