Optimize trie look for char conv.

The lookup function now saves one function call for every character -
to improve performance for conversion from/to MARC8.

diff --git a/src/charconv.tcl b/src/charconv.tcl
index f09b82e..d57f226 100644 (file)
--- a/src/charconv.tcl
+++ b/src/charconv.tcl
@@ -37,19 +37,22 @@ proc preamble_trie {ofilehandle ifiles ofile} {
         static unsigned long lookup(struct yaz_iconv_trie **ptrs, int ptr, unsigned char *inp,
                                     size_t inbytesleft, size_t *no_read, int *combining, unsigned mask, int boffset)
         {
-            struct yaz_iconv_trie *t = (ptr > 0) ? ptrs[ptr-1] : 0;
-            if (!t || inbytesleft < 1)
+            struct yaz_iconv_trie *t = ptrs[ptr-1];
+            if (inbytesleft < 1)
                 return 0;
             if (t->dir)
             {
                 size_t ch = (inp[0] & mask) + boffset;
-                unsigned long code =
-                lookup(ptrs, t->dir[ch].ptr, inp+1, inbytesleft-1, no_read, combining, mask, boffset);
-                if (code)
+                unsigned long code;
+                if (t->dir[ch].ptr)
                 {
-                    (*no_read)++;
-                    return code;
-                }
+                    code = lookup(ptrs, t->dir[ch].ptr, inp+1, inbytesleft-1, no_read, combining, mask, boffset);
+                   if (code)
+                   {
+                       (*no_read)++;
+                       return code;
+                   }
+               }
                 if (t->dir[ch].to)
                 {
                     code = t->dir[ch].to;