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 static void my_lh1_codec_addbuf(struct de_dfilter_ctx *dfctx,
  24         const u8 *buf, i64 buf_len)
  25 {
  26         struct lzahuf_ctx *cctx = (struct lzahuf_ctx*)dfctx->codec_private;
  27
  28         if(dfctx->finished_flag || cctx->errflag) {
  29                 goto done;
  30         }
  31
  32         lzhuf_Decode_continue(cctx, buf, buf_len, 0);
  33
  34 done:
  35         if(cctx->errflag) {
  36                 dfctx->finished_flag = 1;
  37         }
  38 }
  39
  40 static void my_lh1_codec_finish(struct de_dfilter_ctx *dfctx)
  41 {
  42         struct lzahuf_ctx *cctx = (struct lzahuf_ctx*)dfctx->codec_private;
  43
  44         lzhuf_Decode_continue(cctx, NULL, 0, 1);
  45
  46         cctx->total_nbytes_processed -= (i64)(cctx->bbll.nbits_in_bitbuf/8);
  47         de_bitbuf_lowlevel_empty(&cctx->bbll);
  48         dfctx->dres->bytes_consumed = cctx->total_nbytes_processed;
  49         dfctx->dres->bytes_consumed_valid = 1;
  50
  51         if(cctx->errflag) {
  52                 de_dfilter_set_generic_error(cctx->c, dfctx->dres, cctx->modname);
  53         }
  54 }
  55
  56 static void my_lh1_codec_command(struct de_dfilter_ctx *dfctx, int cmd, UI flags)
  57 {
  58         struct lzahuf_ctx *cctx = (struct lzahuf_ctx*)dfctx->codec_private;
  59
  60         if(cmd==DE_DFILTER_COMMAND_FINISH_BLOCK) {
  61                 lzhuf_Decode_continue(cctx, NULL, 0, 1);
  62                 cctx->total_nbytes_processed -= (i64)(cctx->bbll.nbits_in_bitbuf/8);
  63                 de_bitbuf_lowlevel_empty(&cctx->bbll);
  64                 if(cctx->lh1p.is_dms_deep) {
  65                         de_lz77buffer_set_curpos(cctx->ringbuf, cctx->ringbuf->curpos + 60);
  66                 }
  67         }
  68         else if(cmd==DE_DFILTER_COMMAND_RESET_COUNTERS) {
  69                 cctx->nbytes_written = 0;
  70                 cctx->total_nbytes_processed = 0;
  71                 cctx->errflag = 0;
  72                 dfctx->finished_flag = 0;
  73         }
  74 }
  75
  76 static void my_lh1_codec_destroy(struct de_dfilter_ctx *dfctx)
  77 {
  78         struct lzahuf_ctx *cctx = (struct lzahuf_ctx*)dfctx->codec_private;
  79
  80         if(cctx) {
  81                 de_lz77buffer_destroy(cctx->c, cctx->ringbuf);
  82                 cctx->ringbuf = NULL;
  83                 de_free(dfctx->c, cctx);
  84         }
  85         dfctx->codec_private = NULL;
  86 }
  87
  88 // codec_private_params: 'struct de_lh1_params'. Can be NULL.
  89 void dfilter_lh1_codec(struct de_dfilter_ctx *dfctx, void *codec_private_params)
  90 {
  91         struct lzahuf_ctx *cctx = NULL;
  92
  93         cctx = de_malloc(dfctx->c, sizeof(struct lzahuf_ctx));
  94         cctx->c = dfctx->c;
  95         cctx->modname = "lzhuf";
  96         cctx->dfctx = dfctx;
  97         cctx->dcmpro = dfctx->dcmpro;
  98         cctx->dres = dfctx->dres;
  99
 100         dfctx->codec_private = (void*)cctx;
 101         dfctx->codec_addbuf_fn = my_lh1_codec_addbuf;
 102         dfctx->codec_finish_fn = my_lh1_codec_finish;
 103         dfctx->codec_command_fn = my_lh1_codec_command;
 104         dfctx->codec_destroy_fn = my_lh1_codec_destroy;
 105
 106         if(codec_private_params) {
 107                 // Use params from caller, if present.
 108                 de_memcpy(&cctx->lh1p, codec_private_params, sizeof(struct de_lh1_params));
 109         }
 110         else {
 111                 // Set default params.
 112                 cctx->lh1p.history_fill_val = 0x20;
 113         }
 114
 115         lzhuf_Decode_init(cctx);
 116 }
 117
 118 // codec_private_params: 'struct de_lh1_params'. Can be NULL.
 119 void fmtutil_lh1_codectype1(deark *c, struct de_dfilter_in_params *dcmpri,
 120         struct de_dfilter_out_params *dcmpro, struct de_dfilter_results *dres,
 121         void *codec_private_params)
 122 {
 123         de_dfilter_decompress_oneshot(c, dfilter_lh1_codec, codec_private_params,
 124                 dcmpri, dcmpro, dres);
 125 }