}
/* Parse the output of older, unportable tars, which generate
- negative values in two's complement octal. */
- if ((overflow || maxval < value) && '4' <= *where1)
+ negative values in two's complement octal. If the leading
+ nonzero digit is 1, we can't recover the original value
+ reliably; so do this only if the digit is 2 or more. This
+ catches the common case of 32-bit negative time stamps. */
+ if ((overflow || maxval < value) && '2' <= *where1)
{
/* Compute the negative of the input value, assuming two's
complement. */
- for (value = 0, where = where1, overflow = 0; ; )
+ int digit = (*where1 - '0') | 4;
+ overflow = 0;
+ value = 0;
+ where = where1;
+ for (;;)
{
- value += 7 - (*where++ - '0');
+ value += 7 - digit;
+ where++;
if (where == lim || ! ISODIGIT (*where))
break;
+ digit = *where - '0';
overflow |= value ^ (value << LG_8 >> LG_8);
value <<= LG_8;
}