Imported from libpng-0.88.tar

ansi2knr.c

@@ -0,0 +1,488 @@
+/* Copyright (C) 1989, 1991, 1993 Aladdin Enterprises. All rights reserved. */
+
+/* ansi2knr.c */
+/* Convert ANSI function declarations to K&R syntax */
+
+/*
+ansi2knr is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY.  No author or distributor accepts responsibility
+to anyone for the consequences of using it or for whether it serves any
+particular purpose or works at all, unless he says so in writing.  Refer
+to the GNU General Public License for full details.
+
+Everyone is granted permission to copy, modify and redistribute
+ansi2knr, but only under the conditions described in the GNU
+General Public License.  A copy of this license is supposed to have been
+given to you along with ansi2knr so you can know your rights and
+responsibilities.  It should be in a file named COPYING.  Among other
+things, the copyright notice and this notice must be preserved on all
+copies.
+*/
+
+/*
+---------- Here is the GNU GPL file COPYING, referred to above ----------
+----- These terms do NOT apply to the JPEG software itself; see README ------
+
+		    GHOSTSCRIPT GENERAL PUBLIC LICENSE
+		    (Clarified 11 Feb 1988)
+
+ Copyright (C) 1988 Richard M. Stallman
+ Everyone is permitted to copy and distribute verbatim copies of this
+ license, but changing it is not allowed.  You can also use this wording
+ to make the terms for other programs.
+
+  The license agreements of most software companies keep you at the
+mercy of those companies.  By contrast, our general public license is
+intended to give everyone the right to share Ghostscript.  To make sure
+that you get the rights we want you to have, we need to make
+restrictions that forbid anyone to deny you these rights or to ask you
+to surrender the rights.  Hence this license agreement.
+
+  Specifically, we want to make sure that you have the right to give
+away copies of Ghostscript, that you receive source code or else can get
+it if you want it, that you can change Ghostscript or use pieces of it
+in new free programs, and that you know you can do these things.
+
+  To make sure that everyone has such rights, we have to forbid you to
+deprive anyone else of these rights.  For example, if you distribute
+copies of Ghostscript, you must give the recipients all the rights that
+you have.  You must make sure that they, too, receive or can get the
+source code.  And you must tell them their rights.
+
+  Also, for our own protection, we must make certain that everyone finds
+out that there is no warranty for Ghostscript.  If Ghostscript is
+modified by someone else and passed on, we want its recipients to know
+that what they have is not what we distributed, so that any problems
+introduced by others will not reflect on our reputation.
+
+  Therefore we (Richard M. Stallman and the Free Software Foundation,
+Inc.) make the following terms which say what you must do to be allowed
+to distribute or change Ghostscript.
+
+
+			COPYING POLICIES
+
+  1. You may copy and distribute verbatim copies of Ghostscript source
+code as you receive it, in any medium, provided that you conspicuously
+and appropriately publish on each copy a valid copyright and license
+notice "Copyright (C) 1989 Aladdin Enterprises.  All rights reserved.
+Distributed by Free Software Foundation, Inc." (or with whatever year is
+appropriate); keep intact the notices on all files that refer to this
+License Agreement and to the absence of any warranty; and give any other
+recipients of the Ghostscript program a copy of this License Agreement
+along with the program.  You may charge a distribution fee for the
+physical act of transferring a copy.
+
+  2. You may modify your copy or copies of Ghostscript or any portion of
+it, and copy and distribute such modifications under the terms of
+Paragraph 1 above, provided that you also do the following:
+
+    a) cause the modified files to carry prominent notices stating
+    that you changed the files and the date of any change; and
+
+    b) cause the whole of any work that you distribute or publish,
+    that in whole or in part contains or is a derivative of Ghostscript
+    or any part thereof, to be licensed at no charge to all third
