PATCH: zsh/regex and =~

[Phil Pennock <zsh-workers+phil.pennock@spodhuis.org>]

[-- Attachment #1: Type: text/plain, Size: 1425 bytes --]

[ Sorry for not having one diff which creates new files, but "cvs diff -N"
  seems to be ignoring that little 'N' ]

The attached patch and files, which includes documentation, adds a new
loadable module, zsh/regex.  I've not examined widechar issues and which
regex libraries actually do handle these.  I've not looked at linkage
issues on platforms where regex (the POSIX interface, not regexp) is not
a part of libc.

This also includes my previous =~ work, replacing the previous patch.
I'm not sure that auto-unsetting REMATCH_PCRE is a good idea, so invite
comments; also as to which should be the default value; I suppose that
if pcre is not the default, then the warning can be put back in ...

My only test platform has been freebsd/amd64.

I've also cleaned up various memory leaks in zsh/pcre.
zsh/pcre now also sets $MATCH, not just $match.

I went with having $BASH_REMATCH be set instead of, rather than in
addition to, $MATCH and $match.  I'm again very open to persuasion here.

Oh, and the copyright notice in regex.c seems a bit disjointed, with
multiple names.  What's the copyright policy on newly contributed files?

zsh/regex provides the -regex-match conditional operator, the knowledge
of -regex-match and -pcre-match remains in cond.c with the COND_REGEX
handling for =~.

Also, I've decided that I much prefer the PCRE API to the POSIX regex
API.  :-)  I'm off to drink more wine to recover.

-Phil

[-- Attachment #2: regex-both.patch --]
[-- Type: text/x-diff, Size: 16747 bytes --]

Index: Doc/Zsh/cond.yo
===================================================================
RCS file: /cvsroot/zsh/zsh/Doc/Zsh/cond.yo,v
retrieving revision 1.3
diff -p -u -r1.3 cond.yo
--- Doc/Zsh/cond.yo	22 May 2000 15:01:35 -0000	1.3
+++ Doc/Zsh/cond.yo	28 Apr 2007 07:42:51 -0000
@@ -109,6 +109,11 @@ backward compatibility and should be con
 item(var(string) tt(!=) var(pattern))(
 true if var(string) does not match var(pattern).
 )
+item(var(string) tt(=~) var(regexp))(
+true if var(string) matches the PCRE regular expression
+var(regexp).  Requires the tt(zsh/pcre) module to be present,
+which is a compile-time option.
+)
 item(var(string1) tt(<) var(string2))(
 true if var(string1) comes before var(string2)
 based on ASCII value of their characters.
Index: Doc/Zsh/mod_pcre.yo
===================================================================
RCS file: /cvsroot/zsh/zsh/Doc/Zsh/mod_pcre.yo,v
retrieving revision 1.5
diff -p -u -r1.5 mod_pcre.yo
--- Doc/Zsh/mod_pcre.yo	20 Jun 2004 22:47:18 -0000	1.5
+++ Doc/Zsh/mod_pcre.yo	28 Apr 2007 07:42:51 -0000
@@ -22,14 +22,17 @@ Studies the previously-compiled PCRE whi
 matching.
 )
 findex(pcre_match)
-item(tt(pcre_match) [ tt(-a) var(arr) ] var(string))(
+item(tt(pcre_match) [ tt(-v) var(var) ] [ tt(-a) var(arr) ] var(string))(
 Returns successfully if tt(string) matches the previously-compiled
 PCRE.
 
 If the expression captures substrings within parentheses,
 tt(pcre_match) will set the array var($match) to those
 substrings, unless the tt(-a) option is given, in which
-case it will set the array var(arr).
+case it will set the array var(arr).  Similarly, the variable
+var($MATCH) will be set to the entire matched portion of the
+string, unless the tt(-v) option is given, in which var it will
+set the variable var(var).
 )
 enditem()
 
