Custom memory manager for dynamic memory allocation

The goal of the project was to implement a memory manager responsible for managing the heap of a program.

The manager includes custom versions of the malloc, calloc, free, and realloc methods, along with additional utility functions for monitoring the state, coherence, and defragmentation of the heap.

Memory block structure

        +-------------------------------------------------------+
        |  METADATA  |  HEAD FENCE  |  USER DATA  |  TAIL FENCE |
        +-------------------------------------------------------+

• Metadata: Information about the memory block, including pointers to the previous and next blocks, the size of the block, a flag indicating whether the block is free or allocated, and additional metadata for error detection.
• Head Fence: Marker at the beginning to detect potential overflows.
• User Data: The actual data allocated to the user resides in this portion of the block.
• Tail Fence: Marker at the end to detect potential underflows.

Key Features:

• Standard Allocation/Deallocation Tasks: Implementation of memory allocation and deallocation functions following the API specifications of the malloc family. The behavior of these custom implementations mirrors that of standard counterparts from the GNU C Library.
• Heap Initialization and Cleanup: The manager provides functions for initializing the heap and cleaning up the entire allocated memory, allowing for resetting the heap to its initial state.
• Dynamic Heap Expansion: The memory manager can autonomously increase the heap size by generating requests to the operating system when needed.
• Fences for Error Detection: The memory blocks allocated to the user are surrounded by fences (head and tail markers) to facilitate the detection of one-off errors. Violation of fences indicates incorrect usage of allocated memory.

Methods

• heap_setup: Initializes the heap in the designated memory area.
• heap_clean: Returns all allocated memory to the operating system.
• heap_malloc, heap_calloc, heap_realloc, heap_free: Custom implementations of memory allocation, deallocation and reallocation functions.
• heap_get_largest_used_block_size: Returns the size of the largest memory block allocated to the user.
• get_pointer_type: Classifies a pointer based on its relation to different areas of the heap.
• heap_validate: Validates the consistency of the heap, checking for potential errors.

Note: The project utilizes fences, metadata, and control structures to enhance error detection and offers a comprehensive memory management solution.