/*++

Copyright (c) 2024-2025, Quinn Stephens.
Provided under the BSD 3-Clause license.

Module Name:

   wprintf.c

Abstract:

   Provides wide formatted string printing routines.

--*/

#include <wchar.h>

static
size_t
print_hex (
    wchar_t *wcs,
    size_t maxlen,
    unsigned int num
    )

{
    wchar_t *dest;
    size_t n;
    int shift;
    unsigned int x;

    dest = wcs;
    n = 0;
    shift = 28;
    while (n < maxlen && shift >= 0) {
        x = (num >> shift) & 0xF;
        if (x >= 0xa) {
            *dest = 'a' + (x - 0xa);
        } else {
            *dest = '0' + x;
        }

        dest++;
        n++;
        shift -= 4;
    }

    return n;
}

int
vswprintf (
    wchar_t *wcs,
    size_t maxlen,
    const wchar_t *format,
    va_list args
    )

{
    wchar_t *dest;
    size_t n, size;

    dest = wcs;
    n = 0;
    while (n < maxlen && *format != '\0') {
        if (*format != '%') {
            *dest++ = *format++;
            n++;
            continue;
        }

        format++;
        switch (*format) {
        case 'x':
            size = print_hex(dest, maxlen - n, va_arg(args, unsigned int));
            n += size;
            dest += size;
            format++;
            break;
        case '\0':
            break;
        case '%':
        default:
            *dest++ = *format++;
            n++;
            break;
        }
    }

    wcs[n] = '\0';
    return (int)n;
}