+    parties on terms identical to those contained in this License
+    Agreement (except that you may choose to grant more extensive
+    warranty protection to some or all third parties, at your option).
+
+    c) You may charge a distribution fee for the physical act of
+    transferring a copy, and you may at your option offer warranty
+    protection in exchange for a fee.
+
+Mere aggregation of another unrelated program with this program (or its
+derivative) on a volume of a storage or distribution medium does not bring
+the other program under the scope of these terms.
+
+  3. You may copy and distribute Ghostscript (or a portion or derivative
+of it, under Paragraph 2) in object code or executable form under the
+terms of Paragraphs 1 and 2 above provided that you also do one of the
+following:
+
+    a) accompany it with the complete corresponding machine-readable
+    source code, which must be distributed under the terms of
+    Paragraphs 1 and 2 above; or,
+
+    b) accompany it with a written offer, valid for at least three
+    years, to give any third party free (except for a nominal
+    shipping charge) a complete machine-readable copy of the
+    corresponding source code, to be distributed under the terms of
+    Paragraphs 1 and 2 above; or,
+
+    c) accompany it with the information you received as to where the
+    corresponding source code may be obtained.  (This alternative is
+    allowed only for noncommercial distribution and only if you
+    received the program in object code or executable form alone.)
+
+For an executable file, complete source code means all the source code for
+all modules it contains; but, as a special exception, it need not include
+source code for modules which are standard libraries that accompany the
+operating system on which the executable file runs.
+
+  4. You may not copy, sublicense, distribute or transfer Ghostscript
+except as expressly provided under this License Agreement.  Any attempt
+otherwise to copy, sublicense, distribute or transfer Ghostscript is
+void and your rights to use the program under this License agreement
+shall be automatically terminated.  However, parties who have received
+computer software programs from you with this License Agreement will not
+have their licenses terminated so long as such parties remain in full
+compliance.
+
+  5. If you wish to incorporate parts of Ghostscript into other free
+programs whose distribution conditions are different, write to the Free
+Software Foundation at 675 Mass Ave, Cambridge, MA 02139.  We have not
+yet worked out a simple rule that can be stated here, but we will often
+permit this.  We will be guided by the two goals of preserving the free
+status of all derivatives of our free software and of promoting the
+sharing and reuse of software.
+
+Your comments and suggestions about our licensing policies and our
+software are welcome!  Please contact the Free Software Foundation,
+Inc., 675 Mass Ave, Cambridge, MA 02139, or call (617) 876-3296.
+
+		       NO WARRANTY
+
+  BECAUSE GHOSTSCRIPT IS LICENSED FREE OF CHARGE, WE PROVIDE ABSOLUTELY
+NO WARRANTY, TO THE EXTENT PERMITTED BY APPLICABLE STATE LAW.  EXCEPT
+WHEN OTHERWISE STATED IN WRITING, FREE SOFTWARE FOUNDATION, INC, RICHARD
+M. STALLMAN, ALADDIN ENTERPRISES, L. PETER DEUTSCH, AND/OR OTHER PARTIES
+PROVIDE GHOSTSCRIPT "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER
+EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  THE
+ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF GHOSTSCRIPT IS WITH
+YOU.  SHOULD GHOSTSCRIPT PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL
+NECESSARY SERVICING, REPAIR OR CORRECTION.
+
+  IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW WILL RICHARD M.
+STALLMAN, THE FREE SOFTWARE FOUNDATION, INC., L. PETER DEUTSCH, ALADDIN
+ENTERPRISES, AND/OR ANY OTHER PARTY WHO MAY MODIFY AND REDISTRIBUTE
+GHOSTSCRIPT AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING
+ANY LOST PROFITS, LOST MONIES, OR OTHER SPECIAL, INCIDENTAL OR
+CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE
+(INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING RENDERED
+INACCURATE OR LOSSES SUSTAINED BY THIRD PARTIES OR A FAILURE OF THE
+PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS) GHOSTSCRIPT, EVEN IF YOU
+HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES, OR FOR ANY CLAIM
+BY ANY OTHER PARTY.
+
+-------------------- End of file COPYING ------------------------------
+*/
+
+
+#include <stdio.h>
+#include <ctype.h>
+
+#ifdef BSD
+#include <strings.h>
+#else
+#ifdef VMS
+	extern int strlen(), strncmp();
+#else
+#include <string.h>
+#endif
+#endif
+
+/* malloc and free should be declared in stdlib.h, */
+/* but if you've got a K&R compiler, they probably aren't. */
+#ifdef MSDOS
+#include <malloc.h>
+#else
+#ifdef VMS
+     extern char *malloc();
+     extern void free();
+#else
+     extern char *malloc();
+     extern int free();
+#endif
+#endif
+
+/* Usage:
+	ansi2knr input_file [output_file]
+ * If no output_file is supplied, output goes to stdout.
+ * There are no error messages.
+ *
+ * ansi2knr recognizes functions by seeing a non-keyword identifier
+ * at the left margin, followed by a left parenthesis,
+ * with a right parenthesis as the last character on the line.
+ * It will recognize a multi-line header provided that the last character
+ * of the last line of the header is a right parenthesis,
+ * and no intervening line ends with a left brace or a semicolon.
+ * These algorithms ignore whitespace and comments, except that
+ * the function name must be the first thing on the line.
+ * The following constructs will confuse it:
+ *	- Any other construct that starts at the left margin and
+ *	    follows the above syntax (such as a macro or function call).
+ *	- Macros that tinker with the syntax of the function header.
+ */
+
+/* Scanning macros */
+#define isidchar(ch) (isalnum(ch) || (ch) == '_')
+#define isidfirstchar(ch) (isalpha(ch) || (ch) == '_')
+
+/* Forward references */
+char *skipspace();
+int writeblanks();
+int test1();
+int convert1();
+
+/* The main program */
+main(argc, argv)
+    int argc;
+    char *argv[];
+{	FILE *in, *out;
+#define bufsize 5000			/* arbitrary size */
+	char *buf;
+	char *line;
+	switch ( argc )
+	   {
+	default:
+		printf("Usage: ansi2knr input_file [output_file]\n");
+		exit(0);
+	case 2:
+		out = stdout; break;
+	case 3:
+		out = fopen(argv[2], "w");
+		if ( out == NULL )
+		   {	fprintf(stderr, "Cannot open %s\n", argv[2]);
+			exit(1);
+		   }
+	   }
+	in = fopen(argv[1], "r");
+	if ( in == NULL )
+	   {	fprintf(stderr, "Cannot open %s\n", argv[1]);
+		exit(1);
+	   }
+	fprintf(out, "#line 1 \"%s\"\n", argv[1]);
+	buf = malloc(bufsize);
+	line = buf;
+	while ( fgets(line, (unsigned)(buf + bufsize - line), in) != NULL )
+	   {	switch ( test1(buf) )
+		   {
+		case 1:			/* a function */
+			convert1(buf, out);
+			break;
+		case -1:		/* maybe the start of a function */
+			line = buf + strlen(buf);
+			if ( line != buf + (bufsize - 1) ) /* overflow check */
+				continue;
+			/* falls through */
+		default:		/* not a function */
+			fputs(buf, out);
+			break;
+		   }
+		line = buf;
+	   }
+	if ( line != buf ) fputs(buf, out);
+	free(buf);
+	fclose(out);
+	fclose(in);
+	return 0;
+}
+
+/* Skip over space and comments, in either direction. */
+char *
+skipspace(p, dir)
+    register char *p;
+    register int dir;			/* 1 for forward, -1 for backward */
+{	for ( ; ; )
+	   {	while ( isspace(*p) ) p += dir;
+		if ( !(*p == '/' && p[dir] == '*') ) break;
+		p += dir;  p += dir;
+		while ( !(*p == '*' && p[dir] == '/') )
+		   {	if ( *p == 0 ) return p;	/* multi-line comment?? */
+			p += dir;
+		   }
+		p += dir;  p += dir;
+	   }
+	return p;
+}
+
+/*
+ * Write blanks over part of a string.
+ */
+int
+writeblanks(start, end)
+    char *start;
+    char *end;
+{	char *p;
+	for ( p = start; p < end; p++ ) *p = ' ';
+	return 0;
+}
+
+/*
+ * Test whether the string in buf is a function definition.
+ * The string may contain and/or end with a newline.
+ * Return as follows:
+ *	0 - definitely not a function definition;
+ *	1 - definitely a function definition;
+ *	-1 - may be the beginning of a function definition,
+ *		append another line and look again.
+ */
+int
+test1(buf)
+    char *buf;
+{	register char *p = buf;
+	char *bend;
+	char *endfn;
+	int contin;
+	if ( !isidfirstchar(*p) )
+		return 0;		/* no name at left margin */
+	bend = skipspace(buf + strlen(buf) - 1, -1);
