SkStream.h

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/*
 * Copyright 2006 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 SkStream_DEFINED
#define SkStream_DEFINED
 
#include "include/core/SkData.h"
#include "include/core/SkRefCnt.h"
#include "include/core/SkScalar.h"
#include "include/core/SkTypes.h"
#include "include/private/base/SkCPUTypes.h"
#include "include/private/base/SkTo.h"
 
#include <cstdint>
#include <cstdio>
#include <cstring>
#include <memory>
#include <utility>
class SkStreamAsset;
 
class SK_API SkStream {
public:
    virtual ~SkStream() {}
    SkStream() {}
 
    static std::unique_ptr<SkStreamAsset> MakeFromFile(const char path[]);
 
    virtual size_t read(void* buffer, size_t size) = 0;
 
    size_t skip(size_t size) {
        return this->read(nullptr, size);
    }
 
    virtual size_t peek(void* /*buffer*/, size_t /*size*/) const { return 0; }
 
    virtual bool isAtEnd() const = 0;
 
    [[nodiscard]] bool readS8(int8_t*);
    [[nodiscard]] bool readS16(int16_t*);
    [[nodiscard]] bool readS32(int32_t*);
 
    [[nodiscard]] bool readU8(uint8_t* i) { return this->readS8((int8_t*)i); }
    [[nodiscard]] bool readU16(uint16_t* i) { return this->readS16((int16_t*)i); }
    [[nodiscard]] bool readU32(uint32_t* i) { return this->readS32((int32_t*)i); }
 
    [[nodiscard]] bool readBool(bool* b) {
        uint8_t i;
        if (!this->readU8(&i)) { return false; }
        *b = (i != 0);
        return true;
    }
    [[nodiscard]] bool readScalar(SkScalar*);
    [[nodiscard]] bool readPackedUInt(size_t*);
 
//SkStreamRewindable
    virtual bool rewind() { return false; }
 
    std::unique_ptr<SkStream> duplicate() const {
        return std::unique_ptr<SkStream>(this->onDuplicate());
    }
    std::unique_ptr<SkStream> fork() const {
        return std::unique_ptr<SkStream>(this->onFork());
    }
 
//SkStreamSeekable
    virtual bool hasPosition() const { return false; }
    virtual size_t getPosition() const { return 0; }
 
    virtual bool seek(size_t /*position*/) { return false; }
 
    virtual bool move(long /*offset*/) { return false; }
 
//SkStreamAsset
    virtual bool hasLength() const { return false; }
    virtual size_t getLength() const { return 0; }
 
//SkStreamMemory
    //TODO: replace with virtual const SkData* getData()
    virtual const void* getMemoryBase() { return nullptr; }
 
private:
    virtual SkStream* onDuplicate() const { return nullptr; }
    virtual SkStream* onFork() const { return nullptr; }
 
    SkStream(SkStream&&) = delete;
    SkStream(const SkStream&) = delete;
    SkStream& operator=(SkStream&&) = delete;
    SkStream& operator=(const SkStream&) = delete;
};
 
class SK_API SkStreamRewindable : public SkStream {
public:
    bool rewind() override = 0;
    std::unique_ptr<SkStreamRewindable> duplicate() const {
        return std::unique_ptr<SkStreamRewindable>(this->onDuplicate());
    }
private:
    SkStreamRewindable* onDuplicate() const override = 0;
};
 
class SK_API SkStreamSeekable : public SkStreamRewindable {
public:
    std::unique_ptr<SkStreamSeekable> duplicate() const {
        return std::unique_ptr<SkStreamSeekable>(this->onDuplicate());
    }
 
    bool hasPosition() const override { return true; }
    size_t getPosition() const override = 0;
    bool seek(size_t position) override = 0;
    bool move(long offset) override = 0;
 
    std::unique_ptr<SkStreamSeekable> fork() const {
        return std::unique_ptr<SkStreamSeekable>(this->onFork());
    }
private:
    SkStreamSeekable* onDuplicate() const override = 0;
    SkStreamSeekable* onFork() const override = 0;
};
 
class SK_API SkStreamAsset : public SkStreamSeekable {
public:
    bool hasLength() const override { return true; }
    size_t getLength() const override = 0;
 
