Save some serious memory on the lower half of each charset. Also make mapping lookup more elegant.

1 files changed, 15 insertions, 9 deletions

diff --git a/encoding_jis.js b/encoding_jis.js
index d807385..c6152d4 100644
--- a/encoding_jis.js
+++ b/encoding_jis.js
@@ -5,25 +5,31 @@
 // the amount of 19968 to save 5kBytes in this script, so the
 // actual value is 19968 + encoding_jis_0208_1[ x ]
 
+var page = {
+  us_ascii : 0,
+  jis0208  : 1,
+  jis0201  : 2
+};
+
 function decode_jis( str ) {
   var outstring = "";
-  var cur_page = "us-ascii";
+  var cur_page = page.us_ascii;
 
   for( i=0; i<str.length; ++i ) {
     var append = String.fromCharCode(0xfffd);
     if( str.charCodeAt( i ) == 27 ) {
       switch( str.charCodeAt( i + 1 ) * 256 + str.charCodeAt( i + 2 ) ) {
       case 0x2440:
-        cur_page = "jis0208"; // -1978
+        cur_page = page.jis0208; // -1978
         break;
       case 0x2442:
-        cur_page = "jis0208"; // -1983
+        cur_page = page.jis0208; // -1983
         break;
       case 0x2842:
-        cur_page = "us-ascii";
+        cur_page = page.us_ascii;
         break;
       case 0x284a:
-        cur_page = "jis0201";
+        cur_page = page.jis0201;
         break;
       default:
         return outstring + append;
@@ -32,16 +38,16 @@ function decode_jis( str ) {
       continue;
     }
     switch( cur_page ) {
-    case "us-ascii":
-      append = String.fromCharCode( encoding_8859_1[ str.charCodeAt( i ) & 0xff ] );
+    case page.us_ascii:
+      append = String.fromCharCode( str.charCodeAt( i ) & 0xff );
       break;
-    case "jis0201":
+    case page.jis0201:
       var off = str.charCodeAt( i ) & 0xff;
       if( off >= 0x20 && x <= 0xdf ) {
         append = String.fromCharCode( encoding_jis_0201[ off - 32 ] );
       }
       break;
-    case "jis0208":
+    case page.jis0208:
       if( i>str.length-1 ) { return outstring + append; }
       var x0 = ( str.charCodeAt( i++ ) - 0x21 ) & 0xff;
       var x1 = ( str.charCodeAt( i   ) - 0x21 ) & 0xff;