/*
 *   Copyright © 2018 IBM Corporation
 *   This file is part of FbTerm.
 *
 *   This program is free software; you can redistribute it and/or
 *   modify it under the terms of the GNU General Public License
 *   as published by the Free Software Foundation; either version 2
 *   of the License, or (at your option) any later version.
 *
 *   This program 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 General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 */

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/mman.h>
#include "fbconfig.h"
#include "fbshm.h"

int FbShm::parse_shm_desc(const char *desc, char **file,
		int *rows, int *cols, int *bpp)
{
	char *str, *sep, *endp;
	unsigned long tmp;

	str = strdup(desc);

	/* <file>:<cols>x<rows>@<bpp> */

	/* file */
	sep = strchr(str, ':');
	if (!sep)
		goto err_free;

	*file = str;
	*sep = '\0';

	/* cols */
	str = sep + 1;
	sep = strchr(str, 'x');
	if (!sep) {
		fprintf(stderr, "can't parse shm descriptor %s: no geom\n",
				desc);
		goto err_free;
	}
	*sep = '\0';

	tmp = strtoul(str, &endp, 10);
	if (endp != sep) {
		fprintf(stderr,
			"can't parse shm descriptor %s: invalid cols %s\n",
			desc, str);
		goto err_free;
	}

	*cols = (int)(tmp & 0xffffffff);

	/* rows */
	str = sep + 1;
	sep = strchr(str, '@');
	if (!sep) {
		fprintf(stderr, "can't parse shm descriptor %s: no geom\n",
				desc);
		goto err_free;
	}
	*sep = '\0';

	tmp = strtoul(str, &endp, 10);
	if (endp != sep) {
		fprintf(stderr,
			"can't parse shm descriptor %s: invalid rows %s\n",
			desc, str);
		goto err_free;
	}

	*rows = (int)(tmp & 0xffffffff);

	/* bpp */
	tmp = strtoul(sep + 1, &endp, 10);
	if (*endp != '\0' || endp == str) {
		fprintf(stderr,
			"can't parse shm descriptor %s: invalid bpp\n",
			desc);
		goto err_free;
	}

	*bpp = (int)(tmp & 0xff);

	printf("%s: rows %d, cols %d, bpp %d\n", *file, *rows, *cols, *bpp);

	return 0;

err_free:
	free(str);
	return -1;
}

FbShm *FbShm::initFbShm()
{
	int rows, cols, bpp;
	s8 *file, desc[4096];
	int fd;

	Config::instance()->getOption("shared-mem", desc, sizeof(desc));

	if (!strlen(desc))
		return 0;

	if (parse_shm_desc(desc, &file, &rows, &cols, &bpp))
		return 0;

	fd = open(file, O_RDWR);
	if (fd < 0) {
		fprintf(stderr, "can't open frame buffer shm %s: %m\n", file);
		free(file);
		return 0;
	}

	free(file);

	return new FbShm(fd, rows, cols, bpp);
}

FbShm::FbShm(int fd, int rows, int cols, int bpp)
{
	mWidth = cols;
	mHeight = rows;
	mBitsPerPixel = bpp;
	mBytesPerLine = cols * (bpp >> 3);
	mFD = fd;


	mVMemBase = (u8 *)mmap(0, mHeight * mBytesPerLine,
			PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
}

FbShm::~FbShm()
{
	munmap(mVMemBase, mHeight * mBytesPerLine);
	close(mFD);
}

const s8 *FbShm::drvId()
{
	return "shm";
}