gsmpdu7bit.c

encode/decode gsm sms 7bit pdu format text. orginally written for palm os, but it don t make any spe

void IntToHexString(short int len, char *slen)
{
  char hexchar[]={'0','1','2','3','4','5','6','7','8','9',
                  'A','B','C','D','E','F'};
  sprintf(slen, "%c%c",hexchar[(len & 0xF0)>>4],hexchar[len & 0x0F]);
}


void HexStrToInt(char *str, int * result)
{
  //char HexChars[]={'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'};
  int high=0;
  int low=0;
  if ((str[0]>='0') && (str[0]<='9')) high=str[0]-'0';
  if ((str[0]>='A') && (str[0]<='F')) high=str[0]-'A'+10;
  if ((str[0]>='a') && (str[0]<='f')) high=str[0]-'a'+10;
  if ((str[1]>='0') && (str[1]<='9')) low=str[1]-'0';
  if ((str[1]>='A') && (str[1]<='F')) low=str[1]-'A'+10;
  if ((str[1]>='a') && (str[1]<='f')) low=str[1]-'a'+10;
   *result=high*16+low;
}


void EncodePDU7BitData(char* input, char*output)
{
  int pos=0;
  int c1, c2, r, temp;
  int i;
  int inputlen;
  inputlen=StrLen(input);
  IntToHexString(inputlen, output+pos);
  pos+=2;
  for (i=0;i<inputlen;i++)
  {
	if (i==inputlen)
	  c2=0;
	else
	  c2=input[i+1] & 0x7F;
	c1=input[i] & 0x7F;
	r=(i+1) % 8;
	if (r!=0)
	{
	  temp=((c1 >> (r - 1)) | (c2 << (8-r)))& 0xFF;
	  IntToHexString(temp, output+pos);
	  pos+=2;
	}
  }
}
void DecodePDU7BitData(char* input, char*output)
{
  int len, temp;
  char tempstr1[3], tempstr2[3];
  unsigned int tempval,i, j, pos;
  int temp1, temp2;
  int inputlen;

  inputlen=0;
  while ((input[inputlen]!=10)&&(input[inputlen]!=13)) inputlen++;
  
  
  pos=0;
  HexStrToInt(input, &len);
  j=2;
  for (i=1;i<=((inputlen-2) /2);i++)
  {
	if ((i %7)==1)
	{
	  HexStrToInt(input+j, &temp);
	  output[pos]=(temp & 0x7F);
	  //if (output[pos]==0) output[pos]=' ';
	  pos++;
	}
	else if ((i % 7) ==0)
	{
	  tempstr1[0]=input[j];tempstr1[1]=input[j+1];tempstr1[2]=0;
	  tempstr2[0]=input[j-2];tempstr2[1]=input[j-1];tempstr2[2]=0;
	  HexStrToInt(tempstr1, &temp1);
	  HexStrToInt(tempstr2, &temp2);
	  tempval=temp1*0x100+temp2;
	  output[pos]=(tempval>>2)& 0x7F;
	  //if (output[pos]==0) output[pos]=' ';
	  pos++;

	  output[pos]=(tempval>>9)&0x7F;
	  //if (output[pos]==0) output[pos]=' ';
	  pos++;
	}
	else
	{
	  tempstr1[0]=input[j];tempstr1[1]=input[j+1];tempstr1[2]=0;
	  tempstr2[0]=input[j-2];tempstr2[1]=input[j-1];tempstr2[2]=0;
	  HexStrToInt(tempstr1, &temp1);
	  HexStrToInt(tempstr2, &temp2);
	  tempval=temp1*0x100+temp2;

	  output[pos]=(tempval >> (9 - (i % 7))) & 0x7F;
	  //if (output[pos]==0) output[pos]=' ';
	  pos++;
	}
	j+=2;
  }
  output[len]=0;
}