Template of CLI application for linux shell

c-template_linux_cli_application.c

//(1)=========================================================<< File Header >>=
/**
 * @file   c-template_linux_cli_application.c
 * @brief  <Application meaning> Ver 0.01
 * @author TD
 * @date   2020-05-31
 *
 * <pre> 2020 TD LICENSED CC0 </pre>
 ******************************************************************************/
//(2)======================================================<< System Include >>=
#include "stdio.h"
#include "stdlib.h"
#include "unistd.h"

//(3)========================================================<< User Include >>=
//(4)========================================================<< Local Macros >>=
#define CLI_BUF_SZ   (64)
#define VERSION      ("0.01")
#define VERSION_DATE ("2020-05-31")
#define VERSION_TIME ("14:00")

//(5)===============================================<< Local Macro Functions >>=
//(6)==================================================<< Local Type defines >>=
//(7)==================================================<< Local Enum defines >>=
//(8)==================================================<< Local Suruct/Union >>=
typedef struct _configure{
    int (*check)(char*);
    int (*act)(char*);
    const struct _configure* next;
}CONFIGURE;

//(9)===================================================<< Forward reference >>=
// utility
static int isDiff(const char* reference, const char* target);

// judge option argment
static int isHelp(char* arg);
static int isUnknownOption(char* arg);

// act option argment
static int actShowHelp(char* arg);

// application main
static int parseArgs(int argc, char *argv[]);
static int runConsoleTop(void);
static int runPipline(void);

//(10)===================================================<< Static variables >>=
// state machine for option argment
static const CONFIGURE argments[] = {
    {&isHelp, &actShowHelp, argments},
    {&isUnknownOption, &actShowHelp, argments} // Always the end of table.
};

// option configure values
static char* s_OwnName = NULL;

//(11)===================================================<< Static functions >>=
/* @brief Is the string difference.
 * @param target option string
 * @return 0: no !0: yes and value
 *****************************************************************************/
static int isDiff(const char* reference, const char* target)
{

    while(('\0' != *reference) && ('\0' != *target) && (*reference == *target)){
        reference++;
        target++;
    }

    return (unsigned char)*reference - (unsigned char)*target;
}

/* @brief Is the option showing help.
 * @param arg option string
 * @return 0: no !0: yes
 *****************************************************************************/
static int isHelp(char* arg)
{
    int ret = 0;

    if(0 != isDiff("-h", arg)){
        ret = 1;
    }
    else if(0 != isDiff("--help", arg)){
        ret = 1;
    }
    else if(0 != isDiff("-v", arg)){
        ret = 1;
    }
    else if(0 != isDiff("--version", arg)){
        ret = 1;
    }
    else{
        ret = 0;
    }

    return ret;
}

/* @brief Always true.
 * @param arg option string. but not use.
 * @return 0: no !0: yes
 *****************************************************************************/
static int isUnknownOption(char* arg)
{
    arg = NULL;

    return 1;
}

/* @brief Show the help string.
 * @param arg option string. but not use.
 * @return 0: no error !0: error
 *****************************************************************************/
static int actShowHelp(char* arg)
{
    arg = NULL;

    fprintf(stderr, "# About\n\n");
    fprintf(stderr, "The %s is a shell application based on POSIX.\n", s_OwnName);
    fprintf(stderr, "<Description>\n\n");
    fprintf(stderr, "# Usage\n\n## Command\n\n");
    fprintf(stderr, "%s [Options]\n", s_OwnName);
    fprintf(stderr, "\n");
    fprintf(stderr, "## Options\n\n");
    fprintf(stderr, "+ -h |--help |-v |--version\n  - Show this help.\n");
    fprintf(stderr, "\n");
    fprintf(stderr, "# Version\n\n%sT%s %s\n\n", VERSION_DATE, VERSION_TIME, VERSION);
    fprintf(stderr, "# LICENSE\n\n[CC0(Public domain)](https://creativecommons.org/publicdomain/zero/1.0/legalcode)\n\n");
    fprintf(stderr, "# Author\n\n2020 TD\n");

    return 1;
}

/* @brief parsing argments.
 * @param argc numbers of argments.
 * @param argv argment head.
 * @return 0: no error !0: error
 *****************************************************************************/
static int parseArgs(int argc, char *argv[])
{
    size_t option = 0;
    const CONFIGURE* decision = argments;

    s_OwnName = argv[option];
    for(option = 1; argc > option; option++){
        while(0 == decision->check(argv[option])){
            decision++;
        }

        if(decision->act(argv[option])){
            return 1;
        }

        decision = decision->next;
    }

    return 0;
}

/* @brief shell run from console.
 * @return 0: no error !0: error
 * @note The option reference to global values.
 *****************************************************************************/
static int runConsoleTop(void)
{
    int ret = 0;

    ret = actShowHelp(NULL);

    return ret;
}

/* @brief shell run from pipline.
 * @return 0: no error !0: error
 * @note The option reference to global values.
 *****************************************************************************/
static int runPipline(void)
{
    int ret = 0;
    ssize_t length = 0;
    char* buffer = NULL;

    while(!(feof(stdin))){
        length = getline(&buffer, &(size_t){CLI_BUF_SZ}, stdin);
        if(0 < length){
            printf("%s", buffer);
        }
    }
    free(buffer);

    return ret;
}

//(12)===================================================<< Global variables >>=
//(13)===================================================<< Function defines >>=
/* @brief shell command body.
 * @param argc numbers of argments.
 * @param argv argment head
 * @return 0: no error !0: error
 *****************************************************************************/
int main(int argc, char *argv[])
{
    int ret = 0;

    ret = parseArgs(argc, argv);

    if(0 != ret){
        ;
    }
    else if(isatty(fileno(stdin))){
        ret = runConsoleTop();
    }
    else{
        ret = runPipline();
    }

    return ret;
}

//(14)==========================================================<< Chage Log >>=
//(15)========================================================<< End Of File >>=