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//----------------------------------------------------------------
// Statically-allocated memory manager
//
// by Eli Bendersky (eliben@gmail.com)
//
// This code is in the public domain.
//----------------------------------------------------------------
#ifndef MEMMGR_H
#define MEMMGR_H
//
// Memory manager: dynamically allocates memory from
// a fixed pool that is allocated statically at link-time.
//
// Usage: after calling memmgr_init() in your
// initialization routine, just use memmgr_alloc() instead
// of malloc() and memmgr_free() instead of free().
// Naturally, you can use the preprocessor to define
// malloc() and free() as aliases to memmgr_alloc() and
// memmgr_free(). This way the manager will be a drop-in
// replacement for the standard C library allocators, and can
// be useful for debugging memory allocation problems and
// leaks.
//
// Preprocessor flags you can define to customize the
// memory manager:
//
// DEBUG_MEMMGR_FATAL
// Allow printing out a message when allocations fail
//
// DEBUG_MEMMGR_SUPPORT_STATS
// Allow printing out of stats in function
// memmgr_print_stats When this is disabled,
// memmgr_print_stats does nothing.
//
// Note that in production code on an embedded system
// you'll probably want to keep those undefined, because
// they cause printf to be called.
//
// POOL_SIZE
// Size of the pool for new allocations. This is
// effectively the heap size of the application, and can
// be changed in accordance with the available memory
// resources.
//
// MIN_POOL_ALLOC_QUANTAS
// Internally, the memory manager allocates memory in
// quantas roughly the size of two ulong objects. To
// minimize pool fragmentation in case of multiple allocations
// and deallocations, it is advisable to not allocate
// blocks that are too small.
// This flag sets the minimal ammount of quantas for
// an allocation. If the size of a ulong is 4 and you
// set this flag to 16, the minimal size of an allocation
// will be 4 * 2 * 16 = 128 bytes
// If you have a lot of small allocations, keep this value
// low to conserve memory. If you have mostly large
// allocations, it is best to make it higher, to avoid
// fragmentation.
//
// Notes:
// 1. This memory manager is *not thread safe*. Use it only
// for single thread/task applications.
//
#define DEBUG_MEMMGR_SUPPORT_STATS 1
#define POOL_SIZE 8 * 1024
#define MIN_POOL_ALLOC_QUANTAS 16
typedef unsigned char byte;
typedef unsigned long ulong;
// Initialize the memory manager. This function should be called
// only once in the beginning of the program.
//
void memmgr_init();
// 'malloc' clone
//
void* memmgr_alloc(ulong nbytes);
// 'free' clone
//
void memmgr_free(void* ap);
// Prints statistics about the current state of the memory
// manager
//
void memmgr_print_stats();
#endif // MEMMGR_H
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