/* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */
/* util/support/path.c - Portable path manipulation functions */
/*
* Copyright (C) 2011 by the Massachusetts Institute of Technology.
* All rights reserved.
*
* Export of this software from the United States of America may
* require a specific license from the United States Government.
* It is the responsibility of any person or organization contemplating
* export to obtain such a license before exporting.
*
* WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
* distribute this software and its documentation for any purpose and
* without fee is hereby granted, provided that the above copyright
* notice appear in all copies and that both that copyright notice and
* this permission notice appear in supporting documentation, and that
* the name of M.I.T. not be used in advertising or publicity pertaining
* to distribution of the software without specific, written prior
* permission. Furthermore if you modify this software you must label
* your software as modified software and not distribute it in such a
* fashion that it might be confused with the original M.I.T. software.
* M.I.T. makes no representations about the suitability of
* this software for any purpose. It is provided "as is" without express
* or implied warranty.
*/
#include <k5-platform.h>
/* For testing purposes, use a different symbol for Windows path semantics. */
#ifdef _WIN32
#define WINDOWS_PATHS
#endif
/*
* This file implements a limited set of portable path manipulation functions.
* When in doubt about edge cases, we follow the Python os.path semantics.
*/
#ifdef WINDOWS_PATHS
#define SEP '\\'
#define IS_SEPARATOR(c) ((c) == '\\' || (c) == '/')
#else
#define SEP '/'
#define IS_SEPARATOR(c) ((c) == '/')
#endif
/* Find the rightmost path separator in path, or NULL if there is none. */
static inline const char *
find_sep(const char *path)
{
#ifdef WINDOWS_PATHS
const char *slash, *backslash;
slash = strrchr(path, '/');
backslash = strrchr(path, '\\');
if (slash != NULL && backslash != NULL)
return (slash > backslash) ? slash : backslash;
else
return (slash != NULL) ? slash : backslash;
#else
return strrchr(path, '/');
#endif
}
/* XXX drive letter prefixes */
long
k5_path_split(const char *path, char **parent_out, char **basename_out)
{
const char *pathstart, *sep, *pend, *bstart;
char *parent = NULL, *basename = NULL;
if (parent_out != NULL)
*parent_out = NULL;
if (basename_out != NULL)
*basename_out = NULL;
pathstart = path;
#ifdef WINDOWS_PATHS
if (*path != '\0' && path[1] == ':')
pathstart = path + 2;
#endif
sep = find_sep(pathstart);
if (sep != NULL) {
bstart = sep + 1;
/* Strip off excess separators before the one we found. */
pend = sep;
while (pend > pathstart && IS_SEPARATOR(pend[-1]))
pend--;
/* But if we hit the start, keep the whole separator sequence. */
if (pend == pathstart)
pend = sep + 1;
} else {
bstart = pathstart;
pend = pathstart;
}
if (parent_out) {
parent = malloc(pend - path + 1);
if (parent == NULL)
return ENOMEM;
memcpy(parent, path, pend - path);
parent[pend - path] = '\0';
}
if (basename_out) {
basename = strdup(bstart);
if (basename == NULL) {
free(parent);
return ENOMEM;
}
}
if (parent_out)
*parent_out = parent;
if (basename_out)
*basename_out = basename;
return 0;
}
long
k5_path_join(const char *path1, const char *path2, char **path_out)
{
char *path, c;
int ret;
*path_out = NULL;
if (k5_path_isabs(path2) || *path1 == '\0') {
/* Discard path1 and return a copy of path2. */
path = strdup(path2);
if (path == NULL)
return ENOMEM;
} else {
/*
* Compose path1 and path2, adding a separator if path1 is non-empty
* there's no separator between them already. (*path2 can be a
* separator in the weird case where it starts with /: or \: on
* Windows, and Python doesn't insert a separator in this case.)
*/
c = path1[strlen(path1) - 1];
if (IS_SEPARATOR(c) || IS_SEPARATOR(*path2))
ret = asprintf(&path, "%s%s", path1, path2);
else
ret = asprintf(&path, "%s%c%s", path1, SEP, path2);
if (ret < 0)
return ENOMEM;
}
*path_out = path;
return 0;
}
int
k5_path_isabs(const char *path)
{
#ifdef WINDOWS_PATHS
if (*path != '\0' && path[1] == ':')
path += 2;
return (*path == '/' || *path == '\\');
#else
return (*path == '/');
#endif
}