minor speedup

diff --git a/src/dom/util/ziptool.cpp b/src/dom/util/ziptool.cpp
index e6d46557b6d753b4fe939172bca6af8e54952262..b3c5ec9b0f31462190ed882696e595a0a988521f 100644 (file)
--- a/src/dom/util/ziptool.cpp
+++ b/src/dom/util/ziptool.cpp
@@ -1261,17 +1261,21 @@ void Deflater::encodeDistStatic(unsigned int len, unsigned int dist)
 \r
 \r
 /**\r
- *\r
+ * This method does the dirty work of dictionary\r
+ * compression.  Basically it looks for redundant\r
+ * strings and has the current duplicate refer back\r
+ * to the previous one.\r
  */\r
 bool Deflater::compressWindow()\r
 {\r
+    unsigned int windowSize = window.size();\r
     //### Compress as much of the window as possible\r
     int i=0;\r
     std::vector<unsigned char>::iterator iter;\r
     for (iter=window.begin() ; iter!=window.end() ; iter++)\r
         windowBuf[i++] = *iter;\r
 \r
-    while (windowPos < window.size())\r
+    while (windowPos < windowSize)\r
         {\r
         //### Find best match, if any\r
         unsigned int bestMatchLen  = 0;\r
@@ -1280,18 +1284,22 @@ bool Deflater::compressWindow()
             {\r
             for (unsigned int lookBack=0 ; lookBack<windowPos-4 ; lookBack++)\r
                 {\r
-                unsigned int lookAhead;\r
-                unsigned int lookAheadMax = window.size() - windowPos;\r
-                if (lookBack + lookAheadMax >= windowPos)\r
-                    lookAheadMax = windowPos - lookBack;\r
-                if (lookAheadMax > 258)\r
-                    lookAheadMax = 258;\r
-                for (lookAhead = 0 ; lookAhead<lookAheadMax ; lookAhead++)\r
+                unsigned int lookAhead=0;\r
+                unsigned char *wp = &(windowBuf[windowPos]);\r
+                unsigned char *lb = &(windowBuf[lookBack]);\r
+                //Check first char, before continuing with string\r
+                if (*lb++ == *wp++)\r
                     {\r
-                    unsigned int pos1 = lookBack  + lookAhead;\r
-                    unsigned int pos2 = windowPos + lookAhead;\r
-                    if (windowBuf[pos1] != windowBuf[pos2])\r
-                        break;\r
+                    unsigned int lookAheadMax = windowSize - windowPos;\r
+                    if (lookBack + lookAheadMax >= windowPos)\r
+                        lookAheadMax = windowPos - lookBack;\r
+                    if (lookAheadMax > 258)\r
+                        lookAheadMax = 258;\r
+                    for (lookAhead = 1 ; lookAhead<lookAheadMax ; lookAhead++)\r
+                        {\r
+                        if (*lb++ != *wp++)\r
+                            break;\r
+                        }\r
                     }\r
                 if (lookAhead > bestMatchLen)\r
                     {\r