#include "stdio_impl.h"
#include <errno.h>
#include <inttypes.h>
#include <string.h>

#define MIN(a, b) ((a) < (b) ? (a) : (b))

ssize_t getdelim(char** restrict s, size_t* restrict n, int delim, FILE* restrict f) {
    char* tmp;
    unsigned char* z;
    size_t k;
    size_t i = 0;
    int c;

    FLOCK(f);

    if (!n || !s) {
        f->flags |= F_ERR;
        FUNLOCK(f);
        errno = EINVAL;
        return -1;
    }

    if (!*s)
        *n = 0;

    for (;;) {
        z = memchr(f->rpos, delim, f->rend - f->rpos);
        k = z ? z - f->rpos + 1 : f->rend - f->rpos;
        if (i + k + 1 >= *n) {
            if (k >= SIZE_MAX / 2 - i)
                goto oom;
            size_t m = i + k + 2;
            if (!z && m < SIZE_MAX / 4)
                m += m / 2;
            tmp = realloc(*s, m);
            if (!tmp) {
                m = i + k + 2;
                tmp = realloc(*s, m);
                if (!tmp)
                    goto oom;
            }
            *s = tmp;
            *n = m;
        }
        memcpy(*s + i, f->rpos, k);
        f->rpos += k;
        i += k;
        if (z)
            break;
        if ((c = getc_unlocked(f)) == EOF) {
            if (!i || !feof(f)) {
                FUNLOCK(f);
                return -1;
            }
            break;
        }
        if (((*s)[i++] = c) == delim)
            break;
    }
    (*s)[i] = 0;

    FUNLOCK(f);

    return i;
oom:
    f->flags |= F_ERR;
    FUNLOCK(f);
    errno = ENOMEM;
    return -1;
}

weak_alias(getdelim, __getdelim);