workbench/devs/diskimage/dms/u_quick.c

   1 /*
   2  *     xDMS  v1.3  -  Portable DMS archive unpacker  -  Public Domain
   3  *     Written by     Andre Rodrigues de la Rocha  <adlroc@usa.net>
   4  *
   5  *
   6  */
   7
   8 #include "xdms.h"
   9
  10 #define QBITMASK 0xff
  11
  12 UWORD Unpack_QUICK(struct xdms_data *xdms, UBYTE *in, UBYTE *out, UWORD origsize) {
  13         UWORD quick_text_loc = xdms->quick_text_loc;
  14         UBYTE *text = xdms->text;
  15         UWORD i, j;
  16         UBYTE *outend;
  17
  18         INITBITBUF(in);
  19
  20         outend = out+origsize;
  21         while (out < outend) {
  22                 if (GETBITS(1)!=0) {
  23                         DROPBITS(1);
  24                         *out++ = text[quick_text_loc++ & QBITMASK] = (UBYTE)GETBITS(8);  DROPBITS(8);
  25                 } else {
  26                         DROPBITS(1);
  27                         j = (UWORD)(GETBITS(2)+2);  DROPBITS(2);
  28                         i = (UWORD)(quick_text_loc - GETBITS(8) - 1);  DROPBITS(8);
  29                         while(j--) {
  30                                 *out++ = text[quick_text_loc++ & QBITMASK] = text[i++ & QBITMASK];
  31                         }
  32                 }
  33         }
  34         xdms->quick_text_loc = (UWORD)((quick_text_loc+5) & QBITMASK);
  35
  36         return 0;
  37 }