    std::unique_ptr<SkStreamAsset> duplicate() const {
        return std::unique_ptr<SkStreamAsset>(this->onDuplicate());
    }
    std::unique_ptr<SkStreamAsset> fork() const {
        return std::unique_ptr<SkStreamAsset>(this->onFork());
    }
private:
    SkStreamAsset* onDuplicate() const override = 0;
    SkStreamAsset* onFork() const override = 0;
};
 
class SK_API SkStreamMemory : public SkStreamAsset {
public:
    const void* getMemoryBase() override = 0;
 
    std::unique_ptr<SkStreamMemory> duplicate() const {
        return std::unique_ptr<SkStreamMemory>(this->onDuplicate());
    }
    std::unique_ptr<SkStreamMemory> fork() const {
        return std::unique_ptr<SkStreamMemory>(this->onFork());
    }
private:
    SkStreamMemory* onDuplicate() const override = 0;
    SkStreamMemory* onFork() const override = 0;
};
 
class SK_API SkWStream {
public:
    virtual ~SkWStream();
    SkWStream() {}
 
    virtual bool write(const void* buffer, size_t size) = 0;
    virtual void flush();
 
    virtual size_t bytesWritten() const = 0;
 
    // helpers
 
    bool write8(U8CPU value)   {
        uint8_t v = SkToU8(value);
        return this->write(&v, 1);
    }
    bool write16(U16CPU value) {
        uint16_t v = SkToU16(value);
        return this->write(&v, 2);
    }
    bool write32(uint32_t v) {
        return this->write(&v, 4);
    }
 
    bool writeText(const char text[]) {
        SkASSERT(text);
        return this->write(text, std::strlen(text));
    }
 
    bool newline() { return this->write("\n", std::strlen("\n")); }
 
    bool writeDecAsText(int32_t);
    bool writeBigDecAsText(int64_t, int minDigits = 0);
    bool writeHexAsText(uint32_t, int minDigits = 0);
    bool writeScalarAsText(SkScalar);
 
    bool writeBool(bool v) { return this->write8(v); }
    bool writeScalar(SkScalar);
    bool writePackedUInt(size_t);
 
    bool writeStream(SkStream* input, size_t length);
 
    static int SizeOfPackedUInt(size_t value);
 
private:
    SkWStream(const SkWStream&) = delete;
    SkWStream& operator=(const SkWStream&) = delete;
};
 
class SK_API SkNullWStream : public SkWStream {
public:
    SkNullWStream() : fBytesWritten(0) {}
 
    bool write(const void* , size_t n) override { fBytesWritten += n; return true; }
    void flush() override {}
    size_t bytesWritten() const override { return fBytesWritten; }
 
private:
    size_t fBytesWritten;
};
 
 
class SK_API SkFILEStream : public SkStreamAsset {
public:
    explicit SkFILEStream(const char path[] = nullptr);
 
    explicit SkFILEStream(FILE* file);
 
    explicit SkFILEStream(FILE* file, size_t size);
 
    ~SkFILEStream() override;
 
    static std::unique_ptr<SkFILEStream> Make(const char path[]) {
        std::unique_ptr<SkFILEStream> stream(new SkFILEStream(path));
        return stream->isValid() ? std::move(stream) : nullptr;
    }
 
    bool isValid() const { return fFILE != nullptr; }
 
    void close();
 
    size_t read(void* buffer, size_t size) override;
    bool isAtEnd() const override;
 
    bool rewind() override;
    std::unique_ptr<SkStreamAsset> duplicate() const {
        return std::unique_ptr<SkStreamAsset>(this->onDuplicate());
    }
 
    size_t getPosition() const override;
    bool seek(size_t position) override;
    bool move(long offset) override;
 
    std::unique_ptr<SkStreamAsset> fork() const {
        return std::unique_ptr<SkStreamAsset>(this->onFork());
    }
 
    size_t getLength() const override;
 
private:
    explicit SkFILEStream(FILE*, size_t size, size_t start);
    explicit SkFILEStream(std::shared_ptr<FILE>, size_t end, size_t start);
    explicit SkFILEStream(std::shared_ptr<FILE>, size_t end, size_t start, size_t current);
 
