177 lines
4.1 KiB
C++
177 lines
4.1 KiB
C++
/* ScummVM - Graphic Adventure Engine
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*
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* ScummVM is the legal property of its developers, whose names
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* are too numerous to list here. Please refer to the COPYRIGHT
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* file distributed with this source distribution.
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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*/
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//=============================================================================
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//
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// Various utility bit and byte operations
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//
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//=============================================================================
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#ifndef AGS_SHARED_UTIL_BBOP_H
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#define AGS_SHARED_UTIL_BBOP_H
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#include "ags/shared/core/platform.h"
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#include "ags/shared/core/types.h"
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namespace AGS3 {
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#if AGS_PLATFORM_ENDIAN_BIG || defined (TEST_BIGENDIAN)
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#define BITBYTE_BIG_ENDIAN
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#endif
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namespace AGS {
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namespace Shared {
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enum DataEndianess {
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kBigEndian,
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kLittleEndian,
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#if defined (BITBYTE_BIG_ENDIAN)
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kDefaultSystemEndianess = kBigEndian
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#else
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kDefaultSystemEndianess = kLittleEndian
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#endif
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};
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//
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// Various bit flags operations
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//
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// Converts from one flag into another:
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// sets flag2 if flag1 IS set
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// TODO: find more optimal way, using bitwise ops?
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inline int FlagToFlag(int value, int flag1, int flag2) {
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return ((value & flag1) != 0) * flag2;
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}
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// Sets flag2 if flag1 is NOT set
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inline int FlagToNoFlag(int value, int flag1, int flag2) {
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return ((value & flag1) == 0) * flag2;
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}
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namespace BitByteOperations {
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struct IntFloatSwap {
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union {
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float f;
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int32_t i32;
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} val;
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explicit IntFloatSwap(int32_t i) { val.i32 = i; }
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explicit IntFloatSwap(float f) { val.f = f; }
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};
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inline int16_t SwapBytesInt16(const int16_t val) {
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return ((val >> 8) & 0xFF) | ((val << 8) & 0xFF00);
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}
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inline int32_t SwapBytesInt32(const int32_t val) {
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return ((val >> 24) & 0xFF) | ((val >> 8) & 0xFF00) | ((val << 8) & 0xFF0000) | ((val << 24) & 0xFF000000);
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}
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inline int64_t SwapBytesInt64(const int64_t val) {
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return ((val >> 56) & 0xFF) | ((val >> 40) & 0xFF00) | ((val >> 24) & 0xFF0000) |
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((val >> 8) & 0xFF000000) | ((val << 8) & 0xFF00000000LL) |
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((val << 24) & 0xFF0000000000LL) | ((val << 40) & 0xFF000000000000LL) | ((val << 56) & 0xFF00000000000000LL);
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}
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inline float SwapBytesFloat(const float val) {
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IntFloatSwap swap(val);
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swap.val.i32 = SwapBytesInt32(swap.val.i32);
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return swap.val.f;
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}
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inline int16_t Int16FromLE(const int16_t val) {
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#if defined (BITBYTE_BIG_ENDIAN)
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return SwapBytesInt16(val);
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#else
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return val;
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#endif
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}
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inline int32_t Int32FromLE(const int32_t val) {
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#if defined (BITBYTE_BIG_ENDIAN)
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return SwapBytesInt32(val);
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#else
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return val;
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#endif
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}
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inline int64_t Int64FromLE(const int64_t val) {
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#if defined (BITBYTE_BIG_ENDIAN)
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return SwapBytesInt64(val);
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#else
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return val;
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#endif
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}
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inline float FloatFromLE(const float val) {
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#if defined (BITBYTE_BIG_ENDIAN)
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return SwapBytesFloat(val);
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#else
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return val;
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#endif
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}
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inline int16_t Int16FromBE(const int16_t val) {
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#if defined (BITBYTE_BIG_ENDIAN)
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return val;
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#else
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return SwapBytesInt16(val);
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#endif
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}
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inline int32_t Int32FromBE(const int32_t val) {
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#if defined (BITBYTE_BIG_ENDIAN)
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return val;
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#else
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return SwapBytesInt32(val);
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#endif
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}
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inline int64_t Int64FromBE(const int64_t val) {
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#if defined (BITBYTE_BIG_ENDIAN)
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return val;
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#else
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return SwapBytesInt64(val);
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#endif
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}
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inline float FloatFromBE(const float val) {
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#if defined (BITBYTE_BIG_ENDIAN)
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return val;
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#else
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return SwapBytesFloat(val);
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#endif
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}
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} // namespace BitByteOperations
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// Aliases for easier calling
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namespace BBOp = BitByteOperations;
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} // namespace Shared
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} // namespace AGS
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} // namespace AGS3
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#endif
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