diff --git a/library/PolyVoxCore/include/PolyVoxCore/MinizCompressor.h b/library/PolyVoxCore/include/PolyVoxCore/MinizCompressor.h index 2770300e..80a3717a 100644 --- a/library/PolyVoxCore/include/PolyVoxCore/MinizCompressor.h +++ b/library/PolyVoxCore/include/PolyVoxCore/MinizCompressor.h @@ -8,12 +8,20 @@ namespace PolyVox class MinizCompressor : public Compressor { public: - MinizCompressor(); + MinizCompressor(int iCompressionLevel = 6); // Miniz defines MZ_DEFAULT_LEVEL = 6 so we use the same here ~MinizCompressor(); uint32_t getMaxCompressedSize(uint32_t uUncompressedInputSize); uint32_t compress(void* pSrcData, uint32_t uSrcLength, void* pDstData, uint32_t uDstLength); uint32_t decompress(void* pSrcData, uint32_t uSrcLength, void* pDstData, uint32_t uDstLength); + + private: + int m_iCompressionLevel; + + // tdefl_compressor contains all the state needed by the low-level compressor so it's a pretty big struct (~300k). + // We're storing it by void* because miniz does not supply a header and we don't want to include the .c file from + // here as it will cause linker problems. + void* g_deflator; }; } diff --git a/library/PolyVoxCore/source/MinizCompressor.cpp b/library/PolyVoxCore/source/MinizCompressor.cpp index 0c3496d8..19b86c9c 100644 --- a/library/PolyVoxCore/source/MinizCompressor.cpp +++ b/library/PolyVoxCore/source/MinizCompressor.cpp @@ -5,9 +5,9 @@ #define MINIZ_NO_STDIO #define MINIZ_NO_ARCHIVE_APIS #define MINIZ_NO_TIME -//#define MINIZ_NO_ZLIB_APIS +#define MINIZ_NO_ZLIB_APIS #define MINIZ_NO_ZLIB_COMPATIBLE_NAMES -//#define MINIZ_NO_MALLOC +#define MINIZ_NO_MALLOC #include "PolyVoxCore/Impl/ErrorHandling.h" // For some unknown reason the miniz library is supplied only as a @@ -21,19 +21,32 @@ using namespace std; namespace PolyVox { - MinizCompressor::MinizCompressor() + // Compression levels: 0-9 are the standard zlib-style levels, 10 is best possible compression (not zlib compatible, and may be very slow) + MinizCompressor::MinizCompressor(int iCompressionLevel) + :m_iCompressionLevel(iCompressionLevel) + ,g_deflator(0) { + tdefl_compressor* pDeflator = new tdefl_compressor; + g_deflator = reinterpret_cast(pDeflator); } MinizCompressor::~MinizCompressor() { + tdefl_compressor* pDeflator = reinterpret_cast(g_deflator); + delete pDeflator; } uint32_t MinizCompressor::getMaxCompressedSize(uint32_t uUncompressedInputSize) { - return static_cast(mz_compressBound(static_cast(uUncompressedInputSize))); + // The contents of this function are copied from miniz's 'mz_deflateBound()' + // (which we can't use because it is part of the zlib-style higher level API). + unsigned long source_len = uUncompressedInputSize; + + // This is really over conservative. (And lame, but it's actually pretty tricky to compute a true upper bound given the way tdefl's blocking works.) + return MZ_MAX(128 + (source_len * 110) / 100, 128 + source_len + ((source_len / (31 * 1024)) + 1) * 5); } + // The commented out function is left here for reference and debugging purposes. /*uint32_t MinizCompressor::compress(void* pSrcData, uint32_t uSrcLength, void* pDstData, uint32_t uDstLength) { mz_ulong ulDstLength = uDstLength; @@ -51,24 +64,23 @@ namespace PolyVox return ulDstLength; }*/ + // The behaviour of this function should be the same as the commented out version above (except that it requires the destination to be a power of two), + // but it's implemented using the lower level API which does not conflict with zlib or perform any memory allocations. uint32_t MinizCompressor::compress(void* pSrcData, uint32_t uSrcLength, void* pDstData, uint32_t uDstLength) { - int level = 9; - - // tdefl_compressor contains all the state needed by the low-level compressor so it's a pretty big struct (~300k). - // This example makes it a global vs. putting it on the stack, of course in real-world usage you'll probably malloc() or new it. - tdefl_compressor g_deflator; + tdefl_compressor* pDeflator = reinterpret_cast(g_deflator); // The number of dictionary probes to use at each compression level (0-10). 0=implies fastest/minimal possible probing. static const mz_uint s_tdefl_num_probes[11] = { 0, 1, 6, 32, 16, 32, 128, 256, 512, 768, 1500 }; // create tdefl() compatible flags (we have to compose the low-level flags ourselves, or use tdefl_create_comp_flags_from_zip_params() but that means MINIZ_NO_ZLIB_APIS can't be defined). - mz_uint comp_flags = TDEFL_WRITE_ZLIB_HEADER | s_tdefl_num_probes[MZ_MIN(10, level)] | ((level <= 3) ? TDEFL_GREEDY_PARSING_FLAG : 0); - if (!level) + mz_uint comp_flags = TDEFL_WRITE_ZLIB_HEADER | s_tdefl_num_probes[MZ_MIN(10, m_iCompressionLevel)] | ((m_iCompressionLevel <= 3) ? TDEFL_GREEDY_PARSING_FLAG : 0); + if (!m_iCompressionLevel) + { comp_flags |= TDEFL_FORCE_ALL_RAW_BLOCKS; + } - tdefl_status status = tdefl_init(&g_deflator, NULL, NULL, comp_flags); - assert(status == TDEFL_STATUS_OKAY); + tdefl_status status = tdefl_init(pDeflator, NULL, NULL, comp_flags); if (status != TDEFL_STATUS_OKAY) { stringstream ss; @@ -78,9 +90,8 @@ namespace PolyVox size_t ulDstLength = uDstLength; // Compress as much of the input as possible (or all of it) to the output buffer. - status = tdefl_compress(&g_deflator, pSrcData, &uSrcLength, pDstData, &ulDstLength, TDEFL_FINISH); + status = tdefl_compress(pDeflator, pSrcData, &uSrcLength, pDstData, &ulDstLength, TDEFL_FINISH); - assert(status == TDEFL_STATUS_DONE); if (status != TDEFL_STATUS_DONE) { stringstream ss; @@ -91,6 +102,7 @@ namespace PolyVox return ulDstLength; } + // The commented out function is left here for reference and debugging purposes. /*uint32_t MinizCompressor::decompress(void* pSrcData, uint32_t uSrcLength, void* pDstData, uint32_t uDstLength) { mz_ulong ulDstLength = uDstLength; @@ -106,6 +118,8 @@ namespace PolyVox return ulDstLength; }*/ + // The behaviour of this function should be the same as the commented out version above (except that it requires the destination to be a power of two), + // but it's implemented using the lower level API which does not conflict with zlib or perform any memory allocations. uint32_t MinizCompressor::decompress(void* pSrcData, uint32_t uSrcLength, void* pDstData, uint32_t uDstLength) { size_t ulDstLength = uDstLength;