From 49abdbd0092134ab984bddac65a2d6bc4b5f07fd Mon Sep 17 00:00:00 2001
From: Mathieu Lacage <mathieu.lacage@sophia.inria.fr>
Date: Thu, 7 Jun 2007 09:38:51 +0200
Subject: [PATCH] fix Append and optimize GetUleb128Size

---
 src/common/packet-history.cc | 59 ++++++++++++++++++++++++------------
 src/common/packet-history.h  |  2 +-
 2 files changed, 41 insertions(+), 20 deletions(-)

diff --git a/src/common/packet-history.cc b/src/common/packet-history.cc
index 283c1e433..16dd5c7d0 100644
--- a/src/common/packet-history.cc
+++ b/src/common/packet-history.cc
@@ -310,17 +310,6 @@ PacketHistory::PrintStats (void)
   g_three = 0;
   g_four = 0;
   g_five = 0;
-#if 0
-  PacketHistory h (0, 0);
-  for (uint32_t i = 0; i < 0xffffff; i++)
-    {
-      if (h.GetUleb128Size (i) == 4)
-        {
-          std::cout << i << std::endl;
-          break;
-        }
-    }
-#endif
 }
 
 void 
@@ -375,13 +364,23 @@ PacketHistory::Reserve (uint32_t size)
 uint32_t 
 PacketHistory::GetUleb128Size (uint32_t value) const
 {
-  uint32_t n = 0;
-  uint32_t tmp = value;
-  do {
-    tmp >>= 7;
-    n++;
-  } while (tmp != 0);
-  return n;
+  if (value < 0x80)
+    {
+      return 1;
+    }
+  if (value < 0x4000)
+    {
+      return 2;
+    }
+  if (value < 0x200000)
+    {
+      return 3;
+    }
+  if (value < 0x10000000)
+    {
+      return 4;
+    }
+  return 5;
 }
 uint32_t
 PacketHistory::ReadUleb128 (const uint8_t **pBuffer) const
@@ -484,25 +483,47 @@ PacketHistory::TryToAppend (uint32_t value, uint8_t **pBuffer, uint8_t *end)
       uint8_t byte = value & (~0x80);
       start[0] = 0x80 | byte;
       value >>= 7;
+      byte = value & (~0x80);
       start[1] = 0x80 | byte;
       value >>= 7;
+      byte = value & (~0x80);
       start[2] = value;
       *pBuffer = start + 3;
       return true;
     }
-  if (start + 3 < end)
+  if (value < 0x10000000 && start + 3 < end)
     {
       uint8_t byte = value & (~0x80);
       start[0] = 0x80 | byte;
       value >>= 7;
+      byte = value & (~0x80);
       start[1] = 0x80 | byte;
       value >>= 7;
+      byte = value & (~0x80);
       start[2] = 0x80 | byte;
       value >>= 7;
       start[3] = value;
       *pBuffer = start + 4;
       return true;
     }
+  if (start + 4 < end)
+    {
+      uint8_t byte = value & (~0x80);
+      start[0] = 0x80 | byte;
+      value >>= 7;
+      byte = value & (~0x80);
+      start[1] = 0x80 | byte;
+      value >>= 7;
+      byte = value & (~0x80);
+      start[2] = 0x80 | byte;
+      value >>= 7;
+      byte = value & (~0x80);
+      start[3] = 0x80 | byte;
+      value >>= 7;
+      start[4] = value;
+      *pBuffer = start + 5;
+      return true;
+    }
   return false;
 }
 
diff --git a/src/common/packet-history.h b/src/common/packet-history.h
index 93e2d8099..2db574aed 100644
--- a/src/common/packet-history.h
+++ b/src/common/packet-history.h
@@ -107,7 +107,7 @@ private:
                     uint32_t available);
   inline void UpdateHead (uint16_t written);
   inline void UpdateTail (uint16_t written);
-  uint32_t GetUleb128Size (uint32_t value) const;
+  inline uint32_t GetUleb128Size (uint32_t value) const;
   uint32_t ReadUleb128 (const uint8_t **pBuffer) const;
   inline void Append16 (uint16_t value, uint8_t *buffer);
   inline bool TryToAppend (uint32_t value, uint8_t **pBuffer, uint8_t *end);