+	switch ( *bend )
+	   {
+	case ')': contin = 1; break;
+	case '{':
+	case ';': return 0;		/* not a function */
+	default: contin = -1;
+	   }
+	while ( isidchar(*p) ) p++;
+	endfn = p;
+	p = skipspace(p, 1);
+	if ( *p++ != '(' )
+		return 0;		/* not a function */
+	p = skipspace(p, 1);
+	if ( *p == ')' )
+		return 0;		/* no parameters */
+	/* Check that the apparent function name isn't a keyword. */
+	/* We only need to check for keywords that could be followed */
+	/* by a left parenthesis (which, unfortunately, is most of them). */
+	   {	static char *words[] =
+		   {	"asm", "auto", "case", "char", "const", "double",
+			"extern", "float", "for", "if", "int", "long",
+			"register", "return", "short", "signed", "sizeof",
+			"static", "switch", "typedef", "unsigned",
+			"void", "volatile", "while", 0
+		   };
+		char **key = words;
+		char *kp;
+		int len = endfn - buf;
+		while ( (kp = *key) != 0 )
+		   {	if ( strlen(kp) == len && !strncmp(kp, buf, len) )
+				return 0;	/* name is a keyword */
+			key++;
+		   }
+	   }
+	return contin;
+}
+
+int
+convert1(buf, out)
+    char *buf;
+    FILE *out;
+{	char *endfn;
+	register char *p;
+	char **breaks;
+	unsigned num_breaks = 2;	/* for testing */
+	char **btop;
+	char **bp;
+	char **ap;
+	/* Pre-ANSI implementations don't agree on whether strchr */
+	/* is called strchr or index, so we open-code it here. */
+	for ( endfn = buf; *(endfn++) != '('; ) ;
+top:	p = endfn;
+	breaks = (char **)malloc(sizeof(char *) * num_breaks * 2);
+	if ( breaks == 0 )
+	   {	/* Couldn't allocate break table, give up */
+		fprintf(stderr, "Unable to allocate break table!\n");
+		fputs(buf, out);
+		return -1;
+	   }
+	btop = breaks + num_breaks * 2 - 2;
+	bp = breaks;
+	/* Parse the argument list */
+	do
+	   {	int level = 0;
+		char *end = NULL;
+		if ( bp >= btop )
+		   {	/* Filled up break table. */
+			/* Allocate a bigger one and start over. */
+			free((char *)breaks);
+			num_breaks <<= 1;
+			goto top;
+		   }
+		*bp++ = p;
+		/* Find the end of the argument */
+		for ( ; end == NULL; p++ )
+		   {	switch(*p)
+			   {
+			case ',': if ( !level ) end = p; break;
+			case '(': level++; break;
+			case ')': if ( --level < 0 ) end = p; break;
+			case '/': p = skipspace(p, 1) - 1; break;
+			default: ;
+			   }
+		   }
+		p--;			/* back up over terminator */
+		/* Find the name being declared. */
+		/* This is complicated because of procedure and */
+		/* array modifiers. */
+		for ( ; ; )
+		   {	p = skipspace(p - 1, -1);
+			switch ( *p )
+			   {
+			case ']':	/* skip array dimension(s) */
+			case ')':	/* skip procedure args OR name */
+			   {	int level = 1;
+				while ( level )
+				 switch ( *--p )
+				   {
+				case ']': case ')': level++; break;
+				case '[': case '(': level--; break;
+				case '/': p = skipspace(p, -1) + 1; break;
+				default: ;
+				   }
+			   }
+				if ( *p == '(' && *skipspace(p + 1, 1) == '*' )
+				   {	/* We found the name being declared */
+					while ( !isidfirstchar(*p) )
+						p = skipspace(p, 1) + 1;
+					goto found;
+				   }
+				break;
+			default: goto found;
+			   }
+		   }
+found:		if ( *p == '.' && p[-1] == '.' && p[-2] == '.' )
+		   {	p++;
+			if ( bp == breaks + 1 )	/* sole argument */
+				writeblanks(breaks[0], p);
+			else
+				writeblanks(bp[-1] - 1, p);
+			bp--;
+		   }
+		else
+		   {	while ( isidchar(*p) ) p--;
+			*bp++ = p+1;
+		   }
+		p = end;
+	   }
+	while ( *p++ == ',' );
+	*bp = p;
+	/* Make a special check for 'void' arglist */
+	if ( bp == breaks+2 )
+	   {	p = skipspace(breaks[0], 1);
+		if ( !strncmp(p, "void", 4) )
+		   {	p = skipspace(p+4, 1);
+			if ( p == breaks[2] - 1 )
+			   {	bp = breaks;	/* yup, pretend arglist is empty */
+				writeblanks(breaks[0], p + 1);
+			   }
+		   }
+	   }
+	/* Put out the function name */
+	p = buf;
+	while ( p != endfn ) putc(*p, out), p++;
+	/* Put out the declaration */
+	for ( ap = breaks+1; ap < bp; ap += 2 )
+	   {	p = *ap;
+		while ( isidchar(*p) ) putc(*p, out), p++;
+		if ( ap < bp - 1 ) fputs(", ", out);
+	   }
+	fputs(")  ", out);
+	/* Put out the argument declarations */
+	for ( ap = breaks+2; ap <= bp; ap += 2 ) (*ap)[-1] = ';';
+	fputs(breaks[0], out);
+	free((char *)breaks);
+	return 0;
+}

