dshlib.c

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

#include "dshlib.h"

int numInstanceOf(char *str, const char c) {
    int count = 0;
    while (*str != '\0') {
		if (*str == c) count++;
    	str++;
    }

    return count;
}

/*
 *  build_cmd_list
 *    cmd_line:     the command line from the user
 *    clist *:      pointer to clist structure to be populated
 *
 *  This function builds the command_list_t structure passed by the caller
 *  It does this by first splitting the cmd_line into commands by spltting
 *  the string based on any pipe characters '|'.  It then traverses each
 *  command.  For each command (a substring of cmd_line), it then parses
 *  that command by taking the first token as the executable name, and
 *  then the remaining tokens as the arguments.
 *
 *  NOTE your implementation should be able to handle properly removing
 *  leading and trailing spaces!
 *
 *  errors returned:
 *
 *    OK:                      No Error
 *    ERR_TOO_MANY_COMMANDS:   There is a limit of CMD_MAX (see dshlib.h)
strcat(command.args, inner_token); *                             commands.
 *    ERR_CMD_OR_ARGS_TOO_BIG: One of the commands provided by the user
 *                             was larger than allowed, either the
 *                             executable name, or the arg string.
 *
 *  Standard Library Functions You Might Want To Consider Using
 *      memset(), strcmp(), strcpy(), strtok(), strlen(), strchr()
 */
int build_cmd_list(char *cmd_line, command_list_t *clist)
{
	if (numInstanceOf(cmd_line, PIPE_CHAR) > CMD_MAX-1) return ERR_TOO_MANY_COMMANDS;
	
	if ((int)strlen(cmd_line) > SH_CMD_MAX) return ERR_CMD_OR_ARGS_TOO_BIG;
	
	clist->num = 0;

    char *outer_saveptr = NULL;
    char *inner_saveptr = NULL;
    char *outer_token = strtok_r(cmd_line, PIPE_STRING, &outer_saveptr);
    
    while (outer_token != NULL) {
        if (clist->num > CMD_MAX) return ERR_TOO_MANY_COMMANDS;

        command_t command;
        memset(&command, 0, sizeof(command_t));



        char *inner_token = strtok_r(outer_token, SPACE_STRING, &inner_saveptr);
        
		if (inner_token == NULL) {
			outer_token = strtok_r(NULL, PIPE_STRING, &outer_saveptr);
			continue;
		}