/src/dcmtk/dcmjpls/libcharls/ctxtrmod.h
Line | Count | Source |
1 | | // |
2 | | // (C) Jan de Vaan 2007-2010, all rights reserved. See the accompanying "License.txt" for licensed use. |
3 | | // |
4 | | |
5 | | |
6 | | #ifndef CHARLS_CONTEXTRUNMODE |
7 | | #define CHARLS_CONTEXTRUNMODE |
8 | | |
9 | | // Implements statistical modelling for the run mode context. |
10 | | // Computes model dependent parameters like the golomb code lengths |
11 | | |
12 | | struct CContextRunMode |
13 | | { |
14 | | CContextRunMode(LONG a, LONG nRItype, LONG nReset) : |
15 | 0 | A(a), |
16 | 0 | N(1), |
17 | 0 | Nn(0), |
18 | 0 | _nRItype(nRItype), |
19 | 0 | _nReset((BYTE)nReset) |
20 | 0 | { |
21 | 0 | } |
22 | | |
23 | | LONG A; |
24 | | BYTE N; |
25 | | BYTE Nn; |
26 | | LONG _nRItype; |
27 | | BYTE _nReset; |
28 | | |
29 | | CContextRunMode() |
30 | 0 | {} |
31 | | |
32 | | |
33 | | inlinehint LONG GetGolomb() const |
34 | 0 | { |
35 | 0 | LONG Ntest = N; |
36 | 0 | LONG TEMP = A + (N >> 1) * _nRItype; |
37 | 0 | LONG k = 0; |
38 | 0 | for(; Ntest < TEMP; k++) |
39 | 0 | { |
40 | 0 | Ntest <<= 1; |
41 | 0 | ASSERT(k <= 32); |
42 | 0 | }; |
43 | 0 | return k; |
44 | 0 | } |
45 | | |
46 | | |
47 | | void UpdateVariables(LONG Errval, LONG EMErrval) |
48 | 0 | { |
49 | 0 | if (Errval < 0) |
50 | 0 | { |
51 | 0 | Nn = Nn + 1; |
52 | 0 | } |
53 | 0 | A = A + ((EMErrval + 1 - _nRItype) >> 1); |
54 | 0 | if (N == _nReset) |
55 | 0 | { |
56 | 0 | A = A >> 1; |
57 | 0 | N = N >> 1; |
58 | 0 | Nn = Nn >> 1; |
59 | 0 | } |
60 | 0 | N = N + 1; |
61 | 0 | } |
62 | | |
63 | | inlinehint LONG ComputeErrVal(LONG temp, LONG k) |
64 | 0 | { |
65 | 0 | bool map = temp & 1; |
66 | |
|
67 | 0 | LONG errvalabs = (temp + map) / 2; |
68 | |
|
69 | 0 | if ((k != 0 || (2 * Nn >= N)) == map) |
70 | 0 | { |
71 | 0 | ASSERT(map == ComputeMap(-errvalabs, k)); |
72 | 0 | return -errvalabs; |
73 | 0 | } |
74 | | |
75 | 0 | ASSERT(map == ComputeMap(errvalabs, k)); |
76 | 0 | return errvalabs; |
77 | 0 | } |
78 | | |
79 | | |
80 | | bool ComputeMap(LONG Errval, LONG k) const |
81 | 0 | { |
82 | 0 | if ((k == 0) && (Errval > 0) && (2 * Nn < N)) |
83 | 0 | return 1; |
84 | | |
85 | 0 | else if ((Errval < 0) && (2 * Nn >= N)) |
86 | 0 | return 1; |
87 | | |
88 | 0 | else if ((Errval < 0) && (k != 0)) |
89 | 0 | return 1; |
90 | | |
91 | 0 | return 0; |
92 | 0 | } |
93 | | |
94 | | |
95 | | inlinehint LONG ComputeMapNegativeE(LONG k) const |
96 | 0 | { |
97 | 0 | return k != 0 || (2 * Nn >= N ); |
98 | 0 | } |
99 | | }; |
100 | | |
101 | | #endif |