build.bat

@@ -0,0 +1,2 @@
+make -fmakefile.bor -B -DMODEL=m %1 %2 %3 libpng >buildm.out
+make -fmakefile.bor -B -DMODEL=l %1 %2 %3 libpng >buildl.out

descrip.mms

@@ -0,0 +1,50 @@
+
+cc_defs = /inc=$(ZLIBSRC)
+c_deb = 
+
+.ifdef __DECC__
+pref = /prefix=all
+.endif
+
+
+
+OBJS = png.obj, pngrcb.obj, pngrutil.obj, pngtrans.obj, pngwutil.obj,\
+	pngread.obj, pngmem.obj, pngwrite.obj, pngrtran.obj, pngwtran.obj,\
+	pngio.obj, pngerror.obj, pngpread.obj
+
+
+CFLAGS= $(C_DEB) $(CC_DEFS) $(PREF)
+
+all : pngtest.exe libpng.olb
+		@ write sys$output " pngtest available"
+
+libpng.olb : libpng.olb($(OBJS))
+	@ write sys$output " Libpng available"
+
+
+pngtest.exe : pngtest.obj libpng.olb
+              link pngtest,libpng.olb/lib,$(ZLIBSRC)libz.olb/lib
+
+test : pngtest.exe
+   run pngtest
+
+clean :
+	delete *.obj;*,*.exe;*
+
+
+# Other dependencies.
+png.obj : png.h, pngconf.h
+pngpread.obj : png.h, pngconf.h
+pngrcb.obj : png.h, pngconf.h
+pngread.obj : png.h, pngconf.h
+pngrtran.obj : png.h, pngconf.h
+pngrutil.obj : png.h, pngconf.h
+pngerror.obj : png.h, pngconf.h
+pngmem.obj : png.h, pngconf.h
+pngio.obj : png.h, pngconf.h
+pngtest.obj : png.h, pngconf.h
+pngtrans.obj : png.h, pngconf.h
+pngwrite.obj : png.h, pngconf.h
+pngwtran.obj : png.h, pngconf.h
+pngwutil.obj : png.h, pngconf.h
+

libpng.txt

@@ -6,7 +6,7 @@ libpng.txt - a description on how to use and modify libpng
     January 15, 1996
     Updated/rewritten per request in the libpng FAQ
     Copyright (c) 1995 Frank J. T. Wojcik
-	December 18, 1995
+    December 18, 1995 && January 20, 1996
 
