+char *
+unpack_varlen_hex (char *buff, /* packet to parse */
+ ULONGEST *result)
+{
+ int nibble;
+ ULONGEST retval = 0;
+
+ while (ishex (*buff, &nibble))
+ {
+ buff++;
+ retval = retval << 4;
+ retval |= nibble & 0x0f;
+ }
+ *result = retval;
+ return buff;
+}
+
+/* Write a PTID to BUF. Returns BUF+CHARACTERS_WRITTEN. */
+
+char *
+write_ptid (char *buf, ptid_t ptid)
+{
+ int pid, tid;
+
+ if (multi_process)
+ {
+ pid = ptid_get_pid (ptid);
+ if (pid < 0)
+ buf += sprintf (buf, "p-%x.", -pid);
+ else
+ buf += sprintf (buf, "p%x.", pid);
+ }
+ tid = ptid_get_lwp (ptid);
+ if (tid < 0)
+ buf += sprintf (buf, "-%x", -tid);
+ else
+ buf += sprintf (buf, "%x", tid);
+
+ return buf;
+}
+
+ULONGEST
+hex_or_minus_one (char *buf, char **obuf)
+{
+ ULONGEST ret;
+
+ if (strncmp (buf, "-1", 2) == 0)
+ {
+ ret = (ULONGEST) -1;
+ buf += 2;
+ }
+ else
+ buf = unpack_varlen_hex (buf, &ret);
+
+ if (obuf)
+ *obuf = buf;
+
+ return ret;
+}
+
+/* Extract a PTID from BUF. If non-null, OBUF is set to the to one
+ passed the last parsed char. Returns null_ptid on error. */
+ptid_t
+read_ptid (char *buf, char **obuf)
+{
+ char *p = buf;
+ char *pp;
+ ULONGEST pid = 0, tid = 0;
+
+ if (*p == 'p')
+ {
+ /* Multi-process ptid. */
+ pp = unpack_varlen_hex (p + 1, &pid);
+ if (*pp != '.')
+ error ("invalid remote ptid: %s\n", p);
+
+ p = pp + 1;
+
+ tid = hex_or_minus_one (p, &pp);
+
+ if (obuf)
+ *obuf = pp;
+ return ptid_build (pid, tid, 0);
+ }
+
+ /* No multi-process. Just a tid. */
+ tid = hex_or_minus_one (p, &pp);
+
+ /* Since the stub is not sending a process id, then default to
+ what's in the current inferior. */
+ pid = ptid_get_pid (((struct inferior_list_entry *) current_inferior)->id);
+
+ if (obuf)
+ *obuf = pp;
+ return ptid_build (pid, tid, 0);
+}
+