halcanary | a096d7a | 2015-03-27 12:16:53 -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.h" |
| 9 | #include "SkColorPriv.h" |
| 10 | #include "SkStream.h" |
| 11 | #include "SkCodec_wbmp.h" |
| 12 | |
| 13 | // http://en.wikipedia.org/wiki/Variable-length_quantity |
| 14 | static bool read_mbf(SkStream* stream, uint64_t* value) { |
| 15 | uint64_t n = 0; |
| 16 | uint8_t data; |
| 17 | const uint64_t kLimit = 0xFE00000000000000; |
| 18 | SkASSERT(kLimit == ~((~static_cast<uint64_t>(0)) >> 7)); |
| 19 | do { |
| 20 | if (n & kLimit) { // Will overflow on shift by 7. |
| 21 | return false; |
| 22 | } |
| 23 | if (stream->read(&data, 1) != 1) { |
| 24 | return false; |
| 25 | } |
| 26 | n = (n << 7) | (data & 0x7F); |
| 27 | } while (data & 0x80); |
| 28 | *value = n; |
| 29 | return true; |
| 30 | } |
| 31 | |
| 32 | static bool read_header(SkStream* stream, SkISize* size) { |
| 33 | uint64_t width, height; |
| 34 | uint16_t data; |
| 35 | if (stream->read(&data, 2) != 2 || data != 0) { |
| 36 | return false; |
| 37 | } |
| 38 | if (!read_mbf(stream, &width) || width > 0xFFFF || !width) { |
| 39 | return false; |
| 40 | } |
| 41 | if (!read_mbf(stream, &height) || width > 0xFFFF || !height) { |
| 42 | return false; |
| 43 | } |
| 44 | if (size) { |
| 45 | *size = SkISize::Make(SkToS32(width), SkToS32(height)); |
| 46 | } |
| 47 | return true; |
| 48 | } |
| 49 | |
| 50 | #define BLACK SkPackARGB32NoCheck(0xFF, 0, 0, 0) |
| 51 | #define WHITE SkPackARGB32NoCheck(0xFF, 0xFF, 0xFF, 0xFF) |
| 52 | |
| 53 | #define GRAYSCALE_BLACK 0 |
| 54 | #define GRAYSCALE_WHITE 0xFF |
| 55 | |
| 56 | #define RGB565_BLACK 0 |
| 57 | #define RGB565_WHITE 0xFFFF |
| 58 | |
| 59 | static SkPMColor bit_to_pmcolor(U8CPU bit) { return bit ? WHITE : BLACK; } |
| 60 | |
| 61 | static uint8_t bit_to_bit(U8CPU bit) { return bit; } |
| 62 | |
| 63 | static uint8_t bit_to_grayscale(U8CPU bit) { |
| 64 | return bit ? GRAYSCALE_WHITE : GRAYSCALE_BLACK; |
| 65 | } |
| 66 | |
| 67 | static uint16_t bit_to_rgb565(U8CPU bit) { |
| 68 | return bit ? RGB565_WHITE : RGB565_BLACK; |
| 69 | } |
| 70 | |
| 71 | typedef void (*ExpandProc)(uint8_t*, const uint8_t*, int); |
| 72 | |
| 73 | // TODO(halcanary): Add this functionality (grayscale and indexed output) to |
| 74 | // SkSwizzler and use it here. |
| 75 | template <typename T, T (*TRANSFORM)(U8CPU)> |
| 76 | static void expand_bits_to_T(uint8_t* dstptr, const uint8_t* src, int bits) { |
| 77 | T* dst = reinterpret_cast<T*>(dstptr); |
| 78 | int bytes = bits >> 3; |
| 79 | for (int i = 0; i < bytes; i++) { |
| 80 | U8CPU mask = *src++; |
| 81 | for (int j = 0; j < 8; j++) { |
| 82 | dst[j] = TRANSFORM((mask >> (7 - j)) & 1); |
| 83 | } |
| 84 | dst += 8; |
| 85 | } |
| 86 | bits &= 7; |
| 87 | if (bits > 0) { |
| 88 | U8CPU mask = *src; |
| 89 | do { |
| 90 | *dst++ = TRANSFORM((mask >> 7) & 1); |
| 91 | mask <<= 1; |
| 92 | } while (--bits != 0); |
| 93 | } |
| 94 | } |
| 95 | |
| 96 | SkWbmpCodec::SkWbmpCodec(const SkImageInfo& info, SkStream* stream) |
| 97 | : INHERITED(info, stream) {} |
| 98 | |
| 99 | SkEncodedFormat SkWbmpCodec::onGetEncodedFormat() const { |
| 100 | return kWBMP_SkEncodedFormat; |
| 101 | } |
| 102 | |
scroggo | eb602a5 | 2015-07-09 08:16:03 -0700 | [diff] [blame^] | 103 | SkCodec::Result SkWbmpCodec::onGetPixels(const SkImageInfo& info, |
