/*
  * HEVC Annex B format parser
  *
  * Copyright (C) 2012 - 2013 Guillaume Martres
  *
  * 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/common.h"

 #include "golomb.h"

 #include "hevc.h"

 #include "hevc_ps.h"
 #include "hevc_sei.h"

 #include "h2645_parse.h"

 #include "internal.h"

 #include "parser.h"

 
 #define START_CODE 0x000001 ///< start_code_prefix_one_3bytes
 

 #define IS_IRAP_NAL(nal) (nal->type >= 16 && nal->type <= 23)

 #define IS_IDR_NAL(nal) (nal->type == HEVC_NAL_IDR_W_RADL || nal->type == HEVC_NAL_IDR_N_LP)

 typedef struct HEVCParserContext {

     ParseContext pc;

     H2645Packet pkt;

     HEVCParamSets ps;

     HEVCSEIContext sei;
     SliceHeader sh;

 
     int parsed_extradata;

     int poc;
     int pocTid0;

 } HEVCParserContext;
 

 static int hevc_parse_slice_header(AVCodecParserContext *s, H2645NAL *nal,
                                    AVCodecContext *avctx)
 {
     HEVCParserContext *ctx = s->priv_data;
     HEVCParamSets *ps = &ctx->ps;
     HEVCSEIContext *sei = &ctx->sei;
     SliceHeader *sh = &ctx->sh;
     GetBitContext *gb = &nal->gb;

     const HEVCWindow *ow;

     int i, num = 0, den = 0;
 
     sh->first_slice_in_pic_flag = get_bits1(gb);
     s->picture_structure = sei->picture_timing.picture_struct;
     s->field_order = sei->picture_timing.picture_struct;
 
     if (IS_IRAP_NAL(nal)) {
         s->key_frame = 1;
         sh->no_output_of_prior_pics_flag = get_bits1(gb);
     }
 
     sh->pps_id = get_ue_golomb(gb);
     if (sh->pps_id >= HEVC_MAX_PPS_COUNT || !ps->pps_list[sh->pps_id]) {
         av_log(avctx, AV_LOG_ERROR, "PPS id out of range: %d\n", sh->pps_id);
         return AVERROR_INVALIDDATA;
     }
     ps->pps = (HEVCPPS*)ps->pps_list[sh->pps_id]->data;
 
     if (ps->pps->sps_id >= HEVC_MAX_SPS_COUNT || !ps->sps_list[ps->pps->sps_id]) {
         av_log(avctx, AV_LOG_ERROR, "SPS id out of range: %d\n", ps->pps->sps_id);
         return AVERROR_INVALIDDATA;
     }
     if (ps->sps != (HEVCSPS*)ps->sps_list[ps->pps->sps_id]->data) {
         ps->sps = (HEVCSPS*)ps->sps_list[ps->pps->sps_id]->data;
         ps->vps = (HEVCVPS*)ps->vps_list[ps->sps->vps_id]->data;
     }

     ow  = &ps->sps->output_window;

 
     s->coded_width  = ps->sps->width;
     s->coded_height = ps->sps->height;

     s->width        = ps->sps->width  - ow->left_offset - ow->right_offset;
     s->height       = ps->sps->height - ow->top_offset  - ow->bottom_offset;

     s->format       = ps->sps->pix_fmt;
     avctx->profile  = ps->sps->ptl.general_ptl.profile_idc;
     avctx->level    = ps->sps->ptl.general_ptl.level_idc;
 
     if (ps->vps->vps_timing_info_present_flag) {
         num = ps->vps->vps_num_units_in_tick;
         den = ps->vps->vps_time_scale;
     } else if (ps->sps->vui.vui_timing_info_present_flag) {
         num = ps->sps->vui.vui_num_units_in_tick;
         den = ps->sps->vui.vui_time_scale;
     }
 
     if (num != 0 && den != 0)
         av_reduce(&avctx->framerate.den, &avctx->framerate.num,
                   num, den, 1 << 30);
 
     if (!sh->first_slice_in_pic_flag) {
         int slice_address_length;
 
         if (ps->pps->dependent_slice_segments_enabled_flag)
             sh->dependent_slice_segment_flag = get_bits1(gb);
         else
             sh->dependent_slice_segment_flag = 0;
 
         slice_address_length = av_ceil_log2_c(ps->sps->ctb_width *
                                               ps->sps->ctb_height);
         sh->slice_segment_addr = get_bitsz(gb, slice_address_length);
         if (sh->slice_segment_addr >= ps->sps->ctb_width * ps->sps->ctb_height) {
             av_log(avctx, AV_LOG_ERROR, "Invalid slice segment address: %u.\n",
                    sh->slice_segment_addr);
             return AVERROR_INVALIDDATA;
         }
     } else
         sh->dependent_slice_segment_flag = 0;
 
