skia2/include/core/SkWriter32.h
Cary Clark 6d6d603c81 make matrix serialization private
Moves readFromMemory, writeToMemory to private section.
No sign that these are called from google3, android,
chromium, but function names are common enough that
it's hard to know for sure.

These are used inside templates internally and for
testing, so it is not quite as simple as adding alternate
entry points in SkMatrixPriv.

R=reed@google.com
Bug: skia:6898
Change-Id: I1fac142f4bf0f38608ea93438c46f39147606c4d
Reviewed-on: https://skia-review.googlesource.com/62361
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Cary Clark <caryclark@google.com>
2017-10-20 16:49:57 +00:00

278 lines
8.1 KiB
C++

/*
* Copyright 2008 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.
*/
#ifndef SkWriter32_DEFINED
#define SkWriter32_DEFINED
#include "../private/SkTemplates.h"
#include "SkData.h"
#include "SkMatrix.h"
#include "SkPath.h"
#include "SkPoint.h"
#include "SkPoint3.h"
#include "SkRRect.h"
#include "SkRect.h"
#include "SkRegion.h"
#include "SkScalar.h"
#include "SkStream.h"
#include "SkTypes.h"
class SK_API SkWriter32 : SkNoncopyable {
public:
/**
* The caller can specify an initial block of storage, which the caller manages.
*
* SkWriter32 will try to back reserve and write calls with this external storage until the
* first time an allocation doesn't fit. From then it will use dynamically allocated storage.
* This used to be optional behavior, but pipe now relies on it.
*/
SkWriter32(void* external = nullptr, size_t externalBytes = 0) {
this->reset(external, externalBytes);
}
// return the current offset (will always be a multiple of 4)
size_t bytesWritten() const { return fUsed; }
SK_ATTR_DEPRECATED("use bytesWritten")
size_t size() const { return this->bytesWritten(); }
void reset(void* external = nullptr, size_t externalBytes = 0) {
SkASSERT(SkIsAlign4((uintptr_t)external));
SkASSERT(SkIsAlign4(externalBytes));
fData = (uint8_t*)external;
fCapacity = externalBytes;
fUsed = 0;
fExternal = external;
}
// size MUST be multiple of 4
uint32_t* reserve(size_t size) {
SkASSERT(SkAlign4(size) == size);
size_t offset = fUsed;
size_t totalRequired = fUsed + size;
if (totalRequired > fCapacity) {
this->growToAtLeast(totalRequired);
}
fUsed = totalRequired;
return (uint32_t*)(fData + offset);
}
/**
* Read a T record at offset, which must be a multiple of 4. Only legal if the record
* was written atomically using the write methods below.
*/
template<typename T>
const T& readTAt(size_t offset) const {
SkASSERT(SkAlign4(offset) == offset);
SkASSERT(offset < fUsed);
return *(T*)(fData + offset);
}
/**
* Overwrite a T record at offset, which must be a multiple of 4. Only legal if the record
* was written atomically using the write methods below.
*/
template<typename T>
void overwriteTAt(size_t offset, const T& value) {
SkASSERT(SkAlign4(offset) == offset);
SkASSERT(offset < fUsed);
*(T*)(fData + offset) = value;
}
bool writeBool(bool value) {
this->write32(value);
return value;
}
void writeInt(int32_t value) {
this->write32(value);
}
void write8(int32_t value) {
*(int32_t*)this->reserve(sizeof(value)) = value & 0xFF;
}
void write16(int32_t value) {
*(int32_t*)this->reserve(sizeof(value)) = value & 0xFFFF;
}
void write32(int32_t value) {
*(int32_t*)this->reserve(sizeof(value)) = value;
}
void writePtr(void* value) {
*(void**)this->reserve(sizeof(value)) = value;
}
void writeScalar(SkScalar value) {
*(SkScalar*)this->reserve(sizeof(value)) = value;
}
void writePoint(const SkPoint& pt) {
*(SkPoint*)this->reserve(sizeof(pt)) = pt;
}
void writePoint3(const SkPoint3& pt) {
*(SkPoint3*)this->reserve(sizeof(pt)) = pt;
}
void writeRect(const SkRect& rect) {
*(SkRect*)this->reserve(sizeof(rect)) = rect;
}
void writeIRect(const SkIRect& rect) {
*(SkIRect*)this->reserve(sizeof(rect)) = rect;
