source: azure_iot_hub/trunk/musl-1.1.18/src/ctype/wcwidth.c@ 389

#include <wchar.h>

static const unsigned char table[] = {
#include "nonspacing.h"
};

static const unsigned char wtable[] = {
#include "wide.h"
};

int wcwidth(wchar_t wc)
{
        if (wc < 0xffU)
                return (wc+1 & 0x7f) >= 0x21 ? 1 : wc ? -1 : 0;
        if ((wc & 0xfffeffffU) < 0xfffe) {
                if ((table[table[wc>>8]*32+((wc&255)>>3)]>>(wc&7))&1)
                        return 0;
                if ((wtable[wtable[wc>>8]*32+((wc&255)>>3)]>>(wc&7))&1)
                        return 2;
                return 1;
        }
        if ((wc & 0xfffe) == 0xfffe)
                return -1;
        if (wc-0x20000U < 0x20000)
                return 2;
        if (wc == 0xe0001 || wc-0xe0020U < 0x5f || wc-0xe0100 < 0xef)
                return 0;
        return 1;
}