Add support for raw deflate in the zlib filter

2 files changed, 35 insertions, 12 deletions

diff --git a/src/filters/zlib/zlib.cpp b/src/filters/zlib/zlib.cpp
index 0f88b5558..517660e3b 100644
--- a/src/filters/zlib/zlib.cpp
+++ b/src/filters/zlib/zlib.cpp
@@ -91,10 +91,12 @@ class Zlib_Stream
 /*
 * Zlib_Compression Constructor
 */
-Zlib_Compression::Zlib_Compression(size_t l) :
-   level((l >= 9) ? 9 : l), buffer(DEFAULT_BUFFERSIZE)
+Zlib_Compression::Zlib_Compression(size_t l, bool raw_deflate) :
+   level((l >= 9) ? 9 : l),
+   raw_deflate(raw_deflate),
+   buffer(DEFAULT_BUFFERSIZE),
+   zlib(0)
    {
-   zlib = 0;
    }
 
 /*
@@ -104,7 +106,17 @@ void Zlib_Compression::start_msg()
    {
    clear();
    zlib = new Zlib_Stream;
-   if(deflateInit(&(zlib->stream), level) != Z_OK)
+
+   int res = deflateInit2(&(zlib->stream),
+                          level,
+                          Z_DEFLATED,
+                          (raw_deflate ? -15 : 15),
+                          8,
+                          Z_DEFAULT_STRATEGY);
+
+   if(res == Z_STREAM_ERROR)
+      throw Invalid_Argument("Bad setting in deflateInit2");
+   else if(res != Z_OK)
       throw Memory_Exhaustion();
    }
 
@@ -185,10 +197,12 @@ void Zlib_Compression::clear()
 /*
 * Zlib_Decompression Constructor
 */
-Zlib_Decompression::Zlib_Decompression() : buffer(DEFAULT_BUFFERSIZE)
+Zlib_Decompression::Zlib_Decompression(bool raw_deflate) :
+   raw_deflate(raw_deflate),
+   buffer(DEFAULT_BUFFERSIZE),
+   zlib(0),
+   no_writes(true)
    {
-   zlib = 0;
-   no_writes = true;
    }
 
 /*
@@ -198,7 +212,8 @@ void Zlib_Decompression::start_msg()
    {
    clear();
    zlib = new Zlib_Stream;
-   if(inflateInit(&(zlib->stream)) != Z_OK)
+
+   if(inflateInit2(&(zlib->stream), (raw_deflate ? -15 : 15)) != Z_OK)
       throw Memory_Exhaustion();
    }
 
diff --git a/src/filters/zlib/zlib.h b/src/filters/zlib/zlib.h
index 77ec5eecc..60117f2bc 100644
--- a/src/filters/zlib/zlib.h
+++ b/src/filters/zlib/zlib.h
@@ -31,15 +31,20 @@ class BOTAN_DLL Zlib_Compression : public Filter
       void flush();
 
       /**
-      @param level how much effort to use on compressing (0 to 9);
-      higher levels are slower but tend to give better compression
+      * @param level how much effort to use on compressing (0 to 9);
+      *        higher levels are slower but tend to give better
+      *        compression
+      * @param raw_deflate if true no zlib header/trailer will be used
       */
-      Zlib_Compression(size_t level = 6);
+      Zlib_Compression(size_t level = 6,
+                       bool raw_deflate = false);
 
       ~Zlib_Compression() { clear(); }
    private:
       void clear();
       const size_t level;
+      const bool raw_deflate;
+
       SecureVector<byte> buffer;
       class Zlib_Stream* zlib;
    };
@@ -56,10 +61,13 @@ class BOTAN_DLL Zlib_Decompression : public Filter
       void start_msg();
       void end_msg();
 
-      Zlib_Decompression();
+      Zlib_Decompression(bool raw_deflate = false);
       ~Zlib_Decompression() { clear(); }
    private:
       void clear();
+
+      const bool raw_deflate;
+
       SecureVector<byte> buffer;
       class Zlib_Stream* zlib;
       bool no_writes;