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/*
* 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 SkReader32_DEFINED
#define SkReader32_DEFINED
#include "SkData.h"
#include "SkMatrix.h"
#include "SkPath.h"
#include "SkRegion.h"
#include "SkRRect.h"
#include "SkScalar.h"
class SkString;
class SkReader32 : SkNoncopyable {
public:
SkReader32() : fCurr(nullptr), fStop(nullptr), fBase(nullptr) {}
SkReader32(const void* data, size_t size) {
this->setMemory(data, size);
}
void setMemory(const void* data, size_t size) {
SkASSERT(ptr_align_4(data));
SkASSERT(SkAlign4(size) == size);
fBase = fCurr = (const char*)data;
fStop = (const char*)data + size;
}
size_t size() const { return fStop - fBase; }
size_t offset() const { return fCurr - fBase; }
bool eof() const { return fCurr >= fStop; }
const void* base() const { return fBase; }
const void* peek() const { return fCurr; }
size_t available() const { return fStop - fCurr; }
bool isAvailable(size_t size) const { return size <= this->available(); }
void rewind() { fCurr = fBase; }
void setOffset(size_t offset) {
SkASSERT(SkAlign4(offset) == offset);
SkASSERT(offset <= this->size());
fCurr = fBase + offset;
}
bool readBool() { return this->readInt() != 0; }
int32_t readInt() {
SkASSERT(ptr_align_4(fCurr));
int32_t value = *(const int32_t*)fCurr;
fCurr += sizeof(value);
SkASSERT(fCurr <= fStop);
return value;
}
void* readPtr() {
void* ptr;
// we presume this "if" is resolved at compile-time
if (4 == sizeof(void*)) {
ptr = *(void**)fCurr;
} else {
memcpy(&ptr, fCurr, sizeof(void*));
}
fCurr += sizeof(void*);
return ptr;
}
SkScalar readScalar() {
SkASSERT(ptr_align_4(fCurr));
SkScalar value = *(const SkScalar*)fCurr;
fCurr += sizeof(value);
SkASSERT(fCurr <= fStop);
return value;
}
const void* skip(size_t size) {
SkASSERT(ptr_align_4(fCurr));
const void* addr = fCurr;
fCurr += SkAlign4(size);
SkASSERT(fCurr <= fStop);
return addr;
}
template <typename T> const T& skipT() {
SkASSERT(SkAlign4(sizeof(T)) == sizeof(T));
return *(const T*)this->skip(sizeof(T));
}
void read(void* dst, size_t size) {
SkASSERT(0 == size || dst != nullptr);
SkASSERT(ptr_align_4(fCurr));
sk_careful_memcpy(dst, fCurr, size);
fCurr += SkAlign4(size);
SkASSERT(fCurr <= fStop);
}
uint8_t readU8() { return (uint8_t)this->readInt(); }
uint16_t readU16() { return (uint16_t)this->readInt(); }
int32_t readS32() { return this->readInt(); }
uint32_t readU32() { return this->readInt(); }
bool readPath(SkPath* path) {
return this->readObjectFromMemory(path);
}
bool readMatrix(SkMatrix* matrix) {
return this->readObjectFromMemory(matrix);
}
bool readRRect(SkRRect* rrect) {
return this->readObjectFromMemory(rrect);
}
bool readRegion(SkRegion* rgn) {
return this->readObjectFromMemory(rgn);
}
/**
* Read the length of a string (written by SkWriter32::writeString) into
* len (if len is not nullptr) and return the null-ternimated address of the
* string within the reader's buffer.
*/
const char* readString(size_t* len = nullptr);
/**
* Read the string (written by SkWriter32::writeString) and return it in
* copy (if copy is not null). Return the length of the string.
*/
size_t readIntoString(SkString* copy);
sk_sp<SkData> readData() {
uint32_t byteLength = this->readU32();
if (0 == byteLength) {
return SkData::MakeEmpty();
}
return SkData::MakeWithCopy(this->skip(byteLength), byteLength);
}
private:
template <typename T> bool readObjectFromMemory(T* obj) {
size_t size = obj->readFromMemory(this->peek(), this->available());
// If readFromMemory() fails (which means that available() was too small), it returns 0
bool success = (size > 0) && (size <= this->available()) && (SkAlign4(size) == size);
// In case of failure, we want to skip to the end
(void)this->skip(success ? size : this->available());
return success;
}
// these are always 4-byte aligned
const char* fCurr; // current position within buffer
const char* fStop; // end of buffer
const char* fBase; // beginning of buffer
#ifdef SK_DEBUG
static bool ptr_align_4(const void* ptr) {
return (((const char*)ptr - (const char*)nullptr) & 3) == 0;
}
#endif
};
#endif
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