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/*

 * util.c --

 *

 *      Miscellaneous utility procedures.

 *

 */

/*

 * Copyright (c) 1995 The Regents of the University of California.

 * All rights reserved.

 *

 * Permission to use, copy, modify, and distribute this software and its

 * documentation for any purpose, without fee, and without written agreement is

 * hereby granted, provided that the above copyright notice and the following

 * two paragraphs appear in all copies of this software.

 *

 * IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY FOR

 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT

 * OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF THE UNIVERSITY OF

 * CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 *

 * THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES,

 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY

 * AND FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS

 * ON AN "AS IS" BASIS, AND THE UNIVERSITY OF CALIFORNIA HAS NO OBLIGATION TO

 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.

 */

/*

 * Portions of this software Copyright (c) 1995 Brown University.

 * All rights reserved.

 *

 * Permission to use, copy, modify, and distribute this software and its

 * documentation for any purpose, without fee, and without written agreement

 * is hereby granted, provided that the above copyright notice and the

 * following two paragraphs appear in all copies of this software.

 *

 * IN NO EVENT SHALL BROWN UNIVERSITY BE LIABLE TO ANY PARTY FOR

 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT

 * OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF BROWN

 * UNIVERSITY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 *

 * BROWN UNIVERSITY SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT

 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A

 * PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS ON AN "AS IS"

 * BASIS, AND BROWN UNIVERSITY HAS NO OBLIGATION TO PROVIDE MAINTENANCE,

 * SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.

 */

#include <stdlib.h>

#include "video.h"

#include "proto.h"

#include "util.h"

#ifndef NOCONTROLS

#include "ctrlbar.h"

#endif

/*

   Changes to make the code reentrant:

     de-globalized: totNumFrames, realTimeStart, vid_stream, sys_layer,

        bitOffset, bitLength, bitBuffer, curVidStream

     setjmp/longjmp replaced

   Additional changes:

     only call DestroyVidStream up in mpegVidRsrc, not in correct_underflow

   -lsh@cs.brown.edu (Loring Holden)

 */

/* Bit masks used by bit i/o operations. */

unsigned int nBitMask[] = { 0x00000000, 0x80000000, 0xc0000000, 0xe0000000,

                            0xf0000000, 0xf8000000, 0xfc000000, 0xfe000000,

                            0xff000000, 0xff800000, 0xffc00000, 0xffe00000,

                            0xfff00000, 0xfff80000, 0xfffc0000, 0xfffe0000,

                            0xffff0000, 0xffff8000, 0xffffc000, 0xffffe000,

                            0xfffff000, 0xfffff800, 0xfffffc00, 0xfffffe00,

                            0xffffff00, 0xffffff80, 0xffffffc0, 0xffffffe0,

                            0xfffffff0, 0xfffffff8, 0xfffffffc, 0xfffffffe};

unsigned int bitMask[] = {  0xffffffff, 0x7fffffff, 0x3fffffff, 0x1fffffff,

                            0x0fffffff, 0x07ffffff, 0x03ffffff, 0x01ffffff,

                            0x00ffffff, 0x007fffff, 0x003fffff, 0x001fffff,

                            0x000fffff, 0x0007ffff, 0x0003ffff, 0x0001ffff,

                            0x0000ffff, 0x00007fff, 0x00003fff, 0x00001fff,

                            0x00000fff, 0x000007ff, 0x000003ff, 0x000001ff,

                            0x000000ff, 0x0000007f, 0x0000003f, 0x0000001f,

                            0x0000000f, 0x00000007, 0x00000003, 0x00000001};

unsigned int rBitMask[] = { 0xffffffff, 0xfffffffe, 0xfffffffc, 0xfffffff8,

                            0xfffffff0, 0xffffffe0, 0xffffffc0, 0xffffff80,

                            0xffffff00, 0xfffffe00, 0xfffffc00, 0xfffff800,

                            0xfffff000, 0xffffe000, 0xffffc000, 0xffff8000,

                            0xffff0000, 0xfffe0000, 0xfffc0000, 0xfff80000,

                            0xfff00000, 0xffe00000, 0xffc00000, 0xff800000,

                            0xff000000, 0xfe000000, 0xfc000000, 0xf8000000,

                            0xf0000000, 0xe0000000, 0xc0000000, 0x80000000};

unsigned int bitTest[] = {  0x80000000, 0x40000000, 0x20000000, 0x10000000,

                            0x08000000, 0x04000000, 0x02000000, 0x01000000,

                            0x00800000, 0x00400000, 0x00200000, 0x00100000,

                            0x00080000, 0x00040000, 0x00020000, 0x00010000,

                            0x00008000, 0x00004000, 0x00002000, 0x00001000,

                            0x00000800, 0x00000400, 0x00000200, 0x00000100,

                            0x00000080, 0x00000040, 0x00000020, 0x00000010,

                            0x00000008, 0x00000004, 0x00000002, 0x00000001};

/*

 *--------------------------------------------------------------

 *

 * correct_underflow --

 *

 *      Called when buffer does not have sufficient data to

 *      satisfy request for bits.

