1
2 /*
3 * Copyright 2006 The Android Open Source Project
4 *
5 * Use of this source code is governed by a BSD-style license that can be
6 * found in the LICENSE file.
7 */
8
9
10 #ifndef SkEndian_DEFINED
11 #define SkEndian_DEFINED
12
13 #include "SkTypes.h"
14
15 /** \file SkEndian.h
16
17 Macros and helper functions for handling 16 and 32 bit values in
18 big and little endian formats.
19 */
20
21 #if defined(SK_CPU_LENDIAN) && defined(SK_CPU_BENDIAN)
22 #error "can't have both LENDIAN and BENDIAN defined"
23 #endif
24
25 #if !defined(SK_CPU_LENDIAN) && !defined(SK_CPU_BENDIAN)
26 #error "need either LENDIAN or BENDIAN defined"
27 #endif
28
29 /** Swap the two bytes in the low 16bits of the parameters.
30 e.g. 0x1234 -> 0x3412
31 */
SkEndianSwap16(U16CPU value)32 static inline uint16_t SkEndianSwap16(U16CPU value) {
33 SkASSERT(value == (uint16_t)value);
34 return static_cast<uint16_t>((value >> 8) | (value << 8));
35 }
36 template<uint16_t N> struct SkTEndianSwap16 {
37 static const uint16_t value = static_cast<uint16_t>((N >> 8) | ((N & 0xFF) << 8));
38 };
39
40 /** Vector version of SkEndianSwap16(), which swaps the
41 low two bytes of each value in the array.
42 */
SkEndianSwap16s(uint16_t array[],int count)43 static inline void SkEndianSwap16s(uint16_t array[], int count) {
44 SkASSERT(count == 0 || array != NULL);
45
46 while (--count >= 0) {
47 *array = SkEndianSwap16(*array);
48 array += 1;
49 }
50 }
51
52 /** Reverse all 4 bytes in a 32bit value.
53 e.g. 0x12345678 -> 0x78563412
54 */
SkEndianSwap32(uint32_t value)55 static inline uint32_t SkEndianSwap32(uint32_t value) {
56 return ((value & 0xFF) << 24) |
57 ((value & 0xFF00) << 8) |
58 ((value & 0xFF0000) >> 8) |
59 (value >> 24);
60 }
61 template<uint32_t N> struct SkTEndianSwap32 {
62 static const uint32_t value = ((N & 0xFF) << 24) |
63 ((N & 0xFF00) << 8) |
64 ((N & 0xFF0000) >> 8) |
65 (N >> 24);
66 };
67
68 /** Vector version of SkEndianSwap32(), which swaps the
69 bytes of each value in the array.
70 */
SkEndianSwap32s(uint32_t array[],int count)71 static inline void SkEndianSwap32s(uint32_t array[], int count) {
72 SkASSERT(count == 0 || array != NULL);
73
74 while (--count >= 0) {
75 *array = SkEndianSwap32(*array);
76 array += 1;
77 }
78 }
79
80 /** Reverse all 8 bytes in a 64bit value.
81 e.g. 0x1122334455667788 -> 0x8877665544332211
82 */
SkEndianSwap64(uint64_t value)83 static inline uint64_t SkEndianSwap64(uint64_t value) {
84 return (((value & 0x00000000000000FFULL) << (8*7)) |
85 ((value & 0x000000000000FF00ULL) << (8*5)) |
86 ((value & 0x0000000000FF0000ULL) << (8*3)) |
87 ((value & 0x00000000FF000000ULL) << (8*1)) |
88 ((value & 0x000000FF00000000ULL) >> (8*1)) |
89 ((value & 0x0000FF0000000000ULL) >> (8*3)) |
90 ((value & 0x00FF000000000000ULL) >> (8*5)) |
91 ((value) >> (8*7)));
92 }
93 template<uint64_t N> struct SkTEndianSwap64 {
94 static const uint64_t value = (((N & 0x00000000000000FFULL) << (8*7)) |
95 ((N & 0x000000000000FF00ULL) << (8*5)) |
96 ((N & 0x0000000000FF0000ULL) << (8*3)) |
97 ((N & 0x00000000FF000000ULL) << (8*1)) |
98 ((N & 0x000000FF00000000ULL) >> (8*1)) |
99 ((N & 0x0000FF0000000000ULL) >> (8*3)) |
100 ((N & 0x00FF000000000000ULL) >> (8*5)) |
101 ((N) >> (8*7)));
102 };
103
104 /** Vector version of SkEndianSwap64(), which swaps the
105 bytes of each value in the array.
