1/*
2 * Copyright 2015 The Android Open Source Project
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#ifndef SkCodecPriv_DEFINED
9#define SkCodecPriv_DEFINED
10
11#include "SkColorData.h"
12#include "SkColorSpaceXform.h"
13#include "SkColorSpaceXformPriv.h"
14#include "SkColorTable.h"
15#include "SkEncodedInfo.h"
16#include "SkEncodedOrigin.h"
17#include "SkImageInfo.h"
18#include "SkTypes.h"
19
20#ifdef SK_PRINT_CODEC_MESSAGES
21    #define SkCodecPrintf SkDebugf
22#else
23    #define SkCodecPrintf(...)
24#endif
25
26// FIXME: Consider sharing with dm, nanbench, and tools.
27static inline float get_scale_from_sample_size(int sampleSize) {
28    return 1.0f / ((float) sampleSize);
29}
30
31static inline bool is_valid_subset(const SkIRect& subset, const SkISize& imageDims) {
32    return SkIRect::MakeSize(imageDims).contains(subset);
33}
34
35/*
36 * returns a scaled dimension based on the original dimension and the sampleSize
37 * NOTE: we round down here for scaled dimension to match the behavior of SkImageDecoder
38 * FIXME: I think we should call this get_sampled_dimension().
39 */
40static inline int get_scaled_dimension(int srcDimension, int sampleSize) {
41    if (sampleSize > srcDimension) {
42        return 1;
43    }
44    return srcDimension / sampleSize;
45}
46
47/*
48 * Returns the first coordinate that we will keep during a scaled decode.
49 * The output can be interpreted as an x-coordinate or a y-coordinate.
50 *
51 * This does not need to be called and is not called when sampleFactor == 1.
52 */
53static inline int get_start_coord(int sampleFactor) { return sampleFactor / 2; };
54
55/*
56 * Given a coordinate in the original image, this returns the corresponding
57 * coordinate in the scaled image.  This function is meaningless if
58 * IsCoordNecessary returns false.
59 * The output can be interpreted as an x-coordinate or a y-coordinate.
60 *
61 * This does not need to be called and is not called when sampleFactor == 1.
62 */
63static inline int get_dst_coord(int srcCoord, int sampleFactor) { return srcCoord / sampleFactor; };
64
65/*
66 * When scaling, we will discard certain y-coordinates (rows) and
67 * x-coordinates (columns).  This function returns true if we should keep the
68 * coordinate and false otherwise.
69 * The inputs may be x-coordinates or y-coordinates.
70 *
71 * This does not need to be called and is not called when sampleFactor == 1.
72 */
73static inline bool is_coord_necessary(int srcCoord, int sampleFactor, int scaledDim) {
74    // Get the first coordinate that we want to keep
75    int startCoord = get_start_coord(sampleFactor);
76
77    // Return false on edge cases
78    if (srcCoord < startCoord || get_dst_coord(srcCoord, sampleFactor) >= scaledDim) {
79        return false;
80    }
81
82    // Every sampleFactor rows are necessary
83    return ((srcCoord - startCoord) % sampleFactor) == 0;
84}
85
86static inline bool valid_alpha(SkAlphaType dstAlpha, bool srcIsOpaque) {
87    if (kUnknown_SkAlphaType == dstAlpha) {
88        return false;
89    }
90
91    if (srcIsOpaque) {
92        if (kOpaque_SkAlphaType != dstAlpha) {
93            SkCodecPrintf("Warning: an opaque image should be decoded as opaque "
94                          "- it is being decoded as non-opaque, which will draw slower\n");
95        }
96        return true;
97    }
98
99    return dstAlpha != kOpaque_SkAlphaType;
100}
101
102/*
103 * If there is a color table, get a pointer to the colors, otherwise return nullptr
104 */
105static inline const SkPMColor* get_color_ptr(SkColorTable* colorTable) {
106     return nullptr != colorTable ? colorTable->readColors() : nullptr;
107}
108
109/*
110 * Given that the encoded image uses a color table, return the fill value
111 */
112static inline uint64_t get_color_table_fill_value(SkColorType dstColorType, SkAlphaType alphaType,
113        const SkPMColor* colorPtr, uint8_t fillIndex, SkColorSpaceXform* colorXform, bool isRGBA) {
114    SkASSERT(nullptr != colorPtr);
115    switch (dstColorType) {
116        case kRGBA_8888_SkColorType:
117        case kBGRA_8888_SkColorType:
118            return colorPtr[fillIndex];
119        case kRGB_565_SkColorType:
120            return SkPixel32ToPixel16(colorPtr[fillIndex]);
121        case kRGBA_F16_SkColorType: {
122            SkASSERT(colorXform);
123            uint64_t dstColor;
124            uint32_t srcColor = colorPtr[fillIndex];
125            SkColorSpaceXform::ColorFormat srcFormat =
126                    isRGBA ? SkColorSpaceXform::kRGBA_8888_ColorFormat
127                           : SkColorSpaceXform::kBGRA_8888_ColorFormat;
128            SkAssertResult(colorXform->apply(select_xform_format(dstColorType), &dstColor,
129                                             srcFormat, &srcColor, 1, alphaType));
130            return dstColor;
131        }
132        default:
133            SkASSERT(false);
134            return 0;
135    }
136}
137
138/*
139 * Compute row bytes for an image using pixels per byte
140 */
141static inline size_t compute_row_bytes_ppb(int width, uint32_t pixelsPerByte) {
142    return (width + pixelsPerByte - 1) / pixelsPerByte;
143}
