/*

 * PNM image parser

 * Copyright (c) 2002, 2003 Fabrice Bellard

 *

 * This file is part of FFmpeg.

 *

 * FFmpeg is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2.1 of the License, or (at your option) any later version.

 *

 * FFmpeg is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with FFmpeg; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

 */

#include "libavutil/avassert.h"

#include "libavutil/imgutils.h"

#include "parser.h" //for ParseContext

#include "parser_internal.h"

#include "pnm.h"

typedef struct PNMParseContext {

    ParseContext pc;

    int remaining_bytes;

    int ascii_scan;

}PNMParseContext;

static int pnm_parse(AVCodecParserContext *s, AVCodecContext *avctx,

                     const uint8_t **poutbuf, int *poutbuf_size,

                     const uint8_t *buf, int buf_size)

{

    PNMParseContext *pnmpc = s->priv_data;

    ParseContext *pc = &pnmpc->pc;

    PNMContext pnmctx;

    int next = END_NOT_FOUND;

    int skip = 0;

    if (pc->overread > 0) {

        memmove(pc->buffer + pc->index, pc->buffer + pc->overread_index, pc->overread);

        pc->index          += pc->overread;

        pc->overread_index += pc->overread;

        pc->overread = 0;

    }

    if (pnmpc->remaining_bytes) {

        int inc = FFMIN(pnmpc->remaining_bytes, buf_size);

        skip += inc;

        pnmpc->remaining_bytes -= inc;

        if (!pnmpc->remaining_bytes)

            next = skip;

        goto end;

    }

retry:

    if (pc->index) {

        pnmctx.bytestream_start =

        pnmctx.bytestream       = pc->buffer;

        pnmctx.bytestream_end   = pc->buffer + pc->index;

    } else {

        pnmctx.bytestream_start =

        pnmctx.bytestream       = buf + skip;

        pnmctx.bytestream_end   = buf + buf_size - skip;

    }

    if (ff_pnm_decode_header(avctx, &pnmctx) < 0) {

        if (pnmctx.bytestream < pnmctx.bytestream_end) {

            if (pc->index) {

                pc->index = 0;

                pnmpc->ascii_scan = 0;

            } else {

                unsigned step = FFMAX(1, pnmctx.bytestream - pnmctx.bytestream_start);

                skip += step;

            }

            goto retry;

        }

    } else if (pnmctx.type < 4) {

        const uint8_t *bs   = pnmctx.bytestream;

        const uint8_t *end = pnmctx.bytestream_end;

        const uint8_t *sync = bs;

        if (pc->index) {

            av_assert0(pnmpc->ascii_scan <= end - bs);

            bs += pnmpc->ascii_scan;

        }

        while (bs < end) {

            int c;

            sync = bs;

            c = *bs++;

            if (c == '#')  {

                uint8_t *match = memchr(bs, '\n', end-bs);

                if (match)

                    bs = match + 1;

                else

                    break;

            } else if (c == 'P') {

                next = bs - pnmctx.bytestream_start + skip - 1;

                pnmpc->ascii_scan = 0;

                break;

            }

        }

        if (next == END_NOT_FOUND)

            pnmpc->ascii_scan = sync - pnmctx.bytestream + skip;

    } else {

        int ret = av_image_get_buffer_size(avctx->pix_fmt, avctx->width, avctx->height, 1);

        next = pnmctx.bytestream - pnmctx.bytestream_start + skip;

        if (ret > 0 && pnmctx.half)

            ret >>= 1;

        if (ret >= 0 && next + (uint64_t)ret <= INT_MAX)

            next += ret;

    }

    if (next != END_NOT_FOUND && pnmctx.bytestream_start != buf + skip)

        next -= pc->index;

    if (next > buf_size) {

        pnmpc->remaining_bytes = next - buf_size;

        next = END_NOT_FOUND;

    }

end:

    if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {

        *poutbuf      = NULL;

        *poutbuf_size = 0;

        return buf_size;

    }

    *poutbuf      = buf;

    *poutbuf_size = buf_size;

    return next;

}

const FFCodecParser ff_pnm_parser = {

    PARSER_CODEC_LIST(AV_CODEC_ID_PGM, AV_CODEC_ID_PGMYUV, AV_CODEC_ID_PPM,

                      AV_CODEC_ID_PBM, AV_CODEC_ID_PAM, AV_CODEC_ID_PFM,

                      AV_CODEC_ID_PHM),

    .priv_data_size = sizeof(PNMParseContext),

    .parse          = pnm_parse,

    .close          = ff_parse_close,

};