Index: Doc/Zsh/options.yo
===================================================================
RCS file: /cvsroot/zsh/zsh/Doc/Zsh/options.yo,v
retrieving revision 1.53
diff -p -u -r1.53 options.yo
--- Doc/Zsh/options.yo	5 Mar 2007 17:35:18 -0000	1.53
+++ Doc/Zsh/options.yo	28 Apr 2007 07:42:51 -0000
@@ -478,6 +478,19 @@ var(xx) is set to tt(LPAR())var(a b c)tt
 `var(fooabar foobbar foocbar)' instead of the default
 `var(fooa b cbar)'.
 )
+pindex(REMATCH_PCRE)
+cindex(regexp, PCRE)
+cindex(PCRE, regexp)
+item(tt(REMATCH_PCRE) <Z>)(
+If set, regular expression matching with the tt(=~) operator will use
+Perl-Compatible Regular Expressions from the PCRE library, if available.
+If not set, regular expressions will use the extended regexp syntax
+provided by the system libraries.
+Experimental:
+When zsh is invoked as tt(zsh), this option is initially set, but may be
+unset if the tt(zsh/pcre) module can not be loaded.  This behaviour, as
+well as the default status, is subject to change.
+)
 pindex(SH_GLOB)
 cindex(sh, globbing style)
 cindex(globbing style, sh)
@@ -1131,6 +1144,20 @@ enditem()
 
 subsect(Shell Emulation)
 startitem()
+pindex(BASH_REMATCH)
+cindex(bash, BASH_REMATCH variable)
+cindex(regexp, bash BASH_REMATCH variable)
+item(tt(BASH_REMATCH))(
+When set, matches performed with the tt(=~) operator will set the
+tt(BASH_REMATCH) array variable, instead of the default tt(MATCH) and
+tt(match) variables.  The first element of the tt(BASH_REMATCH) array
+will contain the entire matched text and subsequent elements will contain
+extracted substrings.  This option makes more sense when tt(KSH_ARRAYS) is
+also set, so that the entire matched portion is stored at index 0 and the
+first substring is at index 1.  Without this option, the tt(MATCH) variable
+contains the entire matched text and the tt(match) array variable will
+the substrings.
+)
 pindex(BSD_ECHO)
 cindex(echo, BSD compatible)
 item(tt(BSD_ECHO) <S>)(
Index: Src/cond.c
===================================================================
RCS file: /cvsroot/zsh/zsh/Src/cond.c,v
retrieving revision 1.8
diff -p -u -r1.8 cond.c
--- Src/cond.c	30 May 2006 22:35:03 -0000	1.8
+++ Src/cond.c	28 Apr 2007 07:42:51 -0000
@@ -34,7 +34,7 @@ int tracingcond;
 
 static char *condstr[COND_MOD] = {
     "!", "&&", "||", "==", "!=", "<", ">", "-nt", "-ot", "-ef", "-eq",
-    "-ne", "-lt", "-gt", "-le", "-ge"
+    "-ne", "-lt", "-gt", "-le", "-ge", "=~"
 };
 
 /*
@@ -53,14 +53,14 @@ int
 evalcond(Estate state, char *fromtest)
 {
     struct stat *st;
-    char *left, *right;
+    char *left, *right, *overridename;
     Wordcode pcode;
     wordcode code;
     int ctype, htok = 0, ret;
 
  rec:
 
-    left = right = NULL;
+    left = right = overridename = NULL;
     pcode = state->pc++;
     code = *pcode;
     ctype = WC_COND_TYPE(code);
@@ -92,13 +92,42 @@ evalcond(Estate state, char *fromtest)
 	    state->pc = pcode + (WC_COND_SKIP(code) + 1);
 	    return ret;
 	}
+    case COND_REGEX:
+	{
+	    int loaded = 0;
+	    if (isset(REMATCHPCRE)) {
+		loaded = load_module_silence("zsh/pcre", 1);
+		if (loaded) {
+		    overridename = "-pcre-match";
+		} else {
+		    dosetopt(REMATCHPCRE, 0, 1);
+#if 0
+		    zwarnnam(fromtest, "zsh/pcre not available for regex");
+		    return 2;
+#endif
+		}
+	    }
+	    if (!loaded) {
+		loaded = load_module_silence("zsh/regex", 1);
+		if (loaded) {
+		    overridename = "-regex-match";
+		} else {
+		    zwarnnam(fromtest, "zsh/regex not available for regex");
+		    return 2;
+		}
+	    }
+	    ctype = COND_MODI;
+	}
     case COND_MOD:
     case COND_MODI:
 	{
 	    Conddef cd;
-	    char *name = ecgetstr(state, EC_NODUP, NULL), **strs;
+	    char *name = overridename;
+	    char **strs;
 	    int l = WC_COND_SKIP(code);
 
