// COMP1521 21T2 GDB debugging example

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

void trim(char *str);
char **tokenise(char *str, char *sep);
void freeTokens(char **toks);

int main(int argc, char *argv[])
{
	if (argc != 2) exit(1);

	char *string = strdup(argv[1]);
	printf("Input: \"%s\"\n", string);
	trim(string);
	printf("Trimmed: \"%s\"\n", string);
	char **tokens = tokenise(string, " ");
	for (int i = 0; tokens[i] != NULL; i++)
		printf("tok[%d] = \"%s\"\n", i, tokens[i]);
	freeTokens(tokens);
	return 0;
}

// trim: remove leading/trailing spaces from a string
void trim(char *str)
{
	int first, last;
	first = 0;
	while (isspace(str[first])) first++;
	last  = strlen(str)-1;
	while (isspace(str[last])) last--;
	int i, j = 0;
	for (i = first; i <= last; i++) str[j++] = str[i];
	str[j] = '\0';
}

// tokenise: split a string around a set of separators
// create an array of separate strings
// final array element contains NULL
char **tokenise(char *str, char *sep)
{
	// temp copy of string, because strtok() mangles it
	char *tmp;
	// count tokens
	tmp = strdup(str);
	int n = 0;
	strtok(tmp, sep); n++;
	while (strtok(NULL, sep) != NULL) n++;
	free(tmp);
	// allocate array for argv strings
	char **strings = malloc((n+1)*sizeof(char *));
	assert(strings != NULL);
	// now tokenise and fill array
	tmp = strdup(str);
	char *next; int i = 0;
	next = strtok(tmp, sep);
	strings[i++] = strdup(next);
	while ((next = strtok(NULL,sep)) != NULL) strings[i++] = strdup(next);
	strings[i] = NULL;
	free(tmp);
	return strings;
}

// freeTokens: free memory associated with array of tokens
void freeTokens(char **toks)
{
	for (int i = 0; toks[i] != NULL; i++) free(toks[i]);
	free(toks);
}