modules/gemmeta.c

   1 // This file is part of Deark.
   2 // Copyright (C) 2016 Jason Summers
   3 // See the file COPYING for terms of use.
   4
   5 // GEM VDI Metafile (.gem)
   6
   7 #include <deark-config.h>
   8 #include <deark-private.h>
   9 DE_DECLARE_MODULE(de_module_gemmeta);
  10
  11 typedef struct localctx_struct {
  12         int reserved;
  13 } lctx;
  14
  15 struct opcode_data {
  16         i64 pos;
  17         i64 ptsin_pos;
  18         i64 intin_pos;
  19         i64 opcode;
  20
  21         // "Function sub-ID". This is also confusingly called "sub-opcode", but
  22         // "sub-opcode" means something entirely different with respect to opcode 5.
  23         i64 func_id;
  24
  25         i64 ptsin_count, intin_count;
  26 };
  27
  28 typedef void (*record_decoder_fn)(deark *c, lctx *d, struct opcode_data *op);
  29
  30 struct opcode_info {
  31         u16 opcode;
  32         const char *name;
  33         record_decoder_fn fn;
  34 };
  35
  36 static void do_opcode_5(deark *c, lctx *d, struct opcode_data *op);
  37 static void do_opcode_11(deark *c, lctx *d, struct opcode_data *op);
  38
  39 static const struct opcode_info opcode_info_arr[] = {
  40         // This list is not intended to be complete.
  41         { 5, "Escape", do_opcode_5 },
  42         { 6, "Polyline", NULL },
  43         { 9, "Filled area", NULL },
  44         { 11, "GDP", do_opcode_11 },
  45         { 13, "Set character baseline vector", NULL },
  46         { 15, "Set polyline linetype", NULL },
  47         { 16, "Set polyline line width", NULL },
  48         { 17, "Set polyline color index", NULL },
  49         { 18, "Set polymarker type", NULL },
  50         { 19, "Set polymarker height", NULL },
  51         { 20, "Set polymarker color index", NULL },
  52         { 21, "Set text face", NULL },
  53         { 22, "Set graphic text color index", NULL },
  54         { 23, "Set fill interior style", NULL },
  55         { 24, "Set fill style index", NULL },
  56         { 25, "Set fill color index", NULL },
  57         { 32, "Set writing mode", NULL },
  58         { 39, "Set graphic text alignment", NULL },
  59         { 104, "Set fill perimeter visibility", NULL },
  60         { 106, "Set graphic text special effects", NULL },
  61         { 107, "Set character cell height, points mode", NULL },
  62         { 108, "Set polyline end styles", NULL },
  63         { 112, "Set user defined fill pattern", NULL },
  64         { 0xffff, "EOF", NULL },
  65         { 0x0000, NULL, NULL }
  66 };
  67
  68 static void do_opcode_5(deark *c, lctx *d, struct opcode_data *op)
  69 {
  70         i64 sub_opcode_id;
  71         const char *name;
  72
  73         if(op->func_id!=99) return;
  74         if(op->intin_count<1) return;
  75         sub_opcode_id = de_getu16le(op->intin_pos);
  76
  77         switch(sub_opcode_id) {
  78         case 10: name="Start Group"; break;
  79         case 11: name="End Group"; break;
  80         case 49: name="Set No Line Style"; break;
  81         case 50: name="Set Attribute Shadow On"; break;
  82         case 51: name="Set Attribute Shadow Off"; break;
  83         case 80: name="Start Draw Area Type Primitive"; break;
  84         case 81: name="End Draw Area Type Primitive"; break;
  85         default:
  86                 if(sub_opcode_id>100) {
  87                         name="for developer use";
  88                 }
  89                 else {
  90                         name="?";
  91                 }
  92         }
  93
  94         de_dbg(c, "sub-opcode id: %d (%s)", (int)sub_opcode_id, name);
  95 }
  96
  97 static void do_opcode_11(deark *c, lctx *d, struct opcode_data *op)
  98 {
  99         const char *name;
 100
 101         switch(op->func_id) {
 102         case 1: name="Bar"; break;
 103         case 2: name="Arc"; break;
 104         case 3: name="Pie"; break;
 105         case 4: name="Circle"; break;
 106         case 5: name="Ellipse"; break;
 107         case 6: name="Elliptical arc"; break;
 108         case 7: name="Elliptical Pie"; break;
 109         case 8: name="Rounded rectangle"; break;
 110         case 9: name="Filled rounded rectangle"; break;
 111         case 10: name="Jutified graphic text"; break;
 112         default: name="?"; break;
 113         }
 114
 115         de_dbg(c, "function: %s", name);
 116 }
 117
 118 static const struct opcode_info *find_opcode_info(i64 opcode)
 119 {
 120         i64 i;
 121
 122         for(i=0; opcode_info_arr[i].name!=NULL; i++) {
 123                 if(opcode_info_arr[i].opcode == opcode) {
 124                         return &opcode_info_arr[i];
 125                 }
 126         }
 127         return NULL;
 128 }
 129
 130 // Returns 0 if we should stop reading the file.
