Revert of Delete SkImageDecoder

src/images/SkImageDecoder_libbmp.cpp

Index: src/images/SkImageDecoder_libbmp.cpp
diff --git a/src/images/SkImageDecoder_libbmp.cpp b/src/images/SkImageDecoder_libbmp.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..b9359bea7a1e169f8b770a0971c38337a0856bec
--- /dev/null
+++ b/src/images/SkImageDecoder_libbmp.cpp
@@ -0,0 +1,166 @@
+
+/*
+ * Copyright 2007 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 "bmpdecoderhelper.h"
+#include "SkColorPriv.h"
+#include "SkData.h"
+#include "SkImageDecoder.h"
+#include "SkScaledBitmapSampler.h"
+#include "SkStream.h"
+#include "SkStreamPriv.h"
+#include "SkTDArray.h"
+
+class SkBMPImageDecoder : public SkImageDecoder {
+public:
+    SkBMPImageDecoder() {}
+
+    Format getFormat() const override {
+        return kBMP_Format;
+    }
+
+protected:
+    Result onDecode(SkStream* stream, SkBitmap* bm, Mode mode) override;
+
+private:
+    typedef SkImageDecoder INHERITED;
+};
+
+///////////////////////////////////////////////////////////////////////////////
+DEFINE_DECODER_CREATOR(BMPImageDecoder);
+///////////////////////////////////////////////////////////////////////////////
+
+static bool is_bmp(SkStreamRewindable* stream) {
+    static const char kBmpMagic[] = { 'B', 'M' };
+
+
+    char buffer[sizeof(kBmpMagic)];
+
+    return stream->read(buffer, sizeof(kBmpMagic)) == sizeof(kBmpMagic) &&
+        !memcmp(buffer, kBmpMagic, sizeof(kBmpMagic));
+}
+
+static SkImageDecoder* sk_libbmp_dfactory(SkStreamRewindable* stream) {
+    if (is_bmp(stream)) {
+        return new SkBMPImageDecoder;
+    }
+    return nullptr;
+}
+
+static SkImageDecoder_DecodeReg gReg(sk_libbmp_dfactory);
+
+static SkImageDecoder::Format get_format_bmp(SkStreamRewindable* stream) {
+    if (is_bmp(stream)) {
+        return SkImageDecoder::kBMP_Format;
+    }
+    return SkImageDecoder::kUnknown_Format;
+}
+
+static SkImageDecoder_FormatReg gFormatReg(get_format_bmp);
+
+///////////////////////////////////////////////////////////////////////////////
+
+class SkBmpDecoderCallback : public image_codec::BmpDecoderCallback {
+public:
+    // we don't copy the bitmap, just remember the pointer
+    SkBmpDecoderCallback(bool justBounds) : fJustBounds(justBounds) {}
+
+    // override from BmpDecoderCallback
+    virtual uint8* SetSize(int width, int height) {
+        fWidth = width;
+        fHeight = height;
+        if (fJustBounds) {
+            return nullptr;
+        }
+
+        fRGB.setCount(width * height * 3);  // 3 == r, g, b
+        return fRGB.begin();
+    }
+
+    int width() const { return fWidth; }
+    int height() const { return fHeight; }
+    const uint8_t* rgb() const { return fRGB.begin(); }
+
+private:
+    SkTDArray<uint8_t> fRGB;
+    int fWidth;
+    int fHeight;
+    bool fJustBounds;
+};
+
+SkImageDecoder::Result SkBMPImageDecoder::onDecode(SkStream* stream, SkBitmap* bm, Mode mode) {
+    // First read the entire stream, so that all of the data can be passed to
+    // the BmpDecoderHelper.
+
+    auto data = SkCopyStreamToData(stream);
+    if (!data) {
+        return kFailure;
+    }
+
+    // Byte length of all of the data.
+    const size_t length = data->size();
+    if (0 == length) {
+        return kFailure;
+    }
+
+    const bool justBounds = SkImageDecoder::kDecodeBounds_Mode == mode;
+    SkBmpDecoderCallback callback(justBounds);
+
+    // Now decode the BMP into callback's rgb() array [r,g,b, r,g,b, ...]
+    {
+        image_codec::BmpDecoderHelper helper;
+        const int max_pixels = 16383*16383; // max width*height
+        if (!helper.DecodeImage((const char*) data->data(), length,
+                                max_pixels, &callback)) {
+            return kFailure;
+        }
+    }
+
+    // we don't need this anymore, so free it now (before we try to allocate
+    // the bitmap's pixels) rather than waiting for its destructor
+    data.reset(nullptr);
+
+    int width = callback.width();
+    int height = callback.height();
+    SkColorType colorType = this->getPrefColorType(k32Bit_SrcDepth, false);
+
+    // only accept prefConfig if it makes sense for us
+    if (kARGB_4444_SkColorType != colorType && kRGB_565_SkColorType != colorType) {
+        colorType = kN32_SkColorType;
+    }
+
+    SkScaledBitmapSampler sampler(width, height, getSampleSize());
+
+    bm->setInfo(SkImageInfo::Make(sampler.scaledWidth(), sampler.scaledHeight(),
+                                  colorType, kOpaque_SkAlphaType));
+
+    if (justBounds) {
+        return kSuccess;
+    }
+
+    if (!this->allocPixelRef(bm, nullptr)) {
+        return kFailure;
+    }
+
+    SkAutoLockPixels alp(*bm);
+
+    if (!sampler.begin(bm, SkScaledBitmapSampler::kRGB, *this)) {
+        return kFailure;
+    }
+
+    const int srcRowBytes = width * 3;
+    const int dstHeight = sampler.scaledHeight();
+    const uint8_t* srcRow = callback.rgb();
+
+    srcRow += sampler.srcY0() * srcRowBytes;
+    for (int y = 0; y < dstHeight; y++) {
+        sampler.next(srcRow);
+        srcRow += sampler.srcDY() * srcRowBytes;
+    }
+    return kSuccess;
+}