From 540d3f60f378ed26962501c33b335623fe5fb0fa Mon Sep 17 00:00:00 2001 From: Rob Landley Date: Mon, 9 May 2005 21:42:42 +0000 Subject: Patch from Shaun Jackman: > This patch modfies expr to use portable POSIX regex rather than BSD > regex. ... > This updated patch implements an anchored regex by checking that the > match starts at offset 0. More to the point, this patch uses the same regex that sed.c is already using (opportunity to suck in less library code), and even building a dynamically linked busybox with just expr the result is a slightly smaller binary (by 94 bytes, I dunno what nm --size-sort has to say about it because I didn't build with debug info, since that changes the binary size a lot by disabling optimization...) Your mileage may vary. Handle with caution. Do not taunt happy fun ball. --- coreutils/expr.c | 37 +++++++++++++++---------------------- 1 file changed, 15 insertions(+), 22 deletions(-) (limited to 'coreutils/expr.c') diff --git a/coreutils/expr.c b/coreutils/expr.c index cbbd4cd03..3f052d92a 100644 --- a/coreutils/expr.c +++ b/coreutils/expr.c @@ -245,10 +245,9 @@ static int arithmetic_common (VALUE *l, VALUE *r, int op) static VALUE *docolon (VALUE *sv, VALUE *pv) { VALUE *v; - const char *errmsg; - struct re_pattern_buffer re_buffer; - struct re_registers re_regs; - int len; + regex_t re_buffer; + const int NMATCH = 2; + regmatch_t re_regs[NMATCH]; tostring (sv); tostring (pv); @@ -260,27 +259,22 @@ of a basic regular expression is not portable; it is being ignored", pv->u.s); } - len = strlen (pv->u.s); memset (&re_buffer, 0, sizeof (re_buffer)); - memset (&re_regs, 0, sizeof (re_regs)); - re_buffer.allocated = 2 * len; - re_buffer.buffer = (unsigned char *) xmalloc (re_buffer.allocated); - re_buffer.translate = 0; - re_syntax_options = RE_SYNTAX_POSIX_BASIC; - errmsg = re_compile_pattern (pv->u.s, len, &re_buffer); - if (errmsg) { - bb_error_msg_and_die("%s", errmsg); - } - - len = re_match (&re_buffer, sv->u.s, strlen (sv->u.s), 0, &re_regs); - if (len >= 0) { + memset (re_regs, 0, sizeof (*re_regs)); + if( regcomp (&re_buffer, pv->u.s, 0) != 0 ) + bb_error_msg_and_die("Invalid regular expression"); + + /* expr uses an anchored pattern match, so check that there was a + * match and that the match starts at offset 0. */ + if (regexec (&re_buffer, sv->u.s, NMATCH, re_regs, 0) != REG_NOMATCH && + re_regs[0].rm_so == 0) { /* Were \(...\) used? */ - if (re_buffer.re_nsub > 0) { /* was (re_regs.start[1] >= 0) */ - sv->u.s[re_regs.end[1]] = '\0'; - v = str_value (sv->u.s + re_regs.start[1]); + if (re_buffer.re_nsub > 0) { + sv->u.s[re_regs[1].rm_eo] = '\0'; + v = str_value (sv->u.s + re_regs[1].rm_so); } else - v = int_value (len); + v = int_value (re_regs[0].rm_eo); } else { /* Match failed -- return the right kind of null. */ @@ -289,7 +283,6 @@ of a basic regular expression is not portable; it is being ignored", else v = int_value (0); } - free (re_buffer.buffer); return v; } -- cgit v1.2.3