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///////////////////////////////////////////////////////////////////////////////
//
/// \file integer.h
/// \brief Reading and writing integers from and to buffers
//
// This code has been put into the public domain.
//
// This library 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.
//
///////////////////////////////////////////////////////////////////////////////
#ifndef LZMA_INTEGER_H
#define LZMA_INTEGER_H
// On big endian, we need byte swapping. These macros may be used outside
// this file, so don't put these inside HAVE_FAST_UNALIGNED_ACCESS.
#ifdef WORDS_BIGENDIAN
# include "bswap.h"
# define integer_le_16(n) bswap_16(n)
# define integer_le_32(n) bswap_32(n)
# define integer_le_64(n) bswap_64(n)
#else
# define integer_le_16(n) (n)
# define integer_le_32(n) (n)
# define integer_le_64(n) (n)
#endif
// I'm aware of AC_CHECK_ALIGNED_ACCESS_REQUIRED from Autoconf archive, but
// it's not useful here. We don't care if unaligned access is supported,
// we care if it is fast. Some systems can emulate unaligned access in
// software, which is horribly slow; we want to use byte-by-byte access on
// such systems but the Autoconf test would detect such a system as
// supporting unaligned access.
//
// NOTE: HAVE_FAST_UNALIGNED_ACCESS indicates only support for 16-bit and
// 32-bit integer loads and stores. 64-bit integers may or may not work.
// That's why 64-bit functions are commented out.
//
// TODO: Big endian PowerPC supports byte swapping load and store instructions
// that also allow unaligned access. Inline assembler could be OK for that.
//
// Performance of these functions isn't that important until LZMA3, but it
// doesn't hurt to have these ready already.
#ifdef HAVE_FAST_UNALIGNED_ACCESS
static inline uint16_t
integer_read_16(const uint8_t buf[static 2])
{
uint16_t ret = *(const uint16_t *)(buf);
return integer_le_16(ret);
}
static inline uint32_t
integer_read_32(const uint8_t buf[static 4])
{
uint32_t ret = *(const uint32_t *)(buf);
return integer_le_32(ret);
}
/*
static inline uint64_t
integer_read_64(const uint8_t buf[static 8])
{
uint64_t ret = *(const uint64_t *)(buf);
return integer_le_64(ret);
}
*/
static inline void
integer_write_16(uint8_t buf[static 2], uint16_t num)
{
*(uint16_t *)(buf) = integer_le_16(num);
}
static inline void
integer_write_32(uint8_t buf[static 4], uint32_t num)
{
*(uint32_t *)(buf) = integer_le_32(num);
}
/*
static inline void
integer_write_64(uint8_t buf[static 8], uint64_t num)
{
*(uint64_t *)(buf) = integer_le_64(num);
}
*/
#else
static inline uint16_t
integer_read_16(const uint8_t buf[static 2])
{
uint16_t ret = buf[0] | (buf[1] << 8);
return ret;
}
static inline uint32_t
integer_read_32(const uint8_t buf[static 4])
{
uint32_t ret = buf[0];
ret |= (uint32_t)(buf[1]) << 8;
ret |= (uint32_t)(buf[2]) << 16;
ret |= (uint32_t)(buf[3]) << 24;
return ret;
}
/*
static inline uint64_t
integer_read_64(const uint8_t buf[static 8])
{
uint64_t ret = buf[0];
ret |= (uint64_t)(buf[1]) << 8;
ret |= (uint64_t)(buf[2]) << 16;
ret |= (uint64_t)(buf[3]) << 24;
ret |= (uint64_t)(buf[4]) << 32;
ret |= (uint64_t)(buf[5]) << 40;
ret |= (uint64_t)(buf[6]) << 48;
ret |= (uint64_t)(buf[7]) << 56;
return ret;
}
*/
static inline void
integer_write_16(uint8_t buf[static 2], uint16_t num)
{
buf[0] = (uint8_t)(num);
buf[1] = (uint8_t)(num >> 8);
}
static inline void
integer_write_32(uint8_t buf[static 4], uint32_t num)
{
buf[0] = (uint8_t)(num);
buf[1] = (uint8_t)(num >> 8);
buf[2] = (uint8_t)(num >> 16);
buf[3] = (uint8_t)(num >> 24);
}
/*
static inline void
integer_write_64(uint8_t buf[static 8], uint64_t num)
{
buf[0] = (uint8_t)(num);
buf[1] = (uint8_t)(num >> 8);
buf[2] = (uint8_t)(num >> 16);
buf[3] = (uint8_t)(num >> 24);
buf[4] = (uint8_t)(num >> 32);
buf[5] = (uint8_t)(num >> 40);
buf[6] = (uint8_t)(num >> 48);
buf[7] = (uint8_t)(num >> 56);
}
*/
#endif
#endif
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