/* Fax G3/G4 tables */ /* the first 2^(initialbits) entries map bit patterns to decodes let's say initial_bits is 8 for the sake of example and that the code is 1001 that means that entries 0x90 .. 0x9f have the entry { val, 4 } because those are all the bytes that start with the code and the 4 is the length of the code ... if (n_bits > initial_bits) ... anyway, in that case, it basically points to a mini table the n_bits is the maximum length of all codes beginning with that byte so 2^(n_bits - initial_bits) is the size of the mini-table peter came up with this, and it makes sense */ typedef struct cfd_node_s cfd_node; struct cfd_node_s { short val; short nbits; }; enum { cfd_white_initial_bits = 8, cfd_black_initial_bits = 7, cfd_2d_initial_bits = 7, cfd_uncompressed_initial_bits = 6 /* must be 6 */ }; /* non-run codes in tables */ enum { ERROR = -1, ZEROS = -2, /* EOL follows, possibly with more padding first */ UNCOMPRESSED = -3 }; /* semantic codes for cf_2d_decode */ enum { P = -4, H = -5, VR3 = 0, VR2 = 1, VR1 = 2, V0 = 3, VL1 = 4, VL2 = 5, VL3 = 6 }; /* Decoding tables */ extern const cfd_node cf_white_decode[]; extern const cfd_node cf_black_decode[]; extern const cfd_node cf_2d_decode[]; extern const cfd_node cf_uncompressed_decode[];