modules/wad.c

   1 // This file is part of Deark.
   2 // Copyright (C) 2017 Jason Summers
   3 // See the file COPYING for terms of use.
   4
   5 // Doom WAD
   6
   7 #include <deark-config.h>
   8 #include <deark-private.h>
   9 DE_DECLARE_MODULE(de_module_wad);
  10
  11 typedef struct localctx_struct {
  12         i64 nlumps;
  13         i64 dir_pos;
  14 } lctx;
  15
  16 static void do_lump_extract(deark *c, lctx *d, i64 dpos, i64 dlen, struct de_stringreaderdata *srd)
  17 {
  18         de_finfo *fi = NULL;
  19
  20         // 0-length lumps are assumed to be special "virtual" lumps.
  21         if(dlen<=0) return;
  22         if(dpos<0 || dpos>=c->infile->len || dpos+dlen>c->infile->len) return;
  23
  24         fi = de_finfo_create(c);
  25         de_finfo_set_name_from_ucstring(c, fi, srd->str, 0);
  26         fi->original_filename_flag = 1;
  27         dbuf_create_file_from_slice(c->infile, dpos, dlen, NULL, fi, 0);
  28         de_finfo_destroy(c, fi);
  29 }
  30
  31 static void do_lump_entry(deark *c, lctx *d, i64 lump_idx, i64 pos)
  32 {
  33         i64 lump_pos;
  34         i64 lump_size;
  35         struct de_stringreaderdata *srd = NULL;
  36
  37         de_dbg(c, "lump[%d] dir entry at %d", (int)lump_idx, (int)pos);
  38         de_dbg_indent(c, 1);
  39         lump_pos = de_getu32le(pos);
  40         de_dbg(c, "data pos: %d", (int)lump_pos);
  41         lump_size = de_getu32le(pos+4);
  42         de_dbg(c, "data size: %d", (int)lump_size);
  43
  44         // dbuf_read_string is used (instead of dbuf_read_to_ucstring) because
  45         // the names have special meanings, so someday we might want to run
  46         // comparisons against them. But currently we don't do that.
  47         srd = dbuf_read_string(c->infile, pos+8, 8, 8, DE_CONVFLAG_STOP_AT_NUL, DE_ENCODING_ASCII);
  48         de_dbg(c, "name: \"%s\"", ucstring_getpsz_d(srd->str));
  49
  50         do_lump_extract(c, d, lump_pos, lump_size, srd);
  51
  52         de_dbg_indent(c, -1);
  53         de_destroy_stringreaderdata(c, srd);
  54 }
  55
  56 static int do_directory(deark *c, lctx *d, i64 pos)
  57 {
  58         i64 k;
  59         de_dbg(c, "directory at %d", (int)pos);
  60         de_dbg_indent(c, 1);
  61
  62         if(pos<0 || pos>=c->infile->len) goto done;
  63         if(d->nlumps<1 || d->nlumps>10000) goto done;
  64
  65         for(k=0; k<d->nlumps; k++) {
  66                 if(pos+16*k > c->infile->len-16) break;
  67                 do_lump_entry(c, d, k, pos+16*k);
  68         }
  69
  70 done:
  71         de_dbg_indent(c, -1);
  72         return 1;
  73 }
  74
  75 static int do_header(deark *c, lctx *d, i64 pos)
  76 {
  77         de_dbg(c, "header at %d", (int)pos);
  78         de_dbg_indent(c, 1);
  79         d->nlumps = de_getu32le(pos+4);
  80         de_dbg(c, "#lumps: %d", (int)d->nlumps);
  81         d->dir_pos = de_getu32le(pos+8);
  82         de_dbg(c, "dir pos: %d", (int)d->dir_pos);
  83         de_dbg_indent(c, -1);
  84         return 1;
  85 }
  86
  87 static void de_run_wad(deark *c, de_module_params *mparams)
  88 {
  89         lctx *d = NULL;
  90
  91         d = de_malloc(c, sizeof(lctx));
  92
  93         if(!do_header(c, d, 0)) goto done;
  94
  95         do_directory(c, d, d->dir_pos);
  96
  97 done:
  98         de_free(c, d);
  99 }
 100
 101 static int de_identify_wad(deark *c)
 102 {
 103         if(!dbuf_memcmp(c->infile, 1, "WAD", 3)) {
 104                 u8 b0;
 105                 b0 = de_getbyte(0);
 106                 if(b0=='I' || b0=='P') return 80;
 107         }
 108         return 0;
 109 }
 110
 111 void de_module_wad(deark *c, struct deark_module_info *mi)
 112 {
 113         mi->id = "wad";
 114         mi->desc = "Doom WAD";
 115         mi->run_fn = de_run_wad;
 116         mi->identify_fn = de_identify_wad;
 117 }