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#include <kernel/vfs/path.h>
#include <kernel/panic.h>
#include <shared/mem.h>
int path_simplify(const char *in, char *out, size_t len) {
if (len == 0) return -1; // empty paths are invalid
if (in[0] != '/') return -1; // so are relative paths
int seg_len; // the length of the current path segment
int out_pos = 0;
bool directory = 0;
for (size_t i = 0; i < len; i += seg_len + 1) {
assert(in[i] == '/');
seg_len = 0;
directory = false;
for (size_t j = i + 1; j < len; j++) {
if (in[j] == '/') {
directory = true;
break;
}
seg_len++;
}
/* example iteration, illustrated with terrible ASCII art
*
* |i=5 |next i = i + seg_len + 1 = 10
* v v
* /some/path/asdf
* |--|
* seg_len = 4
* (segment starts at i+1) */
if (seg_len == 0 || (seg_len == 1 && in[i + 1] == '.')) {
/* // or /./ */
directory = true;
} else if (seg_len == 2 && in[i + 1] == '.' && in[i + 2] == '.') {
/* /../ */
directory = true;
/* try to backtrack to the last slash */
while (--out_pos >= 0 && out[out_pos] != '/');
if (out_pos < 0) return -1;
} else {
/* a normal segment, e.g. /asdf/ */
out[out_pos] = '/';
memcpy(&out[out_pos + 1], &in[i + 1], seg_len);
out_pos += seg_len + 1;
}
}
/* paths to directories should have a trailing slash */
if (directory) out[out_pos++] = '/';
return out_pos;
}
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