/*
    * printf_internal.h
    * Shared state between the integer printf core (libc.c) and the optional
    * floating-point conversion module (printf_float.c).
    * Copyright (c) 2026 Daniel Hammer
*/

#ifndef _LIBC_PRINTF_INTERNAL_H
#define _LIBC_PRINTF_INTERNAL_H

#include <stddef.h>
#include <stdint.h>

/* Output cursor shared by every conversion. `pos` counts the characters a
   conversion WOULD have written, so it may run past `max`; only writes below
   `max` land in `buf`. That is what gives snprintf its C99 return value. */
struct _pf_state {
    char  *buf;
    size_t pos;
    size_t max;
};

/* Defined in libc.c. External rather than static so the float module can
   reach it; it is the only core helper the float conversions need. */
void _pf_putc(struct _pf_state *st, char c);

/* Union for double bit manipulation (used by float formatting and math). */
typedef union { double d; uint64_t u; } _dbl_bits;

/* Defined in printf_float.c, which is a SEPARATE archive member so that
   --gc-sections can drop the decimal-conversion and pow/exp/log code from
   programs that never format a float. vsnprintf calls this through a WEAK
   reference: link with -Wl,-u,_pf_putfloat to pull the module in. Without
   that flag %e/%f/%g echo their conversion spec instead of a number. */
void _pf_putfloat(struct _pf_state *st, double v, char conv,
                  int precision, int width, char pad,
                  int left_align, int plus, int space, int alt);

#endif /* _LIBC_PRINTF_INTERNAL_H */