86 lines
2.1 KiB
C
86 lines
2.1 KiB
C
/*
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* bits.h -- bit vector manipulation
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*
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* Copyright (C) 2010,2011 Olaf Bergmann <bergmann@tzi.org>
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*
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* This file is part of the CoAP library libcoap. Please see
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* README for terms of use.
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*/
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/**
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* @file bits.h
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* @brief bit vector manipulation
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*/
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#ifndef _BITS_H_
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#define _BITS_H_
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#include <sys/types.h>
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//#include <stdint.h>
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/**
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* Sets the bit @p bit in bit-vector @p vec. This function returns @c
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* 1 if bit was set or @c -1 on error (i.e. when the given bit does
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* not fit in the vector).
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*
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* @param vec The bit-vector to change.
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* @param size The size of @p vec in bytes.
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* @param bit The bit to set in @p vec.
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*
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* @return @c -1 if @p bit does not fit into @p vec, @c 1 otherwise.
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*/
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inline static int
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bits_setb(unsigned char *vec, size_t size, unsigned char bit)
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{
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if (size <= (bit >> 3)) {
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return -1;
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}
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*(vec + (bit >> 3)) |= (unsigned char)(1 << (bit & 0x07));
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return 1;
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}
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/**
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* Clears the bit @p bit from bit-vector @p vec. This function returns
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* @c 1 if bit was cleared or @c -1 on error (i.e. when the given bit
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* does not fit in the vector).
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*
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* @param vec The bit-vector to change.
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* @param size The size of @p vec in bytes.
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* @param bit The bit to clear from @p vec.
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*
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* @return @c -1 if @p bit does not fit into @p vec, @c 1 otherwise.
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*/
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inline static int
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bits_clrb(unsigned char *vec, size_t size, unsigned char bit)
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{
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if (size <= (bit >> 3)) {
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return -1;
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}
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*(vec + (bit >> 3)) &= (unsigned char)(~(1 << (bit & 0x07)));
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return 1;
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}
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/**
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* Gets the status of bit @p bit from bit-vector @p vec. This function returns
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* @c 1 if the bit is set, @c 0 otherwise (even in case of an error)..
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*
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* @param vec The bit-vector to read from..
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* @param size The size of @p vec in bytes.
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* @param bit The bit to get from @p vec.
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*
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* @return @c 1 if the bit is set, @c 0 otherwise.
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*/
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inline static int
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bits_getb(const unsigned char *vec, size_t size, unsigned char bit)
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{
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if (size <= (bit >> 3)) {
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return -1;
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}
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return (*(vec + (bit >> 3)) & (1 << (bit & 0x07))) != 0;
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}
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#endif /* _BITS_H_ */
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