1/*
2 * JPEG-LS common code
3 * Copyright (c) 2003 Michael Niedermayer
4 * Copyright (c) 2006 Konstantin Shishkov
5 *
6 * This file is part of FFmpeg.
7 *
8 * FFmpeg is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
12 *
13 * FFmpeg is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with FFmpeg; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23/**
24 * @file
25 * JPEG-LS common code.
26 */
27
28#ifndef AVCODEC_JPEGLS_H
29#define AVCODEC_JPEGLS_H
30
31#include "libavutil/common.h"
32#include "avcodec.h"
33#include "internal.h"
34
35typedef struct JpeglsContext {
36    AVCodecContext *avctx;
37} JpeglsContext;
38
39typedef struct JLSState {
40    int T1, T2, T3;
41    int A[367], B[367], C[365], N[367];
42    int limit, reset, bpp, qbpp, maxval, range;
43    int near, twonear;
44    int run_index[4];
45} JLSState;
46
47/**
48 * Calculate initial JPEG-LS parameters
49 */
50void ff_jpegls_init_state(JLSState *state);
51
52/**
53 * Calculate quantized gradient value, used for context determination
54 */
55static inline int ff_jpegls_quantize(JLSState *s, int v)
56{
57    if (v == 0)
58        return 0;
59    if (v < 0) {
60        if (v <= -s->T3)
61            return -4;
62        if (v <= -s->T2)
63            return -3;
64        if (v <= -s->T1)
65            return -2;
66        if (v < -s->near)
67            return -1;
68        return 0;
69    } else {
70        if (v <= s->near)
71            return 0;
72        if (v < s->T1)
73            return 1;
74        if (v < s->T2)
75            return 2;
76        if (v < s->T3)
77            return 3;
78        return 4;
79    }
80}
81
82/**
83 * Calculate JPEG-LS codec values
84 */
85void ff_jpegls_reset_coding_parameters(JLSState *s, int reset_all);
86
87static inline void ff_jpegls_downscale_state(JLSState *state, int Q)
88{
89    if (state->N[Q] == state->reset) {
90        state->A[Q] >>= 1;
91        state->B[Q] >>= 1;
92        state->N[Q] >>= 1;
93    }
94    state->N[Q]++;
95}
96
97static inline int ff_jpegls_update_state_regular(JLSState *state,
98                                                 int Q, int err)
99{
100    if(FFABS(err) > 0xFFFF)
101        return -0x10000;
102    state->A[Q] += FFABS(err);
103    err         *= state->twonear;
104    state->B[Q] += err;
105
106    ff_jpegls_downscale_state(state, Q);
107
108    if (state->B[Q] <= -state->N[Q]) {
109        state->B[Q] = FFMAX(state->B[Q] + state->N[Q], 1 - state->N[Q]);
110        if (state->C[Q] > -128)
111            state->C[Q]--;
112    } else if (state->B[Q] > 0) {
113        state->B[Q] = FFMIN(state->B[Q] - state->N[Q], 0);
114        if (state->C[Q] < 127)
115            state->C[Q]++;
116    }
117
118    return err;
119}
120
121#define R(a, i)    (bits == 8 ?  ((uint8_t *)(a))[i]      :  ((uint16_t *)(a))[i])
122#define W(a, i, v) (bits == 8 ? (((uint8_t *)(a))[i] = v) : (((uint16_t *)(a))[i] = v))
123
124#endif /* AVCODEC_JPEGLS_H */
125