modules/msp.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 // Microsoft Paint
   6
   7 #include <deark-config.h>
   8 #include <deark-private.h>
   9 DE_DECLARE_MODULE(de_module_msp);
  10
  11 typedef struct localctx_struct {
  12         int ver; // 1 or 2
  13         i64 width, height;
  14         dbuf *rowbuf;
  15 } lctx;
  16
  17 static void do_ver1(deark *c, lctx *d)
  18 {
  19         i64 src_rowspan;
  20
  21         // TODO: Are version-1 MSP files padded this way?
  22         // (Maybe the width is always a multiple of 8, so it doesn't matter.)
  23         src_rowspan = (d->width+7)/8;
  24
  25         de_convert_and_write_image_bilevel(c->infile, 32,
  26                 d->width, d->height, src_rowspan, 0, NULL, 0);
  27 }
  28
  29 static void do_decompress_scanline(deark *c, lctx *d, de_bitmap *img,
  30         i64 rownum, i64 rowoffset, i64 bytes_in_row)
  31 {
  32         i64 i;
  33         u8 runtype;
  34         i64 runcount;
  35         u8 value;
  36
  37         de_dbg2(c, "decompressing row %d", (int)rownum);
  38
  39         if(!d->rowbuf) {
  40                 d->rowbuf = dbuf_create_membuf(c, (d->width+7)/8, 1);
  41         }
  42
  43         dbuf_empty(d->rowbuf);
  44
  45         // Read the compressed data byte by byte
  46         i = 0;
  47         while(i<bytes_in_row) {
  48                 runtype = de_getbyte(rowoffset+i);
  49                 i++;
  50                 if(runtype==0x00) {
  51                         runcount = (i64)de_getbyte(rowoffset+i);
  52                         i++;
  53                         value = de_getbyte(rowoffset+i);
  54                         i++;
  55                         // write value runcount times
  56                         de_dbg2(c, "compressed, %d bytes of %d", (int)runcount, value);
  57                         dbuf_write_run(d->rowbuf, value, runcount);
  58                 }
  59                 else {
  60                         runcount = (i64)runtype;
  61                         de_dbg2(c, "%d bytes uncompressed", (int)runcount);
  62                         dbuf_copy(c->infile, rowoffset+i, runcount, d->rowbuf);
  63                         i+=runcount;
  64                 }
  65         }
  66
  67         de_convert_row_bilevel(d->rowbuf, 0, img, rownum, 0);
  68 }
  69
  70 static void do_ver2(deark *c, lctx *d)
  71 {
  72         i64 j;
  73         i64 *rowoffset;
  74         i64 *rowsize;
  75         de_bitmap *img = NULL;
  76
  77         rowoffset = de_mallocarray(c, d->height, sizeof(i64));
  78         rowsize = de_mallocarray(c, d->height, sizeof(i64));
  79
  80         // Read the scanline map, and record the row sizes.
  81         for(j=0; j<d->height; j++) {
  82                 rowsize[j] = de_getu16le(32+2*j);
  83         }
  84
  85         // Calculate the position, in the file, of each row.
  86         for(j=0; j<d->height; j++) {
  87                 if(j==0)
  88                         rowoffset[j] = 32 + 2*d->height;
  89                 else
  90                         rowoffset[j] = rowoffset[j-1] + rowsize[j-1];
  91                 de_dbg2(c, "row %d offset=%d size=%d", (int)j, (int)rowoffset[j], (int)rowsize[j]);
  92         }
  93
  94         img = de_bitmap_create(c, d->width, d->height, 1);
  95
  96         for(j=0; j<d->height; j++) {
  97                 do_decompress_scanline(c, d, img, j, rowoffset[j], rowsize[j]);
  98         }
  99
 100         de_bitmap_write_to_file(img, NULL, 0);
 101
 102         de_free(c, rowsize);
 103         de_free(c, rowoffset);
 104         dbuf_close(d->rowbuf);
 105         d->rowbuf = NULL;
 106         de_bitmap_destroy(img);
 107 }
 108
 109 static void de_run_msp(deark *c, de_module_params *mparams)
 110 {
 111         lctx *d;
 112
 113         d = de_malloc(c, sizeof(lctx));
 114
 115         d->ver = de_getbyte(0) == 0x4c ? 2 : 1;
 116         de_dbg(c, "version: %d", d->ver);
 117         de_declare_fmtf(c, "MS Paint v%d", d->ver);
 118
 119         d->width = de_getu16le(4);
 120         d->height = de_getu16le(6);
 121         de_dbg_dimensions(c, d->width, d->height);
 122
 123         if(d->ver==1) {
 124                 do_ver1(c, d);
 125         }
 126         else {
 127                 do_ver2(c, d);
 128         }
 129
 130         de_free(c, d);
 131 }
 132
 133 static int de_identify_msp(deark *c)
 134 {
 135         u8 b[4];
 136         de_read(b, 0, 4);
 137
 138         if(b[0]==0x44 && b[1]==0x61 && b[2]==0x6e && b[3]==0x4d)
 139                 return 100;
 140         if(b[0]==0x4c && b[1]==0x69 && b[2]==0x6e && b[3]==0x53)
 141                 return 100;
 142         return 0;
 143 }
 144
 145 void de_module_msp(deark *c, struct deark_module_info *mi)
 146 {
 147         mi->id = "msp";
 148         mi->desc = "Microsoft Paint image";
 149         mi->run_fn = de_run_msp;
 150         mi->identify_fn = de_identify_msp;
 151 }