buftype.cpp

著名的加密软件的应用于电子邮件中

/*
 * File: BUFTYPE.CPP
 *
 * Date: Wednesday, August 28, 1996
 *
 * Author: Scott Manjourides
 *
 * Copyright (c) 1996 QUALCOMM, Incorporated
 *
 */

#include <stdlib.h>
#include <string.h>

#include "BUFTYPE.H"

#define safefree(p) { if (p) { free(p); (p) = NULL; } }

#ifndef TRUE
#	define TRUE (1)
#endif

#ifndef FALSE
#	define FALSE (0)
#endif

/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

static int resizebuf_buf(BufTypePtr dst, unsigned int newSize);

/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

BufTypePtr makesize_buf(unsigned int n)
{
	BufTypePtr bp = (BufTypePtr) malloc(sizeof(BufType));

	if (!bp)
		return (NULL);

	clear_buf(bp);

	bp->buf = (char *) malloc(n * sizeof(char));

	if (bp->buf)
		bp->buf_size = n;
	else
	{
		delete_buf(bp);
		return (NULL);
	}

	return (bp);
}

/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

BufTypePtr make_buf()
{
	BufTypePtr bp = (BufTypePtr) malloc(sizeof(BufType));

	if (!bp)
		return (NULL);

	clear_buf(bp);

	return (bp);
}

/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

/* boolean */ int isempty_buf(BufTypePtr bp)
{
	if ((!bp) || (bp->buf == NULL) || (bp->len == 0))
		return (TRUE);

	return (FALSE);
}

/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

unsigned int availspace_buf(BufTypePtr bp)
{
	if ((!bp) || (bp->buf == NULL))
		return (0);

	return (bp->buf_size - bp->len);
}

/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

unsigned int buflen_buf(BufTypePtr bp) /* Number of valid chars in buffer. Always < bufsize_buf() */
{
	if (isempty_buf(bp))
		return (0);

	return (bp->len);
}

/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

char *getbuf_buf(BufTypePtr bp)
{
	if (!bp)
		return (NULL);

	return (bp->buf);
}

/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

char *getend_buf(BufTypePtr bp)
{
	if (isempty_buf(bp))
		return (NULL);

	return ((bp->buf) + (bp->len - 1));
}

/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

unsigned int bufsize_buf(BufTypePtr bp)
{
	if (!bp)
		return (0);

	return (bp->buf_size);
}

/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

/* boolean */ int endspan_buf(BufTypePtr buf, BufTypePtr find)
{
	if (isempty_buf(buf) || isempty_buf(find))
		return (FALSE);

	char cEnd = *getend_buf(buf); /* buf->buf[buf->len - 1]; */
	char *pPos = getpos_buf(find); /* find->buf */
	char *pEnd = getend_buf(find); /* (find->buf + find->len - 1); */

	/* Return TRUE if the last char in 'buf' is anywhere in 'find' */
	while (pPos <= pEnd)
	{
		if (*pPos == cEnd)
			return (TRUE);

		pPos++;
	}

	return (FALSE);
}

/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

/* boolean */ int setlen_buf(BufTypePtr bp, const unsigned int n)
{
	if ((!bp) || (bp->buf == NULL) || (n > (bp->buf_size)))
		return (FALSE);

	bp->len = n;

	return (TRUE);
}

/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

unsigned int bufncat_buf(BufTypePtr dst, BufTypePtr src, unsigned int n)
{
	if ((isempty_buf(src)) || (n < 1) || (!dst))
		return (0);

	unsigned int oldSize = buflen_buf(dst);
	unsigned int addSize = poslen_buf(src);

	if (n < addSize)
		addSize = n;

	unsigned int newSize = oldSize + addSize;

	if (newSize > bufsize_buf(dst))
	{
		if (!resizebuf_buf(dst, newSize))
			return (0);
	}

	if (oldSize == 0)
		dst->pos = dst->buf;

	char *cpDst, *cpSrc = getpos_buf(src);
	unsigned int nCopy = addSize;

	if (oldSize > 0)
		cpDst = getend_buf(dst) + 1;
	else
		cpDst = getpos_buf(dst);

	while (nCopy--)
		*cpDst++ = *cpSrc++;

	incpos_buf(src, addSize);
	dst->len = newSize;

