/*
  * MQ-coder encoder
  * Copyright (c) 2007 Kamil Nowosad
  *
  * 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
  */
 
 /**
  * MQ-coder encoder
  * @file
  * @author Kamil Nowosad
  */
 
 #include "mqc.h"
 
 static void byteout(MqcState *mqc)
 {
 retry:
     if (*mqc->bp == 0xff){
         mqc->bp++;
         *mqc->bp = mqc->c >> 20;
         mqc->c &= 0xfffff;
         mqc->ct = 7;
     } else if ((mqc->c & 0x8000000)){
         (*mqc->bp)++;
         mqc->c &= 0x7ffffff;
         goto retry;
     } else{
         mqc->bp++;
         *mqc->bp = mqc->c >> 19;
         mqc->c &= 0x7ffff;
         mqc->ct = 8;
     }
 }
 
 static void renorme(MqcState *mqc)
 {
     do{
         mqc->a += mqc->a;
         mqc->c += mqc->c;
         if (!--mqc->ct)
             byteout(mqc);
     } while (!(mqc->a & 0x8000));
 }
 
 static void setbits(MqcState *mqc)
 {
     int tmp = mqc->c + mqc->a;
     mqc->c |= 0xffff;
     if (mqc->c >= tmp)
         mqc->c -= 0x8000;
 }
 
 void ff_mqc_initenc(MqcState *mqc, uint8_t *bp)
 {
     ff_mqc_init_contexts(mqc);
     mqc->a = 0x8000;
     mqc->c = 0;
     mqc->bp = bp-1;
     mqc->bpstart = bp;
     mqc->ct = 12 + (*mqc->bp == 0xff);
 }
 
 void ff_mqc_encode(MqcState *mqc, uint8_t *cxstate, int d)
 {
     int qe;
 
     qe = ff_mqc_qe[*cxstate];
     mqc->a -= qe;
     if ((*cxstate & 1) == d){
         if (!(mqc->a & 0x8000)){
             if (mqc->a < qe)
                 mqc->a = qe;
             else
                 mqc->c += qe;
             *cxstate = ff_mqc_nmps[*cxstate];
             renorme(mqc);
         } else
             mqc->c += qe;
     } else{
         if (mqc->a < qe)
             mqc->c += qe;
         else
             mqc->a = qe;
         *cxstate = ff_mqc_nlps[*cxstate];
         renorme(mqc);
     }
 }
 
 int ff_mqc_length(MqcState *mqc)
 {
     return mqc->bp - mqc->bpstart;
 }
 
 int ff_mqc_flush(MqcState *mqc)
 {
     setbits(mqc);
     mqc->c = mqc->c << mqc->ct;
     byteout(mqc);
     mqc->c = mqc->c << mqc->ct;
     byteout(mqc);
     if (*mqc->bp != 0xff)
         mqc->bp++;
     return mqc->bp - mqc->bpstart;
 }