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b16e999f55
Run "make update-copyright" and then... * gnulib: Update to latest with copyright year adjusted. * tests/init.sh: Sync with gnulib to pick up copyright year. * bootstrap: Likewise. * tests/sample-test: Adjust to use the single most recent year.
134 lines
3.6 KiB
C
134 lines
3.6 KiB
C
/* relpath - print the relative path
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Copyright (C) 2012-2016 Free Software Foundation, Inc.
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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/* Written by Pádraig Brady. */
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#include <config.h>
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#include "error.h"
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#include "system.h"
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#include "relpath.h"
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/* Return the length of the longest common prefix
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of canonical PATH1 and PATH2, ensuring only full path components
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are matched. Return 0 on no match. */
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static int _GL_ATTRIBUTE_PURE
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path_common_prefix (const char *path1, const char *path2)
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{
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int i = 0;
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int ret = 0;
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/* We already know path1[0] and path2[0] are '/'. Special case
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'//', which is only present in a canonical name on platforms
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where it is distinct. */
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if ((path1[1] == '/') != (path2[1] == '/'))
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return 0;
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while (*path1 && *path2)
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{
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if (*path1 != *path2)
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break;
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if (*path1 == '/')
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ret = i + 1;
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path1++;
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path2++;
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i++;
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}
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if ((!*path1 && !*path2)
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|| (!*path1 && *path2 == '/')
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|| (!*path2 && *path1 == '/'))
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ret = i;
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return ret;
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}
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/* Either output STR to stdout or
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if *PBUF is not NULL then append STR to *PBUF
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and update *PBUF to point to the end of the buffer
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and adjust *PLEN to reflect the remaining space.
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Return TRUE on failure. */
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static bool
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buffer_or_output (const char* str, char **pbuf, size_t *plen)
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{
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if (*pbuf)
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{
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size_t slen = strlen (str);
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if (slen >= *plen)
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return true;
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memcpy (*pbuf, str, slen + 1);
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*pbuf += slen;
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*plen -= slen;
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}
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else
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{
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fputs (str, stdout);
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}
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return false;
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}
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/* Output the relative representation if possible.
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If BUF is non-NULL, write to that buffer rather than to stdout. */
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bool
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relpath (const char *can_fname, const char *can_reldir, char *buf, size_t len)
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{
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bool buf_err = false;
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/* Skip the prefix common to --relative-to and path. */
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int common_index = path_common_prefix (can_reldir, can_fname);
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if (!common_index)
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return false;
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const char *relto_suffix = can_reldir + common_index;
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const char *fname_suffix = can_fname + common_index;
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/* Skip over extraneous '/'. */
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if (*relto_suffix == '/')
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relto_suffix++;
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if (*fname_suffix == '/')
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fname_suffix++;
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/* Replace remaining components of --relative-to with '..', to get
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to a common directory. Then output the remainder of fname. */
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if (*relto_suffix)
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{
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buf_err |= buffer_or_output ("..", &buf, &len);
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for (; *relto_suffix; ++relto_suffix)
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{
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if (*relto_suffix == '/')
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buf_err |= buffer_or_output ("/..", &buf, &len);
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}
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if (*fname_suffix)
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{
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buf_err |= buffer_or_output ("/", &buf, &len);
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buf_err |= buffer_or_output (fname_suffix, &buf, &len);
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}
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}
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else
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{
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buf_err |= buffer_or_output (*fname_suffix ? fname_suffix : ".",
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&buf, &len);
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}
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if (buf_err)
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error (0, ENAMETOOLONG, "%s", _("generating relative path"));
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return !buf_err;
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}
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