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

static int vertical_mode = 0;

typedef struct
{
   int width;     /* Maximum line length, excluding terminating LF */
   int height;    /* Line count */
   int size;      /* File size */
   int capacity;  /* Buffer size */
   char *data;    /* File contents */
   char *cursor;  /* Current read position */
} FileInfo;

int main(int argc, char **argv)
{
   int i, j, k, width, read_size, max_line_count = 0;
   FileInfo *files;
   FILE *infile;

   /* Load files */
   if( (files = (FileInfo*)calloc(sizeof(FileInfo), argc)) == NULL )
      return !puts("Out of memory");
   for(i = 1; i < argc; i++)
   {
      for(j = 1; j < i; j++)
      {
         if( strcmp(argv[i], argv[j]) == 0 )
         {
            /* Duplicate file specified on command line, no need to
               load the same file again.                            */
            memcpy(&files[i], &files[j], sizeof(FileInfo));
            break;
         }
      }
      if( j < i )
         continue;
      if( strcmp(argv[i], "-") != 0 )
      {
         if( (infile = fopen(argv[i], "rb")) == NULL )
            return printf("Can not open %s\n", argv[i]);
      }
      else
      {
         infile = stdin;
      }

      /* Load file to memory */
      do
      {
         files[i].capacity += 0x10000;
         if( (files[i].data = realloc(files[i].data, files[i].capacity + 1)) == NULL )
            return !puts("Out of memory");
         read_size = fread(files[i].data + files[i].size, 1, 0x10000, infile);
         files[i].size += read_size;
      } while( read_size == 0x10000 );

      /* Always make sure file ends with a LF */
      files[i].data[files[i].size] = '\n';
      files[i].cursor = files[i].data;

      fclose(infile);
      for(k = 0; k < files[i].size; k = j + 1)
      {
         for(j = k; j < files[i].size && files[i].data[j] != '\n'; j++);
         width = j - k;
         if( width > files[i].width )
            files[i].width = width;
         files[i].height++;
      }
   }

   /* Output concatenated files */
   for(i = 1; i < argc; i++)
   {
      if( files[i].height > max_line_count )
         max_line_count = files[i].height;
   }
   if( vertical_mode )
   {
      for(i = 1; i < argc; i++)
         fwrite(files[i].data, files[i].size, 1, stdout);
   }
   else
   {
      for(i = 0; i < max_line_count; i++)
      {
         for(j = 1; j < argc; j++)
         {
            width = 0;
            if( files[j].cursor - files[j].data < files[j].size )
            {
               while( *(files[j].cursor) != '\n' )
               {
                  putchar(*(files[j].cursor));
                  width++;
                  files[j].cursor++;
               }
               files[j].cursor++;
            }
            for(; width < files[j].width; width++)
               putchar(' ');
         }
         putchar('\n');
      }
   }

   /* Don't bother freeing memory */
   return 0;
}