Assorted minor corrections to the Zlib C API to make it work with the PNG

implementation better.

6 files changed, 91 insertions, 70 deletions

diff --git a/ChangeLog b/ChangeLog
index 03aa530..9daefa6 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,16 @@
+2008-12-27  Donal K. Fellows  <dkf@users.sf.net>
+
+	* generic/tclZlib.c (Tcl_ZlibStreamGet): Corrected the semantics of
+	this function to be useful to the PNG implementation. If the argument
+	object is empty, this gives the previous semantics.
+	(Tcl_ZlibStreamChecksum): Corrected name to be less misleading; it
+	only produced Adler-32 checksums when the stream was processing the
+	right type of compressed data format.
+	(Tcl_ZlibAdler32, Tcl_ZlibCRC32): Corrected types so that they work
+	naturally with the results of Tcl_GetByteArrayFromObj().
+	*** POTENTIAL INCOMPATIBILITY *** for all above changes, but very
+	unlikely to be difficult for anyone to deal with.
+
 2008-12-26  Donal K. Fellows  <dkf@users.sf.net>
 
 	* generic/tcl.decls: Tidy up the commenting style, adding markers for
diff --git a/doc/TclZlib.3 b/doc/TclZlib.3
index 1b2bb44..42d82b5 100644
--- a/doc/TclZlib.3
+++ b/doc/TclZlib.3
@@ -4,14 +4,14 @@
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
 '\" 
-'\" RCS: @(#) $Id: TclZlib.3,v 1.3 2008/12/21 08:17:37 dkf Exp $
+'\" RCS: @(#) $Id: TclZlib.3,v 1.4 2008/12/27 00:04:17 dkf Exp $
 '\" 
 .so man.macros
 .TH TclZlib 3 8.6 Tcl "Tcl Library Procedures"
 .BS
 '\" Note:  do not modify the .SH NAME line immediately below!
 .SH NAME
-Tcl_ZlibAdler32, Tcl_ZlibCRC32, Tcl_ZlibDeflate, Tcl_ZlibInflate, Tcl_ZlibStreamAdler32, Tcl_ZlibStreamClose, Tcl_ZlibStreamEof, Tcl_ZlibStreamGet, Tcl_ZlibStreamGetCommandName, Tcl_ZlibStreamInit, Tcl_ZlibStreamPut \- compression and decompression functions
+Tcl_ZlibAdler32, Tcl_ZlibCRC32, Tcl_ZlibDeflate, Tcl_ZlibInflate, Tcl_ZlibStreamChecksum, Tcl_ZlibStreamClose, Tcl_ZlibStreamEof, Tcl_ZlibStreamGet, Tcl_ZlibStreamGetCommandName, Tcl_ZlibStreamInit, Tcl_ZlibStreamPut \- compression and decompression functions
 .SH SYNOPSIS
 .nf
 #include <tcl.h>
@@ -41,7 +41,7 @@ int
 \fBTcl_ZlibStreamClose\fR(\fIzshandle\fR)
 .sp
 int
-\fBTcl_ZlibStreamAdler32\fR(\fIzshandle\fR)
+\fBTcl_ZlibStreamChecksum\fR(\fIzshandle\fR)
 .sp
 int
 \fBTcl_ZlibStreamPut\fR(\fIzshandle, dataObj, flush\fR)
@@ -53,7 +53,8 @@ int
 .AS Tcl_ZlibStream *zshandlePtr out
 .AP Tcl_Interp *interp in
 The interpreter to store resulting compressed or uncompressed data in. Also
-where any error messages are written.
+where any error messages are written. For \fBTcl_ZlibStreamInit\fR, this can
+be NULL to create a stream that is not bound to a command.
 .AP int format in
 What format of compressed data to work with. Must be one of
 \fBTCL_ZLIB_FORMAT_ZLIB\fR for zlib-format data, \fBTCL_ZLIB_FORMAT_GZIP\fR
@@ -63,7 +64,7 @@ chosen which can automatically detect whether the compressed data was in zlib
 or gzip format.
 .AP Tcl_Obj *dataObj in/out
 A byte-array object containing the data to be compressed or decompressed, or
-which is set to the data extracted from the stream when passed to
+to which the data extracted from the stream is appended when passed to
 \fBTcl_ZlibStreamGet\fR.
 .AP int level in
 What level of compression to use. Should be a number from 0 to 9 or one of the
