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Diffstat (limited to 'src/backend/utils/adt/like.c')
| -rw-r--r-- | src/backend/utils/adt/like.c | 225 |
1 files changed, 225 insertions, 0 deletions
diff --git a/src/backend/utils/adt/like.c b/src/backend/utils/adt/like.c new file mode 100644 index 00000000000..e33e66ee62d --- /dev/null +++ b/src/backend/utils/adt/like.c @@ -0,0 +1,225 @@ +/*------------------------------------------------------------------------- + * + * like.c-- + * like expression handling code. + * + * Copyright (c) 1994, Regents of the University of California + * + * + * IDENTIFICATION + * /usr/local/devel/pglite/cvs/src/backend/utils/adt/like.c,v 1.1 1995/07/30 23:55:36 emkxp01 Exp + * + * + * NOTES + * A big hack of the regexp.c code!! Contributed by + * Keith Parks <emkxp01@mtcc.demon.co.uk> (7/95). + * + * + *------------------------------------------------------------------------- + */ +#include <string.h> +#include "postgres.h" /* postgres system include file */ +#include "utils/elog.h" /* for logging postgres errors */ +#include "utils/palloc.h" +#include "utils/builtins.h" /* where the function declarations go */ + +int like(char *text, char *p); + +/* + * interface routines called by the function manager + */ + +/* + fixedlen_like: + + a generic fixed length like routine + s - the string to match against (not necessarily null-terminated) + p - the pattern + charlen - the length of the string +*/ +static bool +fixedlen_like(char *s, struct varlena* p, int charlen) +{ + char *sterm, *pterm; + int result; + + if (!s || !p) + return FALSE; + + /* be sure sterm is null-terminated */ + sterm = (char *) palloc(charlen + 1); + memset(sterm, 0, charlen + 1); + strncpy(sterm, s, charlen); + + /* p is a text = varlena, not a string so we have to make + * a string from the vl_data field of the struct. */ + + /* palloc the length of the text + the null character */ + pterm = (char *) palloc(VARSIZE(p) - VARHDRSZ + 1); + memmove(pterm, VARDATA(p), VARSIZE(p) - VARHDRSZ); + *(pterm + VARSIZE(p) - VARHDRSZ) = (char)NULL; + + /* do the regexp matching */ + result = like(sterm, pterm); + + pfree(sterm); + pfree(pterm); + + return ((bool) result); +} + +bool +char2like(uint16 arg1, struct varlena *p) +{ + char *s = (char *) &arg1; + return (fixedlen_like(s, p, 2)); +} + +bool +char2nlike(uint16 arg1, struct varlena *p) +{ + return (!char2like(arg1, p)); +} + +bool +char4like(uint32 arg1, struct varlena *p) +{ + char *s = (char *) &arg1; + return (fixedlen_like(s, p, 4)); +} + +bool +char4nlike(uint32 arg1, struct varlena *p) +{ + return (!char4like(arg1, p)); +} + +bool +char8like(char *s, struct varlena *p) +{ + return (fixedlen_like(s, p, 8)); +} + +bool +char8nlike(char *s, struct varlena *p) +{ + return (!char8like(s, p)); +} + +bool +char16like(char *s, struct varlena *p) +{ + return (fixedlen_like(s, p, 16)); +} +bool +char16nlike(char *s, struct varlena *p) +{ + return (!char16like(s, p)); +} + +bool +namelike(NameData *n, struct varlena *p) +{ + return (fixedlen_like(n->data, p, NAMEDATALEN)); +} + +bool +namenlike(NameData *s, struct varlena *p) +{ + return (!namelike(s, p)); +} + +bool +textlike(struct varlena *s, struct varlena *p) +{ + return (fixedlen_like(VARDATA(s), p, VARSIZE(s) - VARHDRSZ)); +} + +bool textnlike(struct varlena *s, struct varlena *p) +{ + return (!textlike(s, p)); +} + + +/* $Revision: 1.1.1.1 $ +** "like.c" A first attempt at a LIKE operator for Postgres95. +** +** Originally written by Rich $alz, mirror!rs, Wed Nov 26 19:03:17 EST 1986. +** Rich $alz is now <rsalz@bbn.com>. +** Special thanks to Lars Mathiesen <thorinn@diku.dk> for the LABORT code. +** +** This code was shamelessly stolen from the "pql" code by myself and +** slightly modified :) +** +** All references to the word "star" were replaced by "percent" +** All references to the word "wild" were replaced by "like" +** +** All the nice shell RE matching stuff was replaced by just "_" and "%" +** +** As I don't have a copy of the SQL standard handy I wasn't sure whether +** to leave in the '\' escape character handling. (I suspect the standard +** handles "%%" as a single literal percent) +** +** Keith Parks. <keith@mtcc.demon.co.uk> +** +** [SQL92 lets you specify the escape character by saying +** LIKE <pattern> ESCAPE <escape character>. We are a small operation +** so we force you to use '\'. - ay 7/95] +** +*/ + +#define LIKE_TRUE 1 +#define LIKE_FALSE 0 +#define LIKE_ABORT -1 + +/* +** Match text and p, return LIKE_TRUE, LIKE_FALSE, or LIKE_ABORT. +*/ +static int +DoMatch(register char *text, register char *p) +{ + register int matched; + + for ( ; *p; text++, p++) { + if (*text == '\0' && *p != '%') + return LIKE_ABORT; + switch (*p) { + case '\\': + /* Literal match with following character. */ + p++; + /* FALLTHROUGH */ + default: + if (*text != *p) + return LIKE_FALSE; + continue; + case '_': + /* Match anything. */ + continue; + case '%': + while (*++p == '%') + /* Consecutive percents act just like one. */ + continue; + if (*p == '\0') + /* Trailing percent matches everything. */ + return LIKE_TRUE; + while (*text) + if ((matched = DoMatch(text++, p)) != LIKE_FALSE) + return matched; + return LIKE_ABORT; + } + } + + return *text == '\0'; +} + + +/* +** User-level routine. Returns TRUE or FALSE. +*/ +int +like(char *text, char *p) +{ + if (p[0] == '%' && p[1] == '\0') + return TRUE; + return (DoMatch(text, p) == LIKE_TRUE); +} |