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
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155

//! Bit allocations for quantized amplitudes.

use consts::{MIN_HARMONICS, NUM_HARMONICS, MAX_QUANTIZED_AMPS};

/// Retrieve the set of quantized amplitude bit allocations B<sub>m</sub> and
/// max(B<sub>m</sub>) for the given harmonics parameter L.
pub fn allocs(harmonics: u32) -> (&'static [u8], u8) {
    let idx = harmonics as usize - MIN_HARMONICS;
    (&BITS[idx][..], MAX_BITS[idx])
}

/// Each BITS[l][k] represents the bit allocation B<sub>m</sub>, where m = 3 + k, for the
/// gain value G<sub>m-1</sub> when the harmonic parameter L = 9 + l.
///
/// For example, BITS[0][0] represents that B<sub>3</sub> = 10 when L = 9.
///
/// This is a concatenation of the Annex F and Annex G tables.
static BITS: [[u8; MAX_QUANTIZED_AMPS]; NUM_HARMONICS] = [
    [10, 9, 9, 9, 9, 9, 8, 7, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
    [ 9, 9, 8, 8, 8, 9, 7, 6, 5, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
    [ 8, 8, 8, 7, 7, 9, 7, 6, 5, 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
    [ 8, 7, 7, 7, 7, 8, 7, 6, 5, 4, 3, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
    [ 7, 7, 7, 6, 6, 7, 7, 6, 5, 4, 3, 3, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
    [ 7, 6, 6, 6, 6, 7, 7, 5, 4, 4, 3, 4, 3, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
    [ 7, 6, 6, 6, 5, 6, 7, 5, 4, 4, 3, 3, 3, 3, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
    [ 6, 6, 6, 5, 5, 6, 6, 5, 4, 4, 3, 3, 3, 3, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
    [ 6, 6, 5, 5, 5, 5, 5, 5, 4, 4, 4, 3, 3, 2, 3, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
    [ 6, 5, 5, 5, 5, 5, 4, 5, 5, 4, 3, 3, 3, 3, 2, 2, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
    [ 6, 5, 5, 4, 4, 5, 4, 5, 4, 4, 3, 3, 3, 3, 2, 3, 2, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
    [ 6, 5, 5, 4, 4, 5, 4, 5, 4, 4, 3, 3, 2, 3, 2, 1, 3, 2, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
    [ 5, 5, 5, 4, 4, 4, 4, 5, 4, 4, 3, 3, 2, 2, 3, 2, 1, 3, 2, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
    [ 5, 5, 4, 4, 4, 4, 4, 4, 4, 4, 3, 2, 3, 2, 2, 3, 2, 1, 2, 2, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
    [ 5, 4, 4, 4, 4, 4, 3, 4, 4, 3, 4, 3, 2, 3, 2, 2, 2, 2, 1, 2, 2, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
    [ 5, 4, 4, 4, 4, 4, 3, 3, 4, 3, 3, 3, 3, 2, 3, 2, 1, 2, 2, 1, 2, 2, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
    [ 5, 4, 4, 4, 3, 4, 3, 3, 4, 3, 3, 3, 3, 2, 3, 2, 1, 2, 2, 1, 2, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
    [ 5, 4, 4, 3, 3, 4, 3, 3, 4, 3, 3, 3, 2, 2, 3, 2, 1, 2, 2, 1, 1, 2, 2, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
    [ 5, 4, 4, 3, 3, 4, 3, 2, 4, 3, 2, 3, 2, 2, 3, 2, 2, 1, 2, 2, 1, 1, 2, 2, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
    [ 4, 4, 4, 3, 3, 4, 3, 2, 4, 3, 2, 3, 2, 2, 2, 3, 2, 1, 1, 2, 2, 1, 1, 2, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
    [ 4, 4, 4, 3, 3, 3, 3, 2, 4, 3, 2, 2, 3, 2, 2, 2, 3, 2, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
    [ 4, 4, 4, 3, 3, 3, 3, 2, 2, 3, 3, 2, 2, 3, 2, 2, 1, 3, 2, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
    [ 4, 4, 3, 3, 3, 3, 3, 2, 2, 3, 3, 2, 2, 3, 2, 2, 1, 2, 2, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
    [ 4, 4, 3, 3, 3, 3, 3, 2, 2, 3, 3, 2, 2, 3, 2, 2, 1, 2, 2, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
    [ 4, 3, 3, 3, 3, 3, 3, 2, 2, 3, 3, 2, 2, 3, 2, 1, 1, 2, 2, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
    [ 4, 3, 3, 3, 3, 3, 2, 2, 2, 3, 2, 2, 2, 3, 2, 2, 1, 1, 2, 2, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
