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/*
* Copyright 2010 The Android Open Source Project
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "SkDeflate.h"
#include "SkData.h"
#include "SkMakeUnique.h"
#include "SkMalloc.h"
#include "SkTo.h"
#include "SkTraceEvent.h"
#include "zlib.h"
namespace {
// Different zlib implementations use different T.
// We've seen size_t and unsigned.
template <typename T> void* skia_alloc_func(void*, T items, T size) {
return sk_calloc_throw(SkToSizeT(items) * SkToSizeT(size));
}
void skia_free_func(void*, void* address) { sk_free(address); }
} // namespace
#define SKDEFLATEWSTREAM_INPUT_BUFFER_SIZE 4096
#define SKDEFLATEWSTREAM_OUTPUT_BUFFER_SIZE 4224 // 4096 + 128, usually big
// enough to always do a
// single loop.
// called by both write() and finalize()
static void do_deflate(int flush,
z_stream* zStream,
SkWStream* out,
unsigned char* inBuffer,
size_t inBufferSize) {
zStream->next_in = inBuffer;
zStream->avail_in = SkToInt(inBufferSize);
unsigned char outBuffer[SKDEFLATEWSTREAM_OUTPUT_BUFFER_SIZE];
SkDEBUGCODE(int returnValue;)
do {
zStream->next_out = outBuffer;
zStream->avail_out = sizeof(outBuffer);
SkDEBUGCODE(returnValue =) deflate(zStream, flush);
SkASSERT(!zStream->msg);
out->write(outBuffer, sizeof(outBuffer) - zStream->avail_out);
} while (zStream->avail_in || !zStream->avail_out);
SkASSERT(flush == Z_FINISH
? returnValue == Z_STREAM_END
: returnValue == Z_OK);
}
// Hide all zlib impl details.
struct SkDeflateWStream::Impl {
SkWStream* fOut;
unsigned char fInBuffer[SKDEFLATEWSTREAM_INPUT_BUFFER_SIZE];
size_t fInBufferIndex;
z_stream fZStream;
};
SkDeflateWStream::SkDeflateWStream(SkWStream* out,
int compressionLevel,
bool gzip)
: fImpl(skstd::make_unique<SkDeflateWStream::Impl>()) {
fImpl->fOut = out;
fImpl->fInBufferIndex = 0;
if (!fImpl->fOut) {
return;
}
fImpl->fZStream.next_in = nullptr;
fImpl->fZStream.zalloc = &skia_alloc_func;
fImpl->fZStream.zfree = &skia_free_func;
fImpl->fZStream.opaque = nullptr;
SkASSERT(compressionLevel <= 9 && compressionLevel >= -1);
SkDEBUGCODE(int r =) deflateInit2(&fImpl->fZStream, compressionLevel,
Z_DEFLATED, gzip ? 0x1F : 0x0F,
8, Z_DEFAULT_STRATEGY);
SkASSERT(Z_OK == r);
}
SkDeflateWStream::~SkDeflateWStream() { this->finalize(); }
void SkDeflateWStream::finalize() {
TRACE_EVENT0("skia", TRACE_FUNC);
if (!fImpl->fOut) {
return;
}
do_deflate(Z_FINISH, &fImpl->fZStream, fImpl->fOut, fImpl->fInBuffer,
fImpl->fInBufferIndex);
(void)deflateEnd(&fImpl->fZStream);
fImpl->fOut = nullptr;
}
bool SkDeflateWStream::write(const void* void_buffer, size_t len) {
TRACE_EVENT0("skia", TRACE_FUNC);
if (!fImpl->fOut) {
return false;
}
const char* buffer = (const char*)void_buffer;
while (len > 0) {
size_t tocopy =
SkTMin(len, sizeof(fImpl->fInBuffer) - fImpl->fInBufferIndex);
memcpy(fImpl->fInBuffer + fImpl->fInBufferIndex, buffer, tocopy);
len -= tocopy;
buffer += tocopy;
fImpl->fInBufferIndex += tocopy;
SkASSERT(fImpl->fInBufferIndex <= sizeof(fImpl->fInBuffer));
// if the buffer isn't filled, don't call into zlib yet.
if (sizeof(fImpl->fInBuffer) == fImpl->fInBufferIndex) {
do_deflate(Z_NO_FLUSH, &fImpl->fZStream, fImpl->fOut,
fImpl->fInBuffer, fImpl->fInBufferIndex);
fImpl->fInBufferIndex = 0;
}
}
return true;
}
size_t SkDeflateWStream::bytesWritten() const {
return fImpl->fZStream.total_in + fImpl->fInBufferIndex;
}
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