From f408456d14b12152727be31fe00f61b028f18c3b Mon Sep 17 00:00:00 2001
From: Matthew Hoops
Date: Sat, 20 Aug 2011 16:41:10 -0400
Subject: COMMON: Add wrapper for inflating headerless zlib data

---
 common/zlib.cpp | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

(limited to 'common/zlib.cpp')

diff --git a/common/zlib.cpp b/common/zlib.cpp
index 86c618830e..70133fea30 100644
--- a/common/zlib.cpp
+++ b/common/zlib.cpp
@@ -49,6 +49,35 @@ bool uncompress(byte *dst, unsigned long *dstLen, const byte *src, unsigned long
 	return Z_OK == ::uncompress(dst, dstLen, src, srcLen);
 }
 
+bool inflateZlibHeaderless(byte *dst, uint dstLen, const byte *src, uint srcLen) {
+	if (!dst || !dstLen || !src || !srcLen)
+		return false;
+
+	// Initialize zlib
+	z_stream stream;
+	stream.next_in = const_cast<byte *>(src);
+	stream.avail_in = srcLen;
+	stream.next_out = dst;
+	stream.avail_out = dstLen;
+	stream.zalloc = Z_NULL;
+	stream.zfree = Z_NULL;
+	stream.opaque = Z_NULL;
+
+	// Negative MAX_WBITS tells zlib there's no zlib header
+	int err = inflateInit2(&stream, -MAX_WBITS);
+	if (err != Z_OK)
+		return false;
+
+	err = inflate(&stream, Z_SYNC_FLUSH);
+	if (err != Z_OK && err != Z_STREAM_END) {
+		inflateEnd(&stream);
+		return false;
+	}
+
+	inflateEnd(&stream);
+	return true;
+}
+
 /**
  * A simple wrapper class which can be used to wrap around an arbitrary
  * other SeekableReadStream and will then provide on-the-fly decompression support.
-- 
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