michael@0: 
michael@0: /*
michael@0:  * Copyright 2006 The Android Open Source Project
michael@0:  *
michael@0:  * Use of this source code is governed by a BSD-style license that can be
michael@0:  * found in the LICENSE file.
michael@0:  */
michael@0: 
michael@0: 
michael@0: #include "SkImageDecoder.h"
michael@0: #include "SkColor.h"
michael@0: #include "SkColorPriv.h"
michael@0: #include "SkMath.h"
michael@0: #include "SkStream.h"
michael@0: #include "SkTemplates.h"
michael@0: #include "SkUtils.h"
michael@0: 
michael@0: class SkWBMPImageDecoder : public SkImageDecoder {
michael@0: public:
michael@0:     virtual Format getFormat() const SK_OVERRIDE {
michael@0:         return kWBMP_Format;
michael@0:     }
michael@0: 
michael@0: protected:
michael@0:     virtual bool onDecode(SkStream* stream, SkBitmap* bm, Mode) SK_OVERRIDE;
michael@0: 
michael@0: private:
michael@0:     typedef SkImageDecoder INHERITED;
michael@0: };
michael@0: 
michael@0: static bool read_byte(SkStream* stream, uint8_t* data)
michael@0: {
michael@0:     return stream->read(data, 1) == 1;
michael@0: }
michael@0: 
michael@0: static bool read_mbf(SkStream* stream, int* value)
michael@0: {
michael@0:     int n = 0;
michael@0:     uint8_t data;
michael@0:     do {
michael@0:         if (!read_byte(stream, &data)) {
michael@0:             return false;
michael@0:         }
michael@0:         n = (n << 7) | (data & 0x7F);
michael@0:     } while (data & 0x80);
michael@0: 
michael@0:     *value = n;
michael@0:     return true;
michael@0: }
michael@0: 
michael@0: struct wbmp_head {
michael@0:     int fWidth;
michael@0:     int fHeight;
michael@0: 
michael@0:     bool init(SkStream* stream)
michael@0:     {
michael@0:         uint8_t data;
michael@0: 
michael@0:         if (!read_byte(stream, &data) || data != 0) { // unknown type
michael@0:             return false;
michael@0:         }
michael@0:         if (!read_byte(stream, &data) || (data & 0x9F)) { // skip fixed header
michael@0:             return false;
michael@0:         }
michael@0:         if (!read_mbf(stream, &fWidth) || (unsigned)fWidth > 0xFFFF) {
michael@0:             return false;
michael@0:         }
michael@0:         if (!read_mbf(stream, &fHeight) || (unsigned)fHeight > 0xFFFF) {
michael@0:             return false;
michael@0:         }
michael@0:         return fWidth != 0 && fHeight != 0;
michael@0:     }
michael@0: };
michael@0: 
michael@0: static void expand_bits_to_bytes(uint8_t dst[], const uint8_t src[], int bits)
michael@0: {
michael@0:     int bytes = bits >> 3;
michael@0: 
michael@0:     for (int i = 0; i < bytes; i++) {
michael@0:         unsigned mask = *src++;
michael@0:         dst[0] = (mask >> 7) & 1;
michael@0:         dst[1] = (mask >> 6) & 1;
michael@0:         dst[2] = (mask >> 5) & 1;
michael@0:         dst[3] = (mask >> 4) & 1;
michael@0:         dst[4] = (mask >> 3) & 1;
michael@0:         dst[5] = (mask >> 2) & 1;
michael@0:         dst[6] = (mask >> 1) & 1;
michael@0:         dst[7] = (mask >> 0) & 1;
michael@0:         dst += 8;
michael@0:     }
michael@0: 
michael@0:     bits &= 7;
michael@0:     if (bits > 0) {
michael@0:         unsigned mask = *src;
michael@0:         do {
michael@0:             *dst++ = (mask >> 7) & 1;;
michael@0:             mask <<= 1;
michael@0:         } while (--bits != 0);
michael@0:     }
michael@0: }
michael@0: 
michael@0: bool SkWBMPImageDecoder::onDecode(SkStream* stream, SkBitmap* decodedBitmap,
michael@0:                                   Mode mode)
michael@0: {
michael@0:     wbmp_head   head;
michael@0: 
michael@0:     if (!head.init(stream)) {
michael@0:         return false;
michael@0:     }
michael@0: 
michael@0:     int width = head.fWidth;
michael@0:     int height = head.fHeight;
michael@0: 
michael@0:     decodedBitmap->setConfig(SkBitmap::kIndex8_Config, width, height, 0,
michael@0:                              kOpaque_SkAlphaType);
michael@0: 
michael@0:     if (SkImageDecoder::kDecodeBounds_Mode == mode) {
michael@0:         return true;
michael@0:     }
michael@0: 
michael@0:     const SkPMColor colors[] = { SK_ColorBLACK, SK_ColorWHITE };
michael@0:     SkColorTable* ct = SkNEW_ARGS(SkColorTable, (colors, 2));
michael@0:     SkAutoUnref   aur(ct);
michael@0: 
michael@0:     if (!this->allocPixelRef(decodedBitmap, ct)) {
michael@0:         return false;
michael@0:     }
michael@0: 
michael@0:     SkAutoLockPixels alp(*decodedBitmap);
michael@0: 
michael@0:     uint8_t* dst = decodedBitmap->getAddr8(0, 0);
michael@0:     // store the 1-bit valuess at the end of our pixels, so we won't stomp
michael@0:     // on them before we're read them. Just trying to avoid a temp allocation
michael@0:     size_t srcRB = SkAlign8(width) >> 3;
michael@0:     size_t srcSize = height * srcRB;
michael@0:     uint8_t* src = dst + decodedBitmap->getSize() - srcSize;
michael@0:     if (stream->read(src, srcSize) != srcSize) {
michael@0:         return false;
michael@0:     }
michael@0: 
michael@0:     for (int y = 0; y < height; y++)
michael@0:     {
michael@0:         expand_bits_to_bytes(dst, src, width);
michael@0:         dst += decodedBitmap->rowBytes();
michael@0:         src += srcRB;
michael@0:     }
michael@0: 
michael@0:     return true;
michael@0: }
michael@0: 
michael@0: ///////////////////////////////////////////////////////////////////////////////
michael@0: DEFINE_DECODER_CREATOR(WBMPImageDecoder);
michael@0: ///////////////////////////////////////////////////////////////////////////////
michael@0: 
michael@0: static SkImageDecoder* sk_wbmp_dfactory(SkStreamRewindable* stream) {
michael@0:     wbmp_head   head;
michael@0: 
michael@0:     if (head.init(stream)) {
michael@0:         return SkNEW(SkWBMPImageDecoder);
michael@0:     }
michael@0:     return NULL;
michael@0: }
michael@0: 
michael@0: static SkImageDecoder::Format get_format_wbmp(SkStreamRewindable* stream) {
michael@0:     wbmp_head head;
michael@0:     if (head.init(stream)) {
michael@0:         return SkImageDecoder::kWBMP_Format;
michael@0:     }
michael@0:     return SkImageDecoder::kUnknown_Format;
michael@0: }
michael@0: 
michael@0: static SkImageDecoder_DecodeReg gDReg(sk_wbmp_dfactory);
michael@0: static SkImageDecoder_FormatReg gFormatReg(get_format_wbmp);