     if (sh->dependent_slice_segment_flag)
         return 0; /* break; */
 
     for (i = 0; i < ps->pps->num_extra_slice_header_bits; i++)
         skip_bits(gb, 1); // slice_reserved_undetermined_flag[]
 
     sh->slice_type = get_ue_golomb(gb);
     if (!(sh->slice_type == HEVC_SLICE_I || sh->slice_type == HEVC_SLICE_P ||
           sh->slice_type == HEVC_SLICE_B)) {
         av_log(avctx, AV_LOG_ERROR, "Unknown slice type: %d.\n",
                sh->slice_type);
         return AVERROR_INVALIDDATA;
     }
     s->pict_type = sh->slice_type == HEVC_SLICE_B ? AV_PICTURE_TYPE_B :
                    sh->slice_type == HEVC_SLICE_P ? AV_PICTURE_TYPE_P :
                                                AV_PICTURE_TYPE_I;
 
     if (ps->pps->output_flag_present_flag)
         sh->pic_output_flag = get_bits1(gb);
 
     if (ps->sps->separate_colour_plane_flag)
         sh->colour_plane_id = get_bits(gb, 2);
 
     if (!IS_IDR_NAL(nal)) {
         sh->pic_order_cnt_lsb = get_bits(gb, ps->sps->log2_max_poc_lsb);
         s->output_picture_number = ctx->poc = ff_hevc_compute_poc(ps->sps, ctx->pocTid0, sh->pic_order_cnt_lsb, nal->type);
     } else
         s->output_picture_number = ctx->poc = 0;
 
     if (nal->temporal_id == 0 &&
         nal->type != HEVC_NAL_TRAIL_N &&
         nal->type != HEVC_NAL_TSA_N &&
         nal->type != HEVC_NAL_STSA_N &&
         nal->type != HEVC_NAL_RADL_N &&
         nal->type != HEVC_NAL_RASL_N &&
         nal->type != HEVC_NAL_RADL_R &&
         nal->type != HEVC_NAL_RASL_R)
         ctx->pocTid0 = ctx->poc;
 
     return 1; /* no need to evaluate the rest */
 }
 

 /**
  * Parse NAL units of found picture and decode some basic information.
  *
  * @param s parser context.
  * @param avctx codec context.
  * @param buf buffer with field/frame data.
  * @param buf_size size of the buffer.
  */

 static int parse_nal_units(AVCodecParserContext *s, const uint8_t *buf,

                            int buf_size, AVCodecContext *avctx)
 {
     HEVCParserContext *ctx = s->priv_data;

     HEVCParamSets *ps = &ctx->ps;
     HEVCSEIContext *sei = &ctx->sei;

     int is_global = buf == avctx->extradata;

     int ret, i;

 
     /* set some sane default values */
     s->pict_type         = AV_PICTURE_TYPE_I;
     s->key_frame         = 0;
     s->picture_structure = AV_PICTURE_STRUCTURE_UNKNOWN;
 

     ff_hevc_reset_sei(sei);

     ret = ff_h2645_packet_split(&ctx->pkt, buf, buf_size, avctx, 0, 0,
                                 AV_CODEC_ID_HEVC, 1);
     if (ret < 0)
         return ret;

     for (i = 0; i < ctx->pkt.nb_nals; i++) {
         H2645NAL *nal = &ctx->pkt.nals[i];

         GetBitContext *gb = &nal->gb;

         switch (nal->type) {

         case HEVC_NAL_VPS:

             ff_hevc_decode_nal_vps(gb, avctx, ps);
             break;

         case HEVC_NAL_SPS:

             ff_hevc_decode_nal_sps(gb, avctx, ps, 1);
             break;

         case HEVC_NAL_PPS:

             ff_hevc_decode_nal_pps(gb, avctx, ps);
             break;

         case HEVC_NAL_SEI_PREFIX:
         case HEVC_NAL_SEI_SUFFIX:

             ff_hevc_decode_nal_sei(gb, avctx, sei, ps, nal->type);

             break;

         case HEVC_NAL_TRAIL_N:
         case HEVC_NAL_TRAIL_R:
         case HEVC_NAL_TSA_N:
         case HEVC_NAL_TSA_R:
         case HEVC_NAL_STSA_N:
         case HEVC_NAL_STSA_R:
         case HEVC_NAL_BLA_W_LP:
         case HEVC_NAL_BLA_W_RADL:
         case HEVC_NAL_BLA_N_LP:
         case HEVC_NAL_IDR_W_RADL:
         case HEVC_NAL_IDR_N_LP:
         case HEVC_NAL_CRA_NUT:

         case HEVC_NAL_RADL_N:
         case HEVC_NAL_RADL_R:
         case HEVC_NAL_RASL_N:
         case HEVC_NAL_RASL_R:

 
             if (is_global) {

                 av_log(avctx, AV_LOG_ERROR, "Invalid NAL unit: %d\n", nal->type);

                 return AVERROR_INVALIDDATA;
             }
 

             ret = hevc_parse_slice_header(s, nal, avctx);
             if (ret)
                 return ret;
             break;

