FEAT: decompress/deflate - decompression of data which are in raw deflate format (without envelope)

Example:
```
>> decompress/deflate #{2B492D2E01000C7E7FD804}
== #{74657374}

```

Also using it in the ZIP codec.

Author: Oldes

src/core/n-strings.c

@@ -346,6 +346,7 @@ static struct digest {
 //		/zlib {Data are in ZLIB format with Adler32 checksum}
 //		/gzip {Data are in ZLIB format with CRC32 checksum}
 //		/lzma {Data are in LZMA format}
+//		/deflate {Data are raw DEFLATE data}
 //		/size
 //			bytes [integer!] {Number of decompressed bytes. If not used, size is detected from last 4 source data bytes.}
 ]
@@ -357,17 +358,24 @@ static struct digest {
     REBOOL ref_zlib  = D_REF(4);
 	REBOOL ref_gzip  = D_REF(5);
 	REBOOL ref_lzma  = D_REF(6);
-	REBOOL ref_size  = D_REF(7);
-	REBVAL *size     = D_ARG(8);
+	REBOOL ref_defl  = D_REF(7);
+	REBOOL ref_size  = D_REF(8);
+	REBVAL *size     = D_ARG(9);
 
-	REBINT limit = 0;
+	REBCNT limit = 0;
 	REBCNT len;
-
-    if ((ref_zlib && (ref_gzip || ref_lzma)) || (ref_gzip && ref_lzma)) Trap0(RE_BAD_REFINES);
+	REBINT windowBits = MAX_WBITS;
+
+	// test if only one compression type refinement is used 
+    if (
+		(ref_zlib && (ref_gzip || ref_lzma || ref_defl)) ||
+		(ref_gzip && (ref_zlib || ref_lzma || ref_defl)) ||
+		(ref_lzma && (ref_zlib || ref_gzip || ref_defl))
+	)	Trap0(RE_BAD_REFINES);
 
 	len = Partial1(data, length);
 
-	if (ref_size) limit = Int32s(size, 1); // /limit size
+	if (ref_size) limit = (REBCNT)Int32s(size, 1); // /limit size
 
 	if (ref_lzma) {
 #ifdef USE_LZMA
@@ -376,8 +384,8 @@ static struct digest {
 		Trap0(RE_FEATURE_NA);
 #endif
 	} else {
-		int windowBits = MAX_WBITS;
-		if (ref_gzip) windowBits |= 16;
+		if (ref_defl) windowBits = -windowBits;
+		else if (ref_gzip) windowBits |= 16;
 		Set_Binary(D_RET, DecompressZlib(VAL_SERIES(data), VAL_INDEX(data), (REBINT)len, limit, windowBits));
 	}
 

src/core/u-compress.c

@@ -172,6 +172,11 @@ void Trap_ZStream_Error(z_stream *stream, int err, REBOOL while_compression)
 	if (len < 0 || (index + len > BIN_LEN(input))) len = BIN_LEN(input) - index;
 	if (limit > 0) {
 		size = limit;
+	} else if (windowBits < 0) {
+		// limit was not specified, but data are supposed to be raw DEFLATE data
+		// max teoretic DEFLATE ration is 1032:1, but that is quite unrealistic
+		// it will be more around 3:1 or 4:1, so 10:1 could be enough for automatic setup.
+		size = 10 * (REBCNT)len; //@@ fix me, if you don't agree with above claim
 	} else {
 		// Get the uncompressed size from last 4 source data bytes.
 		if (len < 4) Trap0(RE_PAST_END); // !!! better msg needed
@@ -209,8 +214,8 @@ void Trap_ZStream_Error(z_stream *stream, int err, REBOOL while_compression)
 	//printf("total_out: %i\n", stream.total_out);
 	inflateEnd(&stream);
 
-	SET_STR_END(output, size);
-	SERIES_TAIL(output) = size;
+	SET_STR_END(output, stream.total_out);
+	SERIES_TAIL(output) = stream.total_out;
 
 	return output;
 }

src/mezz/codec-zip.r

@@ -14,7 +14,6 @@ register-codec [
 
 	decode: wrap [
 		;- privates
-		buffer: none ; shared binary used for decompression
 		name:   none
 		method: none
 		crc:
@@ -34,12 +33,7 @@ register-codec [
 			]
 			switch/default method [
 				8 [ ;- deflate
-					;@@ TODO: decompress should be able to deflate even without the header bytes!
-					unless buffer [ buffer: make binary! unc-size ]
-					insert buffer #{789C} ;ZLIB header
-					append buffer copy/part data cmp-size
-					output: decompress/zlib/size buffer unc-size
-					clear buffer
+					output: decompress/deflate/size data unc-size
 				]
 				14 [ ;- LZMA
 					output: decompress/lzma/part/size skip data 4  cmp-size  unc-size
@@ -219,7 +213,6 @@ register-codec [
 					if verbose > 1 [sys/log/more 'ZIP ["Unknown ZIP signature:" mold skip to-binary type 4]]
 				]
 			]
-			buffer: none ; cleanup
 			new-line/skip result true 4
 			result
 		][

src/tests/units/compress-test.r3

@@ -43,6 +43,9 @@ data: "test test test"
 
 ===start-group=== "GZIP compression / decompression"
 
+	--test-- "DEFLATE decompress"
+		--assert #{74657374} = decompress/deflate #{2B492D2E01000C7E7FD804}
+
 	--test-- "GZIP compress/decompress"
 		--assert  data = to string! decompress/gzip compress/gzip data