#define _GNU_SOURCE

#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <ctype.h>
#include <string.h>
#include <signal.h>

void *
xmalloc(size_t size) {
    if (size == 0)
        return NULL;
    void *p = malloc(size);
    if (!p)
        abort();
    return p;
}

void *
xrealloc(void *p, size_t size) {
    if ((size == 0) && (p == NULL))
        return NULL;
    p = realloc(p, size);
    if (!p)
        abort();
    return p;
}

char *
uppercase(char *str) {
    int i = 0;
    do {
        str[i] = (char) toupper(str[i]);
    } while (str[i++] != '\0');
    return str;
}

bool
endswith(const char *str, const char *suffix) {
    size_t str_len = strlen(str);
    size_t suffix_len = strlen(suffix);
    return str_len > suffix_len && !strcmp(str + (str_len - suffix_len), suffix);
}

int
get_sig_name(int sig, char *buf) {
    int n = sprintf(buf, "SIG%s", sig < NSIG ? strsignal(sig) : "unknown");
    uppercase(buf);
    return n;
}

int
get_sig(const char *sig_name) {
    if (strcasestr(sig_name, "sig") != sig_name || strlen(sig_name) <= 3) {
        return -1;
    }
    for (int sig = 1; sig < NSIG; sig++) {
        const char *name = strsignal(sig);
        if (strcasecmp(name, sig_name + 3) == 0)
            return sig;
    }
    return -1;
}

// https://github.com/darkk/redsocks/blob/master/base64.c
char *
base64_encode(const unsigned char *buffer, size_t length) {
    static const char b64[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
    char *ret, *dst;
    unsigned i_bits = 0;
    int i_shift = 0;
    int bytes_remaining = (int) length;

    ret = dst = xmalloc((size_t) (((length + 2) / 3 * 4) + 1));
    while (bytes_remaining) {
        i_bits = (i_bits << 8) + *buffer++;
        bytes_remaining--;
        i_shift += 8;

        do {
            *dst++ = b64[(i_bits << 6 >> i_shift) & 0x3f];
            i_shift -= 6;
        } while (i_shift > 6 || (bytes_remaining == 0 && i_shift > 0));
    }
    while ((dst - ret) & 3)
        *dst++ = '=';
    *dst = '\0';

    return ret;
}