MEM.C

/******************************************************************************\ 
*       This is a part of the Microsoft Source Code Samples. 
*       Copyright 1993 - 1998 Microsoft Corporation. 
*       All rights reserved. 
*       This source code is only intended as a supplement to 
*       Microsoft Development Tools and/or WinHelp documentation. 
*       See these sources for detailed information regarding the 
*       Microsoft samples programs. 
\******************************************************************************/ 
 
/*************************************************************************** 
 *                                                                         * 
 *  MODULE      : mem.c                                                    * 
 *                                                                         * 
 *  PURPOSE     : Functions for debugging memory allocation bugs.          * 
 *                                                                         * 
 ***************************************************************************/ 
#include <windows.h> 
 
#define MAX_OBJECTS 200 
 
PTSTR aptrs[MAX_OBJECTS]; 
DWORD cptrs = 0; 
 
/**************************************************************************** 
 *                                                                          * 
 *  FUNCTION   : DbgAlloc()                                                 * 
 *                                                                          * 
 *  PURPOSE    : Useful routine for catching memory allocation errors.      * 
 *               Enters allocated objects into an array to check when freed * 
 *                                                                          * 
 *  RETURNS    : pointer to object allocated.                               * 
 *                                                                          * 
 ****************************************************************************/ 
PTSTR DbgAlloc( 
register DWORD cb) 
{ 
    register PTSTR p; 
 
    p = (PTSTR)LocalAlloc(LPTR, cb); 
    aptrs[cptrs++] = p; 
    if (cptrs >= MAX_OBJECTS) 
        OutputDebugString(TEXT("Too many objects to track")); 
    return p; 
} 
 
/**************************************************************************** 
 *                                                                          * 
 *  FUNCTION   : DbgFree()                                                  * 
 *                                                                          * 
 *  PURPOSE    : To free an object allocated with DbgAlloc().  Checks the   * 
 *               object array to make sure an object isn't freed twice.     * 
 *                                                                          * 
 *  RETURNS    :                                                            * 
 *                                                                          * 
 ****************************************************************************/ 
PTSTR DbgFree( 
register PTSTR p) 
{ 
    register DWORD i; 
 
    if (p == NULL) 
        return p; 
 
    for (i = 0; i < cptrs; i++) { 
        if (aptrs[i] == p) { 
            aptrs[i] = aptrs[cptrs - 1]; 
            break; 
        } 
    } 
    if (i == cptrs) { 
        OutputDebugString(TEXT("Free on non-allocated object")); 
        DebugBreak(); 
    } else { 
        LocalUnlock((HANDLE)p); 
        p = (PTSTR)LocalFree((HANDLE)p); 
    } 
    cptrs--; 
    return p; 
}