#include <stdio.h>
#include <stdlib.h>
#include <dos.h>
#include <string.h>
#include <io.h>
#include <fcntl.h>
#include <ctype.h>
#include <dir.h>

#define max_line_length 250

extern int errno, _doserrno;

int ValidMIME (char *);

char  * ReadInput( FILE * __stream, char * __s, int _q, int * __n);

char char_set[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
int char_table[128];

main (int argc, char *argv[])
{
	 FILE *inputfile;
	 char inputpath[MAXPATH+1];
	 char inputfilename[MAXPATH+1];
	 char input_string[max_line_length];
	 char * tempchar;
	 char argoutputfilename[MAXPATH+1];
	 int files_processed = 0;
	 int ii,jj;
	 int line_counter = 0;

	 for (ii=0 ; ii<128 ; ++ii)
		  char_table[ii] = -1;
	 tempchar = char_set;
	 for (ii=0 ; ii <= strlen(char_set) ; ii++)
		  {
			char_table[*tempchar++] = ii;
		  }

	 if (argc<2 || argc>3)
		 {
		  printf("Invalid number of parameters %u\n",argc-1);
		  printf("Usage: de-mime inputfile [outputfile]\n");
		  return 8;
		 }
	 else
		  strcpy(inputfilename,argv[1]);
	 if (argc > 2)
		  {
			strcpy(argoutputfilename,argv[2]);
		  }

	 inputfile = fopen(inputfilename,"rt");

	 if (inputfile == NULL)
		  {
			printf("Input file - %s - could not be opened\n",inputfilename);
			return 4;
		  }

	 tempchar = strrchr(inputfilename,'\\') ;

	 if  (tempchar != NULL)
		  {
			ii = (int) (tempchar-inputfilename+1);
			strncpy(inputpath,inputfilename,ii);
			inputpath[ii] = '\0';
		  }
	 else
		  {
			inputpath[0] = '\0';
		  }

	 if (ReadInput(inputfile,input_string,max_line_length,&line_counter) == NULL)
		  {
			printf("File %s is empty\n",argv[1]);
			fclose(inputfile);
			return 4;
		  }

	 for (;feof(inputfile)==0;)
		  {
			char *nameptr;
			char suggestedfilename[MAXPATH+1];
			char outputfilename[MAXPATH+1];
			FILE *outputfile;
			int ii;
			int start_line;
			long int output_size;
			char quotechar;

			suggestedfilename[0] = '\0';

			for ( ; (!ValidMIME(input_string) || strlen(input_string) < 12) &&
					  feof(inputfile)==0 ; )
				 {
				  nameptr = strstr(input_string,"name=");
				  if (nameptr != NULL)
						{
						 strcpy(suggestedfilename,nameptr+6);
						 nameptr = nameptr+5;
						 quotechar = *nameptr;
						 for (ii=0 ; suggestedfilename[ii]!=quotechar ; ii++)
							  ;
						 suggestedfilename[ii] = '\0';
						}
				  ReadInput(inputfile,input_string,max_line_length,&line_counter);
				 }

			if (feof(inputfile) != 0)
				 break;

			if (suggestedfilename[0] != '\0')
				 {
				  strcpy(outputfilename,inputpath);
				  strcat(outputfilename,suggestedfilename);
				 }
			else
				 {
				  if (argc > 2)
						{
						 for (ii = 0; (argoutputfilename[ii] != '\\') &&
											(ii < strlen(argoutputfilename)) ; ++ii) ;
						 if (argoutputfilename[ii] != '\\')
							  {
								strcpy(outputfilename,inputpath);
								strcat(outputfilename,argoutputfilename);
							  }
						 else
							  {
								strcpy(outputfilename,argoutputfilename);
							  }
						}
				  else
						{
						 outputfilename[0] = '\0';
						}
				 }

