patch 8.0.0551: the typeahead buffer is reallocated too often

Problem:    The typeahead buffer is reallocated too often.
Solution:   Re-use the existing buffer if possible.

diff --git a/src/getchar.c b/src/getchar.c
index c057861a61698c0f6ecb4d63a8199e008374111a..18af2a3740899a20383478081367c1321230144f 100644 (file)
--- a/src/getchar.c
+++ b/src/getchar.c
@@ -920,7 +920,7 @@ init_typebuf(void)
        typebuf.tb_noremap = noremapbuf_init;
        typebuf.tb_buflen = TYPELEN_INIT;
        typebuf.tb_len = 0;
-       typebuf.tb_off = 0;
+       typebuf.tb_off = MAXMAPLEN + 4;
        typebuf.tb_change_cnt = 1;
     }
 }
@@ -974,11 +974,21 @@ ins_typebuf(
        typebuf.tb_off -= addlen;
        mch_memmove(typebuf.tb_buf + typebuf.tb_off, str, (size_t)addlen);
     }
+    else if (typebuf.tb_len == 0 && typebuf.tb_buflen
+                                              >= addlen + 3 * (MAXMAPLEN + 4))
+    {
+       /*
+        * Buffer is empty and string fits in the existing buffer.
+        * Leave some space before and after, if possible.
+        */
+       typebuf.tb_off = (typebuf.tb_buflen - addlen - 3 * (MAXMAPLEN + 4)) / 2;
+       mch_memmove(typebuf.tb_buf + typebuf.tb_off, str, (size_t)addlen);
+    }
     else
     {
        /*
         * Need to allocate a new buffer.
-        * In typebuf.tb_buf there must always be room for 3 * MAXMAPLEN + 4
+        * In typebuf.tb_buf there must always be room for 3 * (MAXMAPLEN + 4)
         * characters.  We add some extra room to avoid having to allocate too
         * often.
         */
@@ -1291,7 +1301,7 @@ alloc_typebuf(void)
        return FAIL;
     }
     typebuf.tb_buflen = TYPELEN_INIT;
-    typebuf.tb_off = 0;
+    typebuf.tb_off = MAXMAPLEN + 4;  /* can insert without realloc */
     typebuf.tb_len = 0;
     typebuf.tb_maplen = 0;
     typebuf.tb_silent = 0;

diff --git a/src/version.c b/src/version.c
index aba7a80f582cdf06a1b48053cc68ec76030fef93..2ea57088ac326a814b1b995dd8513ea254b48b97 100644 (file)
--- a/src/version.c
+++ b/src/version.c
@@ -764,6 +764,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    551,
 /**/
     550,
 /**/