+	    if (name == NULL)
+		name = ecgetstr(state, EC_NODUP, NULL);
 	    if (ctype == COND_MOD)
 		strs = ecgetarr(state, l, EC_DUP, NULL);
 	    else {
@@ -139,7 +168,8 @@ evalcond(Estate state, char *fromtest)
 		    return !cd->handler(strs, cd->condid);
 		} else {
 		    zwarnnam(fromtest,
-			     "unrecognized condition: `%s'", name);
+			     "unrecognized condition: `%s'",
+			     name ? name : "<null>");
 		}
 	    }
 	    /* module not found, error */
Index: Src/options.c
===================================================================
RCS file: /cvsroot/zsh/zsh/Src/options.c,v
retrieving revision 1.35
diff -p -u -r1.35 options.c
--- Src/options.c	15 Mar 2007 15:16:58 -0000	1.35
+++ Src/options.c	28 Apr 2007 07:42:51 -0000
@@ -88,6 +88,7 @@ static struct optname optns[] = {
 {{NULL, "banghist",	      OPT_NONBOURNE},		 BANGHIST},
 {{NULL, "bareglobqual",       OPT_EMULATE|OPT_ZSH},      BAREGLOBQUAL},
 {{NULL, "bashautolist",	      0},                        BASHAUTOLIST},
+{{NULL, "bashrematch",	      0},			 BASHREMATCH},
 {{NULL, "beep",		      OPT_ALL},			 BEEP},
 {{NULL, "bgnice",	      OPT_EMULATE|OPT_NONBOURNE},BGNICE},
 {{NULL, "braceccl",	      OPT_EMULATE},		 BRACECCL},
@@ -201,6 +202,7 @@ static struct optname optns[] = {
 {{NULL, "rcquotes",	      OPT_EMULATE},		 RCQUOTES},
 {{NULL, "rcs",		      OPT_ALL},			 RCS},
 {{NULL, "recexact",	      0},			 RECEXACT},
+{{NULL, "rematchpcre",	      OPT_ZSH},			 REMATCHPCRE},
 {{NULL, "restricted",	      OPT_SPECIAL},		 RESTRICTED},
 {{NULL, "rmstarsilent",	      OPT_BOURNE},		 RMSTARSILENT},
 {{NULL, "rmstarwait",	      0},			 RMSTARWAIT},
Index: Src/parse.c
===================================================================
RCS file: /cvsroot/zsh/zsh/Src/parse.c,v
retrieving revision 1.64
diff -p -u -r1.64 parse.c
--- Src/parse.c	23 Apr 2007 17:24:23 -0000	1.64
+++ Src/parse.c	28 Apr 2007 07:42:52 -0000
@@ -2124,6 +2124,12 @@ par_cond_triple(char *a, char *b, char *
 	ecstr(a);
 	ecstr(c);
 	ecadd(ecnpats++);
+    } else if ((b[0] == Equals || b[0] == '=') &&
+               (b[1] == '~' || b[1] == Tilde) && ~b[2]) {
+	ecadd(WCB_COND(COND_REGEX, 0));
+	ecstr(a);
+	ecstr(c);
+	ecadd(ecnpats++);
     } else if (b[0] == '-') {
 	if ((t0 = get_cond_num(b + 1)) > -1) {
 	    ecadd(WCB_COND(t0 + COND_NT, 0));
Index: Src/text.c
===================================================================
RCS file: /cvsroot/zsh/zsh/Src/text.c,v
retrieving revision 1.19
diff -p -u -r1.19 text.c
--- Src/text.c	23 Apr 2007 15:24:00 -0000	1.19
+++ Src/text.c	28 Apr 2007 07:42:52 -0000
@@ -640,7 +640,7 @@ gettext2(Estate state)
 	    {
 		static char *c1[] = {
 		    "=", "!=", "<", ">", "-nt", "-ot", "-ef", "-eq",
-		    "-ne", "-lt", "-gt", "-le", "-ge"
+		    "-ne", "-lt", "-gt", "-le", "-ge", "=~"
 		};
 
