src/util/u_dynarray.h

   1 /**************************************************************************
   2  *
   3  * Copyright 2010 Luca Barbieri
   4  *
   5  * Permission is hereby granted, free of charge, to any person obtaining
   6  * a copy of this software and associated documentation files (the
   7  * "Software"), to deal in the Software without restriction, including
   8  * without limitation the rights to use, copy, modify, merge, publish,
   9  * distribute, sublicense, and/or sell copies of the Software, and to
  10  * permit persons to whom the Software is furnished to do so, subject to
  11  * the following conditions:
  12  *
  13  * The above copyright notice and this permission notice (including the
  14  * next paragraph) shall be included in all copies or substantial
  15  * portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  18  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  19  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
  20  * IN NO EVENT SHALL THE COPYRIGHT OWNER(S) AND/OR ITS SUPPLIERS BE
  21  * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  22  * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  23  * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  24  *
  25  **************************************************************************/
  26
  27 #ifndef U_DYNARRAY_H
  28 #define U_DYNARRAY_H
  29
  30 #include <stdlib.h>
  31
  32 /* A zero-initialized version of this is guaranteed to represent an
  33  * empty array.
  34  *
  35  * Also, size <= capacity and data != 0 if and only if capacity != 0
  36  * capacity will always be the allocation size of data
  37  */
  38 struct util_dynarray
  39 {
  40    void *data;
  41    unsigned size;
  42    unsigned capacity;
  43 };
  44
  45 static inline void
  46 util_dynarray_init(struct util_dynarray *buf)
  47 {
  48    memset(buf, 0, sizeof(*buf));
  49 }
  50
  51 static inline void
  52 util_dynarray_fini(struct util_dynarray *buf)
  53 {
  54    if (buf->data) {
  55       free(buf->data);
  56       util_dynarray_init(buf);
  57    }
  58 }
  59
  60 /* use util_dynarray_trim to reduce the allocated storage */
  61 static inline void *
  62 util_dynarray_resize(struct util_dynarray *buf, unsigned newsize)
  63 {
  64    void *p;
  65    if (newsize > buf->capacity) {
  66       unsigned newcap = buf->capacity << 1;
  67       if (newsize > newcap)
  68               newcap = newsize;
  69       buf->data = realloc(buf->data, newcap);
  70       buf->capacity = newcap;
  71    }
  72
  73    p = (void *)((char *)buf->data + buf->size);
  74    buf->size = newsize;
  75
  76    return p;
  77 }
  78
  79 static inline void *
  80 util_dynarray_grow(struct util_dynarray *buf, int diff)
  81 {
  82    return util_dynarray_resize(buf, buf->size + diff);
  83 }
  84
  85 static inline void
  86 util_dynarray_trim(struct util_dynarray *buf)
  87 {
  88    if (buf->size != buf->capacity) {
  89       if (buf->size) {
  90          buf->data = realloc(buf->data, buf->size);
  91          buf->capacity = buf->size;
  92       } else {
  93          free(buf->data);
  94          buf->data = 0;
  95          buf->capacity = 0;
  96       }
  97    }
  98 }
  99
 100 #define util_dynarray_append(buf, type, v) do {type __v = (v); memcpy(util_dynarray_grow((buf), sizeof(type)), &__v, sizeof(type));} while(0)
 101 #define util_dynarray_top_ptr(buf, type) (type*)((char*)(buf)->data + (buf)->size - sizeof(type))
 102 #define util_dynarray_top(buf, type) *util_dynarray_top_ptr(buf, type)
 103 #define util_dynarray_pop_ptr(buf, type) (type*)((char*)(buf)->data + ((buf)->size -= sizeof(type)))
 104 #define util_dynarray_pop(buf, type) *util_dynarray_pop_ptr(buf, type)
 105 #define util_dynarray_contains(buf, type) ((buf)->size >= sizeof(type))
 106 #define util_dynarray_element(buf, type, idx) ((type*)(buf)->data + (idx))
 107 #define util_dynarray_begin(buf) ((buf)->data)
 108 #define util_dynarray_end(buf) ((void*)util_dynarray_element((buf), char, (buf)->size))
 109
 110 #endif /* U_DYNARRAY_H */
 111