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       tmem.h (2610B)
       ---
            1 #ifndef MEM_H
            2 #define MEM_H
            3 
            4 /*
            5  * Lightweight wrapper over malloc, that permit to define a memory pool of
            6  * multiple buffers, and free them all at once.
            7  *
            8  *        *──────────┐   
            9  *        │ mem_pool │   
           10  *        ├──────────┤   
           11  *        │*head     │   
           12  *        └┬─────────┘   
           13  *         v
           14  * NULL<   *───────────┐<  >*───────────┐<  >*───────────┐<  >*───────────┐   >NULL
           15  *      \  │ mem_block │ \/ │ mem_block │ \/ │ mem_block │ \/ │ mem_block │  /
           16  *       \ ├───────────┤ /\ ├───────────┤ /\ ├───────────┤ /\ ├───────────┤ /
           17  *        `┤*prev *next├'  `┤*prev *next├'  `┤*prev *next├'  `┤*prev *next├'
           18  *         │len        │    │len        │    │len        │    │len        │
           19  *         ├─┴─magic───┤    ├─┴─magic───┤    ├─┴─magic───┤    ├─┴─magic───┤
           20  *         │///////////│    │///////////│    │///////////│    │///////////│
           21  *         │///////////│    │///////////│    │///////////│    │///////////│
           22  *         │///////////│    │///////////│    │///////////│    └───────────┘
           23  *         └───────────┘    │///////////│    │///////////│
           24  *                          │///////////│    └───────────┘
           25  *                          └───────────┘
           26  *
           27  * This permits the type checker to still work on all operations while
           28  * providing generic memory management functions for all types of data
           29  * structures and keep track of each object's length.
           30  */
           31 
           32 #include <stddef.h>
           33 
           34 #define MEM_BLOCK_MAGIC "\xcc\x68\x23\xd7\x9b\x7d\x39\xb9"
           35 
           36 struct mem_pool {
           37         struct mem_block *head;
           38 };
           39 
           40 struct mem_block {
           41         struct mem_pool *pool;
           42         struct mem_block *prev, *next;
           43         size_t len;
           44         char magic[8]; /* at the end to detect buffer underflow */
           45         char buf[];
           46 };
           47 
           48 /** src/mem.c **/
           49 void * mem_alloc(struct mem_pool *pool, size_t len);
           50 int mem_resize(void **memp, size_t len);
           51 int mem_grow(void **memp, size_t len);
           52 int mem_shrink(void **memp, size_t len);
           53 size_t mem_length(void *mem);
           54 int mem_append(void **memp, void const *buf, size_t len);
           55 int mem_read(void **memp, struct mem_pool *pool);
           56 void mem_delete(void *mem);
           57 void mem_free(struct mem_pool *pool);
           58 
           59 #endif