MiniMallocPlus

MiniMallocPlus is a custom memory allocator implemented in C.
It simulates dynamic memory allocation using a fixed 1 MB memory pool.
The allocator supports allocation, freeing, memory stats, fragmentation calculation, and logging.

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Features

• First-Fit, Best-Fit, Worst-Fit, Next-Fit, and Quick-Fit allocation strategies.
• Tracks allocations and frees with file/line info.
• Prints memory layout and statistics:
  • Total memory
  • Allocated memory
  • Free memory
  • Fragmentation percentage
  • Active allocations
  • Largest free block
• Logs memory events to memory_log.txt.
• Works on Windows and Linux.
• Merges adjacent free blocks to reduce fragmentation.

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Project Structure

MiniMallocPlus/
│
├─ include/
│   ├─ mini\_malloc.h
│   └─ logger.h
│
├─ src/
│   ├─ main.c
│   ├─ mini\_malloc.c
│   ├─ memory\_stats.c
│   └─ logger.c
│
├─ Makefile
└─ README.md

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Installation & Build

Linux

git clone <repo_url>
cd MiniMallocPlus
make
./MiniMallocPlus

Windows (using MinGW)

1. Install MinGW-w64 and ensure gcc and make are in your PATH.
2. Open PowerShell or cmd, navigate to the project folder:

cd C:\path\to\MiniMallocPlus
make
.\MiniMallocPlus.exe

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Usage

• Run the executable to select a memory allocation strategy and view memory allocation stats.
• Logs of allocations and frees are written to memory_log.txt.
• Modify the allocation strategy in main.c:

set_allocation_strategy(FIRST_FIT);   // FIRST_FIT, BEST_FIT, WORST_FIT, NEXT_FIT, QUICK_FIT

• Add/remove allocations using mini_malloc(size) and mini_free(ptr).
• If you change the allocation strategy: run make clean and then make.

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Interactive Demo Example

=== MiniMallocPlus ===

Select allocation strategy:
1) First-Fit
2) Best-Fit
3) Worst-Fit
4) Next-Fit
5) Quick-Fit
Enter choice: 2

=== BEST-FIT ===

Demo Allocations:
Memory Stats:
  Total Memory       :    1048576 bytes
  Allocated          :        350 bytes
  Free               :    1048226 bytes
  Fragmentation      :      0.02%
  Active Allocations :          3
  Largest Free Block :    1048034 bytes

Free b (200 bytes)
Memory Stats:
  Total Memory       :    1048576 bytes
  Allocated          :        150 bytes
  Free               :    1048426 bytes
  Fragmentation      :      0.04%
  Active Allocations :          2
  Largest Free Block :    1048034 bytes

Allocate d=150 bytes
Memory Stats:
  Total Memory       :    1048576 bytes
  Allocated          :        300 bytes
  Free               :    1048156 bytes
  Fragmentation      :      0.02%
  Active Allocations :          3
  Largest Free Block :    1048034 bytes

Continue? (y/n):

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Allocation Strategies & Example Behaviors

Strategy	How It Works	Example Behavior
First-Fit	Allocates the first free block large enough	Fast allocation; may leave small fragmented blocks at the start
Best-Fit	Allocates the smallest block that fits	Minimizes leftover space; slower search
Worst-Fit	Allocates the largest free block	Leaves medium-sized blocks; may reduce fragmentation later
Next-Fit	Like First-Fit but starts from last allocation	Can improve performance in certain allocation patterns
Quick-Fit	Maintains free lists by block size for fast allocation	Very fast allocation for repeated sizes; simplified in this demo

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Visual Memory Layout Example

Initial State (1 MB Free)

[Free: 1048576 bytes]

After Allocating a=100, b=200, c=50 (First-Fit)

[Allocated a:100] [Allocated b:200] [Allocated c:50] [Free: 1048226]

After Freeing b (200)

[Allocated a:100] [Free:200] [Allocated c:50] [Free: 1048026]

After Allocating d=150

• First-Fit allocates in the first free block >=150 → merges or moves as needed.
• Best-Fit allocates in the smallest free block >=150.
• Worst-Fit allocates in the largest free block.
• Next-Fit continues from the last allocation pointer.
• Quick-Fit allocates using the quick-size free list if available.

Example (First-Fit):
[Allocated a:100] [Allocated d:150] [Allocated c:50] [Free: 1048026]

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License

This project is licensed under the MIT License. See LICENSE for details.