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      1 /**************************************************************************
      2  *
      3  * Copyright 2009 VMware, Inc.
      4  * All Rights Reserved.
      5  *
      6  * Permission is hereby granted, free of charge, to any person obtaining a
      7  * copy of this software and associated documentation files (the
      8  * "Software"), to deal in the Software without restriction, including
      9  * without limitation the rights to use, copy, modify, merge, publish,
     10  * distribute, sub license, and/or sell copies of the Software, and to
     11  * permit persons to whom the Software is furnished to do so, subject to
     12  * the following conditions:
     13  *
     14  * The above copyright notice and this permission notice (including the
     15  * next paragraph) shall be included in all copies or substantial portions
     16  * of the Software.
     17  *
     18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
     19  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
     20  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
     21  * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
     22  * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
     23  * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
     24  * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
     25  *
     26  **************************************************************************/
     27 
     28 /**
     29  * @file
     30  * Generic bitmask.
     31  *
     32  * @author Jose Fonseca <jfonseca (at) vmware.com>
     33  */
     34 
     35 #ifndef U_HANDLE_BITMASK_H_
     36 #define U_HANDLE_BITMASK_H_
     37 
     38 
     39 #include "pipe/p_compiler.h"
     40 
     41 
     42 #ifdef __cplusplus
     43 extern "C" {
     44 #endif
     45 
     46 
     47 #define UTIL_BITMASK_INVALID_INDEX (~0U)
     48 
     49 
     50 /**
     51  * Abstract data type to represent arbitrary set of bits.
     52  */
     53 struct util_bitmask;
     54 
     55 
     56 struct util_bitmask *
     57 util_bitmask_create(void);
     58 
     59 
     60 /**
     61  * Search a cleared bit and set it.
     62  *
     63  * It searches for the first cleared bit.
     64  *
     65  * Returns the bit index on success, or UTIL_BITMASK_INVALID_INDEX on out of
     66  * memory growing the bitmask.
     67  */
     68 unsigned
     69 util_bitmask_add(struct util_bitmask *bm);
     70 
     71 /**
     72  * Set a bit.
     73  *
     74  * Returns the input index on success, or UTIL_BITMASK_INVALID_INDEX on out of
     75  * memory growing the bitmask.
     76  */
     77 unsigned
     78 util_bitmask_set(struct util_bitmask *bm,
     79                  unsigned index);
     80 
     81 void
     82 util_bitmask_clear(struct util_bitmask *bm,
     83                    unsigned index);
     84 
     85 boolean
     86 util_bitmask_get(struct util_bitmask *bm,
     87                  unsigned index);
     88 
     89 
     90 void
     91 util_bitmask_destroy(struct util_bitmask *bm);
     92 
     93 
     94 /**
     95  * Search for the first set bit.
     96  *
     97  * Returns UTIL_BITMASK_INVALID_INDEX if a set bit cannot be found.
     98  */
     99 unsigned
    100 util_bitmask_get_first_index(struct util_bitmask *bm);
    101 
    102 
    103 /**
    104  * Search for the first set bit, starting from the giving index.
    105  *
    106  * Returns UTIL_BITMASK_INVALID_INDEX if a set bit cannot be found.
    107  */
    108 unsigned
    109 util_bitmask_get_next_index(struct util_bitmask *bm,
    110                             unsigned index);
    111 
    112 
    113 #ifdef __cplusplus
    114 }
    115 #endif
    116 
    117 #endif /* U_HANDLE_BITMASK_H_ */
    118