GCC Code Coverage Report
Directory: ../../../ffmpeg/ Exec Total Coverage
File: src/libavcodec/jpeg2000_parser.c Lines: 8 85 9.4 %
Date: 2020-09-21 17:35:45 Branches: 1 72 1.4 %

Line Branch Exec Source
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/*
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 * JPEG2000 parser
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 * Copyright (c) 2020 Gautam Ramakrishnan
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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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/**
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 * @file
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 * JPEG2000 parser.
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 */
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#include "parser.h"
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/* Whether frame is jp2 file or codestream
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*/
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enum frame_type {
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    jp2_file = 1,
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    j2k_cstream
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};
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typedef struct JPEG2000ParserContext {
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    ParseContext pc;
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    uint64_t bytes_read;
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    uint64_t fheader_state;
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    uint32_t skip_bytes; // skip bytes inside codestream data
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    enum frame_type ft; // 1 if file, 2 if codestream
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    uint8_t fheader_read; // are we reading
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    uint8_t reading_file_header;
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    uint8_t skipped_codestream;
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    uint8_t codestream_frame_end;
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    uint8_t read_tp;
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    uint8_t in_codestream;
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} JPEG2000ParserContext;
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static inline void reset_context(JPEG2000ParserContext *m)
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{
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    ParseContext *pc = &m->pc;
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    pc->frame_start_found= 0;
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    pc->state = 0;
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    m->bytes_read = 0;
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    m->ft = 0;
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    m->skipped_codestream = 0;
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    m->fheader_read = 0;
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    m->codestream_frame_end = 0;
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    m->skip_bytes = 0;
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    m->read_tp = 0;
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    m->in_codestream = 0;
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}
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/* Returns 1 if marker has any data which can be skipped
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*/
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static uint8_t info_marker(uint16_t marker)
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{
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    if (marker == 0xFF92 || marker == 0xFF4F ||
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        marker == 0xFF90 || marker == 0xFF93 ||
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        marker == 0xFFD9)
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        return 0;
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    else
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        if (marker > 0xFF00) return 1;
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    return 0;
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}
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/**
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 * Find the end of the current frame in the bitstream.
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 * @return the position of the first byte of the next frame, or -1
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 */
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static int find_frame_end(JPEG2000ParserContext *m, const uint8_t *buf, int buf_size)
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{
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    ParseContext *pc= &m->pc;
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    int i;
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    uint32_t state;
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    uint64_t state64;
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    state= pc->state;
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    state64 = pc->state64;
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    if (buf_size == 0) {
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        return 0;
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    }
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    for (i = 0; i < buf_size; i++) {
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        state = state << 8 | buf[i];
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        state64 = state64 << 8 | buf[i];
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        m->bytes_read++;
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        if (m->skip_bytes) {
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            m->skip_bytes--;
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            continue;
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        }
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        if (m->codestream_frame_end) {
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            reset_context(m);
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            return i;
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        }
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        if (m->read_tp) { // Find out how many bytes inside Tile part codestream to skip.
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            if (m->read_tp == 1) {
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                m->skip_bytes = (state64 & 0xFFFFFFFF) - 10 > 0?
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                                (state64 & 0xFFFFFFFF) - 10 : 0;
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            }
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            m->read_tp--;
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        }
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        if (m->fheader_read) {
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            if (m->fheader_read == 1) {
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                if (state64 == 0x6A5020200D0A870A) { // JP2 signature box value.
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                    if (pc->frame_start_found) {
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                        pc->frame_start_found = 0;
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                        reset_context(m);
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                        return i - 11;
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                    } else {
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                        pc->frame_start_found = 1;
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                        m->ft = jp2_file;
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                    }
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                }
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            }
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            m->fheader_read--;
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        }
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        if (state == 0x0000000C && m->bytes_read >= 3) { // Indicates start of JP2 file. Check signature next.
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            m->fheader_read = 8;
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        } else if ((state & 0xFFFF) == 0xFF4F) {
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            m->in_codestream = 1;
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            if (!pc->frame_start_found) {
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                pc->frame_start_found = 1;
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                m->ft = j2k_cstream;
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            } else if (pc->frame_start_found && m->ft == jp2_file && m->skipped_codestream) {
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                reset_context(m);
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                return i - 1;
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            }
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        } else if ((state & 0xFFFF) == 0xFFD9) {
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            if (pc->frame_start_found && m->ft == jp2_file) {
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                m->skipped_codestream = 1;
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            } else if (pc->frame_start_found && m->ft == j2k_cstream) {
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                m->codestream_frame_end = 1;
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            }
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            m->in_codestream = 0;
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        } else if (m->in_codestream && (state & 0xFFFF) == 0xFF90) { // Are we in tile part header?
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            m->read_tp = 8;
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        } else if (pc->frame_start_found && info_marker((state & 0xFFFF0000)>>16) && m->in_codestream) {
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            m->skip_bytes = (state & 0xFFFF) - 2;
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        }
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    }
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    pc->state = state;
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    pc->state64 = state64;
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    return END_NOT_FOUND;
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}
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static int jpeg2000_parse(AVCodecParserContext *s,
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                          AVCodecContext *avctx,
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                          const uint8_t **poutbuf, int *poutbuf_size,
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                          const uint8_t *buf, int buf_size)
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{
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    JPEG2000ParserContext *m = s->priv_data;
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    ParseContext *pc = &m->pc;
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    int next;
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    if(s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
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        next= buf_size;
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    } else {
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        next= find_frame_end(m, buf, buf_size);
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        if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
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            *poutbuf = NULL;
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            *poutbuf_size = 0;
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            return buf_size;
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        }
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    }
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    *poutbuf = buf;
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    *poutbuf_size = buf_size;
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    return next;
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}
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AVCodecParser ff_jpeg2000_parser = {
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    .codec_ids      = { AV_CODEC_ID_JPEG2000 },
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    .priv_data_size = sizeof(JPEG2000ParserContext),
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    .parser_parse   = jpeg2000_parse,
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    .parser_close   = ff_parse_close,
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};