106 */
SkEndianSwap64s(uint64_t array[],int count)107 static inline void SkEndianSwap64s(uint64_t array[], int count) {
108 SkASSERT(count == 0 || array != NULL);
109
110 while (--count >= 0) {
111 *array = SkEndianSwap64(*array);
112 array += 1;
113 }
114 }
115
116 #ifdef SK_CPU_LENDIAN
117 #define SkEndian_SwapBE16(n) SkEndianSwap16(n)
118 #define SkEndian_SwapBE32(n) SkEndianSwap32(n)
119 #define SkEndian_SwapBE64(n) SkEndianSwap64(n)
120 #define SkEndian_SwapLE16(n) (n)
121 #define SkEndian_SwapLE32(n) (n)
122 #define SkEndian_SwapLE64(n) (n)
123
124 #define SkTEndian_SwapBE16(n) SkTEndianSwap16<n>::value
125 #define SkTEndian_SwapBE32(n) SkTEndianSwap32<n>::value
126 #define SkTEndian_SwapBE64(n) SkTEndianSwap64<n>::value
127 #define SkTEndian_SwapLE16(n) (n)
128 #define SkTEndian_SwapLE32(n) (n)
129 #define SkTEndian_SwapLE64(n) (n)
130 #else // SK_CPU_BENDIAN
131 #define SkEndian_SwapBE16(n) (n)
132 #define SkEndian_SwapBE32(n) (n)
133 #define SkEndian_SwapBE64(n) (n)
134 #define SkEndian_SwapLE16(n) SkEndianSwap16(n)
135 #define SkEndian_SwapLE32(n) SkEndianSwap32(n)
136 #define SkEndian_SwapLE64(n) SkEndianSwap64(n)
137
138 #define SkTEndian_SwapBE16(n) (n)
139 #define SkTEndian_SwapBE32(n) (n)
140 #define SkTEndian_SwapBE64(n) (n)
141 #define SkTEndian_SwapLE16(n) SkTEndianSwap16<n>::value
142 #define SkTEndian_SwapLE32(n) SkTEndianSwap32<n>::value
143 #define SkTEndian_SwapLE64(n) SkTEndianSwap64<n>::value
144 #endif
145
146 // When a bytestream is embedded in a 32-bit word, how far we need to
147 // shift the word to extract each byte from the low 8 bits by anding with 0xff.
148 #ifdef SK_CPU_LENDIAN
149 #define SkEndian_Byte0Shift 0
150 #define SkEndian_Byte1Shift 8
151 #define SkEndian_Byte2Shift 16
152 #define SkEndian_Byte3Shift 24
153 #else // SK_CPU_BENDIAN
154 #define SkEndian_Byte0Shift 24
155 #define SkEndian_Byte1Shift 16
156 #define SkEndian_Byte2Shift 8
157 #define SkEndian_Byte3Shift 0
158 #endif
159
160
161 #if defined(SK_UINT8_BITFIELD_LENDIAN) && defined(SK_UINT8_BITFIELD_BENDIAN)
162 #error "can't have both bitfield LENDIAN and BENDIAN defined"
163 #endif
164
165 #if !defined(SK_UINT8_BITFIELD_LENDIAN) && !defined(SK_UINT8_BITFIELD_BENDIAN)
166 #ifdef SK_CPU_LENDIAN
167 #define SK_UINT8_BITFIELD_LENDIAN
168 #else
169 #define SK_UINT8_BITFIELD_BENDIAN
170 #endif
171 #endif
172
173 #ifdef SK_UINT8_BITFIELD_LENDIAN
174 #define SK_UINT8_BITFIELD(f0, f1, f2, f3, f4, f5, f6, f7) \
175 SK_OT_BYTE f0 : 1; \
176 SK_OT_BYTE f1 : 1; \
177 SK_OT_BYTE f2 : 1; \
178 SK_OT_BYTE f3 : 1; \
179 SK_OT_BYTE f4 : 1; \
180 SK_OT_BYTE f5 : 1; \
181 SK_OT_BYTE f6 : 1; \
182 SK_OT_BYTE f7 : 1;
183 #else
184 #define SK_UINT8_BITFIELD(f0, f1, f2, f3, f4, f5, f6, f7) \
185 SK_OT_BYTE f7 : 1; \
186 SK_OT_BYTE f6 : 1; \
187 SK_OT_BYTE f5 : 1; \
188 SK_OT_BYTE f4 : 1; \
189 SK_OT_BYTE f3 : 1; \
190 SK_OT_BYTE f2 : 1; \
191 SK_OT_BYTE f1 : 1; \
192 SK_OT_BYTE f0 : 1;
193 #endif
194
195 #endif
196