/*
 * upkg: a tool for manipulating Unreal Tournament packages.
 * Very simple PCX writer for saving extracted textures.
 *
 * Copyright © 2012 Nick Bowler
 *
 * 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 3 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, see <http://www.gnu.org/licenses/>.
 */

#include <config.h>
#include <stdio.h>
#include <string.h>
#include <assert.h>

#include <engine/palette.h>
#include <pack.h>

#include "pcx.h"

int pcx_init_header(struct pcx_head *head)
{
	unsigned short stride;

	if (head->width == 0 || head->width > 0xffff)
		return -1;
	if (head->height == 0 || head->height > 0xffff)
		return -1;

	stride = head->width + (head->width & 1);
	if (stride == 0 || stride > 0xffff)
		return -1;

	memset(head->encoded, 0, sizeof head->encoded);

	head->encoded[0] = 10; /* PCX Magic */
	head->encoded[1] = 5;  /* Version 3. */
	head->encoded[2] = 1;  /* Run-length encoding. */
	head->encoded[3] = 8;  /* Bits per pixel. */

	pack_16_le(head->encoded+8,  head->width-1);
	pack_16_le(head->encoded+10, head->height-1);

	head->encoded[65] = 1; /* One plane (indexed colour). */
	pack_16_le(head->encoded+66, stride);

	head->encoded[68] = 1; /* Colour palette. */

	return 0;
}

int pcx_write_scanline(const struct pcx_head *head, const unsigned char *src,
                                                    FILE *f)
{
	size_t len = head->width, offset = 0;
	unsigned char buf[head->width*2ul];

	for (size_t i = 0; i < len;) {
		unsigned run = 0;

		while (i+run < len && src[i] == src[i+run] && run <= 0x3f)
			run++;

		if (run > 1 || src[i] > 0xbf)
			buf[offset++] = 0xc0 | run;
		buf[offset++] = src[i];
		i += run;
	}

	if (fwrite(buf, offset, 1, f) != 1)
		return -1;
	return 0;
}

int pcx_write_palette(EnginePalette *palette, FILE *f)
{
	unsigned char buf[769] = {12};

	for (unsigned i = 0; i < palette->entries; i++) {
		buf[3*i+1] = palette->rgba[i][0];
		buf[3*i+2] = palette->rgba[i][1];
		buf[3*i+3] = palette->rgba[i][2];
	}

	if (fwrite(buf, sizeof buf, 1, f) != 1)
		return -1;
	return 0;
}