}
void writeRRect(const SkRRect& rrect) {
rrect.writeToMemory(this->reserve(SkRRect::kSizeInMemory));
}
void writePath(const SkPath& path) {
size_t size = path.writeToMemory(nullptr);
SkASSERT(SkAlign4(size) == size);
path.writeToMemory(this->reserve(size));
}
void writeMatrix(const SkMatrix& matrix);
void writeRegion(const SkRegion& rgn) {
size_t size = rgn.writeToMemory(nullptr);
SkASSERT(SkAlign4(size) == size);
rgn.writeToMemory(this->reserve(size));
}
// write count bytes (must be a multiple of 4)
void writeMul4(const void* values, size_t size) {
this->write(values, size);
}
/**
* Write size bytes from values. size must be a multiple of 4, though
* values need not be 4-byte aligned.
*/
void write(const void* values, size_t size) {
SkASSERT(SkAlign4(size) == size);
sk_careful_memcpy(this->reserve(size), values, size);
}
/**
* Reserve size bytes. Does not need to be 4 byte aligned. The remaining space (if any) will be
* filled in with zeroes.
*/
uint32_t* reservePad(size_t size) {
size_t alignedSize = SkAlign4(size);
uint32_t* p = this->reserve(alignedSize);
if (alignedSize != size) {
SkASSERT(alignedSize >= 4);
p[alignedSize / 4 - 1] = 0;
}
return p;
}
/**
* Write size bytes from src, and pad to 4 byte alignment with zeroes.
*/
void writePad(const void* src, size_t size) {
sk_careful_memcpy(this->reservePad(size), src, size);
}
/**
* Writes a string to the writer, which can be retrieved with
* SkReader32::readString().
* The length can be specified, or if -1 is passed, it will be computed by
* calling strlen(). The length must be < max size_t.
*
* If you write NULL, it will be read as "".
*/
void writeString(const char* str, size_t len = (size_t)-1);
/**
* Computes the size (aligned to multiple of 4) need to write the string
* in a call to writeString(). If the length is not specified, it will be
* computed by calling strlen().
*/
static size_t WriteStringSize(const char* str, size_t len = (size_t)-1);
void writeData(const SkData* data) {
uint32_t len = data ? SkToU32(data->size()) : 0;
this->write32(len);
if (data) {
this->writePad(data->data(), len);
}
}
static size_t WriteDataSize(const SkData* data) {
return 4 + SkAlign4(data ? data->size() : 0);
}
/**
* Move the cursor back to offset bytes from the beginning.
* offset must be a multiple of 4 no greater than size().
*/
void rewindToOffset(size_t offset) {
SkASSERT(SkAlign4(offset) == offset);
SkASSERT(offset <= bytesWritten());
fUsed = offset;
}
// copy into a single buffer (allocated by caller). Must be at least size()
void flatten(void* dst) const {
memcpy(dst, fData, fUsed);
}
bool writeToStream(SkWStream* stream) const {
return stream->write(fData, fUsed);
}
// read from the stream, and write up to length bytes. Return the actual
// number of bytes written.
size_t readFromStream(SkStream* stream, size_t length) {
return stream->read(this->reservePad(length), length);
}
/**
* Captures a snapshot of the data as it is right now, and return it.
*/
sk_sp<SkData> snapshotAsData() const;
private:
void growToAtLeast(size_t size);
uint8_t* fData; // Points to either fInternal or fExternal.
size_t fCapacity; // Number of bytes we can write to fData.
size_t fUsed; // Number of bytes written.
void* fExternal; // Unmanaged memory block.
SkAutoTMalloc<uint8_t> fInternal; // Managed memory block.
};
/**
* Helper class to allocated SIZE bytes as part of the writer, and to provide
* that storage to the constructor as its initial storage buffer.
*
* This wrapper ensures proper alignment rules are met for the storage.
*/
template <size_t SIZE> class SkSWriter32 : public SkWriter32 {
public:
SkSWriter32() { this->reset(); }
void reset() {this->INHERITED::reset(fData.fStorage, SIZE); }
private:
union {
void* fPtrAlignment;
double fDoubleAlignment;
char fStorage[SIZE];
} fData;
typedef SkWriter32 INHERITED;
};
#endif