Postgres95 1.01 Distribution - Virgin Sources

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);
+}