			for (outputfile = NULL ; outputfile == NULL ; )
				 {
				  if (outputfilename[0] != '\0')
						{
						 outputfile=fopen(outputfilename,"rb");
						 if (outputfile != NULL)
							  {
								printf("Outputfile %s already exists\n",outputfilename);
								fclose(outputfile);
								outputfile = NULL;
							  }
						 else
							  {
								outputfile=fopen(outputfilename,"wb");
								if (outputfile == NULL)
									 {
									  printf("Error creating output file %s",
																			 outputfilename);
									  printf(" Errno=%d, _doserrno=%d\n",
																			errno,_doserrno);
									 }
							  }
						}
				  else
						{
						 printf("Output filename not specified\n");
						}
				  if (outputfile == NULL)
						{
						 printf("Enter outputfile name: ");
						 for (ii = 0; ii < 64; ++ii)
							  {
								int GottonChar;
								GottonChar = getchar();
								suggestedfilename[ii] = GottonChar;
								if (GottonChar == '\n' || GottonChar == EOF)
									 {
									  suggestedfilename[ii] = '\0';
									  break;
									 }
							  }
						 for (ii = 0; (suggestedfilename[ii] != '\\') &&
											(ii < strlen(suggestedfilename)) ; ++ii)
							  ;
						 if (suggestedfilename[ii] != '\\')
							  {
								strcpy(outputfilename,inputpath);
								strcat(outputfilename,suggestedfilename);
							  }
						 else
							  {
								strcpy(outputfilename,suggestedfilename);
							  }
						}
				 }

			printf("Creating output file #%d - %s - starting at line %d\n",
									  ++files_processed,outputfilename,line_counter);

			start_line = line_counter;
			output_size = 0;

			for ( ; feof(inputfile) == 0 ; )
				 {
				  char output_buffer[3];
				  int output_length;
				  char * charptr;
				  int ii;
				  int sextet[4];

				  charptr = &input_string[0];

				  for (ii=0 ; ii<strlen(input_string); ii=ii+4)
						{
						 for (jj=0; jj<4; jj++)
							  {
								sextet[jj] = char_table[*charptr++];
							  }
						 if (sextet[0] < 0)
							  {
								output_length = 0;
								break;
							  }
						 if (sextet[2] < 0)
							  output_length = 1;
						 else
							  if (sextet[3] < 0)
									output_length = 2;
							  else
									output_length = 3;

						 output_buffer[0] = 4*sextet[0]+sextet[1]/16;
						 output_buffer[1] = 16*(sextet[1]%16)+sextet[2]/4;
						 output_buffer[2] = 64*(sextet[2]%64)+sextet[3];

						 fwrite(&output_buffer[0],output_length,1,outputfile);

						 output_size += output_length;

						 if (output_length < 3)
							  break;
						}
				  ReadInput(inputfile,input_string,max_line_length,&line_counter);

				  if (output_length < 3)
						break;
				 }

			printf("%s succesfully created, lines = %d, bytes = %d\n",
						 outputfilename,line_counter-start_line+1,output_size);

			fclose(outputfile);
		  }

	 fclose(inputfile);

	 if (files_processed == 0)
		  {
			printf("No valid MIME input was detected\n");
			return 4;
		  }
	 printf("%d output files created\n",files_processed);
	 return 0 ;
}

int ValidMIME (char *input_string)
{
 if ((strlen(input_string)%4 > 0)  ||  (strlen(input_string)==0))
	  {
		printf("Invalid MIME - %s\n",input_string);
		return 0;
	  }
 return (strspn(input_string,char_set) == strlen(input_string));
}

char * ReadInput (FILE * inputfile, char * input_string,
						int input_string_size, int * line_counter)
{
 char * read_result;
 int ii;
 read_result = fgets(input_string,input_string_size,inputfile);
 if (read_result != NULL)
	  {
		++(*line_counter);
		ii = strlen(input_string)-1;
		input_string[ii] = '\0';
	  }
 return read_result;
}