nothings-stb/stb_leakcheck.h

// stb_leakcheck.h - v0.1 - quick & dirty malloc leak-checking - public domain

#ifdef STB_LEAKCHECK_IMPLEMENTATION
#undef STB_LEAKCHECK_IMPLEMENTATION // don't implenment more than once

// if we've already included leakcheck before, undefine the macros
#ifdef malloc
#undef malloc
#undef free
#undef realloc
#endif

#include <stdlib.h>
#include <stdio.h>
#include <stddef.h>
typedef struct malloc_info stb_leakcheck_malloc_info;

struct malloc_info
{
   char *file;
   int line;
   size_t size;
   stb_leakcheck_malloc_info *next,*prev;
};

static stb_leakcheck_malloc_info *mi_head;

void *stb_leakcheck_malloc(size_t sz, char *file, int line)
{
   stb_leakcheck_malloc_info *mi = malloc(sz + sizeof(*mi));
   if (mi == NULL) return mi;
   mi->file = file;
   mi->line = line;
   mi->next = mi_head;
   if (mi_head)
      mi->next->prev = mi;
   mi->prev = NULL;
   mi->size = (int) sz;
   mi_head = mi;
   return mi+1;
}

void stb_leakcheck_free(void *ptr)
{
   if (ptr != NULL) {
      stb_leakcheck_malloc_info *mi = (stb_leakcheck_malloc_info *) ptr - 1;
      mi->size = ~mi->size;
      #ifndef STB_LEAKCHECK_SHOWALL
      if (mi->prev == NULL) {
         assert(mi_head == mi);
         mi_head = mi->next;
      } else
         mi->prev->next = mi->next;
      if (mi->next)
         mi->next->prev = mi->prev;
      #endif
   }
}

void *stb_leakcheck_realloc(void *ptr, size_t sz, char *file, int line)
{
   if (ptr == NULL) {
      return stb_leakcheck_malloc(sz, file, line);
   } else if (sz == 0) {
      stb_leakcheck_free(ptr);
      return NULL;
   } else {
      stb_leakcheck_malloc_info *mi = (stb_leakcheck_malloc_info *) ptr - 1;
      if (sz <= mi->size)
         return ptr;
      else {
         #ifdef STB_LEAKCHECK_REALLOC_PRESERVE_MALLOC_FILELINE
         void *q = stb_leakcheck_malloc(sz, mi->file, mi->line);
         #else
         void *q = stb_leakcheck_malloc(sz, file, line);
         #endif
         if (q) {
            memcpy(q, ptr, mi->size);
            stb_leakcheck_free(ptr);
         }
         return q;
      }
   }
}

void stb_leakcheck_dumpmem(void)
{
   stb_leakcheck_malloc_info *mi = mi_head;
   while (mi) {
      if ((ptrdiff_t) mi->size >= 0)
         printf("LEAKED: %s (%4d): %8z bytes at %p\n", mi->file, mi->line, mi->size, mi+1);
      mi = mi->next;
   }
   #ifdef STB_LEAKCHECK_SHOWALL
   mi = mi_head;
   while (mi) {
      if ((ptrdiff_t) mi->size < 0)
         printf("FREED : %s (%4d): %8z bytes at %p\n", mi->file, mi->line, ~mi->size, mi+1);
      mi = mi->next;
   }
   #endif
}
#endif // STB_LEAKCHECK_IMPLEMENTATION

#ifndef INCLUDE_STB_LEAKCHECK_H
#define INCLUDE_STB_LEAKCHECK_H

#define malloc(sz)    stb_leakcheck_malloc(sz, __FILE__, __LINE__)
#define free(p)       stb_leakcheck_free(p)
#define realloc(p,sz) stb_leakcheck_realloc(p,sz, __FILE__, __LINE__)

extern void * stb_leakcheck_malloc(size_t sz, char *file, int line);
extern void * stb_leakcheck_realloc(void *ptr, size_t sz, char *file, int line);
extern void   stb_leakcheck_free(void *ptr);
extern void   stb_leakcheck_dumpmem(void);

#endif // INCLUDE_STB_LEAKCHECK_H