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COMMON: Add wrapper for inflating headerless zlib data

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This commit is contained in:
Matthew Hoops 2011-08-20 16:41:10 -04:00
parent 59200bf426
commit f408456d14
2 changed files with 38 additions and 0 deletions
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29
common/zlib.cpp
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@ -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.

9
common/zlib.h
View file

@ -41,6 +41,15 @@ class WriteStream;
*/
bool uncompress(byte *dst, unsigned long *dstLen, const byte *src, unsigned long srcLen);
/**
* Wrapper around zlib's inflate functions. This function will call the
* necessary inflate functions to uncompress data compressed with deflate
* but *not* with the standard zlib header.
*
* @return true on success (Z_OK or Z_STREAM_END), false otherwise
*/
bool inflateZlibHeaderless(byte *dst, uint dstLen, const byte *src, uint srcLen);
#endif
/**