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/***************************************************************************
* Copyright (C) 2004, 2005 by Dominic Rath *
* Dominic.Rath@gmx.de *
* *
* Copyright (C) 2007,2008 Øyvind Harboe *
* oyvind.harboe@zylin.com *
* *
* This program 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. *
* *
* This program 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 this program; if not, write to the *
* Free Software Foundation, Inc., *
* 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. *
***************************************************************************/
#ifndef BINARYBUFFER_H
#define BINARYBUFFER_H
#include "types.h"
/** @file
* Support functions to access arbitrary bits in a byte array
*/
/**
* Sets @c num bits in @c _buffer, starting at the @c first bit,
* using the bits in @c value. This routine fast-paths writes
* of little-endian, byte-aligned, 32-bit words.
* @param _buffer The buffer whose bits will be set.
* @param first The bit offset in @c _buffer to start writing (0-31).
* @param num The number of bits from @c value to copy (1-32).
* @param value Up to 32 bits that will be copied to _buffer.
*/
static inline void buf_set_u32(void *_buffer,
unsigned first, unsigned num, uint32_t value)
{
uint8_t *buffer = (uint8_t *)_buffer;
if ((num == 32) && (first == 0)) {
buffer[3] = (value >> 24) & 0xff;
buffer[2] = (value >> 16) & 0xff;
buffer[1] = (value >> 8) & 0xff;
buffer[0] = (value >> 0) & 0xff;
} else {
for (unsigned i = first; i < first + num; i++)
{
if (((value >> (i - first)) & 1) == 1)
buffer[i / 8] |= 1 << (i % 8);
else
buffer[i / 8] &= ~(1 << (i % 8));
}
}
}
/**
* Retrieves @c num bits from @c _buffer, starting at the @c first bit,
* returning the bits in a 32-bit word. This routine fast-paths reads
* of little-endian, byte-aligned, 32-bit words.
* @param _buffer The buffer whose bits will be read.
* @param first The bit offset in @c _buffer to start reading (0-31).
* @param num The number of bits from @c _buffer to read (1-32).
* @returns Up to 32-bits that were read from @c _buffer.
*/
static inline uint32_t buf_get_u32(const void *_buffer,
unsigned first, unsigned num)
{
uint8_t *buffer = (uint8_t *)_buffer;
if ((num == 32) && (first == 0)) {
return (((uint32_t)buffer[3]) << 24) |
(((uint32_t)buffer[2]) << 16) |
(((uint32_t)buffer[1]) << 8) |
(((uint32_t)buffer[0]) << 0);
} else {
uint32_t result = 0;
for (unsigned i = first; i < first + num; i++)
{
if (((buffer[i / 8] >> (i % 8)) & 1) == 1)
result |= 1 << (i - first);
}
return result;
}
}
/**
* Inverts the ordering of bits inside a 32-bit word (e.g. 31..0 -> 0..31).
* This routine can be used to flip smaller data types by using smaller
* values for @c width.
* @param value The word to flip.
* @param width The number of bits in value (2-32).
* @returns A 32-bit word with @c value in reversed bit-order.
*/
uint32_t flip_u32(uint32_t value, unsigned width);
bool buf_cmp(const void *buf1, const void *buf2, unsigned size);
bool buf_cmp_mask(const void *buf1, const void *buf2,
const void *mask, unsigned size);
/**
* Copies @c size bits out of @c from and into @c to. Any extra
* bits in the final byte will be set to zero.
* @param from The buffer to copy into @c to.
* @param to The buffer that will receive the copy of @c from.
* @param size The number of bits to copy.
*/
void* buf_cpy(const void *from, void *to, unsigned size);
/**
* Set the contents of @c buf with @c count bits, all set to 1.
* @param buf The buffer to fill with ones.
* @param size The number of bits.
* @returns The original buffer (@c buf).
*/
void* buf_set_ones(void *buf, unsigned size);
void* buf_set_buf(const void *src, unsigned src_start,
void *dst, unsigned dst_start, unsigned len);
int str_to_buf(const char *str, unsigned len,
void *bin_buf, unsigned buf_size, unsigned radix);
char* buf_to_str(const void *buf, unsigned size, unsigned radix);
/* read a uint32_t from a buffer in target memory endianness */
static inline uint32_t fast_target_buffer_get_u32(const void *p, bool le)
{
return le ? le_to_h_u32(p) : be_to_h_u32(p);
}
#endif /* BINARYBUFFER_H */
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