 131 static int do_record(deark *c, lctx *d, i64 pos, i64 *bytesused)
 132 {
 133         int retval = 0;
 134         struct opcode_data op;
 135         i64 ptsin_size_bytes;
 136         i64 intin_size_bytes;
 137         i64 data_size_bytes;
 138         const struct opcode_info *opinfo;
 139         const char *opcode_name;
 140
 141         *bytesused = 0;
 142         de_zeromem(&op, sizeof(struct opcode_data));
 143
 144         de_dbg(c, "record at %d", (int)pos);
 145         de_dbg_indent(c, 1);
 146
 147         op.opcode = de_getu16le(pos);
 148         op.ptsin_count = de_getu16le(pos+2);
 149         op.intin_count = de_getu16le(pos+4);
 150         op.func_id = de_getu16le(pos+6);
 151
 152         ptsin_size_bytes = 4*op.ptsin_count;
 153         intin_size_bytes = 2*op.intin_count;
 154         data_size_bytes = ptsin_size_bytes + intin_size_bytes;
 155
 156         op.ptsin_pos = pos + 8;
 157         op.intin_pos = pos + 8 + ptsin_size_bytes;
 158
 159         opinfo = find_opcode_info(op.opcode);
 160         if(opinfo && opinfo->name)
 161                 opcode_name = opinfo->name;
 162         else
 163                 opcode_name = "?";
 164
 165         de_dbg(c, "opcode=%d (%s), func_id=%d, #pts=%d, #int=%d (dlen=%d)",
 166                 (int)op.opcode, opcode_name, (int)op.func_id,
 167                 (int)op.ptsin_count, (int)op.intin_count,
 168                 (int)data_size_bytes);
 169
 170         *bytesused = 8 + data_size_bytes;
 171
 172         if(opinfo && opinfo->fn) {
 173                 opinfo->fn(c, d, &op);
 174         }
 175
 176         if(op.opcode==65535) {
 177                 goto done;
 178         }
 179
 180         retval = 1;
 181 done:
 182         de_dbg_indent(c, -1);
 183         return retval;
 184 }
 185
 186 static void de_run_gemmeta(deark *c, de_module_params *mparams)
 187 {
 188         lctx *d = NULL;
 189         i64 pos;
 190         i64 hdrlen_words;
 191         i64 version;
 192         i64 imgflag;
 193         i64 bytesused;
 194
 195         d = de_malloc(c, sizeof(lctx));
 196
 197         pos = 0;
 198         hdrlen_words = de_getu16le(pos+2);
 199         de_dbg(c, "header length: %d words", (int)hdrlen_words);
 200         version = de_getu16le(pos+4);
 201         de_dbg(c, "version number: %d", (int)version);
 202         // TODO: Read more header fields.
 203         imgflag = de_getu16le(pos+28);
 204         de_dbg(c, "image flag: %d", (int)imgflag);
 205
 206         pos += hdrlen_words*2;
 207
 208         while(1) {
 209                 if(pos >= c->infile->len) break;
 210                 if(!do_record(c, d, pos, &bytesused)) break;
 211                 if(bytesused<=0) break;
 212                 pos += bytesused;
 213         }
 214         de_free(c, d);
 215 }
 216
 217 static int de_identify_gemmeta(deark *c)
 218 {
 219         // FIXME: This will not identify all files.
 220         if(!dbuf_memcmp(c->infile, 0, "\xff\xff\x18\x00", 4))
 221                 return 100;
 222         return 0;
 223 }
 224
 225 void de_module_gemmeta(deark *c, struct deark_module_info *mi)
 226 {
 227         mi->id = "gemmeta";
 228         mi->desc = "GEM VDI Metafile";
 229         mi->run_fn = de_run_gemmeta;
 230         mi->identify_fn = de_identify_gemmeta;
 231 }