Revert of Delete SkImageDecoder

src/images/SkImageDecoder_wbmp.cpp

Index: src/images/SkImageDecoder_wbmp.cpp
diff --git a/src/images/SkImageDecoder_wbmp.cpp b/src/images/SkImageDecoder_wbmp.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..335966b29aab8c4ee2e1f715ceff6afa4625fdd7
--- /dev/null
+++ b/src/images/SkImageDecoder_wbmp.cpp
@@ -0,0 +1,173 @@
+
+/*
+ * 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.
+ */
+
+
+#include "SkImageDecoder.h"
+#include "SkColor.h"
+#include "SkColorPriv.h"
+#include "SkMath.h"
+#include "SkStream.h"
+#include "SkTemplates.h"
+#include "SkUtils.h"
+
+class SkWBMPImageDecoder : public SkImageDecoder {
+public:
+    Format getFormat() const override {
+        return kWBMP_Format;
+    }
+
+protected:
+    Result onDecode(SkStream* stream, SkBitmap* bm, Mode) override;
+
+private:
+    typedef SkImageDecoder INHERITED;
+};
+
+static bool read_byte(SkStream* stream, uint8_t* data)
+{
+    return stream->read(data, 1) == 1;
+}
+
+static bool read_mbf(SkStream* stream, int* value)
+{
+    int n = 0;
+    uint8_t data;
+    do {
+        if (!read_byte(stream, &data)) {
+            return false;
+        }
+        n = (n << 7) | (data & 0x7F);
+    } while (data & 0x80);
+
+    *value = n;
+    return true;
+}
+
+struct wbmp_head {
+    int fWidth;
+    int fHeight;
+
+    bool init(SkStream* stream)
+    {
+        uint8_t data;
+
+        if (!read_byte(stream, &data) || data != 0) { // unknown type
+            return false;
+        }
+        if (!read_byte(stream, &data) || (data & 0x9F)) { // skip fixed header
+            return false;
+        }
+        if (!read_mbf(stream, &fWidth) || (unsigned)fWidth > 0xFFFF) {
+            return false;
+        }
+        if (!read_mbf(stream, &fHeight) || (unsigned)fHeight > 0xFFFF) {
+            return false;
+        }
+        return fWidth != 0 && fHeight != 0;
+    }
+};
+
+static void expand_bits_to_bytes(uint8_t dst[], const uint8_t src[], int bits)
+{
+    int bytes = bits >> 3;
+
+    for (int i = 0; i < bytes; i++) {
+        unsigned mask = *src++;
+        dst[0] = (mask >> 7) & 1;
+        dst[1] = (mask >> 6) & 1;
+        dst[2] = (mask >> 5) & 1;
+        dst[3] = (mask >> 4) & 1;
+        dst[4] = (mask >> 3) & 1;
+        dst[5] = (mask >> 2) & 1;
+        dst[6] = (mask >> 1) & 1;
+        dst[7] = (mask >> 0) & 1;
+        dst += 8;
+    }
+
+    bits &= 7;
+    if (bits > 0) {
+        unsigned mask = *src;
+        do {
+            *dst++ = (mask >> 7) & 1;
+            mask <<= 1;
+        } while (--bits != 0);
+    }
+}
+
+SkImageDecoder::Result SkWBMPImageDecoder::onDecode(SkStream* stream, SkBitmap* decodedBitmap,
+                                                    Mode mode)
+{
+    wbmp_head   head;
+
+    if (!head.init(stream)) {
+        return kFailure;
+    }
+
+    int width = head.fWidth;
+    int height = head.fHeight;
+
+    decodedBitmap->setInfo(SkImageInfo::Make(width, height,
+                                             kIndex_8_SkColorType, kOpaque_SkAlphaType));
+
+    if (SkImageDecoder::kDecodeBounds_Mode == mode) {
+        return kSuccess;
+    }
+
+    const SkPMColor colors[] = { SK_ColorBLACK, SK_ColorWHITE };
+    SkColorTable* ct = new SkColorTable(colors, 2);
+    SkAutoUnref   aur(ct);
+
+    if (!this->allocPixelRef(decodedBitmap, ct)) {
+        return kFailure;
+    }
+
+    SkAutoLockPixels alp(*decodedBitmap);
+
+    uint8_t* dst = decodedBitmap->getAddr8(0, 0);
+    // store the 1-bit valuess at the end of our pixels, so we won't stomp
+    // on them before we're read them. Just trying to avoid a temp allocation
+    size_t srcRB = SkAlign8(width) >> 3;
+    size_t srcSize = height * srcRB;
+    uint8_t* src = dst + decodedBitmap->getSize() - srcSize;
+    if (stream->read(src, srcSize) != srcSize) {
+        return kFailure;
+    }
+
+    for (int y = 0; y < height; y++)
+    {
+        expand_bits_to_bytes(dst, src, width);
+        dst += decodedBitmap->rowBytes();
+        src += srcRB;
+    }
+
+    return kSuccess;
+}
+
+///////////////////////////////////////////////////////////////////////////////
+DEFINE_DECODER_CREATOR(WBMPImageDecoder);
+///////////////////////////////////////////////////////////////////////////////
+
+static SkImageDecoder* sk_wbmp_dfactory(SkStreamRewindable* stream) {
+    wbmp_head   head;
+
+    if (head.init(stream)) {
+        return new SkWBMPImageDecoder;
+    }
+    return nullptr;
+}
+
+static SkImageDecoder::Format get_format_wbmp(SkStreamRewindable* stream) {
+    wbmp_head head;
+    if (head.init(stream)) {
+        return SkImageDecoder::kWBMP_Format;
+    }
+    return SkImageDecoder::kUnknown_Format;
+}
+
+static SkImageDecoder_DecodeReg gDReg(sk_wbmp_dfactory);
+static SkImageDecoder_FormatReg gFormatReg(get_format_wbmp);