msarett | 9bde918 | 2015-03-25 05:27:48 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright 2015 Google Inc. |
| 3 | * |
| 4 | * Use of this source code is governed by a BSD-style license that can be |
| 5 | * found in the LICENSE file. |
| 6 | */ |
| 7 | |
| 8 | #include "SkCodec_libbmp.h" |
| 9 | #include "SkCodec_libico.h" |
| 10 | #include "SkCodec_libpng.h" |
| 11 | #include "SkCodecPriv.h" |
| 12 | #include "SkColorPriv.h" |
| 13 | #include "SkData.h" |
| 14 | #include "SkStream.h" |
| 15 | #include "SkTDArray.h" |
| 16 | #include "SkTSort.h" |
| 17 | |
| 18 | /* |
| 19 | * Checks the start of the stream to see if the image is an Ico or Cur |
| 20 | */ |
| 21 | bool SkIcoCodec::IsIco(SkStream* stream) { |
| 22 | const char icoSig[] = { '\x00', '\x00', '\x01', '\x00' }; |
| 23 | const char curSig[] = { '\x00', '\x00', '\x02', '\x00' }; |
| 24 | char buffer[sizeof(icoSig)]; |
| 25 | return stream->read(buffer, sizeof(icoSig)) == sizeof(icoSig) && |
| 26 | (!memcmp(buffer, icoSig, sizeof(icoSig)) || |
| 27 | !memcmp(buffer, curSig, sizeof(curSig))); |
| 28 | } |
| 29 | |
| 30 | /* |
| 31 | * Assumes IsIco was called and returned true |
| 32 | * Creates an Ico decoder |
| 33 | * Reads enough of the stream to determine the image format |
| 34 | */ |
| 35 | SkCodec* SkIcoCodec::NewFromStream(SkStream* stream) { |
msarett | d0be5bb | 2015-03-25 06:29:18 -0700 | [diff] [blame^] | 36 | // Ensure that we do not leak the input stream |
| 37 | SkAutoTDelete<SkStream> inputStream(stream); |
| 38 | |
msarett | 9bde918 | 2015-03-25 05:27:48 -0700 | [diff] [blame] | 39 | // Header size constants |
| 40 | static const uint32_t kIcoDirectoryBytes = 6; |
| 41 | static const uint32_t kIcoDirEntryBytes = 16; |
| 42 | |
| 43 | // Read the directory header |
| 44 | SkAutoTDeleteArray<uint8_t> dirBuffer( |
| 45 | SkNEW_ARRAY(uint8_t, kIcoDirectoryBytes)); |
msarett | d0be5bb | 2015-03-25 06:29:18 -0700 | [diff] [blame^] | 46 | if (inputStream.get()->read(dirBuffer.get(), kIcoDirectoryBytes) != |
msarett | 9bde918 | 2015-03-25 05:27:48 -0700 | [diff] [blame] | 47 | kIcoDirectoryBytes) { |
| 48 | SkDebugf("Error: unable to read ico directory header.\n"); |
| 49 | return NULL; |
| 50 | } |
| 51 | |
| 52 | // Process the directory header |
| 53 | const uint16_t numImages = get_short(dirBuffer.get(), 4); |
| 54 | if (0 == numImages) { |
| 55 | SkDebugf("Error: No images embedded in ico.\n"); |
| 56 | return NULL; |
| 57 | } |
| 58 | |
| 59 | // Ensure that we can read all of indicated directory entries |
| 60 | SkAutoTDeleteArray<uint8_t> entryBuffer( |
| 61 | SkNEW_ARRAY(uint8_t, numImages*kIcoDirEntryBytes)); |
msarett | d0be5bb | 2015-03-25 06:29:18 -0700 | [diff] [blame^] | 62 | if (inputStream.get()->read(entryBuffer.get(), numImages*kIcoDirEntryBytes) != |
msarett | 9bde918 | 2015-03-25 05:27:48 -0700 | [diff] [blame] | 63 | numImages*kIcoDirEntryBytes) { |
| 64 | SkDebugf("Error: unable to read ico directory entries.\n"); |
| 65 | return NULL; |
| 66 | } |
| 67 | |
| 68 | // This structure is used to represent the vital information about entries |
| 69 | // in the directory header. We will obtain this information for each |
| 70 | // directory entry. |
| 71 | struct Entry { |
| 72 | uint32_t offset; |
| 73 | uint32_t size; |
| 74 | }; |
| 75 | SkAutoTDeleteArray<Entry> directoryEntries(SkNEW_ARRAY(Entry, numImages)); |
| 76 | |
| 77 | // Iterate over directory entries |
| 78 | for (uint32_t i = 0; i < numImages; i++) { |
| 79 | // The directory entry contains information such as width, height, |
| 80 | // bits per pixel, and number of colors in the color palette. We will |
| 81 | // ignore these fields since they are repeated in the header of the |
| 82 | // embedded image. In the event of an inconsistency, we would always |
