1/*
2 * MQ-coder encoder
3 * Copyright (c) 2007 Kamil Nowosad
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22/**
23 * MQ-coder encoder
24 * @file
25 * @author Kamil Nowosad
26 */
27
28#include "mqc.h"
29
30static void byteout(MqcState *mqc)
31{
32retry:
33    if (*mqc->bp == 0xff){
34        mqc->bp++;
35        *mqc->bp = mqc->c >> 20;
36        mqc->c &= 0xfffff;
37        mqc->ct = 7;
38    } else if ((mqc->c & 0x8000000)){
39        (*mqc->bp)++;
40        mqc->c &= 0x7ffffff;
41        goto retry;
42    } else{
43        mqc->bp++;
44        *mqc->bp = mqc->c >> 19;
45        mqc->c &= 0x7ffff;
46        mqc->ct = 8;
47    }
48}
49
50static void renorme(MqcState *mqc)
51{
52    do{
53        mqc->a += mqc->a;
54        mqc->c += mqc->c;
55        if (!--mqc->ct)
56            byteout(mqc);
57    } while (!(mqc->a & 0x8000));
58}
59
60static void setbits(MqcState *mqc)
61{
62    int tmp = mqc->c + mqc->a;
63    mqc->c |= 0xffff;
64    if (mqc->c >= tmp)
65        mqc->c -= 0x8000;
66}
67
68void ff_mqc_initenc(MqcState *mqc, uint8_t *bp)
69{
70    ff_mqc_init_contexts(mqc);
71    mqc->a = 0x8000;
72    mqc->c = 0;
73    mqc->bp = bp-1;
74    mqc->bpstart = bp;
75    mqc->ct = 12 + (*mqc->bp == 0xff);
76}
77
78void ff_mqc_encode(MqcState *mqc, uint8_t *cxstate, int d)
79{
80    int qe;
81
82    qe = ff_mqc_qe[*cxstate];
83    mqc->a -= qe;
84    if ((*cxstate & 1) == d){
85        if (!(mqc->a & 0x8000)){
86            if (mqc->a < qe)
87                mqc->a = qe;
88            else
89                mqc->c += qe;
90            *cxstate = ff_mqc_nmps[*cxstate];
91            renorme(mqc);
92        } else
93            mqc->c += qe;
94    } else{
95        if (mqc->a < qe)
96            mqc->c += qe;
97        else
98            mqc->a = qe;
99        *cxstate = ff_mqc_nlps[*cxstate];
100        renorme(mqc);
101    }
102}
103
104int ff_mqc_length(MqcState *mqc)
105{
106    return mqc->bp - mqc->bpstart;
107}
108
109int ff_mqc_flush(MqcState *mqc)
110{
111    setbits(mqc);
112    mqc->c = mqc->c << mqc->ct;
113    byteout(mqc);
114    mqc->c = mqc->c << mqc->ct;
115    byteout(mqc);
116    if (*mqc->bp != 0xff)
117        mqc->bp++;
118    return mqc->bp - mqc->bpstart;
119}
120