 		int ctype;
@@ -724,7 +724,7 @@ gettext2(Estate state)
 			}
 			break;
 		    default:
-			if (ctype <= COND_GE) {
+			if (ctype < COND_MOD) {
 			    /* Binary test: `a = b' etc. */
 			    taddstr(ecgetstr(state, EC_NODUP, NULL));
 			    taddstr(" ");
Index: Src/zsh.h
===================================================================
RCS file: /cvsroot/zsh/zsh/Src/zsh.h,v
retrieving revision 1.112
diff -p -u -r1.112 zsh.h
--- Src/zsh.h	29 Mar 2007 21:35:39 -0000	1.112
+++ Src/zsh.h	28 Apr 2007 07:42:53 -0000
@@ -519,8 +519,9 @@ struct timedfn {
 #define COND_GT    13
 #define COND_LE    14
 #define COND_GE    15
-#define COND_MOD   16
-#define COND_MODI  17
+#define COND_REGEX 16
+#define COND_MOD   17
+#define COND_MODI  18
 
 typedef int (*CondHandler) _((char **, int));
 
@@ -1588,6 +1589,7 @@ enum {
     BANGHIST,
     BAREGLOBQUAL,
     BASHAUTOLIST,
+    BASHREMATCH,
     BEEP,
     BGNICE,
     BRACECCL,
@@ -1695,6 +1697,7 @@ enum {
     RCQUOTES,
     RCS,
     RECEXACT,
+    REMATCHPCRE,
     RESTRICTED,
     RMSTARSILENT,
     RMSTARWAIT,
Index: Src/Modules/pcre.c
===================================================================
RCS file: /cvsroot/zsh/zsh/Src/Modules/pcre.c,v
retrieving revision 1.11
diff -p -u -r1.11 pcre.c
--- Src/Modules/pcre.c	5 Apr 2007 16:20:15 -0000	1.11
+++ Src/Modules/pcre.c	28 Apr 2007 07:42:53 -0000
@@ -3,7 +3,7 @@
  *
  * This file is part of zsh, the Z shell.
  *
- * Copyright (c) 2001, 2002, 2003, 2004 Clint Adams
+ * Copyright (c) 2001, 2002, 2003, 2004, 2007 Clint Adams
  * All rights reserved.
  *
  * Permission is hereby granted, without written agreement and without
@@ -42,6 +42,37 @@ static pcre_extra *pcre_hints;
 
 /**/
 static int
+zpcre_utf8_enabled(void)
+{
+#if defined(MULTIBYTE_SUPPORT) && defined(HAVE_NL_LANGINFO) && defined(CODESET)
+    static int have_utf8_pcre = -1;
+
+    /* value can toggle based on MULTIBYTE, so don't
+     * be too eager with caching */
+    if (have_utf8_pcre < -1)
+	return 0;
+
+    if (!isset(MULTIBYTE))
+	return 0;
+
+    if ((have_utf8_pcre == -1) &&
+        (!strcmp(nl_langinfo(CODESET), "UTF-8"))) {
+
+	if (pcre_config(PCRE_CONFIG_UTF8, &have_utf8_pcre))
+	    have_utf8_pcre = -2; /* erk, failed to ask */
+    }
+
+    if (have_utf8_pcre < 0)
+	return 0;
+    return have_utf8_pcre;
+
+#else
+    return 0;
+#endif
+}
+
+/**/
+static int
 bin_pcre_compile(char *nam, char **args, Options ops, UNUSED(int func))
 {
     int pcre_opts = 0, pcre_errptr;
@@ -52,8 +83,14 @@ bin_pcre_compile(char *nam, char **args,
     if(OPT_ISSET(ops,'m')) pcre_opts |= PCRE_MULTILINE;
     if(OPT_ISSET(ops,'x')) pcre_opts |= PCRE_EXTENDED;
     
+    if (zpcre_utf8_enabled())
+	pcre_opts |= PCRE_UTF8;
+
     pcre_hints = NULL;  /* Is this necessary? */
     
