/* *****************************************************************************
 * utils/buffer.c -- libg1m custom buffers utilities.
 * Copyright (C) 2017 Thomas "Cakeisalie5" Touhey <thomas@touhey.fr>
 *
 * This file is part of libg1m.
 * libg1m is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 3.0 of the License,
 * or (at your option) any later version.
 *
 * libg1m is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with libg1m; if not, see <http://www.gnu.org/licenses/>.
 * ************************************************************************** */
#include <libg1m/internals.h>
#ifndef G1M_DISABLED_FILE
/* ************************************************************************** */
/*  FILE buffer                                                               */
/* ************************************************************************** */
/**
 *	g1m_filebuffer_read:
 *	Read from a filebuffer.
 *
 *	@arg	vcookie		the FILE* (uncasted)
 *	@arg	buf			the buffer to fill.
 *	@arg	size		the size to read.
 *	@return				the error (if any).
 */

int g1m_filebuffer_read(void *vcookie, unsigned char *buf, size_t size)
{
	FILE *file = (void*)vcookie;
# if LOGLEVEL <= ll_error
	size_t orig = size;
# endif

	while (size) {
		size_t read = fread(buf, 1, size, file);
		size -= read;

		if (!read || read == (size_t)-1) {
			log_error("READING failed: read %" PRIuSIZE "/%" PRIuSIZE
				" bytes, %" PRIuSIZE " missing.", orig - size, orig, size);
			return (feof(file) ? g1m_error_eof : g1m_error_read);
		}
	}

	/* no error */
	return (0);
}

/**
 *	g1m_filebuffer_write:
 *	Write to a filebuffer.
 *
 *	@arg	vcookie		the FILE* (uncasted)
 *	@arg	buf			the buffer to write.
 *	@arg	size		the size to write.
 *	@return				the error (if any).
 */

int g1m_filebuffer_write(void *vcookie, const unsigned char *buf, size_t size)
{
	FILE *file = (void*)vcookie;
# if LOGLEVEL <= ll_error
	size_t orig = size;
# endif

	while (size) {
		size_t written = fwrite(buf, 1, size, file);
		buf += written;
		size -= written;

		if (!written) {
			log_error("WRITING failed: wrote %" PRIuSIZE "/%" PRIuSIZE
				" bytes, %" PRIuSIZE " missing.", orig - size, orig, size);
			return (g1m_error_write);
		}
	}

	/* no error! */
	return (0);
}

#endif
/* ************************************************************************** */
/*  Memory buffer                                                             */
/* ************************************************************************** */
/**
 *	g1m_membuffer_read:
 *	Read from a memory buffer.
 *
 *	@arg	vcookie		the cursor (uncasted)
 *	@arg	dest		the destination buffer.
 *	@arg	size		the size to read.
 *	@return				the error, if any.
 */

int g1m_membuffer_read(void *vcookie, unsigned char *dest, size_t size)
{
	g1m_cursor_t *cursor = (void*)vcookie;

	if (size > cursor->g1m_cursor_left)
		return (g1m_error_eof);
	memcpy(dest, cursor->g1m_cursor_p, size);
	cursor->g1m_cursor_p += size;
	return (0);
}

/* ************************************************************************** */
/*  Limited buffer                                                            */
/* ************************************************************************** */
/**
 *	g1m_limbuffer_read:
 *	Read from a filebuffer.
 *
 *	@arg	vcookie		the FILE* (uncasted)
 *	@arg	buf			the buffer to fill.
 *	@arg	size		the size to read.
 *	@return				the error (if any).
 */

int g1m_limbuffer_read(void *vcookie, unsigned char *buf, size_t size)
{
	/* check if the size is okay */
	g1m_limited_t *lim = (void*)vcookie;
	if (size > lim->g1m_limited_left) return (g1m_error_eof);
	g1m_buffer_t *buffer = lim->g1m_limited_buffer;

	/* read */
	READ(buf, size)

	/* no error */
	return (0);
}

/**
 *	g1m_empty_limbuffer:
 *	Empty the limit buffer.
 *
 *	@arg	limbuf		the limbuffer.
 */

int g1m_empty_limbuffer(g1m_buffer_t *limbuffer)
{
	g1m_limited_t *lim = (void*)limbuffer->g1m_buffer_cookie;
	g1m_buffer_t *buffer = lim->g1m_limited_buffer;
	SKIP(lim->g1m_limited_left)
	return (0);
}
/* ************************************************************************** */
/*  The announce callback                                                     */
/* ************************************************************************** */
/**
 *	g1m_announce_callback:
 *	Main announce callback, that just contributes to a size.
 *
 *	@arg	vpsize		the size_t pointer.
 *	@arg	size		the size to add.
 *	@return				0 because OK.
 */

int g1m_announce_callback(void *vpsize, size_t size)
{
	size_t *psize = (void*)vpsize;
	*psize += size;
	return (0);
}