@@ -122,18 +123,28 @@ bytes. Typical usage is:
 .CS
 checksum = \fBTcl_ZlibCRC32\fR(\fBTcl_ZlibCRC32\fR(0,NULL,0), data, length);
 .CE
+.SS "ZLIB STREAMS"
 .PP
 \fBTcl_ZlibStreamInit\fR creates a compressing or decompressing stream that is
 linked to a Tcl command, according to its arguments, and provides an abstract
-token for the stream; \fBTcl_ZlibStreamGetCommandName\fR returns the name of
-that command given the stream token. Once a stream has been constructed,
-\fBTcl_ZlibStreamPut\fR is used to add data to the stream and
-\fBTcl_ZlibStreamGet\fR is used to retrieve data from the stream after
-processing. \fBTcl_ZlibStreamAdler32\fR returns the checksum computed over the
-uncompressed data, and \fBTcl_ZlibStreamEof\fR returns whether the end of the
-uncompressed data has been reached. Finally, \fBTcl_ZlibStreamClose\fR will
-clean up the stream and delete the associated command: using
-\fBTcl_DeleteCommand\fR on the stream's command is equivalent.
+token for the stream and returns a normal Tcl result code;
+\fBTcl_ZlibStreamGetCommandName\fR returns the name of that command given the
+stream token, or NULL if the stream has no command.
+.PP
+Once a stream has been constructed, \fBTcl_ZlibStreamPut\fR is used to add
+data to the stream and \fBTcl_ZlibStreamGet\fR is used to retrieve data from
+the stream after processing. Both return normal Tcl result codes. With
+\fBTcl_ZlibStreamPut\fR, the data buffer object passed to it should not be
+modified afterwards. With \fBTcl_ZlibStreamGet\fR, the data buffer object
+passed to it will have the data bytes appended to it.
+.PP
+\fBTcl_ZlibStreamChecksum\fR returns the checksum computed over the
+uncompressed data according to the format, and \fBTcl_ZlibStreamEof\fR returns
+whether the end of the uncompressed data has been reached.
+.PP
+Finally, \fBTcl_ZlibStreamClose\fR will clean up the stream and delete the
+associated command: using \fBTcl_DeleteCommand\fR on the stream's command is
+equivalent.
 .SH "PORTABILITY NOTES"
 These functions will fail gracefully if Tcl is not linked with the zlib
 library.
diff --git a/generic/tcl.decls b/generic/tcl.decls
index 5a4b322..dff3242 100644
--- a/generic/tcl.decls
+++ b/generic/tcl.decls
@@ -12,7 +12,7 @@
 # See the file "license.terms" for information on usage and redistribution
 # of this file, and for a DISCLAIMER OF ALL WARRANTIES.
 #
-# RCS: @(#) $Id: tcl.decls,v 1.165 2008/12/26 09:51:11 dkf Exp $
+# RCS: @(#) $Id: tcl.decls,v 1.166 2008/12/27 00:04:17 dkf Exp $
 
 library tcl
 
@@ -2265,7 +2265,7 @@ declare 616 generic {
     int Tcl_ZlibStreamEof(Tcl_ZlibStream zshandle)
 }
 declare 617 generic {
-    int Tcl_ZlibStreamAdler32(Tcl_ZlibStream zshandle)
+    int Tcl_ZlibStreamChecksum(Tcl_ZlibStream zshandle)
 }
 declare 618 generic {
     int Tcl_ZlibStreamPut(Tcl_ZlibStream zshandle, Tcl_Obj *data, int flush)
diff --git a/generic/tclDecls.h b/generic/tclDecls.h
index e2e4366..74284ed 100644
--- a/generic/tclDecls.h
+++ b/generic/tclDecls.h
@@ -8,7 +8,7 @@
  * See the file "license.terms" for information on usage and redistribution
  * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
  *
- * RCS: @(#) $Id: tclDecls.h,v 1.166 2008/12/18 06:40:02 nijtmans Exp $
+ * RCS: @(#) $Id: tclDecls.h,v 1.167 2008/12/27 00:04:17 dkf Exp $
  */
 
