Utility functions for C3

id.c3

module util::id;
import libc;

alias Id = String;

fn Id generate_id(uint length) {
    /* Valid IDs are a-z lowercase *length* char strings */
    DString id = {};
    while (id.len() < length) {
        int r = (97 + (libc::rand() % 26));
        id.appendf("%c", (char)r);
    }

    return id.str_view();
}

util.c3

module util;
import libc;
import std::core;
import std::io;
import std::io::file;
import std::collections;

alias Bytes = char[];

extern fn char* _c_getenv(char* name) @cname("getenv");

fn String cstr_to_str(char* cstr) {
    usz len = 0;
    while (cstr[len] != 0) {
        len++;
    }

    if (len == 0) return "";
    return (String)cstr[0..len];
}

/* This is like env::tget_var("VARIABLE")!! but returns nothing gracefully */
fn String get_env_var(String variable) {
    char* cstr = _c_getenv(variable);
    if (!cstr) return "";
    return cstr_to_str(cstr);
}

fn String str_upper(String s) {
    DString uppercased = {};
    foreach (ch : s) {
        if (ch >= 'a' && ch <= 'z') {
            ch -= 32;
        }
        uppercased.appendf("%c", ch);
    }
    return uppercased.str_view();
}

fn bool char_is_number(char ch) {
    bool number = false;
    if (ch >= '0' && ch <= '9') {
        number = true;
    }
    return number;
}

fn String int_str(int n) {
    DString str = {};
    str.appendf("%d", n);
    return str.str_view();
}

fn String uint_str(uint n) {
    return int_str((int)n);
}

fn int str_int(String n) {
    char* end;
    return (int)libc::strtol(n, &end, 10);
}

fn uint str_uint(String n) {
    return (uint)str_int(n);
}

fn uint hexadecimal_to_uint(String hex) {
    char* end;
    return (uint)libc::strtoul(hex, &end, 16);
}

/* Parses + integers, not negatives */
fn int parse_int_from_string(String str) {
    DString n = {};
    foreach (char ch : str) {
        if (ch >= 48 && ch <= 57) {
            n.appendf("%c", ch);
        }
    }

    if (n.len() == 0) {
        n.appendf("%c", '0');
    }

    return str_int(n.str_view());
}

fn bool int_bool(int n) {
    if (n == 1) return true;
    return false;
}

fn String bool_str(bool b) {
    if (b) return "true";
    return "false";
}

fn bool str_bool(String b) {
    if (b == "true") return true;
    return false;
}

fn Bytes str_to_bytes(String str) {
    return (Bytes)str;
}

fn String join_str_list(List{String}* list, String join_chars) {
    DString joined = {};
    foreach (str : list) {
        joined.appendf("%s%s", str, join_chars);
    }

    return joined.str_view();
}

fn String read_file_to_string(String filename) {
    long size = file::get_size(filename)!!;
    File f = file::open(filename, "rb")!!;
    defer (void)f.close();

    (void)f.seek(0, SeekOrigin.FROM_START);

    char* buffer = mem::alloc_array(char, size);
    long bytes_read = f.read(buffer[:size])!!;

    return (String)buffer[:bytes_read];
}

fn void write_string_to_file(String filename, String data, bool newLine) {
    File f = file::open(filename, "wb")!!;
    defer (void)f.close();

    f.write(data)!!;

    if (newLine) f.write("\n")!!;
}