зеркало из https://github.com/mozilla/moz-skia.git
153 строки
4.4 KiB
C++
153 строки
4.4 KiB
C++
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/*
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* Copyright 2006 The Android Open Source Project
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*
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*/
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#ifndef SkEndian_DEFINED
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#define SkEndian_DEFINED
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#include "SkTypes.h"
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/** \file SkEndian.h
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Macros and helper functions for handling 16 and 32 bit values in
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big and little endian formats.
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*/
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#if defined(SK_CPU_LENDIAN) && defined(SK_CPU_BENDIAN)
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#error "can't have both LENDIAN and BENDIAN defined"
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#endif
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#if !defined(SK_CPU_LENDIAN) && !defined(SK_CPU_BENDIAN)
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#error "need either LENDIAN or BENDIAN defined"
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#endif
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/** Swap the two bytes in the low 16bits of the parameters.
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e.g. 0x1234 -> 0x3412
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*/
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static inline uint16_t SkEndianSwap16(U16CPU value) {
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SkASSERT(value == (uint16_t)value);
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return static_cast<uint16_t>((value >> 8) | (value << 8));
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}
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template<uint16_t N> struct SkTEndianSwap16 {
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static const uint16_t value = static_cast<uint16_t>((N >> 8) | ((N & 0xFF) << 8));
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};
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/** Vector version of SkEndianSwap16(), which swaps the
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low two bytes of each value in the array.
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*/
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static inline void SkEndianSwap16s(uint16_t array[], int count) {
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SkASSERT(count == 0 || array != NULL);
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while (--count >= 0) {
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*array = SkEndianSwap16(*array);
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array += 1;
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}
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}
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/** Reverse all 4 bytes in a 32bit value.
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e.g. 0x12345678 -> 0x78563412
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*/
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static inline uint32_t SkEndianSwap32(uint32_t value) {
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return ((value & 0xFF) << 24) |
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((value & 0xFF00) << 8) |
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((value & 0xFF0000) >> 8) |
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(value >> 24);
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}
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template<uint32_t N> struct SkTEndianSwap32 {
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static const uint32_t value = ((N & 0xFF) << 24) |
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((N & 0xFF00) << 8) |
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((N & 0xFF0000) >> 8) |
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(N >> 24);
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};
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/** Vector version of SkEndianSwap16(), which swaps the
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bytes of each value in the array.
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*/
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static inline void SkEndianSwap32s(uint32_t array[], int count) {
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SkASSERT(count == 0 || array != NULL);
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while (--count >= 0) {
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*array = SkEndianSwap32(*array);
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array += 1;
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}
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}
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#ifdef SK_CPU_LENDIAN
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#define SkEndian_SwapBE16(n) SkEndianSwap16(n)
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#define SkEndian_SwapBE32(n) SkEndianSwap32(n)
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#define SkEndian_SwapLE16(n) (n)
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#define SkEndian_SwapLE32(n) (n)
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#define SkTEndian_SwapBE16(n) SkTEndianSwap16<n>::value
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#define SkTEndian_SwapBE32(n) SkTEndianSwap32<n>::value
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#define SkTEndian_SwapLE16(n) (n)
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#define SkTEndian_SwapLE32(n) (n)
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#else // SK_CPU_BENDIAN
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#define SkEndian_SwapBE16(n) (n)
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#define SkEndian_SwapBE32(n) (n)
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#define SkEndian_SwapLE16(n) SkEndianSwap16(n)
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#define SkEndian_SwapLE32(n) SkEndianSwap32(n)
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#define SkTEndian_SwapBE16(n) (n)
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#define SkTEndian_SwapBE32(n) (n)
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#define SkTEndian_SwapLE16(n) SkTEndianSwap16<n>::value
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#define SkTEndian_SwapLE32(n) SkTEndianSwap32<n>::value
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#endif
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// When a bytestream is embedded in a 32-bit word, how far we need to
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// shift the word to extract each byte from the low 8 bits by anding with 0xff.
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#ifdef SK_CPU_LENDIAN
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#define SkEndian_Byte0Shift 0
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#define SkEndian_Byte1Shift 8
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#define SkEndian_Byte2Shift 16
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#define SkEndian_Byte3Shift 24
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#else // SK_CPU_BENDIAN
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#define SkEndian_Byte0Shift 24
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#define SkEndian_Byte1Shift 16
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#define SkEndian_Byte2Shift 8
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#define SkEndian_Byte3Shift 0
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#endif
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#if defined(SK_UINT8_BITFIELD_LENDIAN) && defined(SK_UINT8_BITFIELD_BENDIAN)
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#error "can't have both bitfield LENDIAN and BENDIAN defined"
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#endif
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#if !defined(SK_UINT8_BITFIELD_LENDIAN) && !defined(SK_UINT8_BITFIELD_BENDIAN)
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#ifdef SK_CPU_LENDIAN
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#define SK_UINT8_BITFIELD_LENDIAN
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#else
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#define SK_UINT8_BITFIELD_BENDIAN
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#endif
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#endif
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#ifdef SK_UINT8_BITFIELD_LENDIAN
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#define SK_UINT8_BITFIELD(f0, f1, f2, f3, f4, f5, f6, f7) \
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SK_OT_BYTE f0 : 1; \
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SK_OT_BYTE f1 : 1; \
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SK_OT_BYTE f2 : 1; \
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SK_OT_BYTE f3 : 1; \
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SK_OT_BYTE f4 : 1; \
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SK_OT_BYTE f5 : 1; \
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SK_OT_BYTE f6 : 1; \
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SK_OT_BYTE f7 : 1;
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#else
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#define SK_UINT8_BITFIELD(f0, f1, f2, f3, f4, f5, f6, f7) \
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SK_OT_BYTE f7 : 1; \
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SK_OT_BYTE f6 : 1; \
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SK_OT_BYTE f5 : 1; \
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SK_OT_BYTE f4 : 1; \
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SK_OT_BYTE f3 : 1; \
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SK_OT_BYTE f2 : 1; \
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SK_OT_BYTE f1 : 1; \
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SK_OT_BYTE f0 : 1;
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#endif
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#endif
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