	return (addSize);
}

/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

unsigned int bufins_buf(BufTypePtr dst, BufTypePtr src)
{
	if (isempty_buf(src))
		return (0);

	unsigned int oldLen = poslen_buf(dst);
	unsigned int bufSize = bufsize_buf(dst);
	unsigned int addLen = poslen_buf(src);
	unsigned int newLen = oldLen + addLen;

	if (newLen > bufSize)
		addLen = bufSize - oldLen;

	if (addLen < 1)
		return (0); /* Buffer is already full */

	return (bufncat_buf(dst, src, addLen));
}

/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

unsigned int bufnins_buf(BufTypePtr dst, BufTypePtr src, unsigned int n)
{
	if ((isempty_buf(src)) || (n < 1))
		return (0);

	unsigned int oldLen = poslen_buf(dst);
	unsigned int bufSize = bufsize_buf(dst);
	unsigned int addLen = poslen_buf(src);
	unsigned int newLen = oldLen + addLen;

	if (newLen > bufSize)
		addLen = bufSize - oldLen;

	if (n < addLen)
		addLen = n;

	if (addLen < 1)
		return (0); /* Buffer is already full */

	return (bufncat_buf(dst, src, addLen));
}

/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

unsigned int poslen_buf(BufTypePtr bp) /* Number of valid chars, starting at current position */
{
	if ((isempty_buf(bp)) || ((bp->pos) == NULL))
		return (0);

	return ( (bp->len) - ((bp->pos) - (bp->buf)) );
}

/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

void incpos_buf(BufTypePtr bp, unsigned int n)
{
	if (!bp)
		return;
	
	if (poslen_buf(bp) > n)
		bp->pos += n;
	else
		bp->pos = NULL;
}

/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

void delpos_buf(BufTypePtr bp)
{
	if (!bp)
		return;

	bp->pos = NULL;
}

/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

void resetpos_buf(BufTypePtr bp)
{
	if (bp)
		bp->pos = bp->buf;
}

/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

char *getpos_buf(BufTypePtr bp)
{
	if (!bp)
		return (NULL);

	if ((bp->pos) == NULL)
		bp->pos = bp->buf;
	
	return (bp->pos);
}

/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

unsigned int strcpy_buf(BufTypePtr dst, const char *src)
{
	if ((!src) || (!dst))
		return (0);

	unsigned int nLen = strlen(src);

	if (nLen > 0)
	{
		if (nLen > bufsize_buf(dst))
		{
			if (!resizebuf_buf(dst, nLen))
				return (0);
		}

		char *cp = dst->buf;

		while (*src)
			*cp++ = *src++;

		dst->pos = dst->buf;
	}
	else /* nLen == 0 */
	{
		dst->pos = NULL;
	}

	dst->len = nLen;

	return (nLen);
}

/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

unsigned int strncpy_buf(BufTypePtr dst, const char *src, const unsigned int n)
{
	if ((!src) || (!dst))
		return (0);

	unsigned int nLen = strlen(src);

	if (n < nLen)
		nLen = n;

	if (nLen > 0)
	{
		if (nLen > bufsize_buf(dst))
		{
			if (!resizebuf_buf(dst, nLen))
				return (0);
		}

		char *cp = dst->buf;

		while (*src)
			*cp++ = *src++;

		dst->pos = dst->buf;
	}
	else /* nLen == 0 */
	{
		dst->pos = NULL;
	}

	dst->len = nLen;

	return (nLen);
}

/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

unsigned int strcat_buf(BufTypePtr dst, const char *src)
{
	if ((!src) || (!dst))
		return (0);

	unsigned int oldSize = buflen_buf(dst);
	unsigned int addSize = strlen(src);
	unsigned int newSize = oldSize + addSize;

	if (newSize > bufsize_buf(dst))
	{
		if (!resizebuf_buf(dst, newSize))
			return (0);
	}

	if (oldSize == 0)
		dst->pos = dst->buf;

	char *cpDst, *cpSrc = (char *) src;
	unsigned int nCopy = addSize;

	if (oldSize > 0)
		cpDst = getend_buf(dst) + 1;
	else
		cpDst = getpos_buf(dst);

	while (nCopy--)
		*cpDst++ = *cpSrc++;

	dst->len = newSize;

	return (addSize);