    [ 4, 3, 3, 3, 3, 3, 2, 2, 2, 3, 2, 2, 2, 2, 3, 2, 1, 1, 1, 2, 2, 1, 1, 1, 2, 1, 1, 1, 0, 2, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
    [ 4, 3, 3, 3, 3, 3, 2, 2, 2, 1, 3, 2, 2, 2, 1, 3, 2, 1, 1, 1, 2, 2, 1, 1, 1, 2, 1, 1, 1, 0, 2, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
    [ 4, 3, 3, 3, 2, 3, 2, 2, 2, 1, 3, 2, 2, 2, 2, 3, 2, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 0, 2, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
    [ 4, 3, 3, 3, 2, 3, 2, 2, 2, 1, 3, 2, 2, 2, 1, 3, 2, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 0, 2, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
    [ 4, 3, 3, 3, 2, 3, 2, 2, 2, 1, 3, 2, 2, 2, 1, 3, 2, 1, 1, 1, 2, 2, 1, 1, 1, 0, 2, 1, 1, 1, 1, 0, 2, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
    [ 4, 3, 3, 3, 2, 3, 2, 2, 2, 1, 3, 2, 2, 1, 1, 3, 2, 1, 1, 1, 1, 2, 2, 1, 1, 1, 0, 2, 1, 1, 1, 1, 0, 2, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
    [ 4, 3, 3, 2, 2, 3, 2, 2, 1, 1, 3, 2, 2, 2, 1, 1, 3, 2, 1, 1, 1, 1, 2, 2, 1, 1, 1, 0, 2, 1, 1, 1, 1, 0, 2, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
    [ 4, 3, 3, 2, 2, 3, 2, 2, 2, 1, 1, 3, 2, 2, 2, 1, 1, 2, 2, 1, 1, 1, 1, 2, 2, 1, 1, 1, 0, 2, 1, 1, 1, 0, 0, 2, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
    [ 4, 3, 3, 2, 2, 3, 2, 2, 2, 1, 1, 3, 2, 2, 2, 1, 1, 2, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 0, 2, 1, 1, 1, 0, 0, 2, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
    [ 4, 3, 3, 2, 2, 3, 2, 2, 1, 1, 1, 3, 2, 2, 2, 1, 1, 2, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 0, 2, 1, 1, 1, 1, 0, 0, 2, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
    [ 4, 3, 3, 2, 2, 3, 2, 2, 1, 1, 1, 3, 2, 2, 1, 1, 1, 2, 2, 1, 1, 1, 1, 2, 2, 1, 1, 1, 0, 0, 2, 1, 1, 1, 1, 0, 0, 2, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
    [ 3, 3, 3, 2, 2, 3, 2, 2, 1, 1, 1, 3, 2, 2, 1, 1, 1, 2, 2, 1, 1, 1, 1, 1, 2, 2, 1, 1, 1, 0, 0, 2, 1, 1, 1, 1, 0, 0, 2, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
    [ 3, 3, 3, 2, 2, 3, 2, 2, 1, 1, 1, 3, 2, 2, 1, 1, 1, 1, 2, 2, 1, 1, 1, 1, 1, 2, 2, 1, 1, 1, 0, 0, 2, 1, 1, 1, 1, 0, 0, 2, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
    [ 3, 3, 3, 2, 2, 3, 2, 2, 1, 1, 1, 1, 3, 2, 2, 1, 1, 1, 1, 2, 2, 1, 1, 1, 1, 1, 2, 2, 1, 1, 1, 0, 0, 2, 1, 1, 1, 0, 0, 0, 2, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
    [ 3, 3, 3, 2, 2, 3, 2, 2, 1, 1, 1, 1, 3, 2, 2, 1, 1, 1, 1, 2, 2, 1, 1, 1, 1, 0, 2, 2, 1, 1, 1, 0, 0, 2, 1, 1, 1, 0, 0, 0, 2, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
    [ 3, 3, 3, 2, 2, 3, 2, 2, 1, 1, 1, 1, 3, 2, 2, 1, 1, 1, 1, 2, 2, 1, 1, 1, 1, 0, 2, 2, 1, 1, 1, 0, 0, 2, 1, 1, 1, 1, 0, 0, 0, 2, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
    [ 3, 3, 3, 2, 2, 3, 2, 2, 1, 1, 1, 1, 3, 2, 1, 1, 1, 1, 1, 2, 2, 1, 1, 1, 1, 0, 2, 2, 1, 1, 1, 0, 0, 0, 2, 1, 1, 1, 1, 0, 0, 0, 2, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0],
    [ 3, 3, 2, 2, 2, 3, 2, 1, 1, 1, 1, 1, 3, 2, 2, 1, 1, 1, 1, 2, 2, 1, 1, 1, 1, 1, 0, 2, 2, 1, 1, 1, 0, 0, 0, 2, 1, 1, 1, 1, 0, 0, 0, 2, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0],
    [ 3, 3, 2, 2, 2, 3, 2, 1, 1, 1, 1, 1, 3, 2, 2, 1, 1, 1, 1, 1, 2, 2, 1, 1, 1, 1, 1, 0, 2, 2, 1, 1, 1, 0, 0, 0, 2, 1, 1, 1, 1, 0, 0, 0, 2, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0],
    [ 3, 3, 2, 2, 2, 3, 2, 2, 1, 1, 1, 1, 0, 3, 2, 2, 1, 1, 1, 1, 0, 2, 2, 1, 1, 1, 1, 1, 0, 2, 2, 1, 1, 1, 0, 0, 0, 2, 1, 1, 1, 1, 0, 0, 0, 2, 1, 1, 1, 0, 0, 0, 0, 0, 0],
    [ 3, 3, 2, 2, 2, 3, 2, 2, 1, 1, 1, 1, 0, 3, 2, 2, 1, 1, 1, 1, 0, 2, 2, 1, 1, 1, 1, 1, 0, 2, 2, 1, 1, 1, 0, 0, 0, 2, 1, 1, 1, 0, 0, 0, 0, 2, 1, 1, 1, 1, 0, 0, 0, 0, 0],
    [ 3, 3, 2, 2, 2, 3, 2, 2, 1, 1, 1, 1, 0, 3, 2, 2, 1, 1, 1, 1, 0, 2, 2, 1, 1, 1, 1, 1, 0, 2, 2, 1, 1, 1, 0, 0, 0, 2, 1, 1, 1, 1, 0, 0, 0, 0, 2, 1, 1, 1, 0, 0, 0, 0, 0],
];

