forked from 0ad/0ad
300 lines
7.8 KiB
C++
300 lines
7.8 KiB
C++
/**
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* =========================================================================
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* File : path_util.cpp
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* Project : 0 A.D.
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* Description : helper functions for path strings.
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*
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* @author Jan.Wassenberg@stud.uni-karlsruhe.de
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* =========================================================================
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*/
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/*
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* Copyright (c) 2004-2006 Jan Wassenberg
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*
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* Redistribution and/or modification are also permitted under the
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* terms of the GNU General Public License as published by the
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* Free Software Foundation (version 2 or later, at your option).
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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*/
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#include "precompiled.h"
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#include <string.h>
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#include "lib.h"
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#include "posix.h"
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#include "path_util.h"
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static inline bool is_dir_sep(char c)
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{
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if(c == '/' || c == DIR_SEP)
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return true;
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return false;
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}
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// is s2 a subpath of s1, or vice versa?
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bool path_is_subpath(const char* s1, const char* s2)
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{
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// make sure s1 is the shorter string
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if(strlen(s1) > strlen(s2))
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std::swap(s1, s2);
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int c1 = 0, last_c1, c2;
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for(;;)
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{
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last_c1 = c1;
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c1 = *s1++, c2 = *s2++;
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// end of s1 reached:
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if(c1 == '\0')
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{
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// s1 matched s2 up until:
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if((c2 == '\0') || // its end (i.e. they're equal length) OR
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is_dir_sep(c2) || // start of next component OR
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is_dir_sep(last_c1)) // ", but both have a trailing slash
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// => is subpath
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return true;
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}
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// mismatch => is not subpath
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if(c1 != c2)
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return false;
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}
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}
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// if path is invalid, return a descriptive error code, otherwise ERR_OK.
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LibError path_validate(const char* path)
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{
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// disallow "/", because it would create a second 'root' (with name = "").
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// root dir is "".
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if(path[0] == '/')
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WARN_RETURN(ERR_PATH_NOT_RELATIVE);
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// scan each char in path string; count length.
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int c = 0; // current char; used for .. detection
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size_t path_len = 0;
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for(;;)
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{
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const int last_c = c;
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c = path[path_len++];
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// whole path is too long
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if(path_len >= PATH_MAX)
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WARN_RETURN(ERR_PATH_LENGTH);
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// disallow:
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// - ".." (prevent going above the VFS root dir)
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// - "./" (security hole when mounting and not supported on Windows).
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// allow "/.", because CVS backup files include it.
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if(last_c == '.' && (c == '.' || c == '/'))
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WARN_RETURN(ERR_PATH_NON_CANONICAL);
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// disallow OS-specific dir separators
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if(c == '\\' || c == ':')
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WARN_RETURN(ERR_PATH_NON_PORTABLE);
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// end of string, no errors encountered
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if(c == '\0')
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break;
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}
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return ERR_OK;
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}
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// if name is invalid, return a descriptive error code, otherwise ERR_OK.
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// (name is a path component, i.e. that between directory separators)
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LibError path_component_validate(const char* name)
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{
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// disallow empty strings
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if(*name == '\0')
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WARN_RETURN(ERR_PATH_EMPTY);
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for(;;)
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{
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const int c = *name++;
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// disallow *any* dir separators (regardless of which
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// platform we're on).
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if(c == '\\' || c == ':' || c == '/')
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WARN_RETURN(ERR_PATH_COMPONENT_SEPARATOR);
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// end of string, no errors encountered
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if(c == '\0')
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break;
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}
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return ERR_OK;
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}
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// copy path strings (provided for convenience).
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void path_copy(char* dst, const char* src)
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{
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strcpy_s(dst, PATH_MAX, src);
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}
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// combine <path1> and <path2> into one path, and write to <dst>.
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// if necessary, a directory separator is added between the paths.
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// each may be empty, filenames, or full paths.
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// total path length (including '\0') must not exceed PATH_MAX.