 #ifndef _TCLDECLS
@@ -3731,10 +3731,10 @@ EXTERN Tcl_Obj *	Tcl_ZlibStreamGetCommandName (
 /* 616 */
 EXTERN int		Tcl_ZlibStreamEof (Tcl_ZlibStream zshandle);
 #endif
-#ifndef Tcl_ZlibStreamAdler32_TCL_DECLARED
-#define Tcl_ZlibStreamAdler32_TCL_DECLARED
+#ifndef Tcl_ZlibStreamChecksum_TCL_DECLARED
+#define Tcl_ZlibStreamChecksum_TCL_DECLARED
 /* 617 */
-EXTERN int		Tcl_ZlibStreamAdler32 (Tcl_ZlibStream zshandle);
+EXTERN int		Tcl_ZlibStreamChecksum (Tcl_ZlibStream zshandle);
 #endif
 #ifndef Tcl_ZlibStreamPut_TCL_DECLARED
 #define Tcl_ZlibStreamPut_TCL_DECLARED
@@ -4451,7 +4451,7 @@ typedef struct TclStubs {
     int (*tcl_ZlibStreamInit) (Tcl_Interp * interp, int mode, int format, int level, Tcl_Obj * dictObj, Tcl_ZlibStream * zshandle); /* 614 */
     Tcl_Obj * (*tcl_ZlibStreamGetCommandName) (Tcl_ZlibStream zshandle); /* 615 */
     int (*tcl_ZlibStreamEof) (Tcl_ZlibStream zshandle); /* 616 */
-    int (*tcl_ZlibStreamAdler32) (Tcl_ZlibStream zshandle); /* 617 */
+    int (*tcl_ZlibStreamChecksum) (Tcl_ZlibStream zshandle); /* 617 */
     int (*tcl_ZlibStreamPut) (Tcl_ZlibStream zshandle, Tcl_Obj * data, int flush); /* 618 */
     int (*tcl_ZlibStreamGet) (Tcl_ZlibStream zshandle, Tcl_Obj * data, int count); /* 619 */
     int (*tcl_ZlibStreamClose) (Tcl_ZlibStream zshandle); /* 620 */
@@ -6999,9 +6999,9 @@ extern const TclStubs *tclStubsPtr;
 #define Tcl_ZlibStreamEof \
 	(tclStubsPtr->tcl_ZlibStreamEof) /* 616 */
 #endif
-#ifndef Tcl_ZlibStreamAdler32
-#define Tcl_ZlibStreamAdler32 \
-	(tclStubsPtr->tcl_ZlibStreamAdler32) /* 617 */
+#ifndef Tcl_ZlibStreamChecksum
+#define Tcl_ZlibStreamChecksum \
+	(tclStubsPtr->tcl_ZlibStreamChecksum) /* 617 */
 #endif
 #ifndef Tcl_ZlibStreamPut
 #define Tcl_ZlibStreamPut \
diff --git a/generic/tclStubInit.c b/generic/tclStubInit.c
index 926a45d..818abf1 100644
--- a/generic/tclStubInit.c
+++ b/generic/tclStubInit.c
@@ -8,7 +8,7 @@
  * See the file "license.terms" for information on usage and redistribution
  * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
  *
- * RCS: @(#) $Id: tclStubInit.c,v 1.177 2008/12/18 04:38:01 dgp Exp $
+ * RCS: @(#) $Id: tclStubInit.c,v 1.178 2008/12/27 00:04:17 dkf Exp $
  */
 