+    if (pcre_pattern)
+	pcre_free(pcre_pattern);
+
     pcre_pattern = pcre_compile(*args, pcre_opts, &pcre_error, &pcre_errptr, NULL);
     
     if (pcre_pattern == NULL)
@@ -100,37 +137,52 @@ bin_pcre_study(char *nam, UNUSED(char **
 
 /**/
 static int
-zpcre_get_substrings(char *arg, int *ovec, int ret, char *receptacle)
+zpcre_get_substrings(char *arg, int *ovec, int ret, char *matchvar, char *substravar, int matchedinarr)
 {
-    char **captures, **matches;
+    char **captures, **match_all, **matches;
+    int capture_start = 1;
 
-	if(!pcre_get_substring_list(arg, ovec, ret, (const char ***)&captures)) {
-	    
-	    matches = zarrdup(&captures[1]); /* first one would be entire string */
-	    if (receptacle == NULL)
-		setaparam("match", matches);
-	    else
-		setaparam(receptacle, matches);
-	    
-	    pcre_free_substring_list((const char **)captures);
-	}
+    if (matchedinarr)
+	capture_start = 0;
+    if (matchvar == NULL)
+	matchvar = "MATCH";
+    if (substravar == NULL)
+	substravar = "match";
+
+    /* captures[0] will be entire matched string, [1] first substring */
+    if(!pcre_get_substring_list(arg, ovec, ret, (const char ***)&captures)) {
+	match_all = ztrdup(captures[0]);
+	setsparam(matchvar, match_all);
+	matches = zarrdup(&captures[capture_start]);
+	setaparam(substravar, matches);
+	pcre_free_substring_list((const char **)captures);
+    }
 
-	return 0;
+    return 0;
 }
 
 /**/
 static int
 bin_pcre_match(char *nam, char **args, Options ops, UNUSED(int func))
 {
-    int ret, capcount, *ovec, ovecsize;
+    int ret, capcount, *ovec, ovecsize, c;
+    char *matched_portion = NULL;
     char *receptacle = NULL;
+    int return_value = 1;
+
+    if (pcre_pattern == NULL) {
+	zwarnnam(nam, "no pattern has been compiled");
+	return 1;
+    }
     
-    if(OPT_ISSET(ops,'a')) {
-	receptacle = *args++;
-	if(!*args) {
-	    zwarnnam(nam, "not enough arguments");
-	    return 1;
-	}
+    if(OPT_HASARG(ops,c='a')) {
+	receptacle = OPT_ARG(ops,c);
+    }
+    if(OPT_HASARG(ops,c='v')) {
+	matched_portion = OPT_ARG(ops,c);
+    }
+    if(!*args) {
+	zwarnnam(nam, "not enough arguments");
     }
     
     if ((ret = pcre_fullinfo(pcre_pattern, pcre_hints, PCRE_INFO_CAPTURECOUNT, &capcount)))
@@ -144,18 +196,20 @@ bin_pcre_match(char *nam, char **args, O
     
     ret = pcre_exec(pcre_pattern, pcre_hints, *args, strlen(*args), 0, 0, ovec, ovecsize);
     
-    if (ret==0) return 0;
-    else if (ret==PCRE_ERROR_NOMATCH) return 1; /* no match */
+    if (ret==0) return_value = 0;
+    else if (ret==PCRE_ERROR_NOMATCH) /* no match */;
     else if (ret>0) {
-	zpcre_get_substrings(*args, ovec, ret, receptacle);
-	return 0;
+	zpcre_get_substrings(*args, ovec, ret, matched_portion, receptacle, 0);
+	return_value = 0;
     }
     else {
 	zwarnnam(nam, "error in pcre_exec");
-	return 1;
     }
     
-    return 1;
+    if (ovec)
+	zfree(ovec, ovecsize*sizeof(int));
+
+    return return_value;
 }
 
