#include "floatscan.h"
#include "shgetc.h"
#include "stdio_impl.h"
#include <wchar.h>
#include <wctype.h>

/* This read function heavily cheats. It knows:
 *  (1) len will always be 1
 *  (2) non-ascii characters don't matter */

static size_t do_read(FILE* f, unsigned char* buf, size_t len) {
    size_t i;
    const wchar_t* wcs = f->cookie;

    if (!wcs[0])
        wcs = L"@";
    for (i = 0; i < f->buf_size && wcs[i]; i++)
        f->buf[i] = wcs[i] < 128 ? wcs[i] : '@';
    f->rpos = f->buf;
    f->rend = f->buf + i;
    f->cookie = (void*)(wcs + i);

    if (i && len) {
        *buf = *f->rpos++;
        return 1;
    }
    return 0;
}

static long double wcstox(const wchar_t* s, wchar_t** p, int prec) {
    wchar_t* t = (wchar_t*)s;
    unsigned char buf[64];
    FILE f = {};
    f.flags = 0;
    f.rpos = f.rend = 0;
    f.buf = buf + 4;
    f.buf_size = sizeof buf - 4;
    f.lock = -1;
    f.read = do_read;
    while (iswspace(*t))
        t++;
    f.cookie = (void*)t;
    shlim(&f, 0);
    long double y = __floatscan(&f, prec, 1);
    if (p) {
        size_t cnt = shcnt(&f);
        *p = cnt ? t + cnt : (wchar_t*)s;
    }
    return y;
}

float wcstof(const wchar_t* restrict s, wchar_t** restrict p) {
    return wcstox(s, p, 0);
}

double wcstod(const wchar_t* restrict s, wchar_t** restrict p) {
    return wcstox(s, p, 1);
}

long double wcstold(const wchar_t* restrict s, wchar_t** restrict p) {
    return wcstox(s, p, 2);
}