src/fmtutil-lzah.c

   1 // This file is part of Deark.
   2 // Copyright (C) 2021 Jason Summers
   3 // See the file COPYING for terms of use.
   4
   5 // LZH with adaptive Huffman coding
   6
   7 #define DE_NOT_IN_MODULE
   8 #include "deark-private.h"
   9 #include "deark-fmtutil.h"
  10
  11 #include "../foreign/lzhuf.h"
  12
  13 void fmtutil_get_lzhuf_d_code_and_len(UI n, UI *pd_code, UI *pd_len)
  14 {
  15         if(n<32 || n>=256) { *pd_code = 0; *pd_len = 3; }
  16         else if(n<80) { *pd_code = (n-16)>>4; *pd_len = 4; }
  17         else if(n<144) { *pd_code = (n-48)>>3; *pd_len = 5; }
  18         else if(n<192) { *pd_code = (n-96)>>2; *pd_len = 6; }
  19         else if(n<240) { *pd_code = (n-144)>>1; *pd_len = 7; }
  20         else { *pd_code = n-192; *pd_len = 8; };
  21 }
  22
  23 // codec_private_params: 'struct de_lh1_params'. Can be NULL.
  24 void fmtutil_lh1_codectype1(deark *c, struct de_dfilter_in_params *dcmpri,
  25         struct de_dfilter_out_params *dcmpro, struct de_dfilter_results *dres,
  26         void *codec_private_params)
  27 {
  28         struct lzahuf_ctx *cctx = NULL;
  29
  30         cctx = de_malloc(c, sizeof(struct lzahuf_ctx));
  31         cctx->c = c;
  32         cctx->modname = "lzhuf";
  33         cctx->dcmpri = dcmpri;
  34         cctx->dcmpro = dcmpro;
  35         cctx->dres = dres;
  36
  37         if(codec_private_params) {
  38                 // Use params from caller, if present.
  39                 de_memcpy(&cctx->lh1p, codec_private_params, sizeof(struct de_lh1_params));
  40         }
  41         else {
  42                 // Set default params.
  43                 cctx->lh1p.history_fill_val = 0x20;
  44         }
  45
  46         cctx->bitrd.f = dcmpri->f;
  47         cctx->bitrd.curpos = dcmpri->pos;
  48         cctx->bitrd.endpos = dcmpri->pos + dcmpri->len;
  49
  50         lzhuf_Decode(cctx);
  51
  52         de_bitreader_skip_to_byte_boundary(&cctx->bitrd);
  53         cctx->dres->bytes_consumed = cctx->bitrd.curpos - cctx->dcmpri->pos;
  54         if(cctx->dres->bytes_consumed<0) {
  55                 cctx->dres->bytes_consumed = 0;
  56         }
  57         cctx->dres->bytes_consumed_valid = 1;
  58
  59         de_free(c, cctx);
  60 }