C Zeichenketten und Speicher

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <assert.h>

char  *read_line(FILE *);

char **split    (const char *, const char *, int *);

int main(int argc, char *argv[])

{

  if (argc != 2) {

    printf("input file expected.\n");

    return EXIT_FAILURE;

  }

  FILE *input_file = fopen(argv[1], "r");

  if (NULL == input_file) {

    printf("couldn't open file %s.\n", argv[1]);

    return EXIT_FAILURE;

  }

  while (feof(input_file) == 0) {

    char *line = read_line(input_file);

    printf("%s\t%d\n", line, strlen(line));

    int num_tokens = 0;

    char **tokens = split(line, " ", &num_tokens);

    for (int i = 0; i < num_tokens; ++i) {

      printf("Token #%d: %s\t(%d)\n", (i + 1), tokens[i], strlen(tokens[i]));

      free(tokens[i]);

    }

    free(tokens);

    free(line);

  }

  fclose(input_file);

  return EXIT_SUCCESS;

}

char *read_line(FILE *input_file)

{

  assert (NULL != input_file);

  char *buffer = malloc(sizeof(char));

  assert (NULL != buffer);

  int length = 1;

  int index  = 0;

  int read = fgetc(input_file);

  while (EOF != read && '\n' != read) {

    if (index >= length) {

      length *= 2;

      buffer = realloc(buffer, length * sizeof(char) + 1);

      assert (NULL != buffer);

    }

    buffer[index] = read;

    ++index;

    read = fgetc(input_file);

  }

  buffer[index] = '\0';

  return buffer;

}

char **split(const char *str, const char *delimiters, int *num_tokens)

{

  assert (NULL != str);

  assert (NULL != delimiters);

  assert (NULL != num_tokens);

  char *string = malloc(strlen(str) + 1);

  assert (NULL != string);

  strcpy(string, str);

  char **tokens = malloc(sizeof(char *));

  assert (NULL != tokens);

  int number_tokens = 1;

  int index = 0;

  char *token = strtok(string, delimiters);

  while (NULL != token) {

    if (index >= number_tokens) {

      ++number_tokens;

      tokens = realloc(tokens, number_tokens * sizeof(char *));

      assert (NULL != tokens);

    }

    tokens[index] = malloc(strlen(token) + 1);

    assert (NULL != tokens[index]);

    strcpy(tokens[index], token);

    ++index;

    token = strtok(NULL, delimiters);

  }

  *num_tokens = number_tokens;

  return tokens;

}