#[inline]
pub fn id_to_fieldnorm(id: u8) -> u32 {
FIELD_NORMS_TABLE[id as usize]
}
#[inline]
pub fn fieldnorm_to_id(fieldnorm: u32) -> u8 {
FIELD_NORMS_TABLE
.binary_search(&fieldnorm)
.unwrap_or_else(|idx| idx - 1) as u8
}
pub const FIELD_NORMS_TABLE: [u32; 256] = [
0,
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,
42,
44,
46,
48,
50,
52,
54,
56,
60,
64,
68,
72,
76,
80,
84,
88,
96,
104,
112,
120,
128,
136,
144,
152,
168,
184,
200,
216,
232,
248,
264,
280,
312,
344,
376,
408,
440,
472,
504,
536,
600,
664,
728,
792,
856,
920,
984,
1_048,
1_176,
1_304,
1_432,
1_560,
1_688,
1_816,
1_944,
2_072,
2_328,
2_584,
2_840,
3_096,
3_352,
3_608,
3_864,
4_120,
4_632,
5_144,
5_656,
6_168,
6_680,
7_192,
7_704,
8_216,
9_240,
10_264,
11_288,
12_312,
13_336,
14_360,
15_384,
16_408,
18_456,
20_504,
22_552,
24_600,
26_648,
28_696,
30_744,
32_792,
36_888,
40_984,
45_080,
49_176,
53_272,
57_368,
61_464,
65_560,
73_752,
81_944,
90_136,
98_328,
106_520,
114_712,
122_904,
131_096,
147_480,
163_864,
180_248,
196_632,
213_016,
229_400,
245_784,
262_168,
294_936,
327_704,
360_472,
393_240,
426_008,
458_776,
491_544,
524_312,
589_848,
655_384,
720_920,
786_456,
851_992,
917_528,
983_064,
1_048_600,
1_179_672,
1_310_744,
1_441_816,
1_572_888,
1_703_960,
1_835_032,
1_966_104,
2_097_176,
2_359_320,
2_621_464,
2_883_608,
3_145_752,
3_407_896,
3_670_040,
3_932_184,
4_194_328,
4_718_616,
5_242_904,
5_767_192,
6_291_480,
6_815_768,
7_340_056,
7_864_344,
8_388_632,
9_437_208,
10_485_784,
11_534_360,
12_582_936,
13_631_512,
14_680_088,
15_728_664,
16_777_240,
18_874_392,
20_971_544,
23_068_696,
25_165_848,
27_263_000,
29_360_152,
31_457_304,
33_554_456,
37_748_760,
41_943_064,
46_137_368,
50_331_672,
54_525_976,
58_720_280,
62_914_584,
67_108_888,
75_497_496,
83_886_104,
92_274_712,
100_663_320,
109_051_928,
117_440_536,
125_829_144,
134_217_752,
150_994_968,
167_772_184,
184_549_400,
201_326_616,
218_103_832,
234_881_048,
251_658_264,
268_435_480,
301_989_912,
335_544_344,
369_098_776,
402_653_208,
436_207_640,
469_762_072,
503_316_504,
536_870_936,
603_979_800,
671_088_664,
738_197_528,
805_306_392,
872_415_256,
939_524_120,
1_006_632_984,
1_073_741_848,
1_207_959_576,
1_342_177_304,
1_476_395_032,
1_610_612_760,
1_744_830_488,
1_879_048_216,
2_013_265_944,
];
#[cfg(test)]
mod tests {
use super::{fieldnorm_to_id, id_to_fieldnorm, FIELD_NORMS_TABLE};
#[test]
fn test_decode_code() {
assert_eq!(fieldnorm_to_id(0), 0);
assert_eq!(fieldnorm_to_id(1), 1);
for i in 0..41 {
assert_eq!(fieldnorm_to_id(i), i as u8);
}
assert_eq!(fieldnorm_to_id(41), 40);
assert_eq!(fieldnorm_to_id(42), 41);
for id in 43..256 {
let field_norm = FIELD_NORMS_TABLE[id];
assert_eq!(id_to_fieldnorm(id as u8), field_norm);
assert_eq!(fieldnorm_to_id(field_norm), id as u8);
assert_eq!(fieldnorm_to_id(field_norm - 1), id as u8 - 1);
assert_eq!(fieldnorm_to_id(field_norm + 1), id as u8);
}
}
#[test]
fn test_u32_max() {
assert_eq!(fieldnorm_to_id(u32::MAX), u8::MAX);
}
#[test]
fn test_fieldnorm_byte() {
const IDENTITY_PART: u8 = 24u8;
fn decode_field_norm_exp_part(b: u8) -> u32 {
let bits = (b & 0b00000111) as u32;
let shift = b >> 3;
if shift == 0 {
bits
} else {
(bits | 8u32) << ((shift - 1u8) as u32)
}
}
fn decode_fieldnorm_byte(b: u8) -> u32 {
if b < IDENTITY_PART {
b as u32
} else {
(IDENTITY_PART as u32) + decode_field_norm_exp_part(b - IDENTITY_PART)
}
}
for i in 0..256 {
assert_eq!(FIELD_NORMS_TABLE[i], decode_fieldnorm_byte(i as u8));
}
}
}