X-Git-Url: https://git.zerfleddert.de/cgi-bin/gitweb.cgi/rsbs2/blobdiff_plain/59a213c089f531918c27395ea8794da8cd3c2b9a..1d359f151c5a8943607207ea24d1092bd2e08ead:/rsb-lz.c?ds=inline

diff --git a/rsb-lz.c b/rsb-lz.c
index 5f290d8..4dddd9b 100644
--- a/rsb-lz.c
+++ b/rsb-lz.c
@@ -15,10 +15,10 @@ void err_exit(const char *fname)
 }
 
 struct data_in_s {
-	unsigned char *start; /* 0 */
-	unsigned char *stop; /* 4 */
-	unsigned char bitpos; /* 8 */
-	unsigned char byte; /* 9 */
+	unsigned char *start;
+	unsigned char *stop;
+	unsigned char bitpos;
+	unsigned char byte;
 };
 
 struct data_out_s {
@@ -39,52 +39,53 @@ unsigned char get_next_in_byte(struct data_in_s *data_in)
 	return byte;
 }
 
-unsigned char fn_59848(struct data_in_s *data_in)
+unsigned char get_next_bit(struct data_in_s *data_in)
 {
-	unsigned char r5;
+	unsigned char bitval;
 
 	if (data_in->bitpos == 0x80) {
 		data_in->byte = get_next_in_byte(data_in);
 	}
 
-	r5 = data_in->bitpos & data_in->byte;
+	bitval = data_in->bitpos & data_in->byte;
 
 	data_in->bitpos >>= 1;
 	if (data_in->bitpos == 0) {
 		data_in->bitpos = 0x80;
 	}
 
-	if (r5 == 0)
+	if (bitval == 0)
 		return 0;
 
 	return 1;
 }
 
-unsigned int fn_598b4(struct data_in_s *r11_data, unsigned int r10_arg2)
+unsigned int get_next_bits(struct data_in_s *data_in, unsigned int bits)
 {
-	unsigned int r6;
-	unsigned int r7;
+	unsigned int bit;
+	unsigned int next_bits;
 
-	r6 = 1 << (r10_arg2 - 1);
+	bit = 1 << (bits - 1);
 
-	r7 = 0;
-	while (r6 != 0) {
-		if (r11_data->bitpos == 0x80) {
-			r11_data->byte = get_next_in_byte(r11_data);
+	next_bits = 0;
+	while (bit != 0) {
+		if (data_in->bitpos == 0x80) {
+			data_in->byte = get_next_in_byte(data_in);
 		}
-		if ((r11_data->bitpos & r11_data->byte) != 0)
-			r7 = r7 | r6;
 
-		r6 = r6 >> 1;
+		if ((data_in->bitpos & data_in->byte) != 0)
+			next_bits = next_bits | bit;
+
+		bit = bit >> 1;
 
-		r11_data->bitpos >>= 1;
+		data_in->bitpos >>= 1;
 
-		if(r11_data->bitpos == 0) {
-			r11_data->bitpos = 0x80;
+		if(data_in->bitpos == 0) {
+			data_in->bitpos = 0x80;
 		}
 	}
 
-	return r7;
+	return next_bits;
 }
 
 void write_byte(unsigned char byte, struct data_out_s *data_out)
@@ -97,87 +98,82 @@ void write_byte(unsigned char byte, struct data_out_s *data_out)
 	data_out->pos++;
 }
 
-void lz_expand(struct data_in_s *r10_data, struct data_out_s *data_out)
+void lz_expand(struct data_in_s *data_in, struct data_out_s *data_out)
 {
-	unsigned int r5;
-	unsigned int r2;
-	unsigned char r4;
-	unsigned int r6;
-	unsigned int r7;
-	unsigned int r11;
-	unsigned char arr_59b64[1024];
+	unsigned int pos;
+	unsigned int wordoffset;
+	unsigned int i;
+	unsigned char byte;
+	unsigned int wordlen;
+	unsigned char buf[1024];
 
-	r5 = 1;
+	pos = 1;
 
 	while (1) {
 		while (1) {
-			r2 = fn_59848(r10_data);
-			if (r2 == 0)
+			/* Compressed/uncompressed? */
+			if (get_next_bit(data_in) == 0)
 				break;
 
-			r2 = fn_598b4(r10_data, 8) & 0xff;
+			/* Uncompressed byte */
+			byte = get_next_bits(data_in, 8);
 
