Coverage Report

Created: 2025-06-13 06:29

/src/MapServer/src/mapbits.c
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Source (jump to first uncovered line)
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/******************************************************************************
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 * $Id$
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 *
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 * Project:  MapServer
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 * Purpose:  Implementation of bit array functions.
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 * Author:   Steve Lime and the MapServer team.
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 *
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 * Notes: Derived from code placed in the public domain by Bob Stout, for more
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 * information see http://c.snippets.org/snip_lister.php?fname=bitarray.c.
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 *
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 ******************************************************************************
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 * Copyright (c) 1996-2005 Regents of the University of Minnesota.
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 * Permission is hereby granted, free of charge, to any person obtaining a
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 * copy of this software and associated documentation files (the "Software"),
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 * to deal in the Software without restriction, including without limitation
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 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
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 * and/or sell copies of the Software, and to permit persons to whom the
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 * Software is furnished to do so, subject to the following conditions:
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 *
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 * The above copyright notice and this permission notice shall be included in
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 * all copies of this Software or works derived from this Software.
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 *
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 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
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 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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 * DEALINGS IN THE SOFTWARE.
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 ****************************************************************************/
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#include "mapserver.h"
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#include <limits.h>
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/*
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 * Hardcoded size of our bit array.
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 * See function msGetNextBit for another hardcoded value.
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 */
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/* #define msGetBit(array, index) (*((array) + (index)/MS_ARRAY_BIT) & ( 1 <<
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 * ((index) % MS_ARRAY_BIT))) */
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size_t msGetBitArraySize(int numbits) {
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  return ((numbits + MS_ARRAY_BIT - 1) / MS_ARRAY_BIT);
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}
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ms_bitarray msAllocBitArray(int numbits) {
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  ms_bitarray array =
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      calloc((numbits + MS_ARRAY_BIT - 1) / MS_ARRAY_BIT, MS_ARRAY_BIT);
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  return (array);
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}
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int msGetBit(ms_const_bitarray array, int index) {
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  array += index / MS_ARRAY_BIT;
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  return (*array & (1U << (index % MS_ARRAY_BIT))) != 0; /* 0 or 1 */
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}
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/*
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** msGetNextBit( status, start, size)
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**
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** Quickly find the next bit set. If start == 0 and 0 is set, will return 0.
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** If hits end of bitmap without finding set bit, will return -1.
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**
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*/
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int msGetNextBit(ms_const_bitarray array, int i, int size) {
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  register ms_uint32 b;
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  while (i < size) {
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    b = *(array + (i / MS_ARRAY_BIT));
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    if (b && (b >> (i % MS_ARRAY_BIT))) {
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      /* There is something in this byte */
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      /* And it is not to the right of us */
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      if (b & (1U << (i % MS_ARRAY_BIT))) {
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        /* There is something at this bit! */
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        return i;
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      } else {
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        i++;
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      }
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    } else {
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      /* Nothing in this byte, move to start of next byte */
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      i += MS_ARRAY_BIT - (i % MS_ARRAY_BIT);
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    }
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  }
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  /* Got to the last byte with no hits! */
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  return -1;
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}
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void msSetBit(ms_bitarray array, int index, int value) {
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  array += index / MS_ARRAY_BIT;
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  if (value)
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    *array |= 1U << (index % MS_ARRAY_BIT); /* set bit */
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  else
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    *array &= ~(1U << (index % MS_ARRAY_BIT)); /* clear bit */
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}
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void msSetAllBits(ms_bitarray array, int numbits, int value) {
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  if (value)
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    memset(array, 0xff, ((numbits + 7) / 8)); /* set bit */
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  else
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    memset(array, 0x0, ((numbits + 7) / 8)); /* clear bit */
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}
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void msFlipBit(ms_bitarray array, int index) {
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  array += index / MS_ARRAY_BIT;
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  *array ^= 1U << (index % MS_ARRAY_BIT); /* flip bit */
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}