blob: 3e216a78bb22ec23aae85033b37d2f70eb232ab1 (
plain) (
blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
|
/* G3 fax format declarations */
#ifndef G3_H_INCLUDED
#define G3_H_INCLUDED
/* G3 is nearly universal as the format for fax transmissions in the
US. Its full name is CCITT Group 3 (G3). It is specified in
Recommendations T.4 and T.30 and in EIA Standards EIA-465 and
EIA-466. It dates to 1993.
G3 faxes are 204 dots per inch (dpi) horizontally and 98 dpi (196
dpi optionally, in fine-detail mode) vertically. Since G3 neither
assumes error free transmission nor retransmits when errors occur,
the encoding scheme used is differential only over small segments
never exceeding 2 lines at standard resolution or 4 lines for
fine-detail. (The incremental G3 encoding scheme is called
two-dimensional and the number of lines so encoded is specified by
a parameter called k.)
G3 specifies much more than the format of the bit stream, which is
the subject of this header file. It also specifies layers
underneath the bit stream.
There is also the newer G4.
*/
#include "pm_config.h" /* uint32_t */
struct BitString {
/* A string of bits, up to as many fit in 32 bits. */
uint32_t intBuffer;
/* The bits are in the 'bitCount' least significant bit positions
of this number. The rest of the bits of this number are always
zero.
*/
unsigned int bitCount;
/* The length of the bit string */
/* Example: The bit string 010100 would be represented by
bitCount = 6, intBuffer = 20
(N.B. 20 = 00000000 00000000 00000000 00010100 in binary)
*/
};
#endif
|