    SkStreamAsset* onDuplicate() const override;
    SkStreamAsset* onFork() const override;
 
    std::shared_ptr<FILE> fFILE;
    // My own council will I keep on sizes and offsets.
    // These are seek positions in the underling FILE, not offsets into the stream.
    size_t fEnd;
    size_t fStart;
    size_t fCurrent;
 
    using INHERITED = SkStreamAsset;
};
 
class SK_API SkMemoryStream : public SkStreamMemory {
public:
    SkMemoryStream();
 
    SkMemoryStream(size_t length);
 
    SkMemoryStream(const void* data, size_t length, bool copyData = false);
 
    SkMemoryStream(sk_sp<SkData> data);
 
    static std::unique_ptr<SkMemoryStream> MakeCopy(const void* data, size_t length);
 
    static std::unique_ptr<SkMemoryStream> MakeDirect(const void* data, size_t length);
 
    static std::unique_ptr<SkMemoryStream> Make(sk_sp<SkData> data);
 
    virtual void setMemory(const void* data, size_t length,
                           bool copyData = false);
    void setMemoryOwned(const void* data, size_t length);
 
    sk_sp<SkData> asData() const { return fData; }
    void setData(sk_sp<SkData> data);
 
    void skipToAlign4();
    const void* getAtPos();
 
    size_t read(void* buffer, size_t size) override;
    bool isAtEnd() const override;
 
    size_t peek(void* buffer, size_t size) const override;
 
    bool rewind() override;
 
    std::unique_ptr<SkMemoryStream> duplicate() const {
        return std::unique_ptr<SkMemoryStream>(this->onDuplicate());
    }
 
    size_t getPosition() const override;
    bool seek(size_t position) override;
    bool move(long offset) override;
 
    std::unique_ptr<SkMemoryStream> fork() const {
        return std::unique_ptr<SkMemoryStream>(this->onFork());
    }
 
    size_t getLength() const override;
 
    const void* getMemoryBase() override;
 
private:
    SkMemoryStream* onDuplicate() const override;
    SkMemoryStream* onFork() const override;
 
    sk_sp<SkData>   fData;
    size_t          fOffset;
 
    using INHERITED = SkStreamMemory;
};
 
 
class SK_API SkFILEWStream : public SkWStream {
public:
    SkFILEWStream(const char path[]);
    ~SkFILEWStream() override;
 
    bool isValid() const { return fFILE != nullptr; }
 
    bool write(const void* buffer, size_t size) override;
    void flush() override;
    void fsync();
    size_t bytesWritten() const override;
 
private:
    FILE* fFILE;
 
    using INHERITED = SkWStream;
};
 
class SK_API SkDynamicMemoryWStream : public SkWStream {
public:
    SkDynamicMemoryWStream() = default;
    SkDynamicMemoryWStream(SkDynamicMemoryWStream&&);
    SkDynamicMemoryWStream& operator=(SkDynamicMemoryWStream&&);
    ~SkDynamicMemoryWStream() override;
 
    bool write(const void* buffer, size_t size) override;
    size_t bytesWritten() const override;
 
    bool read(void* buffer, size_t offset, size_t size);
 
    void copyTo(void* dst) const;
    bool writeToStream(SkWStream* dst) const;
 
    void copyToAndReset(void* dst);
 
    bool writeToAndReset(SkWStream* dst);
 
    bool writeToAndReset(SkDynamicMemoryWStream* dst);
 
    void prependToAndReset(SkDynamicMemoryWStream* dst);
 
    sk_sp<SkData> detachAsData();
 
    std::unique_ptr<SkStreamAsset> detachAsStream();
 
    void reset();
    void padToAlign4();
private:
    struct Block;
    Block*  fHead = nullptr;
    Block*  fTail = nullptr;
    size_t  fBytesWrittenBeforeTail = 0;
 
#ifdef SK_DEBUG
    void validate() const;
#else
    void validate() const {}
#endif
 
    // For access to the Block type.
    friend class SkBlockMemoryStream;
    friend class SkBlockMemoryRefCnt;
 
    using INHERITED = SkWStream;
};
 
#endif