-			write_byte(r2, data_out);
-			arr_59b64[r5] = r2 & 0xff;
-			r5 = (r5 + 1) & 0x3ff;
+			write_byte(byte, data_out);
+
+			/* Save byte in buffer, to be reused later */
+			buf[pos] = byte;
+			pos = (pos + 1) & 0x3ff;
 		}
 
-		r11 = fn_598b4(r10_data, 0x0a);
-		if(r11 == 0)
+		/* offset for start of dictionary word */
+		wordoffset = get_next_bits(data_in, 0x0a);
+		if(wordoffset == 0)
 			return;
 
-		r2 = fn_598b4(r10_data, 0x04);
-		r7 = r2 + 1;
-		r6 = 0;
-		while (r6 <= r7) {
-			r2 = (r6 + r11) & 0x3ff;
-			r4 = arr_59b64[r2];
-			write_byte(r4, data_out);
-			arr_59b64[r5] = r4;
-			r5 = (r5 + 1) & 0x3ff;
-			r6++;
+		/* length of dictionary word used */
+		wordlen = get_next_bits(data_in, 0x04) + 1;
+		for (i = 0; i <= wordlen ; i++) {
+			/* lookup dictionary byte */
+			byte = buf[(wordoffset + i) & 0x3ff];
+			write_byte(byte, data_out);
+			/* Save byte in buffer, to be reused later */
+			buf[pos] = byte;
+			pos = (pos + 1) & 0x3ff;
 		}
 	}
 }
 
 /* Checksum is only used for the compressed firmware in 'firmware' */
-#if 0
-unsigned int crc_check_59684(unsigned char *arg1, unsigned int arg2, unsigned int magic)
+unsigned int crc_check(unsigned char *buf, unsigned int len, unsigned int magic)
 {
-	unsigned int r3;
-	unsigned int r4;
-	unsigned int r5;
-
-#if 0
-	if (r0 < 0xc0000000)
-		return 1;
-#endif
+	unsigned int file_crc;
+	unsigned int my_len;
+	unsigned int crc;
+	unsigned int my_magic;
 
-	/* ??? */
-	r4 = *((unsigned int*)arg1 + 0x20);
-	r5 = *((unsigned int*)arg1 + 0x24);
+	my_len = *((unsigned int*)(buf + 0x20));
+	my_magic = *((unsigned int*)(buf + 0x24));
 
-	printf("magic: 0x%08x <-> 0x%08x\n", r5, magic);
-	if (r5 != magic)
+	if (my_magic != magic) {
+		printf("\nmagic: 0x%08x <-> 0x%08x\n", my_magic, magic);
 		return 2;
+	}
 	
-	if (arg2 >= r4)
-		r5 = 0;
-	else
+	if (len < my_len)
 		return 3;
 
-	r5 = ~rsb_crc(~0x00, arg1, r4);
-	r3 = *((unsigned int*)(arg1 + r4));
-	printf("Checksums: 0x%02x <-> 0x%02x\n", r5, r3);
+	crc = ~rsb_crc(~0x00, buf, len);
+	file_crc = *((unsigned int*)(buf + len));
 
-	if (r3 == r5)
-		return 0;
+	if (file_crc != crc) {
+		printf("\nChecksums: 0x%08x <-> 0x%08x!\n", crc, file_crc);
+		return 4;
+	}
 
-	return 4;
+	return 0;
 }
-#endif
 
-void extract_lz_file(unsigned char *inbuf, unsigned char *name)
+void extract_lz_file(unsigned char *inbuf, unsigned char *name, unsigned char check_crc)
 {
 	unsigned int len;
 	unsigned char *outbuf;
@@ -207,16 +203,17 @@ void extract_lz_file(unsigned char *inbuf, unsigned char *name)
 
 	lz_expand(&data_in, &data_out);
 
-#if 0
-	/* Checksum is only used for the compressed firmware in 'firmware' */
-	r3 = r7 + 0x20;
-	r5 = *((unsigned int*)r3);
+	if (check_crc) {
+		unsigned int crclen;
+		int ret;
 
-	if ((ret = crc_check_59684(r7, r5, 0x46335053)) != 0) {
-		printf("crc_check return: %d\n", ret);
-		err_exit(__func__);
+		crclen = *((unsigned int*)(outbuf + 0x20));
+
+		if ((ret = crc_check(outbuf, crclen, 0x46335053)) != 0) {
+			printf("crc_check return: %d\n", ret);
+			err_exit(__func__);
+		}
 	}
-#endif
 
 	write_file((char*)name, outbuf, len);