 *      Calls get_more_data, an application specific routine

 *      required to fill the buffer with more data.

 *

 * Results:

 *      None really.

 *  

 * Side effects:

 *      buf_length and buffer fields may be changed.

 *

 *--------------------------------------------------------------

 */

void

correct_underflow(vid_stream)

   VidStream *vid_stream;

{

  int status;

  status = get_more_data(vid_stream);

  if (status  < 0) {

    if (!quietFlag) {

      fprintf (stderr, "\n");

      perror("Unexpected read error.");

    }

    exit(1);

  }

  else if ((status == 0) && (vid_stream->buf_length < 1)) {

    if (!quietFlag) {

      fprintf(stderr, "\nImproper or missing sequence end code.\n");

    }

#ifdef ANALYSIS

    PrintAllStats(vid_stream);

#endif

    if (!quietFlag) {

      PrintTimeInfo(vid_stream);

    }

    vid_stream->film_has_ended=TRUE;

#ifndef NOCONTROLS

    /* Hmm, don't really know if this works or not... */

    clear_data_stream(vid_stream);

    return;

#else

    if (loopFlag) {

      clear_data_stream(vid_stream);

    } /* destroy stream up in mpegVidRsrc */

    return;

#endif /* !NOCONTROLS */

  }

#ifdef UTIL2

  vid_stream->curBits = *vid_stream->buffer << vid_stream->bit_offset;

#else

  vid_stream->curBits = *vid_stream->buffer;

#endif

}

/*

 *--------------------------------------------------------------

 *

 * next_bits --

 *

 *      Compares next num bits to low order position in mask.

 *      Buffer pointer is NOT advanced.

 *

 * Results:

 *      TRUE, FALSE, or error code.

 *

 * Side effects:

 *      None.

 *

 *--------------------------------------------------------------

 */

int next_bits(num, mask, vid_stream)

int num;

unsigned int mask;

VidStream *vid_stream;

{

  unsigned int stream;

  int ret_value;

  /* If no current stream, return error. */

  if (vid_stream == NULL)

    return NO_VID_STREAM;

  /* Get next num bits, no buffer pointer advance. */

  show_bitsn(num, stream);

  /* Compare bit stream and mask. Set return value toTRUE if equal, FALSE if

     differs.

  */

  if (mask == stream) {

    ret_value = TRUE;

  } else ret_value = FALSE;

  /* Return return value. */

  return ret_value;

}

/*

 *--------------------------------------------------------------

 *

 * get_ext_data --

 *

 *      Assumes that bit stream is at begining of extension

 *      data. Parses off extension data into dynamically

 *      allocated space until start code is hit.

 *

 * Results:

 *      Pointer to dynamically allocated memory containing

 *      extension data.

 *

 * Side effects:

 *      Bit stream irreversibly parsed.

 *

 *--------------------------------------------------------------

 */

char *get_ext_data (vid_stream)

   VidStream *vid_stream;

{

  unsigned int size, marker;

  char *dataPtr;

  unsigned int data;

  /* Set initial ext data buffer size. */

  size = EXT_BUF_SIZE;

  /* Allocate ext data buffer. */

  dataPtr = (char *) malloc(size);

  /* Initialize marker to keep place in ext data buffer. */

  marker = 0;

  /* While next data is not start code... */

  while (!next_bits(24, 0x000001, vid_stream)) {

    /* Get next byte of ext data. */

    get_bits8(data);

    /* Put ext data into ext data buffer. Advance marker. */

    dataPtr[marker] = (char) data;

    marker++;

    /* If end of ext data buffer reached, resize data buffer. */

    if (marker == size) {

      size += EXT_BUF_SIZE;

      dataPtr = (char *) realloc(dataPtr, size);

    }

  }

  /* Realloc data buffer to free any extra space. */

  dataPtr = (char *) realloc(dataPtr, marker);

  /* Return pointer to ext data buffer. */

  return dataPtr;

}

/*

 *--------------------------------------------------------------

 *

 * next_start_code --

 *

 *      Parses off bitstream until start code reached. When done

 *      next 4 bytes of bitstream will be start code. Bit offset

 *      reset to 0.