}

/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

unsigned int strncat_buf(BufTypePtr dst, const char *src, const unsigned int n)
{
	if ((!src) || (!dst))
		return (0);

	unsigned int oldSize = buflen_buf(dst);
	unsigned int addSize = strlen(src);
	
	if (n < addSize)
		addSize = n;
	
	unsigned int newSize = oldSize + addSize;

	if (newSize > bufsize_buf(dst))
	{
		if (!resizebuf_buf(dst, newSize))
			return (0);
	}

	if (oldSize == 0)
		dst->pos = dst->buf;

	char *cpDst, *cpSrc = (char *) src;
	unsigned int nCopy = addSize;

	if (oldSize > 0)
		cpDst = getend_buf(dst) + 1;
	else
		cpDst = getpos_buf(dst);

	while (nCopy--)
		*cpDst++ = *cpSrc++;

	dst->len = newSize;

	return (addSize);

}

/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

void delete_buf(BufTypePtr bp)
{
	if (!bp)
		return;

	free_buf(bp);
	safefree(bp);
}

/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

void free_buf(BufTypePtr bp)
{
	if (!bp)
		return;

	safefree(bp->buf);
	clear_buf(bp);
}

/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

void clear_buf(BufTypePtr bp)
{
	if (!bp)
		return;

	bp->buf = NULL;
	bp->buf_size = 0;

	emptybuf_buf(bp);
}

/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

void emptybuf_buf(BufTypePtr bp)
{
	if (!bp)
		return;

	bp->pos = bp->buf;
	bp->len = 0;
}

/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */


static /* boolean */ int resizebuf_buf(BufTypePtr bp, unsigned int newSize)
{
	unsigned int oldSize = bp->buf_size;

	if (oldSize == newSize)
		return (TRUE);
	
	char *tmpPtr = (char *) realloc(bp->buf, newSize);

	if (tmpPtr == NULL)
		return (FALSE);

	bp->buf = tmpPtr;
	bp->buf_size = newSize;

	if (newSize < oldSize) /* Getting smaller */
	{
		/* Check for valid length */
		if (bp->len > newSize)
			bp->len = newSize;

		/* Check pos */
		unsigned int nPos = ((bp->pos) - (bp->buf));
		if (nPos >= bp->len)
			bp->pos = NULL;
	}
	else if (oldSize == 0)
	{
		bp->pos = bp->buf;
	}

	return (TRUE);
}

/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

// If doesn't continue match, returns zero
// otherwise returns number of chars of pSearchBuf that have been matched
unsigned int completecount_buf(BufTypePtr buf, BufTypePtr find, const unsigned int nPreMatched)
{
	if (isempty_buf(buf) || isempty_buf(find))
		return (0);

	if (nPreMatched >= poslen_buf(find))
		return (0);

	char *pBuf = getpos_buf(buf);
	char *pBufEnd = getend_buf(buf);

	char *pFind = getpos_buf(find) + nPreMatched;
	char *pFindEnd = getend_buf(find);

	unsigned int nSkipCount = 0;

	while ((pBuf <= pBufEnd) && (pFind <= pFindEnd) && ((*pBuf) == (*pFind)))
		pBuf++, pFind++, nSkipCount++;

	if ((pBuf > pBufEnd) || (pFind > pFindEnd))
		return (nPreMatched + nSkipCount);

	return (0); /* match failed */
}

/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

// Find match of pSearchBuf, either complete or end-spanning
// return number of chars to skip before match
// No match: return length of buf (skip the whole buffer)
unsigned int skipcount_buf(BufTypePtr buf, BufTypePtr find)
{
	if (isempty_buf(buf))
		return (0);

	if (isempty_buf(find))
		return (poslen_buf(buf));

	char *pBuf = getpos_buf(buf);
	char *pFind = getpos_buf(find);
	char *pBufEnd = getend_buf(buf);
	char *pFindEnd = getend_buf(find);

	char *s1 = NULL, *s2 = NULL;

	unsigned int nSkipCount = 0;

	while (pBuf <= pBufEnd)
	{
		s1 = pBuf;
		s2 = pFind;

		while ((s1 <= pBufEnd) && (s2 <= pFindEnd) && ((*s1) == (*s2)))
			s1++, s2++;

		if ((s1 > pBufEnd) || (s2 > pFindEnd))
			return (nSkipCount);

		pBuf++;
		nSkipCount++;
	}

	return (poslen_buf(buf));
}