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/* vi: set sw=4 ts=4: */
/*
* Utility routines.
*
* Copyright (C) many different people.
* If you wrote this, please acknowledge your work.
*
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
#include "libbb.h"
/* Concatenate path and filename to new allocated buffer.
* Add '/' only as needed (no duplicate // are produced).
* If path is NULL, it is assumed to be "/".
* filename should not be NULL.
*/
char* FAST_FUNC concat_path_file(const char *path, const char *filename)
{
#if 0
char *lc;
if (!path)
path = "";
#if ENABLE_PLATFORM_MINGW32
lc = last_char_is_dir_sep(path);
while (is_dir_sep(*filename))
filename++;
#else
lc = last_char_is(path, '/');
while (*filename == '/')
filename++;
#endif
return xasprintf("%s%s%s", path, (lc==NULL ? "/" : ""), filename);
#else
/* ^^^^^^^^^^^ timing of xasprintf-based code above:
* real 7.074s
* user 0.156s <<<
* sys 6.394s
* "rm -rf" of a Linux kernel tree from tmpfs (run time still dominated by in-kernel work, though)
* real 6.989s
* user 0.055s <<< 3 times less CPU used
* sys 6.450s
* vvvvvvvvvvv timing of open-coded malloc+memcpy code below (+59 bytes):
*/
char *buf, *p;
size_t n1, n2, n3;
while (*filename == '/')
filename++;
if (!path || !path[0])
return xstrdup(filename);
n1 = strlen(path);
n2 = (path[n1 - 1] != '/'); /* 1: "path has no trailing slash" */
n3 = strlen(filename) + 1;
buf = xmalloc(n1 + n2 + n3);
p = mempcpy(buf, path, n1);
if (n2)
*p++ = '/';
memcpy(p, filename, n3);
return buf;
#endif
}
/* If second component comes from struct dirent,
* it's possible to eliminate one strlen() by using name length
* provided by kernel in struct dirent. See below.
* However, the win seems to be insignificant.
*/
#if 0
/* Extract d_namlen from struct dirent */
static size_t get_d_namlen(const struct dirent *de)
{
#if defined(_DIRENT_HAVE_D_NAMLEN)
return de->d_namlen;
#elif defined(_DIRENT_HAVE_D_RECLEN)
const size_t prefix_sz = offsetof(struct dirent, d_name);
return de->d_reclen - prefix_sz;
#else
return strlen(de->d_name);
#endif
}
char* FAST_FUNC concat_path_dirent(const char *path, const struct dirent *de)
{
char *buf, *p;
size_t n1, n2, n3;
if (!path || !path[0])
return xstrdup(de->d_name);
n1 = strlen(path);
n2 = (path[n1 - 1] != '/');
n3 = get_d_namlen(de) + 1;
buf = xmalloc(n1 + n2 + n3);
p = mempcpy(buf, path, n1);
if (n2)
*p++ = '/';
memcpy(p, de->d_name, n3);
return buf;
}
#endif
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