New junkcode.

diff --git a/junkcode/fork0@users.sf.net-pathexpand/pathexpand.c b/junkcode/fork0@users.sf.net-pathexpand/pathexpand.c
new file mode 100644 (file)
index 0000000..4b8bcf0
--- /dev/null
+++ b/junkcode/fork0@users.sf.net-pathexpand/pathexpand.c
@@ -0,0 +1,96 @@
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+/*
+ * Returns the analog of "cd path" from a directory "cwd".
+ * The root is defined as empty path (instead of "/")
+ * An attempt to go past the root (with "..") leaves the path at root.
+ * The cwd is not expanded.
+ */
+char *pathexpand(const char *cwd, const char *path)
+{
+       static const char SEP[] = "/";
+       if (!*path) /* empty path -> "." (don't move) */
+               path = ".";
+       if (!*cwd || *SEP == *path) /* no cwd, or path begins with "/" */
+               cwd = "";
+
+       while (*cwd && *SEP == *cwd)
+               ++cwd;
+
+       size_t len = strlen(cwd);
+       char *out = malloc(len + 1 + strlen(path) + 1);
+       char *p = strcpy(out, cwd) + len;
+
+       for (; *path; ++path)
+       {
+               char *pl;
+               if (p > out && p[-1] != *SEP)
+                       *p++ = *SEP;
+               pl = p;
+               while (*path && *SEP != *path)
+                       *p++ = *path++;
+               *p = '\0';
+               /* ..."//"... */
+               if (p == pl)
+                       ; /* just ignore */
+               /* ..."/./"...  */
+               else if ( p - pl == 1 && '.' == *pl )
+                       --p; /* just ignore */
+               /* ..."/../"...  */
+               else if ( p - pl == 2 && '.' == pl[0] && '.' == pl[1] )
+               {
+                       /* drop the last element of the resulting path */
+                       if (pl > out && --pl > out)
+                               for (--pl; pl > out && *SEP != *pl; --pl)
+                                       ;
+                       p = pl > out ? ++pl: out;
+               }
+               /* ..."/path/"...  */
+               else if (*path)
+                       *p++ = *path; /* just add the separator */
+
+               if (!*path)
+                       break;
+       }
+       if (p > out+1 && *SEP == p[-1])
+               --p;
+       *p = '\0';
+       return out;
+}
+
+#ifdef CHECK_PATHEXPAND
+static void check(const char *cwd, const char *path, const char *good)
+{
+       static int n = 0;
+       printf("%-2d: %10s$ cd %s", ++n, cwd, path);
+       char *t = pathexpand(cwd, path);
+       if ( strcmp(t, good) )
+               printf(" ____________________failed(%s)\n", t);
+       else
+               printf(" \033[32m%s\033[0m\n", t);
+       free(t);
+}
+
+int main(int argc, char **argv)
+{
+       /* 1 */ check("/onelevel", "aa", "onelevel/aa");
+       /* 2 */ check("/", "..", "");
+       /* 3 */ check("/", "../..", "");
+       /* 4 */ check("/one", "aa/../bb", "one/bb");
+       /* 5 */ check("/one/two", "aa//bb", "one/two/aa/bb");
+       /* 6 */ check("", "/aa//bb", "aa/bb");
+       /* 7 */ check("/one/two", "", "one/two");
+       /* 8 */ check("/one/two", "aa/..bb/x/../cc/", "one/two/aa/..bb/cc");
+       /* 9 */ check("/one/two", "aa/x/././cc////", "one/two/aa/x/cc");
+       /* 10 */ check("/one/two", "../../../../aa", "aa");
+       /* 11 */ check("one/", "../one/two", "one/two");
+       /* 12 */ check("", "../../two", "two");
+       /* 13 */ check("a/b/c", "../../two", "a/two");
+       /* 14 */ check("a/b/", "../two", "a/two");
+       /* 15 */ check("///", "../two", "two");
+       return 0;
+}
+#endif
+