/// Each MAX_BITS[l] provides that maximum bit allocation for any B<sub>m</sub> when L = l
/// + 1.
const MAX_BITS: [u8; 48] = [
    10,
    9,
    9,
    8,
    7,
    7,
    7,
    6,
    6,
    6,
    6,
    6,
    5,
    5,
    5,
    5,
    5,
    5,
    5,
    4,
    4,
    4,
    4,
    4,
    4,
    4,
    4,
    4,
    4,
    4,
    4,
    4,
    4,
    4,
    4,
    4,
    4,
    3,
    3,
    3,
    3,
    3,
    3,
    3,
    3,
    3,
    3,
    3,
];

#[cfg(test)]
mod test {
    use super::*;

    #[test]
    fn verify_max_bits() {
        // Verify that the values in MAX_BITS are correct.

        for (&allocs, &max) in BITS.iter().zip(MAX_BITS.iter()) {
            assert_eq!(allocs.iter().max().unwrap(), &max);
        }
    }

    #[test]
    fn test_allocs() {
        // Couple verifications from Annex F/G

        let (bits, max) = allocs(13);
        assert_eq!(bits, &[
            7, 7, 7, 6, 6, 7, 7, 6, 5, 4, 3, 3,
            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
        ][..]);
        assert_eq!(max, 7);

        let (bits, max) = allocs(33);
        assert_eq!(bits, &[
            4, 3, 3, 3, 3, 3, 3, 2, 2, 3, 3, 2, 2, 3, 2, 1, 1, 2, 2, 1, 1, 1, 2, 1, 1, 1,
            1, 2, 1, 1, 1, 1,
            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
        ][..]);
        assert_eq!(max, 4);
    }
}