move SkWriter32.h to src

Bug: skia:
Change-Id: If110f1716d2ad3b967aadca1c61d3e22386e17b1
Reviewed-on: https://skia-review.googlesource.com/94862
Commit-Queue: Mike Reed <reed@google.com>
Commit-Queue: Mike Klein <mtklein@chromium.org>
Reviewed-by: Mike Klein <mtklein@chromium.org>

1 files changed, 277 insertions, 0 deletions

diff --git a/src/core/SkWriter32.h b/src/core/SkWriter32.h
new file mode 100644
index 0000000000..e81178d47e
--- /dev/null
+++ b/src/core/SkWriter32.h
@@ -0,0 +1,277 @@
+
+/*
+ * 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