         }
     }
     /* didn't find a picture! */

     if (!is_global)

         av_log(avctx, AV_LOG_ERROR, "missing picture in access unit\n");

     return -1;
 }

 /**
  * Find the end of the current frame in the bitstream.
  * @return the position of the first byte of the next frame, or END_NOT_FOUND
  */
 static int hevc_find_frame_end(AVCodecParserContext *s, const uint8_t *buf,
                                int buf_size)
 {
     HEVCParserContext *ctx = s->priv_data;
     ParseContext       *pc = &ctx->pc;
     int i;
 
     for (i = 0; i < buf_size; i++) {
         int nut;
 
         pc->state64 = (pc->state64 << 8) | buf[i];
 
         if (((pc->state64 >> 3 * 8) & 0xFFFFFF) != START_CODE)
             continue;
 
         nut = (pc->state64 >> 2 * 8 + 1) & 0x3F;
         // Beginning of access unit

         if ((nut >= HEVC_NAL_VPS && nut <= HEVC_NAL_EOB_NUT) || nut == HEVC_NAL_SEI_PREFIX ||

             (nut >= 41 && nut <= 44) || (nut >= 48 && nut <= 55)) {
             if (pc->frame_start_found) {
                 pc->frame_start_found = 0;
                 return i - 5;
             }
         } else if (nut <= HEVC_NAL_RASL_R ||
                    (nut >= HEVC_NAL_BLA_W_LP && nut <= HEVC_NAL_CRA_NUT)) {
             int first_slice_segment_in_pic_flag = buf[i] >> 7;
             if (first_slice_segment_in_pic_flag) {
                 if (!pc->frame_start_found) {
                     pc->frame_start_found = 1;
                 } else { // First slice of next frame found
                     pc->frame_start_found = 0;
                     return i - 5;
                 }
             }
         }
     }
 
     return END_NOT_FOUND;
 }
 

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

                       const uint8_t **poutbuf, int *poutbuf_size,
                       const uint8_t *buf, int buf_size)
 {
     int next;

     HEVCParserContext *ctx = s->priv_data;
     ParseContext *pc = &ctx->pc;
 
     if (avctx->extradata && !ctx->parsed_extradata) {
         parse_nal_units(s, avctx->extradata, avctx->extradata_size, avctx);
         ctx->parsed_extradata = 1;
     }

 
     if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
         next = buf_size;
     } else {
         next = hevc_find_frame_end(s, buf, buf_size);
         if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {

             *poutbuf      = NULL;

             *poutbuf_size = 0;
             return buf_size;
         }
     }
 

     parse_nal_units(s, buf, buf_size, avctx);

     *poutbuf      = buf;

     *poutbuf_size = buf_size;
     return next;
 }
 
 // Split after the parameter sets at the beginning of the stream if they exist.
 static int hevc_split(AVCodecContext *avctx, const uint8_t *buf, int buf_size)
 {

     const uint8_t *ptr = buf, *end = buf + buf_size;

     uint32_t state = -1;

     int has_vps = 0;
     int has_sps = 0;
     int has_pps = 0;
     int nut;

     while (ptr < end) {
         ptr = avpriv_find_start_code(ptr, end, &state);
         if ((state >> 8) != START_CODE)
             break;
         nut = (state >> 1) & 0x3F;

         if (nut == HEVC_NAL_VPS)

             has_vps = 1;

         else if (nut == HEVC_NAL_SPS)

             has_sps = 1;

         else if (nut == HEVC_NAL_PPS)

             has_pps = 1;

         else if ((nut != HEVC_NAL_SEI_PREFIX || has_pps) &&
                   nut != HEVC_NAL_AUD) {

             if (has_vps && has_sps) {
                 while (ptr - 4 > buf && ptr[-5] == 0)
                     ptr--;
                 return ptr - 4 - buf;
             }
         }

     }
     return 0;
 }
 

 static void hevc_parser_close(AVCodecParserContext *s)

 {

     HEVCParserContext *ctx = s->priv_data;

     ff_hevc_ps_uninit(&ctx->ps);

     ff_h2645_packet_uninit(&ctx->pkt);

     ff_hevc_reset_sei(&ctx->sei);

 
     av_freep(&ctx->pc.buffer);

 }
 

 AVCodecParser ff_hevc_parser = {
     .codec_ids      = { AV_CODEC_ID_HEVC },

     .priv_data_size = sizeof(HEVCParserContext),

     .parser_parse   = hevc_parse,

     .parser_close   = hevc_parser_close,

     .split          = hevc_split,
 };