// SPDX-License-Identifier: MIT

#include <string.h>
#include <stdlib.h>
#include <stdarg.h>
#include <stdio.h>
#include "dbuf.h"
#include "util.h"

// va_copy is C99
// nevertheless, Codewarrior Pro 5 defines va_copy without advertising C99 support
// so check for both C99 support and defined(va_copy)
#if (!defined(__STDC_VERSION__) || __STDC_VERSION__ <= 199901L) && !defined(va_copy)
#define va_copy(dst, src) dst = src
#endif

void db_init(struct dbuf* db, size_t capacity)
{
	db->buf = xmalloc(capacity);
	db->capacity = capacity;
	db->len = 0;
}

static void db_grow(struct dbuf* db, size_t new_capacity)
{
	db->buf = xrealloc(db->buf, new_capacity);
	db->capacity = new_capacity;
}

void db_extend(struct dbuf* db, u8* buf, size_t len)
{
	if (db->len + len > db->capacity)
		db_grow(db, (db->capacity + len) * 2);
	
	memcpy(&db->buf[db->len], buf, len);
	db->len += len;
}

void db_printf(struct dbuf* db, const char* fmt, ...)
{
	size_t required_len, len;
	va_list arg, arg2;
	va_start(arg, fmt);
	va_copy(arg2, arg);
	
	required_len = vsnprintf((char*)&db->buf[0], 0, fmt, arg) + 1;
	if (db->len + required_len > db->capacity)
		db_grow(db, 2 * (db->capacity + required_len));
	
	len = vsnprintf((char*)&db->buf[db->len], required_len, fmt, arg2);
	db->len += len;
}

void db_clear(struct dbuf* db)
{
	db->len = 0;
	db->buf[0] = 0;
}

void db_destroy(struct dbuf* db)
{
	free(db->buf);
}