/* File for shell related functions. *
 * By Bryce Schroeder, 2008          */
#ifndef _SHELL_ARGS_H_
#define _SHELL_ARGS_H_
#include <assert.h>
#include <stdlib.h>
#include <unistd.h>
#include <ctype.h>
#include <sys/wait.h>
#include <string.h>
#include <stdio.h>

/* This structure describes a command to be executed.                 *
 * Possible TODO: history array of these rather than strings?         */
typedef struct {
    int    background; /* 1 if it will be executed in the background. */
    int    cmd_index;  /* Index in argv of the command name.          */
    char **argv;       /* Array to hold the parsed commands.          */
    int    argc;       /* Length of the argument array.               */
} command_t;

/* Create a new command_t by parsing a line.                          *
 * line_buffer: the command line to parse.                            *
 * returns NULL if the line is empty. All the command_* functions can *
 * deal with NULL gracefully.                                         */
command_t *command_new  (const char *line_buffer);

/* Execute a command from a command_t struct. The function may or may *
 * not block.                                                         *
 * cmd: command_t to execute.                                         */
void       command_exec (command_t *cmd);

/* Free the memory of a command_t to dispose of it properly.          *
 * cmd: the command_t to be deleted.                                  */
void       command_free (command_t *cmd);

/* Count how many words are in a string.                              *
 * str: the string.                                                   */
int        word_count   (const char *str);

/* Split a string along spaces into an array provided.                *
 * str: the string to be split.                                       *
 * size: pointer to an integer to write argc into. (Or NULL).         *
 * Returns a null-terminated char* array.                             */
char     **argv_new     (const char *str, int *size);

/* Copy a slice from a string, from indicies begin to end inclusive.  */
char      *copy_slice   (const char *str, int begin, int end);

/* Release the memory of an argv type null terminated array.          */
void       argv_free    (char **argv);

/* Return the last character of a nonempty null-terminated string.    */
char       last_char    (char *str);

#endif /* Guard */