| 83 | // defer to the value in the embedded header anyway. |
| 84 | |
| 85 | // Specifies the size of the embedded image, including the header |
| 86 | uint32_t size = get_int(entryBuffer.get(), 8 + i*kIcoDirEntryBytes); |
| 87 | |
| 88 | // Specifies the offset of the embedded image from the start of file. |
| 89 | // It does not indicate the start of the pixel data, but rather the |
| 90 | // start of the embedded image header. |
| 91 | uint32_t offset = get_int(entryBuffer.get(), 12 + i*kIcoDirEntryBytes); |
| 92 | |
| 93 | // Save the vital fields |
| 94 | directoryEntries.get()[i].offset = offset; |
| 95 | directoryEntries.get()[i].size = size; |
| 96 | } |
| 97 | |
| 98 | // It is "customary" that the embedded images will be stored in order of |
| 99 | // increasing offset. However, the specification does not indicate that |
| 100 | // they must be stored in this order, so we will not trust that this is the |
| 101 | // case. Here we sort the embedded images by increasing offset. |
| 102 | struct EntryLessThan { |
| 103 | bool operator() (Entry a, Entry b) const { |
| 104 | return a.offset < b.offset; |
| 105 | } |
| 106 | }; |
| 107 | EntryLessThan lessThan; |
| 108 | SkTQSort(directoryEntries.get(), directoryEntries.get() + numImages - 1, |
| 109 | lessThan); |
| 110 | |
| 111 | // Now will construct a candidate codec for each of the embedded images |
| 112 | uint32_t bytesRead = kIcoDirectoryBytes + numImages * kIcoDirEntryBytes; |
| 113 | SkAutoTDelete<SkTArray<SkAutoTDelete<SkCodec>, true>> codecs( |
| 114 | SkNEW_ARGS((SkTArray<SkAutoTDelete<SkCodec>, true>), (numImages))); |
| 115 | for (uint32_t i = 0; i < numImages; i++) { |
| 116 | uint32_t offset = directoryEntries.get()[i].offset; |
| 117 | uint32_t size = directoryEntries.get()[i].size; |
| 118 | |
| 119 | // Ensure that the offset is valid |
| 120 | if (offset < bytesRead) { |
| 121 | SkDebugf("Warning: invalid ico offset.\n"); |
| 122 | continue; |
| 123 | } |
| 124 | |
| 125 | // If we cannot skip, assume we have reached the end of the stream and |
| 126 | // stop trying to make codecs |
msarett | d0be5bb | 2015-03-25 06:29:18 -0700 | [diff] [blame^] | 127 | if (inputStream.get()->skip(offset - bytesRead) != offset - bytesRead) { |
msarett | 9bde918 | 2015-03-25 05:27:48 -0700 | [diff] [blame] | 128 | SkDebugf("Warning: could not skip to ico offset.\n"); |
| 129 | break; |
| 130 | } |
| 131 | bytesRead = offset; |
| 132 | |
| 133 | // Create a new stream for the embedded codec |
msarett | d0be5bb | 2015-03-25 06:29:18 -0700 | [diff] [blame^] | 134 | SkAutoTUnref<SkData> data( |
| 135 | SkData::NewFromStream(inputStream.get(), size)); |
msarett | 9bde918 | 2015-03-25 05:27:48 -0700 | [diff] [blame] | 136 | if (NULL == data.get()) { |
| 137 | SkDebugf("Warning: could not create embedded stream.\n"); |
| 138 | break; |
| 139 | } |
| 140 | SkAutoTDelete<SkMemoryStream> |
| 141 | embeddedStream(SkNEW_ARGS(SkMemoryStream, (data.get()))); |
| 142 | bytesRead += size; |
| 143 | |
| 144 | // Check if the embedded codec is bmp or png and create the codec |
| 145 | const bool isPng = SkPngCodec::IsPng(embeddedStream); |
| 146 | SkAssertResult(embeddedStream->rewind()); |
| 147 | SkCodec* codec = NULL; |
| 148 | if (isPng) { |
| 149 | codec = SkPngCodec::NewFromStream(embeddedStream.detach()); |
| 150 | } else { |
| 151 | codec = SkBmpCodec::NewFromIco(embeddedStream.detach()); |
| 152 | } |
| 153 | |
| 154 | // Save a valid codec |
| 155 | if (NULL != codec) { |
| 156 | codecs->push_back().reset(codec); |
| 157 | } |
| 158 | } |
| 159 | |
| 160 | // Recognize if there are no valid codecs |
| 161 | if (0 == codecs->count()) { |
| 162 | SkDebugf("Error: could not find any valid embedded ico codecs.\n"); |
