#ifndef VLIBC_UCHAR_H
#define VLIBC_UCHAR_H

/*
 * vlibc — <uchar.h>.
 *
 * Unicode character types and the multibyte conversion declarations (C11,
 * gated at level 1 per the plan's header inventory). In C23 char16_t and
 * char32_t are keywords, so the typedefs below only fire in C17 (and
 * older); the C17 types are the compiler's __CHAR16_TYPE__/__CHAR32_TYPE__,
 * which is what the C23 keywords name as well.
 *
 * The mbrtoc16/mbrtoc32/c16rtomb/c32rtomb functions are DECLARED here but
 * implemented by the multibyte todo (#50): user code compiles against this
 * header today and linking resolves once #50 lands.
 */

#include <vlibc/features.h>

#include <stddef.h>

#if VLIBC_HAS_HEADER_UCHAR_H

/*
 * char16_t/char32_t remain typedefs in C23 (unlike bool/alignas/... they were
 * NOT promoted to keywords), so they are defined in every C mode from the
 * compiler's __CHAR16_TYPE__/__CHAR32_TYPE__; in C++ they are keywords and
 * no typedef fires.
 */
#ifndef __cplusplus
typedef __CHAR16_TYPE__ char16_t;
typedef __CHAR32_TYPE__ char32_t;
#endif

/*
 * Conversion state for multibyte conversions. Two opaque words; the real
 * layout is owned by the multibyte todo (#50), which may extend this
 * definition when it lands (see the learnings note).
 */
typedef struct
{
    unsigned int state[2];
} mbstate_t;

/*
 * Multibyte <-> UTF-16/UTF-32 conversions (implemented in #50).
 *
 * mbrtoc16: convert at most n bytes of the multibyte string s to a char16_t
 * stored through pc16, consuming the corresponding number of bytes.
 * c16rtomb: convert char16_t c16 to at most MB_CUR_MAX bytes at s.
 * The char32_t forms are the same for UTF-32.
 */
size_t
mbrtoc16(char16_t *restrict pc16, const char *restrict s, size_t n, mbstate_t *restrict ps);
size_t
c16rtomb(char *restrict s, char16_t c16, mbstate_t *restrict ps);
size_t
mbrtoc32(char32_t *restrict pc32, const char *restrict s, size_t n, mbstate_t *restrict ps);
size_t
c32rtomb(char *restrict s, char32_t c32, mbstate_t *restrict ps);

#endif /* VLIBC_HAS_HEADER_UCHAR_H */

#endif /* VLIBC_UCHAR_H */