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LibError path_append(char* dst, const char* path1, const char* path2)
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{
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const size_t len1 = strlen(path1);
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const size_t len2 = strlen(path2);
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size_t total_len = len1 + len2 + 1; // includes '\0'
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// check if we need to add '/' between path1 and path2
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// note: the second can't start with '/' (not allowed by path_validate)
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bool need_separator = false;
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if(len1 != 0 && !is_dir_sep(path1[len1-1]))
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{
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total_len++; // for '/'
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need_separator = true;
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}
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if(total_len+1 > PATH_MAX)
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WARN_RETURN(ERR_PATH_LENGTH);
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strcpy(dst, path1); // safe
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dst += len1;
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if(need_separator)
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*dst++ = '/';
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strcpy(dst, path2); // safe
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return ERR_OK;
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}
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// strip <remove> from the start of <src>, prepend <replace>,
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// and write to <dst>.
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// returns ERR_FAIL if the beginning of <src> doesn't match <remove>.
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LibError path_replace(char* dst, const char* src, const char* remove, const char* replace)
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{
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// remove doesn't match start of <src>
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const size_t remove_len = strlen(remove);
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if(strncmp(src, remove, remove_len) != 0)
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WARN_RETURN(ERR_FAIL);
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// get rid of trailing / in src (must not be included in remove)
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const char* start = src+remove_len;
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if(is_dir_sep(*start))
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start++;
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// prepend replace.
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RETURN_ERR(path_append(dst, replace, start));
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return ERR_OK;
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}
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//-----------------------------------------------------------------------------
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// split paths into specific parts
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// return pointer to the name component within path (i.e. skips over all
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// characters up to the last dir separator, if any).
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const char* path_name_only(const char* path)
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{
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// first try: look for portable '/'
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const char* slash = strrchr(path, '/');
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// not present
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if(!slash)
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{
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// now look for platform-specific DIR_SEP
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slash = strrchr(path, DIR_SEP);
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// neither present, it's a filename only
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if(!slash)
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return path;
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}
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const char* name = slash+1;
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return name;
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}
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// if <path> contains a name component, it is stripped away.
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void path_strip_fn(char* path)
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{
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char* name = (char*)path_name_only(path);
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*name = '\0'; // cut off string here
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}
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// fill <dir> with the directory path portion of <path>
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// ("" if root dir, otherwise ending with '/').
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// note: copies to <dir> and proceeds to path_strip_fn it.
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void path_dir_only(const char* path, char* dir)
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{
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path_copy(dir, path);
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path_strip_fn(dir);
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}
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// return extension of <fn>, or "" if there is none.
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// NOTE: does not include the period; e.g. "a.bmp" yields "bmp".
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const char* path_extension(const char* fn)
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{
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const char* dot = strrchr(fn, '.');
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if(!dot)
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return "";
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const char* ext = dot+1;
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return ext;
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}
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//-----------------------------------------------------------------------------
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// convenience "class" that simplifies successively appending a filename to
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// its parent directory. this avoids needing to allocate memory and calling
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// strlen/strcat. used by wdll_ver and dir_next_ent.
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// we want to maintain C compatibility, so this isn't a C++ class.
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// write the given directory path into our buffer and set end/chars_left
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// accordingly. <dir> need not but can end with a directory separator.
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//
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// note: <dir> and the filename set via path_package_append_file are separated by
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// '/'. this is to allow use on portable paths; the function otherwise
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// does not care if paths are relative/portable/absolute.
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LibError path_package_set_dir(PathPackage* pp, const char* dir)
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{
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// -1 allows for trailing DIR_SEP that will be added if not
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// already present.
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if(strcpy_s(pp->path, ARRAY_SIZE(pp->path)-1, dir) != 0)
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WARN_RETURN(ERR_PATH_LENGTH);
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size_t len = strlen(pp->path);
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// add directory separator if not already present
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// .. but only check this if dir != "" (=> len-1 is safe)
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if(len != 0)
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{
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char* last_char = pp->path+len-1;
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if(!is_dir_sep(*last_char))
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{
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*(last_char+1) = '/';
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// note: need to 0-terminate because pp.path is uninitialized
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// and we overwrite strcpy_s's terminator above.
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*(last_char+2) = '\0';
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// only bump by 1 - filename must overwrite '\0'.
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len++;
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}
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}
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pp->end = pp->path+len;
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pp->chars_left = ARRAY_SIZE(pp->path)-len;
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return ERR_OK;
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}
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// append the given filename to the directory established by the last
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// path_package_set_dir on this package. the whole path is accessible at pp->path.
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LibError path_package_append_file(PathPackage* pp, const char* path)
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{
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CHECK_ERR(strcpy_s(pp->end, pp->chars_left, path));
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return ERR_OK;
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}
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