 /**/
@@ -164,33 +218,63 @@ cond_pcre_match(char **a, int id)
 {
     pcre *pcre_pat;
     const char *pcre_err;
-    char *lhstr, *rhre;
+    char *lhstr, *rhre, *avar=NULL;
     int r = 0, pcre_opts = 0, pcre_errptr, capcnt, *ov, ovsize;
+    int return_value = 0;
+
+    if (zpcre_utf8_enabled())
+	pcre_opts |= PCRE_UTF8;
 
     lhstr = cond_str(a,0,0);
     rhre = cond_str(a,1,0);
+    pcre_pat = ov = NULL;
+
+    if (isset(BASHREMATCH))
+	avar="BASH_REMATCH";
 
     switch(id) {
 	 case CPCRE_PLAIN:
-		 pcre_pat = pcre_compile(rhre, pcre_opts, &pcre_err, &pcre_errptr, NULL);
-                 pcre_fullinfo(pcre_pat, NULL, PCRE_INFO_CAPTURECOUNT, &capcnt);
-    		 ovsize = (capcnt+1)*3;
-		 ov = zalloc(ovsize*sizeof(int));
-    		 r = pcre_exec(pcre_pat, NULL, lhstr, strlen(lhstr), 0, 0, ov, ovsize);
-    		if (r==0) return 1;
+		pcre_pat = pcre_compile(rhre, pcre_opts, &pcre_err, &pcre_errptr, NULL);
+		if (pcre_pat == NULL) {
+		    zwarn("failed to compile regexp /%s/: %s", rhre, pcre_err);
+		    break;
+		}
+                pcre_fullinfo(pcre_pat, NULL, PCRE_INFO_CAPTURECOUNT, &capcnt);
+    		ovsize = (capcnt+1)*3;
+		ov = zalloc(ovsize*sizeof(int));
+    		r = pcre_exec(pcre_pat, NULL, lhstr, strlen(lhstr), 0, 0, ov, ovsize);
+		/* r < 0 => error; r==0 match but not enough size in ov
+		 * r > 0 => (r-1) substrings found; r==1 => no substrings
+		 */
+    		if (r==0) {
+		    zwarn("reportable zsh problem: pcre_exec() returned 0");
+		    return_value = 1;
+		    break;
+		}
 	        else if (r==PCRE_ERROR_NOMATCH) return 0; /* no match */
+		else if (r<0) {
+		    zwarn("pcre_exec() error: %d", r);
+		    break;
+		}
                 else if (r>0) {
-		    zpcre_get_substrings(lhstr, ov, r, NULL);
-		    return 1;
+		    zpcre_get_substrings(lhstr, ov, r, NULL, avar, isset(BASHREMATCH));
+		    return_value = 1;
+		    break;
 		}
 		break;
     }
 
-    return 0;
+    if (pcre_pat)
+	pcre_free(pcre_pat);
+    if (ov)
+	zfree(ov, ovsize*sizeof(int));
+
+    return return_value;
 }
 
 static struct conddef cotab[] = {
     CONDDEF("pcre-match", CONDF_INFIX, cond_pcre_match, 0, 0, CPCRE_PLAIN)
+    /* CONDDEF can register =~ but it won't be found */
 };
 
 /**/
@@ -206,7 +290,7 @@ static struct conddef cotab[] = {
 static struct builtin bintab[] = {
     BUILTIN("pcre_compile", 0, bin_pcre_compile, 1, 1, 0, "aimx",  NULL),
     BUILTIN("pcre_study",   0, bin_pcre_study,   0, 0, 0, NULL,    NULL),
-    BUILTIN("pcre_match",   0, bin_pcre_match,   1, 2, 0, "a",    NULL)
+    BUILTIN("pcre_match",   0, bin_pcre_match,   1, 1, 0, "a:v:",    NULL)
 };
 
 

[-- Attachment #3: regex.mdd --]
[-- Type: text/plain, Size: 68 bytes --]

name=zsh/regex
link=dynamic
load=no

autobins=""

objects="regex.o"

[-- Attachment #4: regex.c --]
[-- Type: text/x-csrc, Size: 3879 bytes --]

