numerus_cli.c

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#include <stdio.h>   /* For `printf()` */
#include <stdlib.h>  /* For `malloc()`, `free()`, `strtod()` */
#include <ctype.h>   /* For `isspace()`, `tolower()` */
#include <string.h>  /* For `strcmp()` */
#include "numerus.h"

#define NUMERUS_PROMPT_AGAIN 1


#define NUMERUS_STOP_REPL 0

static const char *PROMPT_TEXT = "numerus> ";
static const char *WELCOME_TEXT = ""
"+-----------------+\n"
"|  N V M E R V S  |\n"
"+-----------------+\n";
static const char *INFO_TEXT = ""
"Numerus, C library for conversion and manipulation of roman numerals.\n"
"Version 2.0.0, Command Line Interface\n"
"Copyright (c) 2015-2016 Matjaž Guštin <dev@matjaz.it> http://matjaz.it\n"
"This software is subject to the terms of the BSD 3-Clause license.\n"
"Project page and source code: https://github.com/TheMatjaz/Numerus\n";
static const char *MOO_TEXT = "This is not an easter egg. Try `ascii`.\n";
static const char *PING_TEXT = "Pong.\n";
static const char *AVE_TEXT = "Ave tibi!\n";
static const char *HELP_TEXT = ""
"For ANY information about the library or the syntax of roman numeral, \n"
"check the documentation available on https://thematjaz.github.io/Numerus/\n\n"
""
"To convert an (arabic) integer to a roman numeral or vice-versa,\n"
"just type it in the shell and press enter.\n"
"Other Numerus commands are:\n\n"
""
"pretty        switches on/off the pretty printing of long roman numerals\n"
"              (with overlined notation instead of underscore notation)\n"
"              and the pretty printing of values as integer and fractional part\n"
"?, help       shows this help text\n"
"info, about   shows version, credits, licence, repository of Numerus\n"
"exit, quit    ends this shell\n\n"
""
"We also have: moo, ping, ave.\n";
static const char *QUIT_TEXT = "Vale!\n";
static const char *ASCII_TEXT = ""
" ____  _____   ____   ____   ____    ____   _________   _______    ____   ____    _______ \n"
"|_   \\|_   _| |_  _| |_  _| |_   \\  /   _| |_   ___  | |_   __ \\  |_  _| |_  _|  /  ___  |\n"
"  |   \\ | |     \\ \\   / /     |   \\/   |     | |_  \\_|   | |__) |   \\ \\   / /   |  (__ \\_|\n"
"  | |\\ \\| |      \\ \\ / /      | |\\  /| |     |  _|  _    |  __ /     \\ \\ / /     '.___`-. \n"
" _| |_\\   |_      \\ ' /      _| |_\\/_| |_   _| |___/ |  _| |  \\ \\_    \\ ' /     |`\\____) |\n"
"|_____|\\____|      \\_/      |_____||_____| |_________| |____| |___|    \\_/      |_______.'\n";
static const char *UNKNOWN_COMMAND_TEXT = "Unknown command or wrong roman numeral syntax:\n";
static const char *PRETTY_ON_TEXT = "Pretty printing is enabled.\n";
static const char *PRETTY_OFF_TEXT = "Pretty printing is disabled.\n";
static int pretty_printing = 0;


static char *_num_get_first_word_trimmed_lowercased(char *string) {
    while(isspace(*string)) {
        string++;
    }
    if(*string == '\0') {
        /* The string was full of whitespaces */
        return string;
    }
    char *first_word_start = string;
    while (*string != '\0' && !isspace(*string)) {
        *string = (char) tolower(*string);
        string++;
    }
    *string = '\0';
    return first_word_start;
}


static short _num_string_is_double_zero(char *zero_as_string) {
    if (*zero_as_string == '-') {
        zero_as_string++;
    }
    while (*zero_as_string == '0') {
        zero_as_string++;
    }
    if (*zero_as_string == '.' || *zero_as_string == ',') {
        zero_as_string++;
        if (*zero_as_string == '0') {
            while (*zero_as_string == '0') {
                zero_as_string++;
            }
        } else {
            return 0;
        }
    }
    if (*zero_as_string == '\0') {
        return 1;
    } else {
        return 0;
    }
}


