Bug #14637: trim trailing spaces processes data only byte wise

(From: gkodinov)
Use and int * where possible to scan for trailing space in a
string instead of always iterating char-by-char.
Using the attached benchmark file on a 32 bit Intel Core 2 
Duo CPU I've got 43485 ms run with the fix compared to 44373 
without it.

Backported to 5.6.0 (next-mr-runtime)
6.0-codebase revid: 2476.1362.1

4 files changed, 8 insertions, 17 deletions

diff --git a/strings/ctype-bin.c b/strings/ctype-bin.c
index 95d97af2bfb..3b6a977e47c 100644
--- a/strings/ctype-bin.c
+++ b/strings/ctype-bin.c
@@ -278,14 +278,11 @@ void my_hash_sort_8bit_bin(CHARSET_INFO *cs __attribute__((unused)),
 {
   const uchar *pos = key;
   
-  key+= len;
-  
   /*
      Remove trailing spaces. We have to do this to be able to compare
     'A ' and 'A' as identical
   */
-  while (key > pos && key[-1] == ' ')
-    key--;
+  key= skip_trailing_space(key, len);
 
   for (; pos < (uchar*) key ; pos++)
   {
diff --git a/strings/ctype-latin1.c b/strings/ctype-latin1.c
index e5333c4101b..dbd91c09637 100644
--- a/strings/ctype-latin1.c
+++ b/strings/ctype-latin1.c
@@ -678,13 +678,12 @@ void my_hash_sort_latin1_de(CHARSET_INFO *cs __attribute__((unused)),
 			    const uchar *key, size_t len,
 			    ulong *nr1, ulong *nr2)
 {
-  const uchar *end= key+len;
+  const uchar *end;
   /*
     Remove end space. We have to do this to be able to compare
     'AE' and 'Ä' as identical
   */
-  while (end > key && end[-1] == ' ')
-    end--;
+  end= skip_trailing_space(key, len);
 
   for (; key < end ; key++)
   {
diff --git a/strings/ctype-mb.c b/strings/ctype-mb.c
index 903811e2ab9..b0f7c297260 100644
--- a/strings/ctype-mb.c
+++ b/strings/ctype-mb.c
@@ -469,14 +469,11 @@ static void my_hash_sort_mb_bin(CHARSET_INFO *cs __attribute__((unused)),
 {
   const uchar *pos = key;
   
-  key+= len;
-  
   /*
      Remove trailing spaces. We have to do this to be able to compare
     'A ' and 'A' as identical
   */
-  while (key > pos && key[-1] == ' ')
-    key--;
+  key= skip_trailing_space(key, len);
   
   for (; pos < (uchar*) key ; pos++)
   {
diff --git a/strings/ctype-simple.c b/strings/ctype-simple.c
index 4f3aaa6f668..6ff8c83dcf7 100644
--- a/strings/ctype-simple.c
+++ b/strings/ctype-simple.c
@@ -304,14 +304,13 @@ void my_hash_sort_simple(CHARSET_INFO *cs,
 			 ulong *nr1, ulong *nr2)
 {
   register uchar *sort_order=cs->sort_order;
-  const uchar *end= key + len;
+  const uchar *end;
   
   /*
     Remove end space. We have to do this to be able to compare
     'A ' and 'A' as identical
   */
-  while (end > key && end[-1] == ' ')
-    end--;
+  end= skip_trailing_space(key, len);
   
   for (; key < (uchar*) end ; key++)
   {
@@ -1165,9 +1164,8 @@ size_t my_well_formed_len_8bit(CHARSET_INFO *cs __attribute__((unused)),
 size_t my_lengthsp_8bit(CHARSET_INFO *cs __attribute__((unused)),
                         const char *ptr, size_t length)
 {
-  const char *end= ptr+length;
-  while (end > ptr && end[-1] == ' ')
-    end--;
+  const char *end;
+  end= (const char *) skip_trailing_space((const uchar *)ptr, length);
   return (size_t) (end-ptr);
 }