Luna/apps/cat.cpp

#include <os/ArgumentParser.h>

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

static void do_cat(StringView path)
{
    FILE* f;

    if (path == "-") f = stdin;
    else
    {
        f = fopen(path.chars(), "r");
        if (!f)
        {
            perror(path.chars());
            exit(1);
        }
    }

    char buffer[4096];

    while (1)
    {
        size_t nread = fread(buffer, 1, sizeof(buffer), f);
        if (nread == 0) return;
        fwrite(buffer, 1, nread, stdout);
    }

    if (f != stdin) fclose(f);
}

int main(int argc, char** argv)
{
    StringView filename;

    os::ArgumentParser parser;
    parser.add_positional_argument(filename, "file"_sv, "-"_sv);
    Vector<StringView> extra_files = parser.parse(argc, argv).value();

    do_cat(filename);

    for (auto file : extra_files) { do_cat(file); }
}