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C:/temp/src/j2k/Beta/fast_alloc.h

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#ifndef __J2K__FAST_ALLOC_H__
#define __J2K__FAST_ALLOC_H__   1

#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <malloc.h>

/*
  The fast and basic allocation primitive:
  ========================================
  Always round request to something close to a power of two.
  This ensures a bit of padding, which often means that
  buffer increase won't have to realloc. Plus it tends to
  be faster when lots of objects are created and discarded,
  since just about any version of malloc will be faster 
  when it can reuse identically-sized chunks.

  Basically, we use internal memory fragmentation 
  for our own space craving needs, which is a very good thing to do!
  Why bothering realloc() when space is already there for us !?
*/

/* 
  Roughtly the length of the memory allocated, 
  which is 4 bytes on 32-bit machines 
*/
#ifndef MALLOC_MIN_OVERHEAD
#define MALLOC_MIN_OVERHEAD   sizeof( size_t )
#endif

/* 16 bit == sizeof( short ) */
#ifndef MALLOC_MAX_THRESHOLD
#define MALLOC_MAX_THRESHOLD      sizeof( short )
#define MALLOC_MAX_THRESHOLD_BIT  16
#endif

/* Using register and shifting for optimal performance */

/* Calculate the amount of memory needed ideally */
size_t fast_mem_size( register size_t min_size );

/* Malloc using the ideal amount of memory */
void* fast_malloc(    register size_t min_size );

/* Realloc using the ideal amount of memory for the extra bytes */
void* fast_realloc(   register void* buffer, register size_t buf_size, register size_t extra );

/* Same as free, provide for convenience */
void fast_free( void* buffer );

#endif

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