third_party/ulib/musl/src/ctype/iswalpha.c

#include <wctype.h>

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

int iswalpha(wint_t wc) {
    if (wc < 0x20000U)
        return (table[table[wc >> 8] * 32 + ((wc & 255) >> 3)] >> (wc & 7)) & 1;
    if (wc < 0x2fffeU)
        return 1;
    return 0;
}