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ffmpeg / libavcodec / pnm.c @ 9ac2e797

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/*
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 * PNM image format
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 * Copyright (c) 2002, 2003 Fabrice Bellard.
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 *
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 * This file is part of FFmpeg.
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 *
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 * FFmpeg is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * FFmpeg is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with FFmpeg; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
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#include "avcodec.h"
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#include "pnm.h"
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static inline int pnm_space(int c)
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{
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    return (c == ' ' || c == '\n' || c == '\r' || c == '\t');
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}
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static void pnm_get(PNMContext *sc, char *str, int buf_size)
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{
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    char *s;
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    int c;
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    /* skip spaces and comments */
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    for(;;) {
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        c = *sc->bytestream++;
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        if (c == '#')  {
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            do  {
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                c = *sc->bytestream++;
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            } while (c != '\n' && sc->bytestream < sc->bytestream_end);
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        } else if (!pnm_space(c)) {
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            break;
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        }
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    }
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    s = str;
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    while (sc->bytestream < sc->bytestream_end && !pnm_space(c)) {
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        if ((s - str)  < buf_size - 1)
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            *s++ = c;
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        c = *sc->bytestream++;
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    }
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    *s = '\0';
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}
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int ff_pnm_decode_header(AVCodecContext *avctx, PNMContext * const s){
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    char buf1[32], tuple_type[32];
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    int h, w, depth, maxval;
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    pnm_get(s, buf1, sizeof(buf1));
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    if (!strcmp(buf1, "P4")) {
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        avctx->pix_fmt = PIX_FMT_MONOWHITE;
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    } else if (!strcmp(buf1, "P5")) {
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        if (avctx->codec_id == CODEC_ID_PGMYUV)
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            avctx->pix_fmt = PIX_FMT_YUV420P;
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        else
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            avctx->pix_fmt = PIX_FMT_GRAY8;
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    } else if (!strcmp(buf1, "P6")) {
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        avctx->pix_fmt = PIX_FMT_RGB24;
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    } else if (!strcmp(buf1, "P7")) {
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        w = -1;
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        h = -1;
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        maxval = -1;
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        depth = -1;
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        tuple_type[0] = '\0';
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        for(;;) {
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            pnm_get(s, buf1, sizeof(buf1));
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            if (!strcmp(buf1, "WIDTH")) {
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                pnm_get(s, buf1, sizeof(buf1));
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                w = strtol(buf1, NULL, 10);
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            } else if (!strcmp(buf1, "HEIGHT")) {
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                pnm_get(s, buf1, sizeof(buf1));
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                h = strtol(buf1, NULL, 10);
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            } else if (!strcmp(buf1, "DEPTH")) {
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                pnm_get(s, buf1, sizeof(buf1));
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                depth = strtol(buf1, NULL, 10);
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            } else if (!strcmp(buf1, "MAXVAL")) {
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                pnm_get(s, buf1, sizeof(buf1));
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                maxval = strtol(buf1, NULL, 10);
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            } else if (!strcmp(buf1, "TUPLETYPE")) {
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                pnm_get(s, tuple_type, sizeof(tuple_type));
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            } else if (!strcmp(buf1, "ENDHDR")) {
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                break;
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            } else {
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                return -1;
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            }
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        }
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        /* check that all tags are present */
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        if (w <= 0 || h <= 0 || maxval <= 0 || depth <= 0 || tuple_type[0] == '\0' || avcodec_check_dimensions(avctx, w, h))
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            return -1;
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        avctx->width = w;
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        avctx->height = h;
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        if (depth == 1) {
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            if (maxval == 1)
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                avctx->pix_fmt = PIX_FMT_MONOWHITE;
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            else
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                avctx->pix_fmt = PIX_FMT_GRAY8;
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        } else if (depth == 3) {
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            avctx->pix_fmt = PIX_FMT_RGB24;
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        } else if (depth == 4) {
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            avctx->pix_fmt = PIX_FMT_RGB32;
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        } else {
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            return -1;
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        }
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        return 0;
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    } else {
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        return -1;
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    }
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    pnm_get(s, buf1, sizeof(buf1));
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    avctx->width = atoi(buf1);
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    if (avctx->width <= 0)
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        return -1;
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    pnm_get(s, buf1, sizeof(buf1));
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    avctx->height = atoi(buf1);
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    if(avcodec_check_dimensions(avctx, avctx->width, avctx->height))
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        return -1;
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    if (avctx->pix_fmt != PIX_FMT_MONOWHITE) {
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        pnm_get(s, buf1, sizeof(buf1));
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        s->maxval = atoi(buf1);
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        if(s->maxval >= 256 && avctx->pix_fmt == PIX_FMT_GRAY8) {
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            avctx->pix_fmt = PIX_FMT_GRAY16BE;
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            if (s->maxval != 65535)
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                avctx->pix_fmt = PIX_FMT_GRAY16;
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        }
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    }
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    /* more check if YUV420 */
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    if (avctx->pix_fmt == PIX_FMT_YUV420P) {
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        if ((avctx->width & 1) != 0)
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            return -1;
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        h = (avctx->height * 2);
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        if ((h % 3) != 0)
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            return -1;
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        h /= 3;
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        avctx->height = h;
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    }
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    return 0;
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}