path: root/support/dktools/dk4a85d.c

/*
	WARNING: This file was generated by dkct.
	Changes you make here will be lost if dkct is run again!
	You should modify the original source and run dkct on it.
	Original source: dk4a85d.ctr
*/

/*
Copyright (C) 2015-2017, Dirk Krause

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

* Redistributions of source code must retain the above copyright notice,
  this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above opyright notice,
  this list of conditions and the following disclaimer in the documentation
  and/or other materials provided with the distribution.
* Neither the name of the author nor the names of contributors may be used
  to endorse or promote products derived from this software without specific
  prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS''
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED.
IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY
DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

/**	@file dk4a85d.c The dk4a85d module.
*/


#line 119 "dk4a85d.ctr"

#include "dk4a85d.h"
#include "dk4mem.h"
#include "dk4edstm.h"





#line 127 "dk4a85d.ctr"



/**	Powers of 85.
*/
static const unsigned long	dk4a85e_pow_85[] = {
  (85UL * 85UL * 85UL * 85UL),
  (85UL * 85UL * 85UL),
  (85UL * 85UL),
  85UL
};



void
dk4a85_dec_init(dk4_a85_dec_t	*dec, dk4_er_t *erp)
{
  if (NULL != dec) {
    DK4_MEMRES(dec, sizeof(dk4_a85_dec_t));
    dec->os = 0;
    dec->is = 0;
    dec->tf = 0;
  } else {
    dk4error_set_simple_error_code(erp, DK4_E_INVALID_ARGUMENTS);
  }
}



int
dk4a85_dec_add(dk4_a85_dec_t *dec, char input, dk4_er_t *erp)
{
  unsigned long	 val;
  int		 back	=	DK4_EDSTM_ERROR;
  if (NULL != dec) {
    if (0 != dec->tf) {
      if ('>' == input) {
        back = DK4_EDSTM_STOP;
      } else {
	dk4error_set_simple_error_code(erp, DK4_E_SYNTAX);
      }
    } else {
      switch (input) {
        case ' ' : case '\t' : case '\r' : case '\n' : case 0x00 : case 0x0C : {
	  back = DK4_EDSTM_ACCEPT;
	} break;
        case '~' : {
	  back = DK4_EDSTM_ACCEPT;
	  dec->tf = 1;
	} break;
	case 'z' : {
	  if (0 == dec->is) {
	    dec->ob[0] = 0x00;
	    dec->ob[1] = 0x00;
	    dec->ob[2] = 0x00;
	    dec->ob[3] = 0x00;
	    dec->os    = 4;
	    back = DK4_EDSTM_FINISHED;
	  } else {
	    dk4error_set_simple_error_code(erp, DK4_E_SYNTAX);
	  }
	} break;
	default : {
	  if (((char)32 < input) && ((char)118 > input)) {
	    dec->ib[dec->is] = input;
	    dec->is += 1;
	    back = DK4_EDSTM_ACCEPT;
	    if (5 <= dec->is) {
	      val =
	      dk4a85e_pow_85[0] *
	      ((unsigned long)((unsigned char)(dec->ib[0] - (char)33)) & 0xFFUL)
	      +
	      dk4a85e_pow_85[1] *
	      ((unsigned long)((unsigned char)(dec->ib[1] - (char)33)) & 0xFFUL)
	      +
	      dk4a85e_pow_85[2] *
	      ((unsigned long)((unsigned char)(dec->ib[2] - (char)33)) & 0xFFUL)
	      +
	      dk4a85e_pow_85[3] *
	      ((unsigned long)((unsigned char)(dec->ib[3] - (char)33)) & 0xFFUL)
	      +
	      ((unsigned long)((unsigned char)(dec->ib[4] - (char)33)) & 0xFFUL)
	      ;
	      dec->ob[0] = (unsigned char)((val >> 24) & 0xFFUL);
	      dec->ob[1] = (unsigned char)((val >> 16) & 0xFFUL);
	      dec->ob[2] = (unsigned char)((val >>  8) & 0xFFUL);
	      dec->ob[3] = (unsigned char)((val      ) & 0xFFUL);
	      dec->is = 0;
	      dec->os = 4;
	      back = DK4_EDSTM_FINISHED;
	    }
	  } else {
	    dk4error_set_simple_error_code(erp, DK4_E_SYNTAX);
	  }
	} break;
      }
    }
  } else {
    dk4error_set_simple_error_code(erp, DK4_E_INVALID_ARGUMENTS);
  }
  return back;
}



/*
	During encoding sequences of 4 binary bytes b1, b2, b3, and b4
	are converted to five base-85 values a1, a2, a3, a4, and a5
	fullfilling the equation
	v=b1*256^3+b2*256^2+b3*256+b4=a1*85^4+a2*85^3+a3*85^2+a4*85+a5

	For complete sequences encoding and decoding are straightforward.

	For an incomplete final sequence of n binary bytes (1<=n<=3),
	only n+1 a values are encoded.
	In the example we assume a 2 byte sequence b1 and b2.
	The value v is calculated as
	v=b1*256^3+b2*256^2+0*256+0=a1*85^4+a2*85^3+a3*85^2+a4*85+a5.
	As we have 2 binary bytes, 3 text coefficients a1, a2, and a3
	are written to encoded output, a4 and a5 are skipped.
	From these 3 coefficients the decoder can calculate
	v'=a1*85^4+a2*85^3+a3*85^2+0*85+0
	which we can split into
	v'=b1'*256^3+b2'*256^2+b3'*256+b4'
	Obviously v' is less than or equal to v because v'=v-a4*85-a5.
	We have v=v' only if a4=0 and a5=0, this results in
	b3=0 and b4=0. Otherwise we have v>v'.
	As the final 2 bytes of v are zero, decreasing v to v' results
	in a non-zero value in the final 2 bytes and a decrease by
	1 in the first 2 bytes.
	So if v' & 0x0000FFFF is nonzero we have to calculate
	v = v' + 0x00010000 before splitting v into b1, b2, b3, and b4.
*/



int
dk4a85_dec_finish(dk4_a85_dec_t *dec, dk4_er_t *erp)
{
  unsigned long	 val;					/* 32 bit value */
  int		 back	=	DK4_EDSTM_ERROR;
  

