forked from 0ad/0ad
231 lines
3.7 KiB
C++
231 lines
3.7 KiB
C++
/* Copyright (C) 2009 Wildfire Games.
|
|
* This file is part of 0 A.D.
|
|
*
|
|
* 0 A.D. is free software: you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation, either version 2 of the License, or
|
|
* (at your option) any later version.
|
|
*
|
|
* 0 A.D. is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with 0 A.D. If not, see <http://www.gnu.org/licenses/>.
|
|
*/
|
|
|
|
/*
|
|
* byte order (endianness) support routines.
|
|
*/
|
|
|
|
#include "precompiled.h"
|
|
#include "byte_order.h"
|
|
|
|
#include "bits.h"
|
|
|
|
#ifndef swap16
|
|
|
|
u16 swap16(const u16 x)
|
|
{
|
|
return (u16)(((x & 0xff) << 8) | (x >> 8));
|
|
}
|
|
|
|
u32 swap32(const u32 x)
|
|
{
|
|
return (x << 24) |
|
|
(x >> 24) |
|
|
((x << 8) & 0x00ff0000) |
|
|
((x >> 8) & 0x0000ff00);
|
|
}
|
|
|
|
u64 swap64(const u64 x)
|
|
{
|
|
const u32 lo = (u32)(x & 0xFFFFFFFF);
|
|
const u32 hi = (u32)(x >> 32);
|
|
u64 ret = swap32(lo);
|
|
ret <<= 32;
|
|
// careful: must shift var of type u64, not u32
|
|
ret |= swap32(hi);
|
|
return ret;
|
|
}
|
|
|
|
#endif // #ifndef swap16
|
|
|
|
|
|
//-----------------------------------------------------------------------------
|
|
|
|
u16 to_le16(u16 x)
|
|
{
|
|
#if BYTE_ORDER == BIG_ENDIAN
|
|
return swap16(x);
|
|
#else
|
|
return x;
|
|
#endif
|
|
}
|
|
|
|
u32 to_le32(u32 x)
|
|
{
|
|
#if BYTE_ORDER == BIG_ENDIAN
|
|
return swap32(x);
|
|
#else
|
|
return x;
|
|
#endif
|
|
}
|
|
|
|
u64 to_le64(u64 x)
|
|
{
|
|
#if BYTE_ORDER == BIG_ENDIAN
|
|
return swap64(x);
|
|
#else
|
|
return x;
|
|
#endif
|
|
}
|
|
|
|
|
|
u16 to_be16(u16 x)
|
|
{
|
|
#if BYTE_ORDER == BIG_ENDIAN
|
|
return x;
|
|
#else
|
|
return swap16(x);
|
|
#endif
|
|
}
|
|
|
|
u32 to_be32(u32 x)
|
|
{
|
|
#if BYTE_ORDER == BIG_ENDIAN
|
|
return x;
|
|
#else
|
|
return swap32(x);
|
|
#endif
|
|
}
|
|
|
|
u64 to_be64(u64 x)
|
|
{
|
|
#if BYTE_ORDER == BIG_ENDIAN
|
|
return x;
|
|
#else
|
|
return swap64(x);
|
|
#endif
|
|
}
|
|
|
|
|
|
u16 read_le16(const void* p)
|
|
{
|
|
return to_le16(*(u16*)p);
|
|
}
|
|
|
|
u32 read_le32(const void* p)
|
|
{
|
|
return to_le32(*(u32*)p);
|
|
}
|
|
|
|
u64 read_le64(const void* p)
|
|
{
|
|
return to_le64(*(u64*)p);
|
|
}
|
|
|
|
|
|
u16 read_be16(const void* p)
|
|
{
|
|
return to_be16(*(u16*)p);
|
|
}
|
|
|
|
u32 read_be32(const void* p)
|
|
{
|
|
return to_be32(*(u32*)p);
|
|
}
|
|
|
|
u64 read_be64(const void* p)
|
|
{
|
|
return to_be64(*(u64*)p);
|
|
}
|
|
|
|
|
|
void write_le16(void* p, u16 x)
|
|
{
|
|
*(u16*)p = to_le16(x);
|
|
}
|
|
|
|
void write_le32(void* p, u32 x)
|
|
{
|
|
*(u32*)p = to_le32(x);
|
|
}
|
|
|
|
void write_le64(void* p, u64 x)
|
|
{
|
|
*(u64*)p = to_le64(x);
|
|
}
|
|
|
|
|
|
void write_be16(void* p, u16 x)
|
|
{
|
|
*(u16*)p = to_be16(x);
|
|
}
|
|
|
|
void write_be32(void* p, u32 x)
|
|
{
|
|
*(u32*)p = to_be32(x);
|
|
}
|
|
|
|
void write_be64(void* p, u64 x)
|
|
{
|
|
*(u64*)p = to_be64(x);
|
|
}
|
|
|
|
|
|
u64 movzx_le64(const u8* p, size_t size_bytes)
|
|
{
|
|
u64 number = 0;
|
|
for(size_t i = 0; i < std::min(size_bytes, (size_t)8u); i++)
|
|
number |= ((u64)p[i]) << (i*8);
|
|
|
|
return number;
|
|
}
|
|
|
|
u64 movzx_be64(const u8* p, size_t size_bytes)
|
|
{
|
|
u64 number = 0;
|
|
for(size_t i = 0; i < std::min(size_bytes, (size_t)8u); i++)
|
|
{
|
|
number <<= 8;
|
|
number |= p[i];
|
|
}
|
|
|
|
return number;
|
|
}
|
|
|
|
|
|
static inline i64 SignExtend(u64 bits, size_t size_bytes)
|
|
{
|
|
// no point in sign-extending if >= 8 bytes were requested
|
|
if(size_bytes < 8)
|
|
{
|
|
const u64 sign_bit = Bit<u64>((size_bytes*8)-1);
|
|
|
|
// number would be negative in the smaller type,
|
|
// so sign-extend, i.e. set all more significant bits.
|
|
if(bits & sign_bit)
|
|
{
|
|
const u64 valid_bit_mask = (sign_bit+sign_bit)-1;
|
|
bits |= ~valid_bit_mask;
|
|
}
|
|
}
|
|
|
|
const i64 number = static_cast<i64>(bits);
|
|
return number;
|
|
}
|
|
|
|
i64 movsx_le64(const u8* p, size_t size_bytes)
|
|
{
|
|
const u64 number = movzx_le64(p, size_bytes);
|
|
return SignExtend(number, size_bytes);
|
|
}
|
|
|
|
i64 movsx_be64(const u8* p, size_t size_bytes)
|
|
{
|
|
const u64 number = movzx_be64(p, size_bytes);
|
|
return SignExtend(number, size_bytes);
|
|
}
|