From ef8969d975a371aa0ebabf5a56915bd4dc6e13bd Mon Sep 17 00:00:00 2001
From: "zik.saleeba" <zik.saleeba@21eae674-98b7-11dd-bd71-f92a316d2d60>
Date: Mon, 5 Jan 2009 04:52:33 +0000
Subject: [PATCH] Added lexer token caching for improved performance

git-svn-id: http://picoc.googlecode.com/svn/trunk@29 21eae674-98b7-11dd-bd71-f92a316d2d60
---
 lex.c | 24 +++++++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

diff --git a/lex.c b/lex.c
index cff7111..39b8803 100644
--- a/lex.c
+++ b/lex.c
@@ -159,7 +159,7 @@ enum LexToken LexGetComment(struct LexState *Lexer, char NextChar, union AnyValu
     return LexGetToken(Lexer, Value);
 }
 
-enum LexToken LexGetToken(struct LexState *Lexer, union AnyValue *Value)
+enum LexToken LexGetTokenUncached(struct LexState *Lexer, union AnyValue *Value)
 {
     char ThisChar;
     char NextChar;
@@ -215,6 +215,28 @@ enum LexToken LexGetToken(struct LexState *Lexer, union AnyValue *Value)
     return TokenEOF;
 }
 
+enum LexToken LexGetToken(struct LexState *Lexer, union AnyValue *Value)
+{
+    static const char *CachedPos = NULL;
+    static union AnyValue CachedValue;
+    static struct LexState CachedLexer;
+    static enum LexToken CachedToken;
+    
+    if (Lexer->Pos == CachedPos)
+    {
+        *Value = CachedValue;
+        *Lexer = CachedLexer;
+    }
+    else
+    {
+        CachedToken = LexGetTokenUncached(Lexer, Value);
+        CachedLexer = *Lexer;
+        CachedValue = *Value;
+    }
+    
+    return CachedToken;
+}
+
 enum LexToken LexGetPlainToken(struct LexState *Lexer)
 {
     union AnyValue Value;