#line 269 "dk4a85d.ctr"
  if (NULL != dec) {
    if (0 == dec->is) {
      back = DK4_EDSTM_ACCEPT;
    } else {
      switch (dec->is) {
        case 4: {			

#line 275 "dk4a85d.ctr"
	  /*	Calculate 32 bit value from encoded values.
	  */
	  val =
	  dk4a85e_pow_85[0] *
	  ((unsigned long)((unsigned char)(dec->ib[0] - (char)33)) & 0xFFUL)
	  +
	  dk4a85e_pow_85[1] *
	  ((unsigned long)((unsigned char)(dec->ib[1] - (char)33)) & 0xFFUL)
	  +
	  dk4a85e_pow_85[2] *
	  ((unsigned long)((unsigned char)(dec->ib[2] - (char)33)) & 0xFFUL)
	  +
	  dk4a85e_pow_85[3] *
	  ((unsigned long)((unsigned char)(dec->ib[3] - (char)33)) & 0xFFUL)
	  ;
	  

#line 291 "dk4a85d.ctr"
	  /*	Check whether truncation of a5 modified the 32 bit
	  	value, correct least significant used byte if necessary.
	  */
	  if (0UL != (val & 0x000000FFUL)) {
	    val += 0x00000100UL;
	  }
	  /*	Split 32 bit value into bytes.
	  */
	  

#line 300 "dk4a85d.ctr"
	  dec->ob[0] = (unsigned char)((val >> 24) & 0xFFUL);
	  dec->ob[1] = (unsigned char)((val >> 16) & 0xFFUL);
	  dec->ob[2] = (unsigned char)((val >>  8) & 0xFFUL);
	  /*	Set input size, output size and result.
	  */
	  dec->is = 0;
	  dec->os = 3;
	  back = DK4_EDSTM_FINISHED;
	} break;
	case 3: {			

#line 310 "dk4a85d.ctr"
	  /*	Calculate 32 bit value from encoded values.
	  */
	  val =
	  dk4a85e_pow_85[0] *
	  ((unsigned long)((unsigned char)(dec->ib[0] - (char)33)) & 0xFFUL)
	  +
	  dk4a85e_pow_85[1] *
	  ((unsigned long)((unsigned char)(dec->ib[1] - (char)33)) & 0xFFUL)
	  +
	  dk4a85e_pow_85[2] *
	  ((unsigned long)((unsigned char)(dec->ib[2] - (char)33)) & 0xFFUL)
	  ;
	  

#line 323 "dk4a85d.ctr"
	  /*	Check whether truncation of a4 and a5 modified the 32 bit
	  	value, correct least significant used byte if necessary.
	  */
	  if (0UL != (val & 0x0000FFFFUL)) {
	    val += 0x00010000UL;
	  }
	  

#line 330 "dk4a85d.ctr"
	  /*	Split 32 bit value into bytes.
	  */
	  dec->ob[0] = (unsigned char)((val >> 24) & 0xFFUL);
	  dec->ob[1] = (unsigned char)((val >> 16) & 0xFFUL);
	  /*	Set input size, output size and result.
	  */
	  dec->is = 0;
	  dec->os = 2;
	  back = DK4_EDSTM_FINISHED;
	} break;
	case 2: {				

#line 341 "dk4a85d.ctr"
	  /*	Calculate 32 bit value from encoded values.
	  */
	  val =
	  dk4a85e_pow_85[0] *
	  ((unsigned long)((unsigned char)(dec->ib[0] - (char)33)) & 0xFFUL)
	  +
	  dk4a85e_pow_85[1] *
	  ((unsigned long)((unsigned char)(dec->ib[1] - (char)33)) & 0xFFUL)
	  ;
	  

#line 351 "dk4a85d.ctr"
	  /*	Check whether truncation of a3, a4, and a5 modified the 32 bit
	  	value, correct least significant used byte if necessary.
	  */
	  if (0UL != (val & 0x00FFFFFFUL)) {
	    val += 0x01000000UL;
	  }
	  

#line 358 "dk4a85d.ctr"
	  /*	Split 32 bit value into bytes.
	  */
	  dec->ob[0] = (unsigned char)((val >> 24) & 0xFFUL);
	  /*	Set input size, output size and result.
	  */
	  dec->is = 0;
	  dec->os = 1;
	  back = DK4_EDSTM_FINISHED;
	} break;
	default: {
	  dk4error_set_simple_error_code(erp, DK4_E_SYNTAX);
	} break;
      }
    }
  } else {
    dk4error_set_simple_error_code(erp, DK4_E_INVALID_ARGUMENTS);
  } 

#line 375 "dk4a85d.ctr"
  return back;
}



int
dk4a85_dec_output(
  const unsigned char **dptr, size_t *szptr, dk4_a85_dec_t *dec, dk4_er_t *erp
)
{
  int		 back	=	0;
  if ((NULL != dec) && (NULL != dptr) && (NULL != szptr)) {
    if (0 < dec->os) {
      *dptr = &(dec->ob[0]);
      *szptr = dec->os;
      back = 1;
    } else {
      *dptr = NULL;
      *szptr = 0;
      back = 0;
    }
  } else {
    dk4error_set_simple_error_code(erp, DK4_E_INVALID_ARGUMENTS);
  }
  return back;
}