 #include "tclInt.h"
@@ -1142,7 +1142,7 @@ static const TclStubs tclStubs = {
     Tcl_ZlibStreamInit, /* 614 */
     Tcl_ZlibStreamGetCommandName, /* 615 */
     Tcl_ZlibStreamEof, /* 616 */
-    Tcl_ZlibStreamAdler32, /* 617 */
+    Tcl_ZlibStreamChecksum, /* 617 */
     Tcl_ZlibStreamPut, /* 618 */
     Tcl_ZlibStreamGet, /* 619 */
     Tcl_ZlibStreamClose, /* 620 */
diff --git a/generic/tclZlib.c b/generic/tclZlib.c
index 4fc56e1..8db482a 100644
--- a/generic/tclZlib.c
+++ b/generic/tclZlib.c
@@ -13,7 +13,7 @@
  * See the file "license.terms" for information on usage and redistribution of
  * this file, and for a DISCLAIMER OF ALL WARRANTIES.
  *
- * RCS: @(#) $Id: tclZlib.c,v 1.18 2008/12/22 01:39:33 patthoyts Exp $
+ * RCS: @(#) $Id: tclZlib.c,v 1.19 2008/12/27 00:04:17 dkf Exp $
  */
 
 #include "tclInt.h"
@@ -818,8 +818,13 @@ Tcl_ZlibStreamGetCommandName(
     Tcl_ZlibStream zshandle) /* as obtained from Tcl_ZlibStreamInit */
 {
     ZlibStreamHandle *zsh = (ZlibStreamHandle *) zshandle;
-    Tcl_Obj *objPtr = Tcl_NewObj();
+    Tcl_Obj *objPtr;
 
+    if (!zsh->interp) {
+	return NULL;
+    }
+
+    TclNewObj(objPtr);
     Tcl_GetCommandFullName(zsh->interp, zsh->cmd, objPtr);
     return objPtr;
 }
@@ -855,7 +860,7 @@ Tcl_ZlibStreamEof(
 /*
  *----------------------------------------------------------------------
  *
- * Tcl_ZlibStreamAdler32 --
+ * Tcl_ZlibStreamChecksum --
  *
  *	Return the checksum of the uncompressed data seen so far by the
  *	stream.
@@ -864,7 +869,7 @@ Tcl_ZlibStreamEof(
  */
 
 int
-Tcl_ZlibStreamAdler32(
+Tcl_ZlibStreamChecksum(
     Tcl_ZlibStream zshandle)	/* As obtained from Tcl_ZlibStreamInit */
 {
     ZlibStreamHandle *zsh = (ZlibStreamHandle *) zshandle;
@@ -877,7 +882,8 @@ Tcl_ZlibStreamAdler32(
  *
  * Tcl_ZlibStreamPut --
  *
- *	Add data to the stream for compression or decompression.
+ *	Add data to the stream for compression or decompression from a
+ *	bytearray Tcl_Obj.
  *
  *----------------------------------------------------------------------
  */
@@ -929,7 +935,7 @@ Tcl_ZlibStreamPut(
 		 * Now append the compressed data to the outData list.
 		 */
 
-		Tcl_ListObjAppendElement(zsh->interp, zsh->outData, obj);
+		Tcl_ListObjAppendElement(NULL, zsh->outData, obj);
 	    }
 	    if (outSize < 0xFFFF) {
 		outSize = 0xFFFF;	/* There may be *lots* of data left to
@@ -955,14 +961,14 @@ Tcl_ZlibStreamPut(
 	     * Now append the compressed data to the outData list.
 	     */
 
-	    Tcl_ListObjAppendElement(zsh->interp, zsh->outData, obj);
+	    Tcl_ListObjAppendElement(NULL, zsh->outData, obj);
 	}
     } else {
 	/*
 	 * This is easy. Just append to the inData list.
 	 */
 
-	Tcl_ListObjAppendElement(zsh->interp, zsh->inData, data);
+	Tcl_ListObjAppendElement(NULL, zsh->inData, data);
 
