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[unix-history] / .ref-BSD-4 / usr / src / cmd / compact / compact.c

/*
*  Adaptive Huffman code input to output
*
*  On - line algorithm
*
*  Does not prepend decoding tree
*
*  Written by Colin L. Mc Master (UCB) February 28, 1979
*/


#include "compact.h"

union cio d;
int bits;


main (argc, argv)
short argc;
char *argv [ ];
{
       register short i, j;
       register int m;
       union cio c;
       short l;
       longint ic, n;
       char *cp, fname [LNAME];

       dir [513] . next = NULL;
       for (head = dir + (j = 513); j--; ) {
               dirp = head--;
               head -> next = dirp;
       }
       bottom = dirp -> pt = dict;
       dict [0] . top [0] = dict [0] . top [1] = dirp;
       dirq = dirp -> next;
       in [EF] . flags = FBIT | SEEN;

       for (i = 1; ; i++) {
               ic = oc =  0;
               (bottom -> top [1]) -> next = flist;
               bottom -> top [1] = dirp;
               flist = dirq;
               if (i >= argc) {
                       uncfp = stdin;
                       cfp = stdout;
               }
               else {
                       m = -1;
                       cp = fname;
                       for (l = 0; l < (LNAME - 3) && (*cp = argv [i][l]); l++)
                               if (*cp++ == '/') m = l;
                       if (l >= (LNAME - 3) || (l - m) > 13) {
                               fprintf (stderr, "%s: File name too long\n", argv [i]);
                               if (i == argc - 1) break;
                               continue;
                       }
                       if ((uncfp = fopen (argv [i], "r")) == NULL) {
                               perror (argv [i]);
                               if (i == argc - 1) break;
                               continue;
                       }
               }

               fstat (fileno (uncfp), &status);
               if ((status.st_mode & 040000) == 040000) {
                       fprintf (stderr, "%s: Can't compact a directory\n", argv [i]);
                       if (i < argc) goto closein;
                       break;
               }

               if ((d . integ = getc (uncfp)) != EOF) {
                       ic++;
                       if ((c . integ = getc (uncfp)) != EOF) {
                               d . chars . hib = c . integ & 0377;
                               if ((d . integ &= 0177777) == COMPACTED) {
                                       fprintf (stderr, "%s: Already compacted.\n", argv [i]);
                                       if (i < argc) goto closein;
                                       break;
                               }
                               if (d . integ == PACKED) {
                                       fprintf (stderr, "%s: Already packed using program pack.  Use unpack.\n", argv [i]);
                                       if (i < argc) goto closein;
                                       break;
                               }
                               if (i < argc) {
                                       *cp++ = '.'; *cp++ = 'C'; *cp = '\0';
                                       if ((cfp = fopen (fname, "w")) == NULL) {
                                               perror (fname);
                                               goto closein;
                                       }
                                       chmod (fname, status.st_mode);
                               }
                               c . integ = COMPACTED;
                               putc (c . chars . lob, cfp);
                               putc (c . chars . hib, cfp);
                               if (ferror (cfp))
                                       if (i < argc) {
                                               perror (fname);
                                               unlink (fname);
                                               goto closeboth;
                                       }
                                       else goto fail;
                               bits = 8;
                               oc = 2;
                               c . integ = d . integ & 0377;
       
                               in [NC] . fp = in [EF] . fp = dict [0] . sp [0] . p = bottom = dict + 1;
                               bottom -> count [0] = bottom -> count [1] = dict [0] . count [1] = 1;
                               dirp -> next = dict [0] . top [1] = bottom -> top [0] = bottom -> top [1] = dirq = NEW;
                               dirq -> next = NULL;
                               dict [0] . fath . fp = NULL;
                               dirq -> pt = bottom -> fath . fp = in [c . integ] . fp = dict;
                               in [c . integ] . flags = (FBIT | SEEN);
                               in [NC] . flags = SEEN;
                               dict [0] . fath . flags = RLEAF;
                               bottom -> fath . flags = (LLEAF | RLEAF);
                               dict [0] . count [0] = 2;
       
                               dict [0] . sp [1] . ch = c . integ;
                               bottom -> sp [0] . ch = NC;
                               bottom -> sp [1] . ch = EF;
       
