bnimem.c

著名的加密软件的应用于电子邮件中

/*
* bnimem.c - low-level bignum memory handling.
*
* Copyright (C) 1995-1997 Pretty Good Privacy, Inc. All rights reserved.
*
* Written by Colin Plumb
*
* $Id: bnimem.c,v 1.5.2.1 1997/06/07 09:49:36 mhw Exp $
*
* Note that in all cases, the pointers passed around
* are pointers to the *least* significant end of the word.
* On big-endian machines, these are pointers to the *end*
* of the allocated range.
*
* BNSECURE is a simple level of security; for more security
* change these function to use locked unswappable memory.
*/
#ifndef HAVE_CONFIG_H
#define HAVE_CONFIG_H 0
#endif
#if HAVE_CONFIG_H
#include "config.h"
#endif

/*
* Some compilers complain about #if FOO if FOO isn't defined,
* so do the ANSI-mandated thing explicitly...
*/
#ifndef NO_STDLIB_H
#define NO_STDLIB_H 0
#endif
#ifndef NO_STRING_H
#define NO_STRING_H 0
#endif
#ifndef HAVE_STRINGS_H
#define HAVE_STRINGS_H 0
#endif
#ifndef NEED_MEMORY_H
#define NEED_MEMORY_H 0
#endif

#if !NO_STDLIB_H
#include <stdlib.h>	 /* For malloc() & co. */
#else
void *malloc();
void *realloc();
void free();
#endif

#if !NO_STRING_H
#include <string.h>	 /* For memset */
#elif HAVE_STRINGS_H
#include <strings.h>
#endif
#if NEED_MEMORY_H
#include <memory.h>
#endif

#ifndef DBMALLOC
#define DBMALLOC 0
#endif
#if DBMALLOC
/* Development debugging */
#include "../dbmalloc/malloc.h"
#endif

#include "bni.h"
#include "bnimem.h"

#include "bnkludge.h"

#ifndef bniMemWipe
void
bniMemWipe(void *ptr, unsigned bytes)
{
	memset(ptr, 0, bytes);
}
#define bniMemWipe(ptr, bytes) memset(ptr, 0, bytes)
#endif

#ifndef bniMemAlloc
void *
bniMemAlloc(unsigned bytes)
{
	return malloc(bytes);
}
#define bniMemAlloc(bytes) malloc(bytes)
#endif

#ifndef bniMemFree
void
bniMemFree(void *ptr, unsigned bytes)
{
			bniMemWipe(ptr, bytes);
			free(ptr);
}
#endif

#ifndef bniRealloc
#if defined(bniMemRealloc) || !BNSECURE
void *
bniRealloc(void *ptr, unsigned oldbytes, unsigned newbytes)
{
		if (ptr) {
				BIG(ptr = (char *)ptr - oldbytes;)
				if (newbytes < oldbytes)
					memmove(ptr, (char *)ptr + oldbytes-newbytes,
								oldbytes);
		}
#ifdef bniMemRealloc
			ptr = bniMemRealloc(ptr, oldbytes, newbytes);
#else
			ptr = realloc(ptr, newbytes);
#endif
			if (ptr) {
				 if (newbytes > oldbytes)
	memmove((char *)ptr + newbytes-oldbytes, ptr,
				oldbytes);
BIG(ptr = (char *)ptr + newbytes;)
}

return ptr;
}

#else /* BNSECURE */

void *
bniRealloc(void *oldptr, unsigned oldbytes, unsigned newbytes)
	{
			void *newptr = bniMemAlloc(newbytes);

			if (!newptr)
				 return newptr;
			if (!oldptr)
				 return BIGLITTLE((char *)newptr+newbytes, newptr);

			/*
			* The following copies are a bit non-obvious in the big-endian case
			* because one of the pointers points to the *end* of allocated memory.
			*/
			if (newbytes > oldbytes) {	/* Copy all of old into part of new */
				 BIG(newptr = (char *)newptr + newbytes;)
				 BIG(oldptr = (char *)oldptr - oldbytes;)
				 memcpy(BIGLITTLE((char *)newptr-oldbytes, newptr), oldptr,
					oldbytes);
			} else {	 /* Copy part of old into all of new */
					memcpy(newptr, BIGLITTLE((char *)oldptr-newbytes, oldptr),
					newbytes);
					BIG(newptr = (char *)newptr + newbytes;)
					BIG(oldptr = (char *)oldptr - oldbytes;)
			}

			bniMemFree(oldptr, oldbytes);
			return newptr;
	}
#endif /* BNSECURE */
#endif /* !bniRealloc */