 	/*
 	 * and we'll need the flush parameter for the Inflate call.
@@ -979,7 +985,8 @@ Tcl_ZlibStreamPut(
  *
  * Tcl_ZlibStreamGet --
  *
- *	Retrieve data (now compressed or decompressed) from the stream.
+ *	Retrieve data (now compressed or decompressed) from the stream into a
+ *	bytearray Tcl_Obj.
  *
  *----------------------------------------------------------------------
  */
@@ -987,7 +994,7 @@ Tcl_ZlibStreamPut(
 int
 Tcl_ZlibStreamGet(
     Tcl_ZlibStream zshandle,	/* As obtained from Tcl_ZlibStreamInit */
-    Tcl_Obj *data,		/* A place to put the data */
+    Tcl_Obj *data,		/* A place to append the data. */
     int count)			/* Number of bytes to grab as a maximum, you
 				 * may get less! */
 {
@@ -995,6 +1002,7 @@ Tcl_ZlibStreamGet(
     int e, i, listLen, itemLen, dataPos = 0;
     Tcl_Obj *itemObj;
     unsigned char *dataPtr, *itemPtr;
+    int existing;
 
     /*
      * Getting beyond the of stream, just return empty string.
@@ -1004,6 +1012,8 @@ Tcl_ZlibStreamGet(
 	return TCL_OK;
     }
 
+    (void) Tcl_GetByteArrayFromObj(data, &existing);
+
     if (zsh->mode == TCL_ZLIB_STREAM_INFLATE) {
 	if (count == -1) {
 	    /*
@@ -1018,7 +1028,8 @@ Tcl_ZlibStreamGet(
 	 * Prepare the place to store the data.
 	 */
 
-	dataPtr = Tcl_SetByteArrayLength(data, count);
+	dataPtr = Tcl_SetByteArrayLength(data, existing+count);
+	dataPtr += existing;
 
 	zsh->stream.next_out = dataPtr;
 	zsh->stream.avail_out = count;
@@ -1031,20 +1042,14 @@ Tcl_ZlibStreamGet(
 		Tcl_DecrRefCount(zsh->currentInput);
 		zsh->currentInput = NULL;
 	    }
-	    if (Tcl_ListObjLength(zsh->interp, zsh->inData,
-		    &listLen) != TCL_OK) {
-		return TCL_ERROR;
-	    }
+	    Tcl_ListObjLength(NULL, zsh->inData, &listLen);
 	    if (listLen > 0) {
 		/*
 		 * There is more input available, get it from the list and
 		 * give it to zlib.
 		 */
 
-		if (Tcl_ListObjIndex(zsh->interp, zsh->inData, 0,
-			&itemObj) != TCL_OK) {
-		    return TCL_ERROR;
-		}
+		Tcl_ListObjIndex(NULL, zsh->inData, 0, &itemObj);
 		itemPtr = Tcl_GetByteArrayFromObj(itemObj, &itemLen);
 		Tcl_IncrRefCount(itemObj);
 		zsh->currentInput = itemObj;
@@ -1061,11 +1066,9 @@ Tcl_ZlibStreamGet(
 	}
 
 	e = inflate(&zsh->stream, zsh->flush);
-	if (Tcl_ListObjLength(zsh->interp, zsh->inData, &listLen) != TCL_OK) {
-	    return TCL_ERROR;
-	}
+	Tcl_ListObjLength(NULL, zsh->inData, &listLen);
 
-	while ((zsh->stream.avail_out > 0) && (e==Z_OK || e==Z_BUF_ERROR)
+	while ((zsh->stream.avail_out > 0) && (e == Z_OK || e == Z_BUF_ERROR)
 		&& (listLen > 0)) {
 	    /*
 	     * State: We have not satisfied the request yet and there may be
@@ -1078,6 +1081,7 @@ Tcl_ZlibStreamGet(
 			"Unexpected zlib internal state during decompression",
 			TCL_STATIC);
 		}
+		Tcl_SetByteArrayLength(data, existing);
 		return TCL_ERROR;
 	    }
 
