5 * In place, rewrite name to compress multiple /, eliminate ., and process ..
7 #define SEP(x) ((x)=='/' || (x) == 0)
14 rooted = name[0] == '/';
18 * p points at beginning of path element we're considering.
19 * q points just past the last path element we wrote (no slash).
20 * dotdot points just past the point where .. cannot backtrack
21 * any further (no slash).
23 p = q = dotdot = name+rooted;
25 if(p[0] == '/') /* null element */
27 else if(p[0] == '.' && SEP(p[1]))
28 p += 1; /* don't count the separator in case it is nul */
29 else if(p[0] == '.' && p[1] == '.' && SEP(p[2])) {
31 if(q > dotdot) { /* can backtrack */
32 while(--q > dotdot && *q != '/')
34 } else if(!rooted) { /* /.. is / but ./../ is .. */
41 } else { /* real path element */
44 while((*q = *p) != '/' && *q != 0)
48 if(q == name) /* empty string is really ``.'' */