This is an automated email from the git hooks/post-receive script. It was generated because a ref change was pushed to the repository containing the project "GNU M4 source repository".
http://git.sv.gnu.org/gitweb/?p=m4.git;a=commitdiff;h=000a6507a4ab5b46a609efc6fc5152e34c86e095 The branch, branch-1_4 has been updated via 000a6507a4ab5b46a609efc6fc5152e34c86e095 (commit) from aa46ced67010190918295b965f5e2879dcd9a30c (commit) Those revisions listed above that are new to this repository have not appeared on any other notification email; so we list those revisions in full, below. - Log ----------------------------------------------------------------- commit 000a6507a4ab5b46a609efc6fc5152e34c86e095 Author: Eric Blake <[EMAIL PROTECTED]> Date: Mon Oct 1 14:30:25 2007 -0600 Another Autoconf usage pattern optimization. * src/builtin.c (m4_index): Optimize search for one byte. * doc/m4.texinfo (Index macro, Regexp, Patsubst): Test the new code paths. Signed-off-by: Eric Blake <[EMAIL PROTECTED]> ----------------------------------------------------------------------- Summary of changes: ChangeLog | 7 +++++++ doc/m4.texinfo | 21 ++++++++++++++++++--- src/builtin.c | 19 +++++++++++++++---- 3 files changed, 40 insertions(+), 7 deletions(-) diff --git a/ChangeLog b/ChangeLog index f29b557..396a64f 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,10 @@ +2007-10-01 Eric Blake <[EMAIL PROTECTED]> + + Another Autoconf usage pattern optimization. + * src/builtin.c (m4_index): Optimize search for one byte. + * doc/m4.texinfo (Index macro, Regexp, Patsubst): Test the new + code paths. + 2007-09-29 Eric Blake <[EMAIL PROTECTED]> Optimize for Autoconf usage pattern. diff --git a/doc/m4.texinfo b/doc/m4.texinfo index a24d36e..6c76b7b 100644 --- a/doc/m4.texinfo +++ b/doc/m4.texinfo @@ -4610,12 +4610,17 @@ index(`gnus, gnats, and armadillos', `dag') @result{}-1 @end example -Omitting @var{substring} evokes a warning, but still produces output. +Omitting @var{substring} evokes a warning, but still produces output; +contrast this with an empty @var{substring}. @example index(`abc') @error{}m4:stdin:1: Warning: too few arguments to builtin `index' @result{}0 +index(`abc', `') [EMAIL PROTECTED] +index(`abc', `b') [EMAIL PROTECTED] @end example @node Regexp @@ -4688,12 +4693,17 @@ regexp(`abc', `\(\(d\)?\)\(c\)', `\1\2\3\4\5\6') @result{}c @end example -Omitting @var{regexp} evokes a warning, but still produces output. +Omitting @var{regexp} evokes a warning, but still produces output; +contrast this with an empty @var{regexp} argument. @example regexp(`abc') @error{}m4:stdin:1: Warning: too few arguments to builtin `regexp' @result{}0 +regexp(`abc', `') [EMAIL PROTECTED] +regexp(`abc', `', `def') [EMAIL PROTECTED] @end example @node Substr @@ -4904,12 +4914,17 @@ patreg(`aba abb 121', `\(.\)\(.\)\1', `\2\1\2') @result{}bab @end example -Omitting @var{regexp} evokes a warning, but still produces output. +Omitting @var{regexp} evokes a warning, but still produces output; +contrast this with an empty @var{regexp} argument. @example patsubst(`abc') @error{}m4:stdin:1: Warning: too few arguments to builtin `patsubst' @result{}abc +patsubst(`abc', `') [EMAIL PROTECTED] +patsubst(`abc', `', `-') [EMAIL PROTECTED] @end example @node Format diff --git a/src/builtin.c b/src/builtin.c index 65f4585..8974b1a 100644 --- a/src/builtin.c +++ b/src/builtin.c @@ -1677,8 +1677,9 @@ static void m4_index (struct obstack *obs, int argc, token_data **argv) { const char *haystack; - const char *result; - int retval; + const char *needle; + const char *result = NULL; + int retval = -1; if (bad_argc (argv[0], argc, 3, 3)) { @@ -1689,8 +1690,18 @@ m4_index (struct obstack *obs, int argc, token_data **argv) } haystack = ARG (1); - result = strstr (haystack, ARG (2)); - retval = result ? result - haystack : -1; + needle = ARG (2); + + /* Optimize searching for the empty string (always 0) and one byte + (strchr tends to be more efficient than strstr). */ + if (!needle[0]) + retval = 0; + else if (!needle[1]) + result = strchr (haystack, *needle); + else + result = strstr (haystack, needle); + if (result) + retval = result - haystack; shipout_int (obs, retval); } hooks/post-receive -- GNU M4 source repository
