jpeg_turbod.decompress source code

1 module jpeg_turbod.decompress;
2 
3 import jpeg_turbod.libjpeg_turbo;
4 
5 class Decompressor
6 {
7     private
8     {
9         tjhandle decompressor;
10         int width, height, jpegSubsamp, jpegColorspace;
11         enum int rgbPixelSize = 3;
12     }
13 
14     this()
15     {
16         decompressor = tjInitDecompress();
17     }
18 
19     ~this()
20     {
21         tjDestroy(decompressor);
22     }
23 
24     final char[] errorInfo()
25     {
26         import std.string : fromStringz;
27 
28         return fromStringz(tjGetErrorStr2(decompressor));
29     }
30 
31     final bool decompress(in ubyte[] jpeg, ref ubyte[] pixels, out int width, out int height)
32     {
33         auto jpegLength = cast(int) jpeg.length;
34 
35         auto result = tjDecompressHeader3(decompressor, jpeg.ptr, jpegLength,
36                 &width, &height, &jpegSubsamp, &jpegColorspace);
37 
38         if (result == -1)
39         {
40             return false;
41         }
42 
43         width = width;
44         height = height;
45 
46         if (pixels.length != width * height * rgbPixelSize)
47         {
48             pixels.length = width * height * rgbPixelSize;
49         }
50 
51         result = tjDecompress2(decompressor, jpeg.ptr, jpegLength, pixels.ptr,
52                 width, 0, height, TJPF.TJPF_RGB, TJFLAG_ACCURATEDCT);
53 
54         return result == 0;
55     }
56 }