Heap memory allocator for microcontrollers, and more (should work everywhere). Ultra fast and efficient, O(1) operations
MC-Heap is a heap allocator (malloc, free, ...) that was designed for microcontrollers (currently running on ARM Cortex M4), but it can be used anywhere - I use it for testing on a macbook. The main limitation when not used on a microcontroller is that it's not been designed to grow dynamically.
MC-Heap is fast and predictable: most operations are 0(1). A malloc takes ~180 cycles typically (armv7em), regardless of the size of the allocation, the size of the heap, and the number of allocations already performed. Same goes for free().
MC-Heap is efficient: it uses only ~1.5% of the heap size for its internal book-keeping.
MC-Heap is small: less than 1000 LOCs.
MC-Heap is secure: it allows you to query how much data can be accessed from a given pointer, provided the pointer if from within an allocated memory block.
e.g.
char * x = MC_HEAP_Alloc(256); /* we assume we don't get NULL */
U32 avail = MC_Heap_Avail(&x[16]); /* will return 240 */This could be used for ex. in a custom memcpy function to double check if enough data can be read and written from/to passed pointers to prevent buffer overflows.
MC-Heap allocations are always rounded to 16 bytes. Allocating 1 bytes will give you 16, allocating 1000 bytes will give you 1008.
MC-Heap allocations are always aligned on the largest nibble of the size: when size is 0x001002FF, the returned memory block is aligned on 0x00100000; when size is 0x0000FFF0, the returned memory block is aligned on 0x00001000
MC-Heap uses a best-fit allocation.
MC-Heap automatically coalesces memory blocks at free() time: no need to run a coalescing task on a regular basis.