From 6e5a5a3b27257f212fcd10a3580cfca3ea224fab Mon Sep 17 00:00:00 2001 From: dzwdz Date: Wed, 4 Aug 2021 12:27:02 +0200 Subject: partial path_simplify implementation it currently only checks if the path is valid, it's the bare minimum needed to write tests --- src/kernel/vfs/path.c | 44 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 44 insertions(+) create mode 100644 src/kernel/vfs/path.c (limited to 'src/kernel/vfs/path.c') diff --git a/src/kernel/vfs/path.c b/src/kernel/vfs/path.c new file mode 100644 index 0000000..8662f03 --- /dev/null +++ b/src/kernel/vfs/path.c @@ -0,0 +1,44 @@ +#include +#include + +bool path_simplify(const char *in, char *out, size_t len) { + if (len == 0) return false; // empty paths are invalid + if (in[0] != '/') return false; // so are relative paths + + int depth = 0; + int seg_len; // the length of the current path segment + + for (int i = 0; i < len; i += seg_len + 1) { + // TODO implement assert + if (in[i] != '/') panic(); + + seg_len = 0; + for (int j = i + 1; j < len; j++) { + if (in[j] == '/') 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] == '.')) { + // the segment is // or /./ + // the depth doesn't change + } else if (seg_len == 2 && in[i + 1] == '.' && in[i + 2] == '.') { + // the segment is /../ + if (--depth < 0) + return false; + } else { + // normal segment + depth++; + } + } + + return true; +} -- cgit v1.2.3