/*
 * LZSS level compressor
 *
 * This wasn't the main compressor after a while, so this might not be
 * compatible with the latest release of GEMINI. But it's the core code for
 * compressing data, used in the level editor.
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define MAX_SIZE	(96*16/8)

typedef unsigned char	byte;
typedef unsigned short	word;

FILE	*file;
int		fileSize;
byte	text[65536],
		original[65536],
		buffer[65536];
int		originalPos,
		bufferPos,
		searchPos,
		pos, len;

/*
 * Clean up the text-file content
 */
char textToOriginal() {
	int	i, j,
		hex,
		digit;

	i = 0;
	j = 0;
	do {
		hex = 0;
		while ((text[i] < '0' || text[i] > '9') && text[i] != '$') i++;
		if (text[i] == '$') {
			hex = 1;
			i++;
		}
		original[j] = 0;
		if (hex) {
			do {
				digit = 0;
				if (text[i] >= '0' && text[i] <= '9') {
					digit = 1;
					original[j] = (original[j] << 4) + text[i] - '0';
				}
				if (text[i] >= 'A' && text[i] <= 'F') {
					digit = 1;
					original[j] = (original[j] << 4) + (text[i] - 'A' + 10);
				}
				if (text[i] >= 'a' && text[i] <= 'f') {
					digit = 1;
					original[j] = (original[j] << 4) + (text[i] - 'a' + 10);
				}
				i++;
			} while (digit);
		}
		else
			while (text[i] >= '0' && text[i] <= '9') {
				original[j] = original[j] * 10 + text[i] - '0';
				i++;
			}
		j++;
	} while (j < MAX_SIZE && i < fileSize);
	return (i < fileSize);
}

/*
 * Match the bytes after searchPos to the bytes after originalPos
 */
void match() {
	int	span,
		ofs;

	span = originalPos - searchPos;
	if (originalPos + span >= MAX_SIZE) span = MAX_SIZE - originalPos;
	do {
		ofs = 0;
		do {
			if (!memcmp(original + searchPos + ofs,
							original + originalPos, span)) {
				pos = originalPos - (searchPos + ofs);
				len = span;
				return;
			}
			ofs++;
		} while (ofs + span < 129 && ofs + span < originalPos);
		span--;
	} while (span >= 2);
	pos = 0;
	len = 0;
}

int main(int argc, char **argv) {

	int	patterns,
		rawCopies,
		i;

	/* Read input file */

	if (argc < 2) {
		puts("No file input.");
		return 0;
	}

	if (!(file = fopen(argv[1], "rb"))) {
		puts("Input file not found.");
		return 0;
	}

	fileSize = fread(text, 1, 65536, file);
	if (fileSize < MAX_SIZE) {
		fclose(file);
		puts("File does not contain enough data.");
		return 0;
	}

	fclose(file);

	if (!textToOriginal()) {
		puts("Not enough data to compress.");
		return 0;
	}

	puts("\nLoaded data info:");
	printf("\tSize: %d bytes\n", MAX_SIZE);

	/* Compress */

	patterns = 0;
	rawCopies = 0;

	buffer[0] = original[0];
	buffer[1] = original[1];

	originalPos = 2;
	bufferPos = 2;
	do {
		searchPos = originalPos - 129;
		if (searchPos < 0) searchPos = 0;

		match();

		if (len >= 2) {
			buffer[bufferPos] = (pos - 2) | 0x80;
			bufferPos++;
			buffer[bufferPos] = len;
			bufferPos++;
			originalPos += len;
			patterns++;
		}
		else {
			buffer[bufferPos] = 0;
			bufferPos++;
			buffer[bufferPos] = original[originalPos];
			bufferPos++;
			originalPos++;
			rawCopies++;
		}
	} while (originalPos < MAX_SIZE);

	puts("Compressed data info:");
	printf("\tSize: %d bytes\n", bufferPos);
	printf("\tRatio: %6.1f%\n", 100.0f * bufferPos / MAX_SIZE);
	printf("\tPattern matches: %d\n", patterns);
	printf("\tNo matches: %d\n", rawCopies);

	/* Write data */
	if (!(file = fopen("out", "wb"))) {
		puts("Couldn't write compressed data.");
		return 0;
	}

	fprintf(file, "\t.dw\t%d", bufferPos);

	for (i = 0; i < bufferPos; i++) {
		if (!(i & 15)) fprintf(file, "\n\t.db\t");
		fprintf(file, "$%02X", buffer[i]);
		if ((i & 15) < 15 && i < bufferPos - 1) fprintf(file, ",");
	}

	fclose(file);

	puts("Compressed data successfully.");

	original[0] = buffer[0];
	original[1] = buffer[1];
	originalPos = 2;
	bufferPos = 2;
	do {
		if ((buffer[bufferPos] & 0x80)) {
			patterns = buffer[bufferPos] & 0x7F;
			bufferPos++;
			rawCopies = buffer[bufferPos];
			bufferPos++;
			do {
				original[originalPos] = original[originalPos - patterns - 2];
				originalPos++;
				rawCopies--;
			} while (rawCopies);
		}
		else {
			bufferPos++;
			original[originalPos] = buffer[bufferPos];
			originalPos++;
			bufferPos++;
		}
	} while (originalPos < MAX_SIZE);

	for (i = 0; i < MAX_SIZE; i++) printf("%d ", original[i]);

	return 0;
}