@@ -1086,10 +1090,7 @@ Tcl_ZlibStreamGet(
 		zsh->currentInput = 0;
 	    }
 
-	    if (Tcl_ListObjIndex(zsh->interp, zsh->inData, 0,
-		   &itemObj) != TCL_OK) {
-		return TCL_ERROR;
-	    }
+	    Tcl_ListObjIndex(zsh->interp, zsh->inData, 0, &itemObj);
 	    itemPtr = Tcl_GetByteArrayFromObj(itemObj, &itemLen);
 	    Tcl_IncrRefCount(itemObj);
 	    zsh->currentInput = itemObj;
@@ -1110,9 +1111,11 @@ Tcl_ZlibStreamGet(
 	    e = inflate(&zsh->stream, zsh->flush);
 	}
 	if (zsh->stream.avail_out > 0) {
-	    Tcl_SetByteArrayLength(data, count - zsh->stream.avail_out);
+	    Tcl_SetByteArrayLength(data,
+		    existing + count - zsh->stream.avail_out);
 	}
 	if (!(e==Z_OK || e==Z_STREAM_END || e==Z_BUF_ERROR)) {
+	    Tcl_SetByteArrayLength(data, existing);
 	    ConvertError(zsh->interp, e);
 	    return TCL_ERROR;
 	}
@@ -1125,18 +1128,11 @@ Tcl_ZlibStreamGet(
 	    inflateEnd(&zsh->stream);
 	}
     } else {
-	if (Tcl_ListObjLength(zsh->interp, zsh->outData,
-		&listLen) != TCL_OK) {
-	    return TCL_ERROR;
-	}
-
+	Tcl_ListObjLength(NULL, zsh->outData, &listLen);
 	if (count == -1) {
 	    count = 0;
 	    for (i=0; i<listLen; i++) {
-		if (Tcl_ListObjIndex(zsh->interp, zsh->outData, i,
-			&itemObj) != TCL_OK) {
-		    return TCL_ERROR;
-		}
+		Tcl_ListObjIndex(NULL, zsh->outData, i, &itemObj);
 		itemPtr = Tcl_GetByteArrayFromObj(itemObj, &itemLen);
 		if (i == 0) {
 		    count += itemLen - zsh->outPos;
@@ -1150,11 +1146,12 @@ Tcl_ZlibStreamGet(
 	 * Prepare the place to store the data.
 	 */
 
-	dataPtr = Tcl_SetByteArrayLength(data, count);
+	dataPtr = Tcl_SetByteArrayLength(data, existing + count);
+	dataPtr += existing;
 
-	while ((count > dataPos) && (Tcl_ListObjLength(zsh->interp,
-		zsh->outData, &listLen) == TCL_OK) && (listLen > 0)) {
-	    Tcl_ListObjIndex(zsh->interp, zsh->outData, 0, &itemObj);
+	while ((count > dataPos) && (Tcl_ListObjLength(NULL, zsh->outData,
+		&listLen) == TCL_OK) && (listLen > 0)) {
+	    Tcl_ListObjIndex(NULL, zsh->outData, 0, &itemObj);
 	    itemPtr = Tcl_GetByteArrayFromObj(itemObj, &itemLen);
 	    if (itemLen-zsh->outPos >= count-dataPos) {
 		unsigned len = count - dataPos;
@@ -1177,7 +1174,7 @@ Tcl_ZlibStreamGet(
 		listLen--;
 	    }
 	}
-	Tcl_SetByteArrayLength(data, dataPos);
+	Tcl_SetByteArrayLength(data, existing + dataPos);
     }
     return TCL_OK;
 }
@@ -1537,7 +1534,7 @@ Tcl_ZlibInflate(
 unsigned int
 Tcl_ZlibCRC32(
     unsigned int crc,
-    const char *buf,
+    const unsigned char *buf,
     int len)
 {
     /* Nothing much to do, just wrap the crc32(). */
@@ -1547,7 +1544,7 @@ Tcl_ZlibCRC32(
 unsigned int
 Tcl_ZlibAdler32(
     unsigned int adler,
-    const char *buf,
+    const unsigned char *buf,
     int len)
 {
     return adler32(adler, (Bytef *) buf, (unsigned) len);