pgpappfile.c

著名的加密软件的应用于电子邮件中

/*
 * pgpAppFile.c -- Functions to handle filenames
 *
 * Copyright (C) 1996,1997 Pretty Good Privacy, Inc.  All rights reserved.
 *
 * Written by:	Colin Plumb and Derek Atkins <[e-mail]>
 *
 * $Id: pgpAppFile.c,v 1.3.2.1 1997/06/07 09:49:03 mhw Exp $
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <stdarg.h>
#include <stdio.h>
#include <string.h>

#include "pgpDebug.h"
#include "pgpMem.h"
#include "pgpAppFile.h"

/*
 * DIRSEPS is a string of possible directory-separation characters
 * The first one is the preferred one, which goes in between
 * PGPPATH and the file name if PGPPATH is not terminated with a
 * directory separator.
 *
 * PATHSEP is a the directory separator within a PATH of directories.
 * Only one character per platform, please
 */

#if defined(MSDOS) || defined(ATARI) || defined(_WIN32)
static char const DIRSEPS[] = "\\/:";
#define PATHSEP ';'
#define SINGLE_EXT 1

#elif defined(UNIX)
static char const DIRSEPS[] = "/";
#define PATHSEP ':'

#elif defined(AMIGA)
static char const DIRSEPS[] = "/:";
#define PATHSEP ';'

#elif defined(VMS)
static char const DIRSEPS[] = "]:";	/* Any more? */
#define PATHSEP ';'
#define SINGLE_EXT 1

#elif defined(MACINTOSH)
static char const DIRSEPS[] = ":";
#define PATHSEP ';'

#else
#error Unknown operating system - need one of\
 UNIX, MSDOS, AMIGA, ATARI, VMS, or MACINTOSH.
#endif

/*
 * Build a path name out of a number of segments.
 * Each segment is separated from the next with DIRSEPS[0] if
 * it does not end in a directory separator already.
 *
 * A first pass over the argument list adds up the length of the result,
 * then space is allocated for it, then a second pass copies the result
 * to the allocated space.
 *
 * The first pass records in "flag" whether the previous segment did NOT end
 * in a directory separator and, if the current segment exists, adds space
 * for a separator if flag is true.
 *
 * Then, if there was only one segment of note, that is returned directly.
 * Otherwise, space is allocated in the MiscPool.
 * Finally, the loop is repeated, copying to the allocated space and inserting
 * directory separators as needed.
 *
 * This function always returns a newly allocated buffer.  It is the
 * responsibility of the caller to free it when finished.
 */
char *
fileNameBuild(char const *seg, ...)
{
	va_list ap;
	unsigned seglen, len, flag;
	char const *curseg, *prevseg;
	char *p, *ret;

	/* Start by counting the length of the result */
	va_start (ap, seg);
	prevseg = 0;
	len = seglen = flag = 0;
	for (curseg = seg; curseg; curseg = va_arg(ap, char const *)) {
		seglen = strlen (curseg);
		if (!seglen)
			continue;
		prevseg = curseg;
		len += seglen + flag;
		/* Does curseg need a directory separator added? */
		flag = (strchr(DIRSEPS, curseg[seglen-1]) == 0);
	}
	va_end (ap);

	/* Allocate space for the combined string */
	p = (char *)pgpMemAlloc (len+1);	/* +1 for trailing null */
	if (!p)
		return 0;
	ret = p;

	/* Combine the elements together */
	va_start (ap, seg);
	flag = 0;
	for (curseg = seg; curseg; curseg = va_arg (ap, char const *)) {
		seglen = strlen (curseg);
		if (!seglen)
			continue;
		if (flag)
			*p++ = DIRSEPS[0];
		memcpy (p, curseg, seglen);
		p += seglen;
		/* Does curseg need a directory separator added? */
		flag = (strchr (DIRSEPS, curseg[seglen-1]) == 0);
	}
	va_end(ap);

	*p = '\0';	/* Null-terminate the string */
	return ret;
}

char *
fileNameExtend (char const *base, char const *ext)
{
	char *name = (char *)pgpMemAlloc (strlen (base) + strlen (ext) + 1);

	if (!name)
		return NULL;

	strcpy (name, base);
	strcat (name, ext);

	return name;
}

char *
fileNameContract (char const *base)
{
	char *name = (char *)pgpMemAlloc (strlen (base) + 1);
	char *p;

	if (!name)
		return NULL;

	strcpy (name, base);
	/* remove an ending */
	p = strrchr (name, '.');
	if (p)
		*p = '\0';

	return name;
}

char *
fileNameNextDirectory (char const *path, char const **rest)
{
	char const *d;
	char *name;
	unsigned len;
	
	d = strchr (path, PATHSEP);
	if (d) {
		len = d - path;
		d++;
	} else
		len = strlen (path);

	if (rest)
		*rest = d;

	name = (char *)pgpMemAlloc (len + 1);
	if (!name)
		return NULL;

	memcpy (name, path, len);
	name[len] = '\0';
	return name;
}

char *
fileNameExtendPath (char const *path, char const *dir, int front)
{
	char *p, *t;

	pgpAssert (dir);

	p = (char *)pgpMemAlloc ((path ? strlen (path) : 0) + strlen (dir)
				 + 2);
	if (p) {
		t = p;
		if (front) {
			memcpy (t, dir, strlen (dir));
			t += strlen (dir);
			if (path) {
				*(t++) = PATHSEP;
				memcpy (t, path, strlen (path));
				t += strlen (path);
			}
			*t = '\0';
		} else {
			if (path) {
				memcpy (t, path, strlen (path));
				t += strlen (path);
				*(t++) = PATHSEP;
			}
			memcpy (t, dir, strlen (dir));
			t += strlen (dir);
			*t = '\0';
		}
	}
	return p;
}