From e578faea202a4e6eeb32e81e489b59119a2e02a0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ludovic=20Court=C3=A8s?= <ludo@gnu.org>
Date: Wed, 26 Jan 2011 22:59:45 +0100
Subject: [PATCH] Tweak `read-line'.

* libguile/rdelim.c (LINE_BUFFER_SIZE): Set to 1 KiB instead of 4 KiB.
  (scm_read_line): Initialize STRING to #f so we actually use the fast
  path.
---
 libguile/rdelim.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/libguile/rdelim.c b/libguile/rdelim.c
index 0fa0b8f61..760aa47ee 100644
--- a/libguile/rdelim.c
+++ b/libguile/rdelim.c
@@ -122,7 +122,7 @@ SCM_DEFINE (scm_read_line, "%read-line", 0, 1, 0,
 {
 /* Threshold under which the only allocation performed is that of the
    resulting string and pair.  */
-#define LINE_BUFFER_SIZE 1024
+#define LINE_BUFFER_SIZE 256
 
   SCM line, strings, result;
   scm_t_wchar buf[LINE_BUFFER_SIZE], delim;
@@ -135,11 +135,11 @@ SCM_DEFINE (scm_read_line, "%read-line", 0, 1, 0,
 
   index = 0;
   delim = 0;
-  strings = SCM_EOL;
+  strings = SCM_BOOL_F;
 
   do
     {
-      if (index >= sizeof (buf))
+      if (SCM_UNLIKELY (index >= sizeof (buf)))
 	{
 	  /* The line is getting longer than BUF so store its current
 	     contents in STRINGS.  */
@@ -164,7 +164,8 @@ SCM_DEFINE (scm_read_line, "%read-line", 0, 1, 0,
     }
   while (delim == 0);
 
-  if (scm_is_false (strings))
+  if (SCM_LIKELY (scm_is_false (strings)))
+    /* The fast path.  */
     line = scm_from_utf32_stringn (buf, index);
   else
     {