/*
 * regex.c
 *
 * This file is part of zsh, the Z shell.
 *
 * Copyright (c) 2007 Phil Pennock
 * All Rights Reserved.
 *
 * Permission is hereby granted, without written agreement and without
 * license or royalty fees, to use, copy, modify, and distribute this
 * software and to distribute modified versions of this software for any
 * purpose, provided that the above copyright notice and the following
 * two paragraphs appear in all copies of this software.
 *
 * In no event shall Clint Adams or the Zsh Development Group be liable
 * to any party for direct, indirect, special, incidental, or consequential
 * damages arising out of the use of this software and its documentation,
 * even if Andrew Main and the Zsh Development Group have been advised of
 * the possibility of such damage.
 *
 * Clint Adams and the Zsh Development Group specifically disclaim any
 * warranties, including, but not limited to, the implied warranties of
 * merchantability and fitness for a particular purpose.  The software
 * provided hereunder is on an "as is" basis, and Andrew Main and the
 * Zsh Development Group have no obligation to provide maintenance,
 * support, updates, enhancements, or modifications.
 *
 */

#include "regex.mdh"
#include "regex.pro"

#include <regex.h>

/* we default to a vaguely modern syntax and set of capabilities */
#define ZREGEX_EXTENDED 0
/* if you want Basic syntax, make it an alternative options */

static void
zregex_regerrwarn(int r, regex_t *re, char *msg)
{
    char *errbuf;
    size_t errbufsz;

    errbufsz = regerror(r, re, NULL, 0);
    errbuf = zalloc(errbufsz*sizeof(char));
    regerror(r, re, errbuf, errbufsz);
    zwarn("%s: %s", msg, errbuf);
    zfree(errbuf, errbufsz);
}

/**/
static int
zcond_regex_match(char **a, int id)
{
    regex_t re;
    regmatch_t *m, *matches = NULL;
    size_t matchessz;
    char *lhstr, *rhre, *s, **arr, **x;
    int r, n, return_value, rcflags, reflags, nelem, start;

    lhstr = cond_str(a,0,0);
    rhre = cond_str(a,1,0);
    rcflags = reflags = 0;
    return_value = 0; /* 1 => matched successfully */

    switch(id) {
    case ZREGEX_EXTENDED:
	rcflags |= REG_EXTENDED;
	r = regcomp(&re, rhre, rcflags);
	if (r) {
	    zregex_regerrwarn(r, &re, "failed to compile regex");
	    break;
	}
	/* re.re_nsub is number of parenthesized groups, we also need
	 * 1 for the 0 offset, which is the entire matched portion
	 */
	matchessz = (re.re_nsub + 1) * sizeof(regmatch_t);
	matches = zalloc(matchessz);
	r = regexec(&re, lhstr, re.re_nsub+1, matches, reflags);
	if (r == REG_NOMATCH) /**/;
	else if (r == 0) {
	    return_value = 1;
	    if (isset(BASHREMATCH)) {
		start = 0;
		nelem = re.re_nsub + 1;
	    } else {
		start = 1;
		nelem = re.re_nsub;
	    }
	    /* entire matched portion + re_nsub substrings + NULL */
	    if (nelem) {
		arr = x = (char **) zalloc(sizeof(char *) * (nelem + 1));
		for (m = matches + start, n = start; n <= re.re_nsub; ++n, ++m, ++x) {
		    *x = ztrduppfx(lhstr + m->rm_so, m->rm_eo - m->rm_so);
		}
		*x = NULL;
	    }
	    if (isset(BASHREMATCH)) {
		setaparam("BASH_REMATCH", arr);
	    } else {
		m = matches;
		s = ztrduppfx(lhstr + m->rm_so, m->rm_eo - m->rm_so);
		setsparam("MATCH", s);
		if (nelem)
		    setaparam("match", arr);
	    }
	}
	else zregex_regerrwarn(r, &re, "regex matching error");
	break;
    }

    if (matches)
	zfree(matches, matchessz);
    regfree(&re);
    return return_value;
}

static struct conddef cotab[] = {
    CONDDEF("regex-match", CONDF_INFIX, zcond_regex_match, 0, 0, ZREGEX_EXTENDED)
};

/**/
int
setup_(UNUSED(Module m))
{
    return 0;
}

/**/
int
boot_(Module m)
{
    return !addconddefs(m->nam, cotab, sizeof(cotab)/sizeof(*cotab));
}

/**/
int
cleanup_(Module m)
{
    deleteconddefs(m->nam, cotab, sizeof(cotab)/sizeof(*cotab));
    return 0;
}

/**/
int
finish_(UNUSED(Module m))
{
    return 0;
}