3 * Copyright (c) 2006-2012 by Roland Riegel <feedback@roland-riegel.de>
5 * This file is free software; you can redistribute it and/or modify
6 * it under the terms of either the GNU General Public License version 2
7 * or the GNU Lesser General Public License version 2.1, both as
8 * published by the Free Software Foundation.
11 #include "byteordering.h"
14 * \addtogroup byteordering
16 * Architecture-dependent handling of byte-ordering.
22 * Byte-order handling implementation (license: GPLv2 or LGPLv2.1)
24 * \author Roland Riegel
27 #if DOXYGEN || SWAP_NEEDED
31 * Swaps the bytes of a 16-bit integer.
33 * \param[in] i A 16-bit integer which to swap.
34 * \returns The swapped 16-bit integer.
36 uint16_t swap16(uint16_t i)
43 * Swaps the bytes of a 32-bit integer.
45 * \param[in] i A 32-bit integer which to swap.
46 * \returns The swapped 32-bit integer.
48 uint32_t swap32(uint32_t i)
56 * Reads a 16-bit integer from memory in little-endian byte order.
58 * \param[in] p Pointer from where to read the integer.
59 * \returns The 16-bit integer read from memory.
61 uint16_t read16(const uint8_t* p)
63 return (((uint16_t) p[1]) << 8) |
64 (((uint16_t) p[0]) << 0);
68 * Reads a 32-bit integer from memory in little-endian byte order.
70 * \param[in] p Pointer from where to read the integer.
71 * \returns The 32-bit integer read from memory.
73 uint32_t read32(const uint8_t* p)
75 return (((uint32_t) p[3]) << 24) |
76 (((uint32_t) p[2]) << 16) |
77 (((uint32_t) p[1]) << 8) |
78 (((uint32_t) p[0]) << 0);
82 * Writes a 16-bit integer into memory in little-endian byte order.
84 * \param[in] p Pointer where to write the integer to.
85 * \param[in] i The 16-bit integer to write.
87 void write16(uint8_t* p, uint16_t i)
89 p[1] = (uint8_t) ((i & 0xff00) >> 8);
90 p[0] = (uint8_t) ((i & 0x00ff) >> 0);
94 * Writes a 32-bit integer into memory in little-endian byte order.
96 * \param[in] p Pointer where to write the integer to.
97 * \param[in] i The 32-bit integer to write.
99 void write32(uint8_t* p, uint32_t i)
101 p[3] = (uint8_t) ((i & 0xff000000) >> 24);
102 p[2] = (uint8_t) ((i & 0x00ff0000) >> 16);
103 p[1] = (uint8_t) ((i & 0x0000ff00) >> 8);
104 p[0] = (uint8_t) ((i & 0x000000ff) >> 0);