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209feeb0 H |
1 | /* (c) GPL 2007 Karel 'Clock' Kulhavy, Twibright Labs */ |
2 | ||
3 | #define MIN(x,y) ((x)<(y)?(x):(y)) | |
4 | #define MAX(x,y) ((x)>(y)?(x):(y)) | |
5 | ||
6 | #define BORDER 2 /* In pixels. Thickness of the border */ | |
7 | #define CHALF 3 /* Size of the cross half. Size of the cross is CHALF*2 x CHALF*2. | |
8 | */ | |
9 | #define CPITCH 24 /* Distance between cross centers */ | |
10 | ||
11 | /* XCROSSES A4 65, US Letter 67. */ | |
12 | #define XCROSSES 32 /* Number of crosses horizontally */ | |
13 | /* YCROSSES A4 93, US Letter 87. */ | |
14 | #define YCROSSES 46 /* Number of crosses vertically */ | |
15 | ||
16 | #define DATA_WIDTH (CPITCH*(XCROSSES-1)+2*CHALF) /* The rectangle occupied by | |
17 | the data and crosses */ | |
18 | #define DATA_HEIGHT (CPITCH*(YCROSSES-1)+2*CHALF) | |
19 | #define WIDTH (2*BORDER+DATA_WIDTH) /* In pixels, including the border */ | |
20 | /* In pixels, including the border and the label */ | |
21 | ||
22 | #define TEXT_WIDTH 13 /* Width of a single letter */ | |
23 | ||
24 | /* Definitions for seq2xy */ | |
25 | ||
26 | /* Properties of the narrow horizontal strip, with crosses */ | |
27 | #define NARROWHEIGHT (2*CHALF) | |
28 | #define GAPWIDTH (CPITCH-2*CHALF) | |
29 | #define NARROWWIDTH (GAPWIDTH*(XCROSSES-1)) /* Useful width */ | |
30 | #define NARROWPIXELS (NARROWHEIGHT*NARROWWIDTH) /* Useful pixels */ | |
31 | ||
32 | /* Properties of the wide horizontal strip, without crosses */ | |
33 | #define WIDEHEIGHT GAPWIDTH | |
34 | #define WIDEWIDTH (WIDTH-2*BORDER) | |
35 | #define WIDEPIXELS (WIDEHEIGHT*WIDEWIDTH) | |
36 | ||
37 | /* Amount of raw payload pixels in one narrow-wide strip pair */ | |
38 | #define REPHEIGHT (NARROWHEIGHT+WIDEHEIGHT) | |
39 | #define REPPIXELS (WIDEPIXELS+NARROWPIXELS) | |
40 | ||
41 | /* Total bits before hamming including the unused */ | |
42 | #define TOTALBITS ((long)REPPIXELS*(YCROSSES-1)+NARROWPIXELS) | |
43 | ||
44 | /* Hamming codes with parity */ | |
45 | #define FEC_ORDER 1 /* Can be 2 to 5 inclusive. | |
46 | 5 is 26/32, | |
47 | 4 is 11/16, | |
48 | 3 is 4/8, | |
49 | 2 is 4/1 | |
50 | 1 is golay codes */ | |
51 | #if FEC_ORDER==1 | |
52 | /* Golay */ | |
53 | #define FEC_LARGEBITS 24 | |
54 | #define FEC_SMALLBITS 12 | |
55 | #else | |
56 | /* Hamming */ | |
57 | #define FEC_LARGEBITS (1<<FEC_ORDER) | |
58 | #define FEC_SMALLBITS (FEC_LARGEBITS-1-FEC_ORDER) | |
59 | #endif | |
60 | ||
61 | /* Hamming net channel capacity */ | |
62 | #define FEC_SYMS (TOTALBITS/FEC_LARGEBITS) | |
63 | #define NETBITS (FEC_SYMS*FEC_SMALLBITS) /* Net payload bits */ | |
64 | #define USEDBITS (FEC_SYMS*FEC_LARGEBITS) /* Used raw bits to store | |
65 | Hamming symbols */ | |
66 | ||
67 | /* Functions from common.c */ | |
68 | extern unsigned long parity(unsigned long in); | |
69 | extern int is_cross(unsigned x, unsigned y); | |
70 | extern void seq2xy(int *x, int *y, unsigned seq); | |
71 | ||
72 | /* Counts number of '1' bits */ | |
73 | unsigned ones(unsigned long in); | |
74 | ||
75 | /* Golay codes */ | |
76 | unsigned long golay(unsigned long in); | |
77 | extern unsigned long golay_codes[4096]; |