From 4dfe9d52e98299021341cbf6dd4101c5579d734d Mon Sep 17 00:00:00 2001
From: "Markus F.X.J. Oberhumer" <markus@oberhumer.com>
Date: Mon, 20 Nov 2006 09:40:46 +0100
Subject: [PATCH] Don't be too strict when checking the compression ratio
 (sf.net feature request #1596111).

---
 src/packer.cpp | 41 +++++++++++++++++++----------------------
 src/packer.h   |  1 +
 2 files changed, 20 insertions(+), 22 deletions(-)

diff --git a/src/packer.cpp b/src/packer.cpp
index 3ea013fb..556afbe0 100644
--- a/src/packer.cpp
+++ b/src/packer.cpp
@@ -274,41 +274,38 @@ bool Packer::compress(upx_bytep in, upx_bytep out,
 #endif
 
 
-bool Packer::checkCompressionRatio(unsigned u_len, unsigned c_len) const
+bool Packer::checkDefaultCompressionRatio(unsigned u_len, unsigned c_len) const
 {
     assert((int)u_len > 0);
     assert((int)c_len > 0);
-
-#if 1
-    if (c_len + 512 >= u_len)           // min. 512 bytes gain
-        return false;
-    if (c_len >= u_len - u_len / 8)     // min. 12.5% gain
-        return false;
-#else
     if (c_len >= u_len)
         return false;
-#endif
+    unsigned gain = u_len - c_len;
+
+    if (gain < 512)                     // need at least 512 bytes gain
+        return false;
+#if 1
+    if (gain >= 4096)                   // ok if we have 4096 bytes gain
+        return true;
+    if (c_len >= u_len - u_len / 8)     // ok if we have 12.5% gain
+        return true;
+    return false;
+#else
     return true;
+#endif
 }
 
 
+bool Packer::checkCompressionRatio(unsigned u_len, unsigned c_len) const
+{
+    return checkDefaultCompressionRatio(u_len, c_len);
+}
+
 bool Packer::checkFinalCompressionRatio(const OutputFile *fo) const
 {
     const unsigned u_len = file_size;
     const unsigned c_len = fo->getBytesWritten();
-
-    assert((int)u_len > 0);
-    assert((int)c_len > 0);
-
-    if (c_len + 4096 <= u_len)          // ok if we have 4096 bytes gain
-        return true;
-
-    if (c_len + 512 >= u_len)           // min. 512 bytes gain
-        return false;
-    if (c_len >= u_len - u_len / 8)     // min. 12.5% gain
-        return false;
-
-    return true;
+    return checkDefaultCompressionRatio(u_len, c_len);
 }
 
 
diff --git a/src/packer.h b/src/packer.h
index 0771acdb..b7b836bf 100644
--- a/src/packer.h
+++ b/src/packer.h
@@ -171,6 +171,7 @@ protected:
                           const upx_compress_config_t *cconf = NULL);
     virtual void decompress(const upx_bytep in, upx_bytep out,
                             bool verify_checksum = true, Filter *ft = NULL);
+    virtual bool checkDefaultCompressionRatio(unsigned u_len, unsigned c_len) const;
     virtual bool checkCompressionRatio(unsigned u_len, unsigned c_len) const;
     virtual bool checkFinalCompressionRatio(const OutputFile *fo) const;