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      1 /*
      2   tre-mem.h - TRE memory allocator interface
      3 
      4   This software is released under a BSD-style license.
      5   See the file LICENSE for details and copyright.
      6 
      7 */
      8 
      9 #ifndef TRE_MEM_H
     10 #define TRE_MEM_H 1
     11 
     12 #include <stdlib.h>
     13 
     14 #define TRE_MEM_BLOCK_SIZE 1024
     15 
     16 typedef struct tre_list {
     17   void *data;
     18   struct tre_list *next;
     19 } tre_list_t;
     20 
     21 typedef struct tre_mem_struct {
     22   tre_list_t *blocks;
     23   tre_list_t *current;
     24   char *ptr;
     25   size_t n;
     26   int failed;
     27   void **provided;
     28 } *tre_mem_t;
     29 
     30 
     31 tre_mem_t tre_mem_new_impl(int provided, void *provided_block);
     32 void *tre_mem_alloc_impl(tre_mem_t mem, int provided, void *provided_block,
     33 			 int zero, size_t size);
     34 
     35 /* Returns a new memory allocator or NULL if out of memory. */
     36 #define tre_mem_new()  tre_mem_new_impl(0, NULL)
     37 
     38 /* Allocates a block of `size' bytes from `mem'.  Returns a pointer to the
     39    allocated block or NULL if an underlying malloc() failed. */
     40 #define tre_mem_alloc(mem, size) tre_mem_alloc_impl(mem, 0, NULL, 0, size)
     41 
     42 /* Allocates a block of `size' bytes from `mem'.  Returns a pointer to the
     43    allocated block or NULL if an underlying malloc() failed.  The memory
     44    is set to zero. */
     45 #define tre_mem_calloc(mem, size) tre_mem_alloc_impl(mem, 0, NULL, 1, size)
     46 
     47 #ifdef TRE_USE_ALLOCA
     48 /* alloca() versions.  Like above, but memory is allocated with alloca()
     49    instead of malloc(). */
     50 
     51 #define tre_mem_newa() \
     52   tre_mem_new_impl(1, alloca(sizeof(struct tre_mem_struct)))
     53 
     54 #define tre_mem_alloca(mem, size)					      \
     55   ((mem)->n >= (size)							      \
     56    ? tre_mem_alloc_impl((mem), 1, NULL, 0, (size))			      \
     57    : tre_mem_alloc_impl((mem), 1, alloca(TRE_MEM_BLOCK_SIZE), 0, (size)))
     58 #endif /* TRE_USE_ALLOCA */
     59 
     60 
     61 /* Frees the memory allocator and all memory allocated with it. */
     62 void tre_mem_destroy(tre_mem_t mem);
     63 
     64 #endif /* TRE_MEM_H */
     65 
     66 /* EOF */
     67