1/*
2 * PNM image format
3 * Copyright (c) 2002, 2003 Fabrice Bellard
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#include "avcodec.h"
22#include "pnm.h"
23
24static inline int pnm_space(int c)
25{
26    return c == ' ' || c == '\n' || c == '\r' || c == '\t';
27}
28
29static void pnm_get(PNMContext *sc, char *str, int buf_size)
30{
31    char *s;
32    int c;
33
34    /* skip spaces and comments */
35    for(;;) {
36        c = *sc->bytestream++;
37        if (c == '#')  {
38            do  {
39                c = *sc->bytestream++;
40            } while (c != '\n' && sc->bytestream < sc->bytestream_end);
41        } else if (!pnm_space(c)) {
42            break;
43        }
44    }
45
46    s = str;
47    while (sc->bytestream < sc->bytestream_end && !pnm_space(c)) {
48        if ((s - str)  < buf_size - 1)
49            *s++ = c;
50        c = *sc->bytestream++;
51    }
52    *s = '\0';
53}
54
55int ff_pnm_decode_header(AVCodecContext *avctx, PNMContext * const s){
56    char buf1[32], tuple_type[32];
57    int h, w, depth, maxval;
58
59    pnm_get(s, buf1, sizeof(buf1));
60    if (!strcmp(buf1, "P4")) {
61        avctx->pix_fmt = PIX_FMT_MONOWHITE;
62    } else if (!strcmp(buf1, "P5")) {
63        if (avctx->codec_id == CODEC_ID_PGMYUV)
64            avctx->pix_fmt = PIX_FMT_YUV420P;
65        else
66            avctx->pix_fmt = PIX_FMT_GRAY8;
67    } else if (!strcmp(buf1, "P6")) {
68        avctx->pix_fmt = PIX_FMT_RGB24;
69    } else if (!strcmp(buf1, "P7")) {
70        w = -1;
71        h = -1;
72        maxval = -1;
73        depth = -1;
74        tuple_type[0] = '\0';
75        for(;;) {
76            pnm_get(s, buf1, sizeof(buf1));
77            if (!strcmp(buf1, "WIDTH")) {
78                pnm_get(s, buf1, sizeof(buf1));
79                w = strtol(buf1, NULL, 10);
80            } else if (!strcmp(buf1, "HEIGHT")) {
81                pnm_get(s, buf1, sizeof(buf1));
82                h = strtol(buf1, NULL, 10);
83            } else if (!strcmp(buf1, "DEPTH")) {
84                pnm_get(s, buf1, sizeof(buf1));
85                depth = strtol(buf1, NULL, 10);
86            } else if (!strcmp(buf1, "MAXVAL")) {
87                pnm_get(s, buf1, sizeof(buf1));
88                maxval = strtol(buf1, NULL, 10);
89            } else if (!strcmp(buf1, "TUPLETYPE")) {
90                pnm_get(s, tuple_type, sizeof(tuple_type));
91            } else if (!strcmp(buf1, "ENDHDR")) {
92                break;
93            } else {
94                return -1;
95            }
96        }
97        /* check that all tags are present */
98        if (w <= 0 || h <= 0 || maxval <= 0 || depth <= 0 || tuple_type[0] == '\0' || avcodec_check_dimensions(avctx, w, h))
99            return -1;
100
101        avctx->width = w;
102        avctx->height = h;
103        if (depth == 1) {
104            if (maxval == 1)
105                avctx->pix_fmt = PIX_FMT_MONOWHITE;
106            else
107                avctx->pix_fmt = PIX_FMT_GRAY8;
108        } else if (depth == 3) {
109            if (maxval < 256) {
110            avctx->pix_fmt = PIX_FMT_RGB24;
111            } else {
112                av_log(avctx, AV_LOG_ERROR, "16-bit components are only supported for grayscale\n");
113                avctx->pix_fmt = PIX_FMT_NONE;
114                return -1;
115            }
116        } else if (depth == 4) {
117            avctx->pix_fmt = PIX_FMT_RGB32;
118        } else {
119            return -1;
120        }
121        return 0;
122    } else {
123        return -1;
124    }
125    pnm_get(s, buf1, sizeof(buf1));
126    avctx->width = atoi(buf1);
127    if (avctx->width <= 0)
128        return -1;
129    pnm_get(s, buf1, sizeof(buf1));
130    avctx->height = atoi(buf1);
131    if(avcodec_check_dimensions(avctx, avctx->width, avctx->height))
132        return -1;
133    if (avctx->pix_fmt != PIX_FMT_MONOWHITE) {
134        pnm_get(s, buf1, sizeof(buf1));
135        s->maxval = atoi(buf1);
136        if (s->maxval >= 256) {
137            if (avctx->pix_fmt == PIX_FMT_GRAY8) {
138                avctx->pix_fmt = PIX_FMT_GRAY16BE;
139                if (s->maxval != 65535)
140                    avctx->pix_fmt = PIX_FMT_GRAY16;
141            } if (avctx->pix_fmt == PIX_FMT_RGB24) {
142                if (s->maxval > 255)
143                    avctx->pix_fmt = PIX_FMT_RGB48BE;
144            } else {
145                av_log(avctx, AV_LOG_ERROR, "Unsupported pixel format\n");
146                avctx->pix_fmt = PIX_FMT_NONE;
147                return -1;
148            }
149        }
150    }
151    /* more check if YUV420 */
152    if (avctx->pix_fmt == PIX_FMT_YUV420P) {
153        if ((avctx->width & 1) != 0)
154            return -1;
155        h = (avctx->height * 2);
156        if ((h % 3) != 0)
157            return -1;
158        h /= 3;
159        avctx->height = h;
160    }
161    return 0;
162}
163