 *

 * Results:

 *      Status code.

 *

 * Side effects:

 *      Bit stream irreversibly parsed.

 *

 *--------------------------------------------------------------

 */

int next_start_code(vid_stream)

   VidStream *vid_stream;

{

  int state;

  int byteoff;

  unsigned int data;

  /* If no current stream, return error. */

  if (vid_stream== NULL)

    return NO_VID_STREAM;

  /* If insufficient buffer length, correct underflow. */

  if (vid_stream->buf_length < 4) {

    correct_underflow(vid_stream);

  }

  /* If bit offset not zero, reset and advance buffer pointer. */

  byteoff = vid_stream->bit_offset % 8;

  if (byteoff != 0) {

    flush_bits((8-byteoff));

  }

  /* Set state = 0. */

  state = 0;

  /* While buffer has data ... */

  while(vid_stream->buf_length > 0) {

    /* If insufficient data exists, correct underflow. */

    if (vid_stream->buf_length < 4) {

      correct_underflow(vid_stream);

    }

    /* If next byte is zero... */

    get_bits8(data);

    if (data == 0) {

      /* If state < 2, advance state. */

      if (state < 2) state++;

    }

    /* If next byte is one... */

    else if (data == 1) {

      /* If state == 2, advance state (i.e. start code found). */

      if (state == 2) state++;

      /* Otherwise, reset state to zero. */

      else state = 0;

    }

    /* Otherwise byte is neither 1 or 0, reset state to 0. */

    else {

      state = 0;

    }

    /* If state == 3 (i.e. start code found)... */

    if (state == 3) {

      /* Set buffer pointer back and reset length & bit offsets so

       * next bytes will be beginning of start code.

       */

      vid_stream->bit_offset = vid_stream->bit_offset - 24;

#ifdef ANALYSIS

      bitCount -= 24;

#endif

      if (vid_stream->bit_offset < 0) {

        vid_stream->bit_offset = 32 + vid_stream->bit_offset;

        vid_stream->buf_length++;

        vid_stream->buffer--;

#ifdef UTIL2

        vid_stream->curBits = *vid_stream->buffer << vid_stream->bit_offset;

#else

        vid_stream->curBits = *vid_stream->buffer;

#endif

      }

      else {

#ifdef UTIL2

        vid_stream->curBits = *vid_stream->buffer << vid_stream->bit_offset;

#else

        vid_stream->curBits = *vid_stream->buffer;

#endif

      }

      /* Return success. */

      return OK;

    }

  }

  /* Return underflow error. */

  return STREAM_UNDERFLOW;

}

/*

 *--------------------------------------------------------------

 *

 * get_extra_bit_info --

 *

 *      Parses off extra bit info stream into dynamically

 *      allocated memory. Extra bit info is indicated by

 *      a flag bit set to 1, followed by 8 bits of data.

 *      This continues until the flag bit is zero. Assumes

 *      that bit stream set to first flag bit in extra

 *      bit info stream.

 *

 * Results:

 *      Pointer to dynamically allocated memory with extra

 *      bit info in it. Flag bits are NOT included.

 *

 * Side effects:

 *      Bit stream irreversibly parsed.

 *

 *--------------------------------------------------------------

 */

char *get_extra_bit_info(vid_stream)

VidStream *vid_stream;

{

  unsigned int size, marker;

  char *dataPtr;

  unsigned int data;

  /* Get first flag bit. */

  get_bits1(data);

  /* If flag is false, return NULL pointer (i.e. no extra bit info). */

  if (!data) return NULL;

  /* Initialize size of extra bit info buffer and allocate. */

  size = EXT_BUF_SIZE;

  dataPtr = (char *) malloc(size);

  /* Reset marker to hold place in buffer. */

  marker = 0;

  /* While flag bit is true. */

  while (data) {

    /* Get next 8 bits of data. */

    get_bits8(data);

    /* Place in extra bit info buffer. */

    dataPtr[marker] = (char) data;

    marker++;

    /* If buffer is full, reallocate. */

    if (marker == size) {

      size += EXT_BUF_SIZE;

      dataPtr = (char *) realloc(dataPtr, size);

    }

    /* Get next flag bit. */

    get_bits1(data);

  }

  /* Reallocate buffer to free extra space. */

  dataPtr = (char *) realloc(dataPtr, marker);

  /* Return pointer to extra bit info buffer. */

  return dataPtr;

}