144
145/*
146 * Compute row bytes for an image using bytes per pixel
147 */
148static inline size_t compute_row_bytes_bpp(int width, uint32_t bytesPerPixel) {
149    return width * bytesPerPixel;
150}
151
152/*
153 * Compute row bytes for an image
154 */
155static inline size_t compute_row_bytes(int width, uint32_t bitsPerPixel) {
156    if (bitsPerPixel < 16) {
157        SkASSERT(0 == 8 % bitsPerPixel);
158        const uint32_t pixelsPerByte = 8 / bitsPerPixel;
159        return compute_row_bytes_ppb(width, pixelsPerByte);
160    } else {
161        SkASSERT(0 == bitsPerPixel % 8);
162        const uint32_t bytesPerPixel = bitsPerPixel / 8;
163        return compute_row_bytes_bpp(width, bytesPerPixel);
164    }
165}
166
167/*
168 * Get a byte from a buffer
169 * This method is unsafe, the caller is responsible for performing a check
170 */
171static inline uint8_t get_byte(uint8_t* buffer, uint32_t i) {
172    return buffer[i];
173}
174
175/*
176 * Get a short from a buffer
177 * This method is unsafe, the caller is responsible for performing a check
178 */
179static inline uint16_t get_short(uint8_t* buffer, uint32_t i) {
180    uint16_t result;
181    memcpy(&result, &(buffer[i]), 2);
182#ifdef SK_CPU_BENDIAN
183    return SkEndianSwap16(result);
184#else
185    return result;
186#endif
187}
188
189/*
190 * Get an int from a buffer
191 * This method is unsafe, the caller is responsible for performing a check
192 */
193static inline uint32_t get_int(uint8_t* buffer, uint32_t i) {
194    uint32_t result;
195    memcpy(&result, &(buffer[i]), 4);
196#ifdef SK_CPU_BENDIAN
197    return SkEndianSwap32(result);
198#else
199    return result;
200#endif
201}
202
203/*
204 * @param data           Buffer to read bytes from
205 * @param isLittleEndian Output parameter
206 *                       Indicates if the data is little endian
207 *                       Is unaffected on false returns
208 */
209static inline bool is_valid_endian_marker(const uint8_t* data, bool* isLittleEndian) {
210    // II indicates Intel (little endian) and MM indicates motorola (big endian).
211    if (('I' != data[0] || 'I' != data[1]) && ('M' != data[0] || 'M' != data[1])) {
212        return false;
213    }
214
215    *isLittleEndian = ('I' == data[0]);
216    return true;
217}
218
219static inline uint16_t get_endian_short(const uint8_t* data, bool littleEndian) {
220    if (littleEndian) {
221        return (data[1] << 8) | (data[0]);
222    }
223
224    return (data[0] << 8) | (data[1]);
225}
226
227static inline SkPMColor premultiply_argb_as_rgba(U8CPU a, U8CPU r, U8CPU g, U8CPU b) {
228    if (a != 255) {
229        r = SkMulDiv255Round(r, a);
230        g = SkMulDiv255Round(g, a);
231        b = SkMulDiv255Round(b, a);
232    }
233
234    return SkPackARGB_as_RGBA(a, r, g, b);
235}
236
237static inline SkPMColor premultiply_argb_as_bgra(U8CPU a, U8CPU r, U8CPU g, U8CPU b) {
238    if (a != 255) {
239        r = SkMulDiv255Round(r, a);
240        g = SkMulDiv255Round(g, a);
241        b = SkMulDiv255Round(b, a);
242    }
243
244    return SkPackARGB_as_BGRA(a, r, g, b);
245}
246
247static inline bool is_rgba(SkColorType colorType) {
248#ifdef SK_PMCOLOR_IS_RGBA
249    return (kBGRA_8888_SkColorType != colorType);
250#else
251    return (kRGBA_8888_SkColorType == colorType);
252#endif
253}
254
255// Method for coverting to a 32 bit pixel.
256typedef uint32_t (*PackColorProc)(U8CPU a, U8CPU r, U8CPU g, U8CPU b);
257
258static inline PackColorProc choose_pack_color_proc(bool isPremul, SkColorType colorType) {
259    bool isRGBA = is_rgba(colorType);
260    if (isPremul) {
261        if (isRGBA) {
262            return &premultiply_argb_as_rgba;
263        } else {
264            return &premultiply_argb_as_bgra;
265        }
266    } else {
267        if (isRGBA) {
268            return &SkPackARGB_as_RGBA;
269        } else {
270            return &SkPackARGB_as_BGRA;
271        }
272    }
273}
274
275static inline bool needs_premul(SkAlphaType dstAT, SkEncodedInfo::Alpha encodedAlpha) {
276    return kPremul_SkAlphaType == dstAT && SkEncodedInfo::kUnpremul_Alpha == encodedAlpha;
277}
278
279static inline bool needs_color_xform(const SkImageInfo& dstInfo, const SkColorSpace* srcCS,
280                                     bool needsColorCorrectPremul) {
281    // We never perform a color xform in legacy mode.
282    if (!dstInfo.colorSpace()) {
283        return false;
284    }
285
286    // F16 is by definition a linear space, so we always must perform a color xform.
287    bool isF16 = kRGBA_F16_SkColorType == dstInfo.colorType();
288
289    // Need a color xform when dst space does not match the src.
290    bool srcDstNotEqual = !SkColorSpace::Equals(srcCS, dstInfo.colorSpace());
291
292    return needsColorCorrectPremul || isF16 || srcDstNotEqual;
293}
294
295static inline SkAlphaType select_xform_alpha(SkAlphaType dstAlphaType, SkAlphaType srcAlphaType) {
296    return (kOpaque_SkAlphaType == srcAlphaType) ? kOpaque_SkAlphaType : dstAlphaType;
297}
298
299bool is_orientation_marker(const uint8_t* data, size_t data_length, SkEncodedOrigin* orientation);
300
301#endif // SkCodecPriv_DEFINED
302