void _num_convert_to_other_form_and_print(char *string) {
    double value;
    char *roman;
    int errcode;
    /* This check is necessary because strtod() returns 0 in case of errors
     * AND in case finds an actual zero. Duh! */
    if (_num_string_is_double_zero(string)) {
        printf("%s\n", roman = numerus_double_to_roman(0, NULL));
        free(roman);
        return;
    }
    value = strtod(string, NULL);
    if (value != 0) {
        /* The string is a double */
        roman = numerus_double_to_roman(value, &errcode);
        if (errcode != NUMERUS_OK) {
            printf("%s\n", numerus_explain_error(errcode));
            if (errcode != NUMERUS_ERROR_MALLOC_FAIL) {
                free(roman);
            }
            return;
        }
        /* Successful conversion */
        if (pretty_printing == 1) {
            /* Enabled pretty printing */
            char *roman_pretty = numerus_overline_long_numerals(roman, &errcode);
            if (errcode != NUMERUS_OK) {
                printf("%s\n", numerus_explain_error(errcode));
            } else {
                /* Successful transformed into pretty format */
                printf("%s\n", roman_pretty);
                free(roman_pretty);
            }
        } else {
            /* Disabled pretty printing, just print the roman numeral */
            printf("%s\n", roman);
        }
        free(roman);
        return;
    }
    /* The string is not a double, trying as a roman numeral */
    value = numerus_roman_to_double(string, &errcode);
    if (errcode == NUMERUS_OK) {
        /* The string is a roman numeral */
        if (pretty_printing == 1) {
            /* Pretty printing enabled */
            char *pretty_value = numerus_create_pretty_value_as_double(value);
            if (pretty_value == NULL) {
                printf("%s\n", numerus_explain_error(NUMERUS_ERROR_MALLOC_FAIL));
            } else {
                /* Successful transformed into pretty format */
                printf("%s\n", pretty_value);
                free(pretty_value);
            }
        } else {
            /* Pretty printing disabled, just print the value */
            printf("%f\n", value);
        }
    } else {
        /* The command is not a value/a roman numeral or it has wrong syntax */
        printf("%s -> %s\n", UNKNOWN_COMMAND_TEXT, numerus_explain_error(errcode));
    }
}


static int _num_parse_command(char *command) {
    if (strcmp(command, "?") == 0 || strcmp(command, "help") == 0) {
        printf("%s", HELP_TEXT);
        return NUMERUS_PROMPT_AGAIN;
    } else if (strcmp(command, "moo") == 0) {
        printf("%s", MOO_TEXT);
        return NUMERUS_PROMPT_AGAIN;
    } else if (strcmp(command, "ascii") == 0) {
        printf("%s", ASCII_TEXT);
        return NUMERUS_PROMPT_AGAIN;
    } else if (strcmp(command, "info") == 0 || strcmp(command, "about") == 0) {
        printf("%s", INFO_TEXT);
        return NUMERUS_PROMPT_AGAIN;
    } else if (strcmp(command, "ave") == 0) {
        printf("%s", AVE_TEXT);
        return NUMERUS_PROMPT_AGAIN;
    } else if (strcmp(command, "pretty") == 0) {
        /* Toggles pretty printing */
        if (pretty_printing == 1) {
            pretty_printing = 0;
            printf("%s", PRETTY_OFF_TEXT);
            return NUMERUS_PROMPT_AGAIN;
        } else {
            pretty_printing = 1;
            printf("%s", PRETTY_ON_TEXT);
            return NUMERUS_PROMPT_AGAIN;
        }
    } else if (strcmp(command, "ping") == 0) {
        printf("%s", PING_TEXT);
        return NUMERUS_PROMPT_AGAIN;
    } else if (strcmp(command, "exit") == 0 || strcmp(command, "quit") == 0) {
        printf("%s", QUIT_TEXT);
        return NUMERUS_STOP_REPL;
    } else if (*command == '\0') {
        /* No inserted command, just an <enter> */
        return NUMERUS_PROMPT_AGAIN;
    } else {
        _num_convert_to_other_form_and_print(command);
        return NUMERUS_PROMPT_AGAIN;
    }
}


int numerus_cli(int argc, char **args) {
    char *command;
    /* line_buffer_size = 50 enough for every command,
     * gets reallocated by getline() if not enough */
    size_t line_buffer_size = 50;
    char *line = malloc(line_buffer_size);
    if (line == NULL) {
        numerus_error_code = NUMERUS_ERROR_MALLOC_FAIL;
        return NUMERUS_ERROR_MALLOC_FAIL;
    }
    if (argc > 1) {
        /* Parse main arguments and exit */
        args++;
        pretty_printing = 0;
        while (argc > 1) {
            command = _num_get_first_word_trimmed_lowercased(*args);
            _num_parse_command(command);
            args++;
            argc--;
        }
    } else {
        /* Enter command line interface */
        pretty_printing = 1;
        printf("%s", WELCOME_TEXT);
        int command_result = NUMERUS_PROMPT_AGAIN;
        while (command_result == NUMERUS_PROMPT_AGAIN) {
            printf("%s", PROMPT_TEXT);
            if (getline(&line, &line_buffer_size, stdin) == -1) {
                break;
            } else {
                command = _num_get_first_word_trimmed_lowercased(line);
                command_result = _num_parse_command(command);
            }
        }
    }
    free(line);
    return 0;
}