                               for (c . integ = ((d . integ >> 8) & 0377); c . integ != EOF; c . integ = getc (uncfp)) {
                                       ic++;
                                       if (in [c . integ] . flags & SEEN) encode (c . integ);
                                       else {
                                               encode (NC);
                                               uptree (NC);
                                               insert (c . integ);
       
                                               m = 0200;
                                               for (j = 8; j--; m >>= 1) {
                                                       d . integ <<= 1;
                                                       if (m & c . integ) d . integ++;
                                                       ++bits;
                                                       if ((bits &= 017) == 0) {
                                                               putc (d . chars . hib, cfp);
                                                               putc (d . chars . lob, cfp);
                                                               oc += 2;
                                                       }
                                               }
                                       }
                                       if (ferror (cfp))
                                               if (i < argc) {
                                                       perror (fname);
                                                       unlink (fname);
                                                       goto closeboth;
                                               }
                                               else goto fail;
                                       uptree (c . integ);
       
                               }

                               if (ferror (uncfp))
                                       if (i < argc) {
                                               perror (argv [i]);
                                               unlink (fname);
                                               goto closeboth;
                                       }
                                       else goto fail;
       
                               encode (EF);
       
                               if (bits) {
                                       d . integ <<= (16 - bits);
                                       oc++;
                                       putc (d . chars . hib, cfp);
                                       if (bits > 8) {
                                               oc++;
                                               putc (d . chars . lob, cfp);
                                       }
                                       bits = 0;
                               }
                       }
                       else oc = ic;
               }

               if (ferror (uncfp) || ferror (cfp))
                       if (i < argc) {
                               if (ferror (cfp))
                                       perror (fname);
                               else
                                       perror (argv [i]);
                               if (oc > 1) {
                                       unlink (fname);
                                       goto closeboth;
                               }
                               goto closein;
                       }
                       else goto fail;
               else {
                       if (oc >= ic) {
                               if (i < argc) fprintf (stderr, "%s: ", argv [i]);
                               if (i < argc) fprintf (stderr, "Not compacted.  ");
                               fprintf (stderr, "Does not save bytes.\n");
                               if (i < argc) {
                                       if (oc > 1) {
                                               unlink (fname);
                                               goto closeboth;
                                       }
                                       goto closein;
                               }
                               else break;
                       }
                       while ((ic - oc) > 21474) {
                               ic /= 10;
                               oc /= 10;
                       }
                       n = 100000 * (ic - oc) / ic + 5;
                       m = (n % 1000) / 10;
                       bits = m % 10 + '0';
                       c . integ = m / 10 + '0';
                       if (i < argc) fprintf (stderr, "%s:  ", argv [i]);
                       fprintf (stderr, "Compression : %4ld.%c%c%%\n", n / 1000, c . chars . lob, bits);
               }

                           if (i >= argc) break;
                           unlink (argv [i]);
               closeboth : fclose (cfp);
               closein   : fclose (uncfp);
                           if (i == argc - 1) break;
                           for (j = 256; j--; ) in [j] . flags = 0;
                           continue;
               fail      : fprintf (stderr, "Unsuccessful compact of standard input to standard output.\n");
                           break;
       }
}

encode (ch)
int ch;
{

       register struct node *pp;
       register char j;
       union cio c;
       int stack [17], stp, stbits;

       c . integ = ch;
       stack [stp = 0] = in [c . integ] . flags & FBIT;
       stbits = 1;
       pp = in [c . integ] . fp;

       while (pp -> fath . fp) {
               stack [stp] <<= 1;
               if (pp -> fath . flags & FBIT) stack [stp]++;
               stbits++;
               if ((stbits &= 017) == 0) stp++;
               pp = pp ->  fath . fp;
       }

       /* pop the output stack */

       for (stp++; stp--; ) {
               for (j = 0; j < stbits; j++) {
                       d . integ <<= 1;
                       if (stack [stp] & 01) d . integ++;
                       ++bits;
                       if ((bits &= 017) == 0) {
                               putc (d . chars . hib, cfp);
                               putc (d . chars . lob, cfp);
                               if (ferror (cfp)) return;
                               oc += 2;
                       }
                       stack [stp] >>= 1;
               }
               stbits = 16;
       }
}