Cleanup

cli/lz/build.sh

@@ -17,43 +17,29 @@ fi
 
 # Building
 
-cc lz_main.c -o main
+cc ulzdec.c $DEBUG_flags -o ulzdec
-cc ulzdec.c -o ulzdec
+cc ulzenc.c $DEBUG_flags -o ulzenc
-cc ulzenc.c -o ulzenc
 $ASM ulzdec.tal ulzdec.rom
 
 # Make compressed file
 
-./main && ./main # read example.txt, write compressed.bin
-
-# C Decoder
-
-echo ""
-echo "C Decoder"
-echo ""
-./ulzdec a.ulz b.bin && cat b.bin
-
-# Uxn Decoding
-
-echo ""
-echo "Uxn Decoder"
-echo ""
-uxncli ulzdec.rom a.ulz b.bin && cat b.bin
-
-# C Encoder
-
-echo ""
-echo "C Encoder"
-echo ""
 ./ulzenc example.txt a.ulz
-
+./ulzdec a.ulz b.bin
-# Uxn Decoding
+echo ""
+echo "c decoder:"
+echo ""
+cat b.bin
+echo ""
+echo ""
+echo "uxn decoder:"
+echo ""
 uxncli ulzdec.rom a.ulz b.bin && cat b.bin
-# ./ulzdec a.ulz b.bin && cat b.bin
+echo ""
+echo ""
 
-rm ./main
 rm ./ulzdec
 rm ./ulzenc
 rm ./a.ulz
 rm ./b.bin
 rm ./ulzdec.rom
+rm *.sym

cli/lz/ulzenc.c

@@ -3,6 +3,8 @@
 
 /* cc ulzenc.c -o ulzenc && ./ulzenc example.txt */
 
+enum { MinMatchLength = 4 };
+
 static int
 error(const char *name, const char *msg)
 {
@@ -10,37 +12,101 @@ error(const char *name, const char *msg)
 	return 0;
 }
 
-char *ptr, *a, mem[0x10000];
+char *raw, *mem;
 
 int
-get_lit(int i)
+uxn_lz_compress(void *output, int output_size, const void *input, int input_size)
 {
-	return 0;
+	int dict_len, match_len, i, string_len, match_ctl;
+	unsigned char *out = output, *combine = 0;
+	const unsigned char *dict, *dict_best = 0, *in = input, *start = in,
+							   *end = in + input_size;
+	while(in != end) {
+		dict_len = (int)(in - start); /* Get available dictionary size (history of
+                                     original output) */
+		if(dict_len > 256)
+			dict_len = 256;           /* Limit history lookback to 256 bytes */
+		dict = in - dict_len;         /* Start of dictionary */
+		string_len = (int)(end - in); /* Size of the string to search for */
+		if(string_len > 0x3FFF + MinMatchLength)
+			string_len = 0x3FFF + MinMatchLength;
+		/* ^ Limit string length to what we can fit in 14 bits, plus the minimum
+     * match length */
+		match_len = 0; /* This will hold the length of our best match */
+		for(; dict_len;
+			dict += 1, dict_len -= 1) /* Iterate through the dictionary */
+		{
+			for(i = 0;; i++) /* Find common prefix length with the string */
+			{
+				if(i == string_len) {
+					match_len = i;
+					dict_best = dict;
+					goto done_search;
+				}
+				/* ^ If we reach the end of the string, this is the best possible match.
+         * End. */
+				if(in[i] != dict[i % dict_len])
+					break; /* Dictionary repeats if we hit the end */
+			}
+			if(i > match_len) {
+				match_len = i;
+				dict_best = dict;
+			}
+		}
+	done_search:
+		if(match_len >= MinMatchLength) /* Long enough? Use dictionary match */
+		{
+			if((output_size -= 2) < 0)
+				goto overflow;
+			match_ctl =
+				match_len -
+				MinMatchLength; /* More numeric range: treat 0 as 4, 1 as 5, etc. */
+			if(match_ctl >
+				0x3F) /* Match is long enough to use 2 bytes for the size */
+			{
+				if((output_size -= 1) < 0)
+					goto overflow;
+				*out++ = match_ctl >> 8 | 0x40 |
+					0x80;           /* High byte of the size, with both flags set */
+				*out++ = match_ctl; /* Low byte of the size */
+			} else                  /* Use 1 byte for the size */
+			{
+				*out++ = match_ctl | 0x80; /* Set the "dictionary" flag */
+			}
+			*out++ = in - dict_best -
+				1;           /* Write offset into history. (0 is -1, 1 is -2, ...) */
+			in += match_len; /* Advance input by size of the match */
+			combine = 0;     /* Disable combining previous literal, if any */
+			continue;
+		}
+		if(combine) /* Combine with previous literal */
+		{
+			if((output_size -= 1) < 0)
+				goto overflow;
+			if(++*combine == 127)
+				combine = 0; /* If the literal hits its size limit, terminate it. */
+		} else               /* Start a new literal */
+		{
+			if((output_size -= 2) < 0)
+				goto overflow;
+			combine = out++; /* Store this address, and later use it to increment the
+                          literal size. */
+			*combine = 0;    /* The 0 here means literal of length 1. */
+		}
+		*out++ = *in++; /* Write 1 literal byte from the input to the output. */
+	}
+	return (int)(out - (unsigned char *)output);
+overflow:
+	return -1;
 }
 
 int
 encode_ulz(FILE *src)
 {
-	int i, j, ptr = 0, length = 0;
+	int length = 0;
-	a = malloc(0x10000);
+	mem = malloc(1000000), raw = malloc(0x10000);
-	/* load */
+	while(fread(raw + length, 1, 1, src) && ++length) {}
-	while(fread(a + length, 1, 1, src) && ++length) {}
+	return uxn_lz_compress(mem, 1000000, raw, length);
-	/* encode */
-	for(i = 0; i < length; i++) {
-		/* try to make a CPY */
-
-		/* try to make a LIT */
-		for(j = i; j - i < 127 && j < length; j++) {}
-		if(i != j) {
-			int litlen = j - i;
-			/* LIT */
-			mem[ptr++] = litlen;
-			/* LIT(body) */
-			for(j = i; j - i < litlen + 1; j++) mem[ptr++] = a[j];
-		}
-		i += j - 1;
-	}
-	return ptr - 1;
 }
 
 int
@@ -57,7 +123,7 @@ main(int argc, char *argv[])
 	res = encode_ulz(src);
 	if(!(dst = fopen(argv[2], "wb")))
 		return !error("Invalid output file", argv[1]);
-	fwrite(&mem, res, 1, dst);
+	fwrite(mem, res, 1, dst);
 	printf("Compressed %s -> %s(%d bytes).\n", argv[1], argv[2], res);
 	return 0;
 }