/*
  Split the lines of the input files, in a sequential way,
  between up to 10 output files.

  The supplied file name should contain the list of files to
  merge and split, one file name per line
*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

int main(int argc, char *argv[])
{
  char fullLine[1024], fn[6][1024];
  int totalLines;
  int outputLines;
  int splitWay;

  char *cPnt;
  FILE *fList;
  FILE *f1,*f2,*f3,*f4,*f5,*f6, *o1,*o2,*o3,*o4,*o5,*o6,*o7,*o8,*o9,*o10;
  int red1, red2, red3, red4, red5, red6, rIn;
  int i,j,fin;

  if( argc != 3 ) {
    printf ("%d is the wrong number of arguments\n", argc-1);
    printf("Split the lines of the input files, in a sequential way,\n");
    printf("between up to 10 output files.\n\n");

    printf("The supplied file name should contain the list of files to\n");
    printf("merge and split (up to 6), one file name per line\n");
    printf ("   Please supply: input_file_name AND split-way (from 2-10)\n");
    exit(1);
  }

  splitWay = atoi(argv[2]);
  if ( splitWay < 2 || splitWay > 10 ) {
    printf ("%d-way split is not legal\n", splitWay);
    exit(1);
  }

  fList = fopen(argv[1], "r");
  rIn = 0;
  while(1) {
    cPnt = fgets( fullLine, 1024, fList );
    if (cPnt == NULL ) break;
    strcpy((char *) &(fn[rIn][0]), cPnt);
    fn[rIn][strlen(cPnt)-1] = '\0';
    if( ++rIn > 5 ) break;
  }
  fclose(fList);
  if( rIn == 0 ) {
    printf ("No input file names read, abort\n");
    exit(1);
  }

  totalLines=0;
  outputLines=0;
  red1=0;
  red2=1;
  red3=1;
  red4=1;
  red5=1;
  red6=1;
  switch (rIn)
    {
    case 6:
      red6=0;
      f6 = fopen((char *)&(fn[5][0]), "r");
    case 5:
      red5=0;
      f5 = fopen((char *)&(fn[4][0]), "r");
    case 4:
      red4=0;
      f4 = fopen((char *)&(fn[3][0]), "r");
    case 3:
      red3=0;
      f3 = fopen((char *)&(fn[2][0]), "r");
    case 2:
      red2=0;
      f2 = fopen((char *)&(fn[1][0]), "r");
    case 1:
      red1=0;
      f1 = fopen((char *)&(fn[0][0]), "r");
      break;
    }
  i=1;
  j=1;
  fin=0;

  switch ( splitWay ) {
  case 10:
    o10 = fopen("mrg10.txt", "w");
  case 9:
    o9 = fopen("mrg09.txt", "w");
  case 8:
    o8 = fopen("mrg08.txt", "w");
  case 7:
    o7 = fopen("mrg07.txt", "w");
  case 6:
    o6 = fopen("mrg06.txt", "w");
  case 5:
    o5 = fopen("mrg05.txt", "w");
  case 4:
    o4 = fopen("mrg04.txt", "w");
  case 3:
    o3 = fopen("mrg03.txt", "w");
  case 2:
    o2 = fopen("mrg02.txt", "w");
    o1 = fopen("mrg01.txt", "w");
    break;
  default:
    printf ("%d-way split is not legal\n", splitWay);
    exit(1);
    break;
  }

  while(1) {
    fin=0;
    if ( red1+red2+red3+red4+red5+red6 == 6 ) {
      break;
    }
    switch (i)
      {
      case 1:
	if (red1 == 0 ) {
	  cPnt = fgets( fullLine, 512, f1 );
	  if ( cPnt == NULL ) {
	    red1=1;
	    fin=1;
	  }
	}
	else {
	  fin=1;
	}
	break;
      case 2:
	if (red2 == 0 ) {
	  cPnt = fgets( fullLine, 512, f2 );
	  if ( cPnt == NULL ) {
	    red2=1;
	    fin=1;
	  }
	}
	else {
	  fin=1;
	}
	break;
      case 3:
	if (red3 == 0 ) {
	  cPnt = fgets( fullLine, 512, f3 );
	  if ( cPnt == NULL ) {
	    red3=1;
	    fin=1;
	  }
	}
	else {
	  fin=1;
	}
	break;
      case 4:
	if (red4 == 0 ) {
	  cPnt = fgets( fullLine, 512, f4 );
	  if ( cPnt == NULL ) {
	    red4=1;
	    fin=1;
	  }
	}
	else {
	  fin=1;
	}
	break;
      case 5:
	if (red5 == 0 ) {
	  cPnt = fgets( fullLine, 512, f5 );
	  if ( cPnt == NULL ) {
	    red5=1;
	    fin=1;
	  }
	}
	else {
	  fin=1;
	}
	break;
      case 6:
	if (red6 == 0 ) {
	  cPnt = fgets( fullLine, 512, f6 );
	  if ( cPnt == NULL ) {
	    red6=1;
	    fin=1;
	  }
	}
	else {
	  fin=1;
	}
	break;
      default:
	fin=1;
	break;
      }
    i=(i<6)?i+1:1;
    if ( fin == 1 ) {
      continue;
    }
    totalLines++;
    //    pLast = cPnt + strlen(fullLine);

    switch (j) 
      {
      case 1:
	fputs(fullLine, o1);
	break;
      case 2:
	fputs(fullLine, o2);
	break;
      case 3:
	fputs(fullLine, o3);
	break;
      case 4:
	fputs(fullLine, o4);
	break;
      case 5:
	fputs(fullLine, o5);
	break;
      case 6:
	fputs(fullLine, o6);
	break;
      case 7:
	fputs(fullLine, o7);
	break;
      case 8:
	fputs(fullLine, o8);
	break;
      case 9:
	fputs(fullLine, o9);
	break;
      case 10:
	fputs(fullLine, o10);
	break;
      default:
	break;
      }
    j=(j<splitWay)?j+1:1;
    outputLines++;
  }
  switch (rIn)
    {
    case 6:
      fclose(f6);
    case 5:
      fclose(f5);
    case 4:
      fclose(f4);
    case 3:
      fclose(f3);
    case 2:
      fclose(f2);
    case 1:
      fclose(f1);
      break;
    }

  switch ( splitWay ) {
  case 10:
    fclose(o10);
  case 9:
    fclose(o9);
  case 8:
    fclose(o8);
  case 7:
    fclose(o7);
  case 6:
    fclose(o6);
  case 5:
    fclose(o5);
  case 4:
    fclose(o4);
  case 3:
    fclose(o3);
  case 2:
    fclose(o2);
    fclose(o1);
    break;
  }

  printf( "%d lines read\n%d lines output\n",
	  totalLines, outputLines);
  exit(0);
}