[Lldb-commits] [lldb] r144581 - /lldb/trunk/source/Core/DataExtractor.cpp

[Greg Clayton]

Author: gclayton
Date: Mon Nov 14 16:56:58 2011
New Revision: 144581

URL: http://llvm.org/viewvc/llvm-project?rev=144581&view=rev
Log:
Speed improvements for ULEB128 reading from James McIlree.


Modified:
    lldb/trunk/source/Core/DataExtractor.cpp

Modified: lldb/trunk/source/Core/DataExtractor.cpp
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Core/DataExtractor.cpp?rev=144581&r1=144580&r2=144581&view=diff
==============================================================================
--- lldb/trunk/source/Core/DataExtractor.cpp (original)
+++ lldb/trunk/source/Core/DataExtractor.cpp Mon Nov 14 16:56:58 2011
@@ -1147,27 +1147,30 @@
 uint64_t
 DataExtractor::GetULEB128 (uint32_t *offset_ptr) const
 {
-    uint64_t result = 0;
-    if ( m_start < m_end )
+    const uint8_t *src = m_start + *offset_ptr;
+    const uint8_t *end = m_end;
+    
+    if (src < end)
     {
-        int shift = 0;
-        const uint8_t *src = m_start + *offset_ptr;
-        uint8_t byte;
-        int bytecount = 0;
-
-        while (src < m_end)
+        uint64_t result = *src++;
+        if (result >= 0x80)
         {
-            bytecount++;
-            byte = *src++;
-            result |= (byte & 0x7f) << shift;
-            if ((byte & 0x80) == 0)
-                break;
-            shift += 7;
+            result &= 0x7f;
+            int shift = 7;
+            while (src < end)
+            {
+                uint8_t byte = *src++;
+                result |= (byte & 0x7f) << shift;
+                if ((byte & 0x80) == 0)
+                    break;
+                shift += 7;
+            }
         }
-
-        *offset_ptr += bytecount;
+        *offset_ptr = (uint32_t)(src - m_start);
+        return result;
     }
-    return result;
+    
+    return 0;
 }
 
 //----------------------------------------------------------------------