From fd6a133fdcd6bcdc240c05cfe645cd9064f9e744 Mon Sep 17 00:00:00 2001 From: Dmitry Antipov Date: Thu, 30 Jun 2016 09:30:41 +0300 Subject: [PATCH] Minor tweaks to openp * src/lread.c (openp): Move invariant code out of the loop and thus avoid redundant calls to memcpy. Adjust comments. --- src/lread.c | 24 ++++++++++++++---------- 1 file changed, 14 insertions(+), 10 deletions(-) diff --git a/src/lread.c b/src/lread.c index 5c47f78f8e4..ecd482793a9 100644 --- a/src/lread.c +++ b/src/lread.c @@ -1464,6 +1464,8 @@ openp (Lisp_Object path, Lisp_Object str, Lisp_Object suffixes, for (; CONSP (path); path = XCDR (path)) { + ptrdiff_t baselen, prefixlen; + filename = Fexpand_file_name (str, XCAR (path)); if (!complete_filename_p (filename)) /* If there are non-absolute elts in PATH (eg "."). */ @@ -1485,6 +1487,14 @@ openp (Lisp_Object path, Lisp_Object str, Lisp_Object suffixes, fn = SAFE_ALLOCA (fn_size); } + /* Copy FILENAME's data to FN but remove starting /: if any. */ + prefixlen = ((SCHARS (filename) > 2 + && SREF (filename, 0) == '/' + && SREF (filename, 1) == ':') + ? 2 : 0); + baselen = SBYTES (filename) - prefixlen; + memcpy (fn, SDATA (filename) + prefixlen, baselen); + /* Loop over suffixes. */ for (tail = NILP (suffixes) ? list1 (empty_unibyte_string) : suffixes; CONSP (tail); tail = XCDR (tail)) @@ -1493,16 +1503,10 @@ openp (Lisp_Object path, Lisp_Object str, Lisp_Object suffixes, ptrdiff_t fnlen, lsuffix = SBYTES (suffix); Lisp_Object handler; - /* Concatenate path element/specified name with the suffix. - If the directory starts with /:, remove that. */ - int prefixlen = ((SCHARS (filename) > 2 - && SREF (filename, 0) == '/' - && SREF (filename, 1) == ':') - ? 2 : 0); - fnlen = SBYTES (filename) - prefixlen; - memcpy (fn, SDATA (filename) + prefixlen, fnlen); - memcpy (fn + fnlen, SDATA (suffix), lsuffix + 1); - fnlen += lsuffix; + /* Make complete filename by appending SUFFIX. */ + memcpy (fn + baselen, SDATA (suffix), lsuffix + 1); + fnlen = baselen + lsuffix; + /* Check that the file exists and is not a directory. */ /* We used to only check for handlers on non-absolute file names: if (absolute) -- 2.39.2