#include <stdlib.h>
#include <string.h>
#include "readnums.h"

static int *get_number_line(FILE *f)
{
  int *nums;
  int size = 10, count = 0, num = 0, digits = 0;
  int ch;

  nums = (int*)malloc(sizeof(int) * size);

  while (1) {
    ch = fgetc(f);

    if ((ch == ' ') || (ch == '\r') || (ch == '\n') || (ch == EOF)) {
      if (digits != 0) {
        if (!num) {
          fprintf(stderr, "found a zero\n");
          abort();
        }
        if (count + 1 >= size) {
          int *new_nums;
          size *= 2;
          new_nums = (int*)malloc(sizeof(int) * size);
          memcpy(new_nums, nums, sizeof(int) * (count + 1));
          nums = new_nums;
        }
        nums[count] = num;
        count++;
        digits = 0;
        num = 0;
      }
    } 

    if (ch == '\r') {
      ch = fgetc(f);
      if (ch != '\n') {
        fprintf(stderr, "expected a newline after a carriage return\n");
        abort();
      }
      break;
    } else if (ch == '\n')
      break;
    else if (ch == EOF) {
      if (!count) return NULL;
      break;
    } else if (ch == ' ') {
      /* ignore space */
    } else if ((ch >= '0') && (ch <= '9')) {
      int new_num;
      digits++;
      new_num = (num * 10) + (ch - '0');
      
      if ((new_num / 10) != num) {
        fprintf(stderr, "number too large: %d...\n", num);
        abort();
      }

      num = new_num;
    } else {
      fprintf(stderr, "not a space, newline, return, or digit: %c\n", ch);
      abort();
    }
  }

  if (!count) {
    fprintf(stderr, "found an empty line\n");
    abort();
  } else {
    nums[count] = 0;
    return nums;
  }
}

int **get_number_lines(FILE *f)
{
  int **numss, *nums;
  int size = 10, count = 0;
 
  numss = (int**)malloc(sizeof(int*) * size);
 
  while (1) {
    nums = get_number_line(f);
    if (!nums)
      break;
    if (count + 1 >= size) {
      int **new_numss;
      size *= 2;
      new_numss = (int**)malloc(sizeof(int*) * size);
      memcpy(new_numss, numss, sizeof(int*) * (count + 1));
      numss = new_numss;
    }
    numss[count] = nums;
    count++;
  }

  numss[count] = NULL;

  return numss;
}