| 104 | void* pixels, |
| 105 | size_t rowBytes, |
| 106 | const Options&, |
| 107 | SkPMColor ctable[], |
| 108 | int* ctableCount) { |
halcanary | a096d7a | 2015-03-27 12:16:53 -0700 | [diff] [blame] | 109 | SkCodec::RewindState rewindState = this->rewindIfNeeded(); |
| 110 | if (rewindState == kCouldNotRewind_RewindState) { |
scroggo | eb602a5 | 2015-07-09 08:16:03 -0700 | [diff] [blame^] | 111 | return kCouldNotRewind; |
halcanary | a096d7a | 2015-03-27 12:16:53 -0700 | [diff] [blame] | 112 | } else if (rewindState == kRewound_RewindState) { |
| 113 | (void)read_header(this->stream(), NULL); |
| 114 | } |
| 115 | if (info.dimensions() != this->getInfo().dimensions()) { |
scroggo | eb602a5 | 2015-07-09 08:16:03 -0700 | [diff] [blame^] | 116 | return kInvalidScale; |
halcanary | a096d7a | 2015-03-27 12:16:53 -0700 | [diff] [blame] | 117 | } |
| 118 | ExpandProc proc = NULL; |
| 119 | switch (info.colorType()) { |
| 120 | case kGray_8_SkColorType: |
| 121 | proc = expand_bits_to_T<uint8_t, bit_to_grayscale>; |
| 122 | break; |
| 123 | case kN32_SkColorType: |
| 124 | proc = expand_bits_to_T<SkPMColor, bit_to_pmcolor>; |
| 125 | break; |
| 126 | case kIndex_8_SkColorType: |
| 127 | ctable[0] = BLACK; |
| 128 | ctable[1] = WHITE; |
| 129 | *ctableCount = 2; |
| 130 | proc = expand_bits_to_T<uint8_t, bit_to_bit>; |
| 131 | break; |
| 132 | case kRGB_565_SkColorType: |
| 133 | proc = expand_bits_to_T<uint16_t, bit_to_rgb565>; |
| 134 | break; |
| 135 | default: |
scroggo | eb602a5 | 2015-07-09 08:16:03 -0700 | [diff] [blame^] | 136 | return kInvalidConversion; |
halcanary | a096d7a | 2015-03-27 12:16:53 -0700 | [diff] [blame] | 137 | } |
| 138 | SkISize size = info.dimensions(); |
| 139 | uint8_t* dst = static_cast<uint8_t*>(pixels); |
| 140 | size_t srcRowBytes = SkAlign8(size.width()) >> 3; |
| 141 | SkAutoTMalloc<uint8_t> src(srcRowBytes); |
| 142 | for (int y = 0; y < size.height(); ++y) { |
| 143 | if (this->stream()->read(src.get(), srcRowBytes) != srcRowBytes) { |
scroggo | eb602a5 | 2015-07-09 08:16:03 -0700 | [diff] [blame^] | 144 | return kIncompleteInput; |
halcanary | a096d7a | 2015-03-27 12:16:53 -0700 | [diff] [blame] | 145 | } |
| 146 | proc(dst, src.get(), size.width()); |
| 147 | dst += rowBytes; |
| 148 | } |
scroggo | eb602a5 | 2015-07-09 08:16:03 -0700 | [diff] [blame^] | 149 | return kSuccess; |
halcanary | a096d7a | 2015-03-27 12:16:53 -0700 | [diff] [blame] | 150 | } |
| 151 | |
| 152 | bool SkWbmpCodec::IsWbmp(SkStream* stream) { |
| 153 | return read_header(stream, NULL); |
| 154 | } |
| 155 | |
| 156 | SkCodec* SkWbmpCodec::NewFromStream(SkStream* stream) { |
scroggo | 0a7e69c | 2015-04-03 07:22:22 -0700 | [diff] [blame] | 157 | SkAutoTDelete<SkStream> streamDeleter(stream); |
halcanary | a096d7a | 2015-03-27 12:16:53 -0700 | [diff] [blame] | 158 | SkISize size; |
| 159 | if (!read_header(stream, &size)) { |
| 160 | return NULL; |
| 161 | } |
| 162 | SkImageInfo info = |
| 163 | SkImageInfo::Make(size.width(), size.height(), kGray_8_SkColorType, |
| 164 | kOpaque_SkAlphaType); |
scroggo | 0a7e69c | 2015-04-03 07:22:22 -0700 | [diff] [blame] | 165 | return SkNEW_ARGS(SkWbmpCodec, (info, streamDeleter.detach())); |
halcanary | a096d7a | 2015-03-27 12:16:53 -0700 | [diff] [blame] | 166 | } |