line-range.hon commit t3404: todo list with commented-out commands only aborts (d078c39)
   1#ifndef LINE_RANGE_H
   2#define LINE_RANGE_H
   3
   4/*
   5 * Parse one item in an -L begin,end option w.r.t. the notional file
   6 * object 'cb_data' consisting of 'lines' lines.
   7 *
   8 * The 'nth_line_cb' callback is used to determine the start of the
   9 * line 'lno' inside the 'cb_data'.  The caller is expected to already
  10 * have a suitable map at hand to make this a constant-time lookup.
  11 *
  12 * 'anchor' is the 1-based line at which relative range specifications
  13 * should be anchored. Absolute ranges are unaffected by this value.
  14 *
  15 * Returns 0 in case of success and -1 if there was an error.  The
  16 * actual range is stored in *begin and *end.  The counting starts
  17 * at 1!  In case of error, the caller should show usage message.
  18 */
  19
  20typedef const char *(*nth_line_fn_t)(void *data, long lno);
  21
  22extern int parse_range_arg(const char *arg,
  23                           nth_line_fn_t nth_line_cb,
  24                           void *cb_data, long lines, long anchor,
  25                           long *begin, long *end,
  26                           const char *path);
  27
  28/*
  29 * Scan past a range argument that could be parsed by
  30 * 'parse_range_arg', to help the caller determine the start of the
  31 * filename in '-L n,m:file' syntax.
  32 *
  33 * Returns a pointer to the first character after the 'n,m' part, or
  34 * NULL in case the argument is obviously malformed.
  35 */
  36
  37extern const char *skip_range_arg(const char *arg);
  38
  39#endif /* LINE_RANGE_H */