1/*
2 * Copyright (c) 1990 James Ashton - Sydney University
3 * Copyright (c) 2012 Stefano Sabatini
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 * @file
24 * X-Face decoder, based on libcompface, by James Ashton.
25 */
26
27#include "libavutil/pixdesc.h"
28#include "avcodec.h"
29#include "bytestream.h"
30#include "internal.h"
31#include "xface.h"
32
33static int pop_integer(BigInt *b, const ProbRange *pranges)
34{
35    uint8_t r;
36    int i;
37
38    /* extract the last byte into r, and shift right b by 8 bits */
39    ff_big_div(b, 0, &r);
40
41    i = 0;
42    while (r < pranges->offset || r >= pranges->range + pranges->offset) {
43        pranges++;
44        i++;
45    }
46    ff_big_mul(b, pranges->range);
47    ff_big_add(b, r - pranges->offset);
48    return i;
49}
50
51static void pop_greys(BigInt *b, char *bitmap, int w, int h)
52{
53    if (w > 3) {
54        w /= 2;
55        h /= 2;
56        pop_greys(b, bitmap,                       w, h);
57        pop_greys(b, bitmap + w,                   w, h);
58        pop_greys(b, bitmap + XFACE_WIDTH * h,     w, h);
59        pop_greys(b, bitmap + XFACE_WIDTH * h + w, w, h);
60    } else {
61        w = pop_integer(b, ff_xface_probranges_2x2);
62        if (w & 1) bitmap[0]               = 1;
63        if (w & 2) bitmap[1]               = 1;
64        if (w & 4) bitmap[XFACE_WIDTH]     = 1;
65        if (w & 8) bitmap[XFACE_WIDTH + 1] = 1;
66    }
67}
68
69static void decode_block(BigInt *b, char *bitmap, int w, int h, int level)
70{
71    switch (pop_integer(b, &ff_xface_probranges_per_level[level][0])) {
72    case XFACE_COLOR_WHITE:
73        return;
74    case XFACE_COLOR_BLACK:
75        pop_greys(b, bitmap, w, h);
76        return;
77    default:
78        w /= 2;
79        h /= 2;
80        level++;
81        decode_block(b, bitmap,                       w, h, level);
82        decode_block(b, bitmap + w,                   w, h, level);
83        decode_block(b, bitmap + h * XFACE_WIDTH,     w, h, level);
84        decode_block(b, bitmap + w + h * XFACE_WIDTH, w, h, level);
85        return;
86    }
87}
88
89typedef struct XFaceContext {
90    uint8_t bitmap[XFACE_PIXELS]; ///< image used internally for decoding
91} XFaceContext;
92
93static av_cold int xface_decode_init(AVCodecContext *avctx)
94{
95    if (avctx->width || avctx->height) {
96        if (avctx->width != XFACE_WIDTH || avctx->height != XFACE_HEIGHT) {
97            av_log(avctx, AV_LOG_ERROR,
98                   "Size value %dx%d not supported, only accepts a size of %dx%d\n",
99                   avctx->width, avctx->height, XFACE_WIDTH, XFACE_HEIGHT);
100            return AVERROR(EINVAL);
101        }
102    }
103
104    avctx->width   = XFACE_WIDTH;
105    avctx->height  = XFACE_HEIGHT;
106    avctx->pix_fmt = AV_PIX_FMT_MONOWHITE;
107
108    return 0;
109}
110
111static int xface_decode_frame(AVCodecContext *avctx,
112                              void *data, int *got_frame,
113                              AVPacket *avpkt)
114{
115    XFaceContext *xface = avctx->priv_data;
116    int ret, i, j, k;
117    uint8_t byte;
118    BigInt b = {0};
119    char *buf;
120    int64_t c;
121    AVFrame *frame = data;
122
123    if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
124        return ret;
125
126    for (i = 0, k = 0; avpkt->data[i] && i < avpkt->size; i++) {
127        c = avpkt->data[i];
128
129        /* ignore invalid digits */
130        if (c < XFACE_FIRST_PRINT || c > XFACE_LAST_PRINT)
131            continue;
132
133        if (++k > XFACE_MAX_DIGITS) {
134            av_log(avctx, AV_LOG_WARNING,
135                   "Buffer is longer than expected, truncating at byte %d\n", i);
136            break;
137        }
138        ff_big_mul(&b, XFACE_PRINTS);
139        ff_big_add(&b, c - XFACE_FIRST_PRINT);
140    }
141
142    /* decode image and put it in bitmap */
143    memset(xface->bitmap, 0, XFACE_PIXELS);
144    buf = xface->bitmap;
145    decode_block(&b, buf,                         16, 16, 0);
146    decode_block(&b, buf + 16,                    16, 16, 0);
147    decode_block(&b, buf + 32,                    16, 16, 0);
148    decode_block(&b, buf + XFACE_WIDTH * 16,      16, 16, 0);
149    decode_block(&b, buf + XFACE_WIDTH * 16 + 16, 16, 16, 0);
150    decode_block(&b, buf + XFACE_WIDTH * 16 + 32, 16, 16, 0);
151    decode_block(&b, buf + XFACE_WIDTH * 32     , 16, 16, 0);
152    decode_block(&b, buf + XFACE_WIDTH * 32 + 16, 16, 16, 0);
153    decode_block(&b, buf + XFACE_WIDTH * 32 + 32, 16, 16, 0);
154
155    ff_xface_generate_face(xface->bitmap, xface->bitmap);
156
157    /* convert image from 1=black 0=white bitmap to MONOWHITE */
158    buf = frame->data[0];
159    for (i = 0, j = 0, k = 0, byte = 0; i < XFACE_PIXELS; i++) {
160        byte += xface->bitmap[i];
161        if (k == 7) {
162            buf[j++] = byte;
163            byte = k = 0;
164        } else {
165            k++;
166            byte <<= 1;
167        }
168        if (j == XFACE_WIDTH/8) {
169            j = 0;
170            buf += frame->linesize[0];
171        }
172    }
173
174    *got_frame = 1;
175
176    return avpkt->size;
177}
178
179AVCodec ff_xface_decoder = {
180    .name           = "xface",
181    .long_name      = NULL_IF_CONFIG_SMALL("X-face image"),
182    .type           = AVMEDIA_TYPE_VIDEO,
183    .id             = AV_CODEC_ID_XFACE,
184    .priv_data_size = sizeof(XFaceContext),
185    .init           = xface_decode_init,
186    .decode         = xface_decode_frame,
187    .pix_fmts       = (const enum AVPixelFormat[]) { AV_PIX_FMT_MONOWHITE, AV_PIX_FMT_NONE },
188};
189