| 163 | return NULL; |
| 164 | } |
| 165 | |
| 166 | // Use the largest codec as a "suggestion" for image info |
| 167 | uint32_t maxSize = 0; |
| 168 | uint32_t maxIndex = 0; |
| 169 | for (int32_t i = 0; i < codecs->count(); i++) { |
| 170 | SkImageInfo info = codecs->operator[](i)->getInfo(); |
| 171 | uint32_t size = info.width() * info.height(); |
| 172 | if (size > maxSize) { |
| 173 | maxSize = size; |
| 174 | maxIndex = i; |
| 175 | } |
| 176 | } |
| 177 | SkImageInfo info = codecs->operator[](maxIndex)->getInfo(); |
| 178 | |
| 179 | // Note that stream is owned by the embedded codec, the ico does not need |
| 180 | // direct access to the stream. |
| 181 | return SkNEW_ARGS(SkIcoCodec, (info, codecs.detach())); |
| 182 | } |
| 183 | |
| 184 | /* |
| 185 | * Creates an instance of the decoder |
| 186 | * Called only by NewFromStream |
| 187 | */ |
| 188 | SkIcoCodec::SkIcoCodec(const SkImageInfo& info, |
| 189 | SkTArray<SkAutoTDelete<SkCodec>, true>* codecs) |
| 190 | : INHERITED(info, NULL) |
| 191 | , fEmbeddedCodecs(codecs) |
| 192 | {} |
| 193 | |
| 194 | /* |
| 195 | * Chooses the best dimensions given the desired scale |
| 196 | */ |
| 197 | SkISize SkIcoCodec::onGetScaledDimensions(float desiredScale) const { |
| 198 | // We set the dimensions to the largest candidate image by default. |
| 199 | // Regardless of the scale request, this is the largest image that we |
| 200 | // will decode. |
| 201 | if (desiredScale >= 1.0) { |
| 202 | return this->getInfo().dimensions(); |
| 203 | } |
| 204 | |
| 205 | int origWidth = this->getInfo().width(); |
| 206 | int origHeight = this->getInfo().height(); |
| 207 | float desiredSize = desiredScale * origWidth * origHeight; |
| 208 | // At least one image will have smaller error than this initial value |
| 209 | float minError = ((float) (origWidth * origHeight)) - desiredSize + 1.0f; |
| 210 | int32_t minIndex = -1; |
| 211 | for (int32_t i = 0; i < fEmbeddedCodecs->count(); i++) { |
| 212 | int width = fEmbeddedCodecs->operator[](i)->getInfo().width(); |
| 213 | int height = fEmbeddedCodecs->operator[](i)->getInfo().height(); |
| 214 | float error = SkTAbs(((float) (width * height)) - desiredSize); |
| 215 | if (error < minError) { |
| 216 | minError = error; |
| 217 | minIndex = i; |
| 218 | } |
| 219 | } |
| 220 | SkASSERT(minIndex >= 0); |
| 221 | |
| 222 | return fEmbeddedCodecs->operator[](minIndex)->getInfo().dimensions(); |
| 223 | } |
| 224 | |
| 225 | /* |
| 226 | * Initiates the Ico decode |
| 227 | */ |
| 228 | SkCodec::Result SkIcoCodec::onGetPixels(const SkImageInfo& dstInfo, |
| 229 | void* dst, size_t dstRowBytes, |
| 230 | const Options& opts, SkPMColor* ct, |
| 231 | int* ptr) { |
| 232 | // We return invalid scale if there is no candidate image with matching |
| 233 | // dimensions. |
| 234 | Result result = kInvalidScale; |
| 235 | for (int32_t i = 0; i < fEmbeddedCodecs->count(); i++) { |
| 236 | // If the dimensions match, try to decode |
| 237 | if (dstInfo.dimensions() == |
| 238 | fEmbeddedCodecs->operator[](i)->getInfo().dimensions()) { |
| 239 | |
| 240 | // Perform the decode |
| 241 | result = fEmbeddedCodecs->operator[](i)->getPixels(dstInfo, |
| 242 | dst, dstRowBytes, &opts, ct, ptr); |
| 243 | |
| 244 | // On a fatal error, keep trying to find an image to decode |
| 245 | if (kInvalidConversion == result || kInvalidInput == result || |
| 246 | kInvalidScale == result) { |
| 247 | SkDebugf("Warning: Attempt to decode candidate ico failed.\n"); |
| 248 | continue; |
| 249 | } |
| 250 | |
| 251 | // On success or partial success, return the result |
| 252 | return result; |
| 253 | } |
| 254 | } |
| 255 | |
| 256 | SkDebugf("Error: No matching candidate image in ico.\n"); |
| 257 | return result; |
| 258 | } |