1 2/* 3 * Copyright 2010 The Android Open Source Project 4 * 5 * Use of this source code is governed by a BSD-style license that can be 6 * found in the LICENSE file. 7 */ 8 9 10#include "SkData.h" 11#include "SkDeflate.h" 12#include "SkStream.h" 13 14#ifdef ZLIB_INCLUDE 15 #include ZLIB_INCLUDE 16#else 17 #include "zlib.h" 18#endif 19 20namespace { 21 22// Different zlib implementations use different T. 23// We've seen size_t and unsigned. 24template <typename T> void* skia_alloc_func(void*, T items, T size) { 25 return sk_calloc_throw(SkToSizeT(items) * SkToSizeT(size)); 26} 27 28void skia_free_func(void*, void* address) { sk_free(address); } 29 30} // namespace 31 32#define SKDEFLATEWSTREAM_INPUT_BUFFER_SIZE 4096 33#define SKDEFLATEWSTREAM_OUTPUT_BUFFER_SIZE 4224 // 4096 + 128, usually big 34 // enough to always do a 35 // single loop. 36 37// called by both write() and finalize() 38static void do_deflate(int flush, 39 z_stream* zStream, 40 SkWStream* out, 41 unsigned char* inBuffer, 42 size_t inBufferSize) { 43 zStream->next_in = inBuffer; 44 zStream->avail_in = SkToInt(inBufferSize); 45 unsigned char outBuffer[SKDEFLATEWSTREAM_OUTPUT_BUFFER_SIZE]; 46 SkDEBUGCODE(int returnValue;) 47 do { 48 zStream->next_out = outBuffer; 49 zStream->avail_out = sizeof(outBuffer); 50 SkDEBUGCODE(returnValue =) deflate(zStream, flush); 51 SkASSERT(!zStream->msg); 52 53 out->write(outBuffer, sizeof(outBuffer) - zStream->avail_out); 54 } while (zStream->avail_in || !zStream->avail_out); 55 SkASSERT(flush == Z_FINISH 56 ? returnValue == Z_STREAM_END 57 : returnValue == Z_OK); 58} 59 60// Hide all zlib impl details. 61struct SkDeflateWStream::Impl { 62 SkWStream* fOut; 63 unsigned char fInBuffer[SKDEFLATEWSTREAM_INPUT_BUFFER_SIZE]; 64 size_t fInBufferIndex; 65 z_stream fZStream; 66}; 67 68SkDeflateWStream::SkDeflateWStream(SkWStream* out, 69 int compressionLevel, 70 bool gzip) 71 : fImpl(new SkDeflateWStream::Impl) { 72 fImpl->fOut = out; 73 fImpl->fInBufferIndex = 0; 74 if (!fImpl->fOut) { 75 return; 76 } 77 fImpl->fZStream.next_in = nullptr; 78 fImpl->fZStream.zalloc = &skia_alloc_func; 79 fImpl->fZStream.zfree = &skia_free_func; 80 fImpl->fZStream.opaque = nullptr; 81 SkASSERT(compressionLevel <= 9 && compressionLevel >= -1); 82 SkDEBUGCODE(int r =) deflateInit2(&fImpl->fZStream, compressionLevel, 83 Z_DEFLATED, gzip ? 0x1F : 0x0F, 84 8, Z_DEFAULT_STRATEGY); 85 SkASSERT(Z_OK == r); 86} 87 88SkDeflateWStream::~SkDeflateWStream() { this->finalize(); } 89 90void SkDeflateWStream::finalize() { 91 if (!fImpl->fOut) { 92 return; 93 } 94 do_deflate(Z_FINISH, &fImpl->fZStream, fImpl->fOut, fImpl->fInBuffer, 95 fImpl->fInBufferIndex); 96 (void)deflateEnd(&fImpl->fZStream); 97 fImpl->fOut = nullptr; 98} 99 100bool SkDeflateWStream::write(const void* void_buffer, size_t len) { 101 if (!fImpl->fOut) { 102 return false; 103 } 104 const char* buffer = (const char*)void_buffer; 105 while (len > 0) { 106 size_t tocopy = 107 SkTMin(len, sizeof(fImpl->fInBuffer) - fImpl->fInBufferIndex); 108 memcpy(fImpl->fInBuffer + fImpl->fInBufferIndex, buffer, tocopy); 109 len -= tocopy; 110 buffer += tocopy; 111 fImpl->fInBufferIndex += tocopy; 112 SkASSERT(fImpl->fInBufferIndex <= sizeof(fImpl->fInBuffer)); 113 114 // if the buffer isn't filled, don't call into zlib yet. 115 if (sizeof(fImpl->fInBuffer) == fImpl->fInBufferIndex) { 116 do_deflate(Z_NO_FLUSH, &fImpl->fZStream, fImpl->fOut, 117 fImpl->fInBuffer, fImpl->fInBufferIndex); 118 fImpl->fInBufferIndex = 0; 119 } 120 } 121 return true; 122} 123 124size_t SkDeflateWStream::bytesWritten() const { 125 return fImpl->fZStream.total_in + fImpl->fInBufferIndex; 126} 127