/*****************************************************************************
 * Copyright (C) 2004-2021
 * ProbeStar Technical Systems, LLC
 * All Rights Reserved.  Proprietary and Confidential.
 *============================================================================
*****************************************************************************/

/*****************************************************************************
 * includes
*****************************************************************************/

#include "embtypes.h"
#include "asn1uper.h"

/*****************************************************************************
 * defines
*****************************************************************************/

/*****************************************************************************
 * macros
*****************************************************************************/

#define min(A,B)        ((A)<(B)?(A):(B))
#define max(A,B)        ((A)>(B)?(A):(B))

/*****************************************************************************
 * structs & typedefs
*****************************************************************************/

/*****************************************************************************
 * global constants
*****************************************************************************/

/*****************************************************************************
 * global variables
*****************************************************************************/

/*****************************************************************************
 * static constants
*****************************************************************************/

/*****************************************************************************
 * static variables
*****************************************************************************/

/*****************************************************************************
 * static prototypes
*****************************************************************************/

/*****************************************************************************
 * C functions
*****************************************************************************/

// grab extension bits, check for extension defined by ellipses
uint uper_get_extension(UPER_Stream *uper, UPER_Extension *ext, uint noptions, uint ellipses)
{
  if (!uper || !ext)
    return 0;

  uper_init_extension(ext);

  ellipses &= 1;
  if ((noptions+ellipses)==0) {
    uper->error = 1;
    return 0;
  }
  
  // check for extensions
  if (ellipses) {
    ext->ellipses = uper_get_bits_stream(uper, 1);
  }
  
  // check for options
  if (noptions) {
    ext->value = uper_get_bits_stream(uper, noptions);
    ext->options = noptions;
  }
  
  if (ext->ellipses) {
    uper_get_ext_length(uper, ext);
    
    if (_asn1_debug_on_)
      printf("\tEXT_LEN = %d\n", ext->length);
    // otherwise no ...
  }  

  return ellipses + noptions;
}

uint uper_get_ext_length(UPER_Stream *uper, UPER_Extension *ext)
{
  if (!ext->ellipses)
    return 0;
  
  uint len = uper_get_bits_stream(uper, 8);
  
  if (len & 0x80) {
    len = (len & 0x7f) << 8;
    len |= uper_get_bits_stream(uper, 8);
  }
  else
    len &= 0x7f;
  ext->length = len;
  
  return len;
}

// if ellipses extension available
uint uper_get_ext_ellipses(UPER_Extension *ext)
{
  if (ext)
    return ext->ellipses;
  return 0;
}

// from the front (high->low bits)
uint uper_get_ext_optional(UPER_Extension *ext, uint bit)
{
  if (!ext || (bit>=ext->options))
    return 0;
  
  return (ext->value & 1<<(ext->options-bit));
}

uint uper_get_ext_skip(UPER_Stream *uper, UPER_Extension *ext)
{
  if (!uper && !ext && !ext->length)
    return 0;
  
  int bits = ext->length;
  
  // copy in
  int sbit = uper->bit;        // bit order in stream (not byte)
  int ebit = (sbit+bits) % 8; // after last bit

  // copy out
  uper->ptr += (sbit + bits) / 8;
  uper->bit = ebit;
  uper->consumed += bits;
  
  return bits;
}