 I. Introduction
 
@@ -18,13 +18,12 @@ file, example.c is a good starting point for using the library, as
 it is heavily commented and should include everything most people
 will need.
 
-Libpng was written as a companion to the PNG specification, as a
+Libpng was written as a companion to the PNG specification, as a way
-way to reduce the amount of time and effort it takes to support
+to reduce the amount of time and effort it takes to support the PNG
-the PNG file format in application programs.  Most users will not
+file format in application programs.  Most users will not have to
-have to modify the library significantly; advanced users may want
+modify the library significantly; advanced users may want to modify it
-to modify it more.  The library was coded for both kinds of users.
+more.  All attempts were made to make it as complete as possible,
-All attempts were made to make it as complete as possible, while
+while keeping the code easy to understand.  Currently, this library
-keeping the code easy to understand.  Currently, this library
 only supports C.  Support for other languages is being considered.
 
 Libpng has been designed to handle multiple sessions at one time,
@@ -32,7 +31,7 @@ to be easily modifiable, to be portable to the vast majority of
 machines (ANSI, K&R, 16 bit, 32 bit) available, and to be easy to
 use.  The ultimate goal of libpng is to promote the acceptance of
 the PNG file format in whatever way possible.  While there is still
-work to be done (see the todo.txt file), libpng should cover the
+work to be done (see the pngtodo.txt file), libpng should cover the
 majority of the needs of it's users.
 
 Libpng uses zlib for its compression and decompression of PNG files.
@@ -40,7 +39,7 @@ The zlib compression utility is a general purpose utility that is
 useful for more than PNG files, and can be used without libpng.
 See the documentation delivered with zlib for more details.
 
-Libpng is thread safe provided the threads are using different
+Libpng is thread safe, provided the threads are using different
 instances of the structures.  Each thread should have its own
 png_struct and png_info instances, and thus its own image.
 Libpng does not protect itself against two threads using the
@@ -68,18 +67,6 @@ And while I'm on the topic, make sure you include the png header file:
 
 III. Reading
 
-Checking PNG files:
-
-Libpng provides a simple check to see if a file is a PNG file.  To
-use it, pass in the first 1 to 8 bytes of the file, and it will return
-true or false (1 or 0) depending on whether the bytes could be part
-of a PNG file.  Of course, the more bytes you pass in, the greater
-the accuracy of the prediction.  If you pass in more then eight bytes,
-libpng will only look at the first eight bytes.
-
-	fread(header, 1, number, fp);
-	is_png = png_check_sig(header, number);
-
 Reading PNG files:
 
 We'll now walk you through the possible functions to call when reading
@@ -88,11 +75,36 @@ See example.c and png.h for more detail.  While Progressive reading
 is covered in the next section, you will still need some of the
 functions discussed in this section to read a PNG file.
 
-The first thing you need to do while reading a PNG file, aside from
+You will want to do the I/O initialization(*) before you get into libpng,
-the standard I/O initialization, is to allocate and initialize
+so if it doesn't work, you don't have much to undo.  Of course, you
-png_struct and png_info.  As these are both large, you may not want to
+will also want to insure that you are, in fact, dealing with a PNG
-store these on the stack, unless you have stack space to spare.  Of
+file.  Libpng provides a simple check to see if a file is a PNG file.
-course, you will want to check if malloc returns NULL.
+To use it, pass in the first 1 to 8 bytes of the file, and it will
+return true or false (1 or 0) depending on whether the bytes could be
+part of a PNG file.  Of course, the more bytes you pass in, the
+greater the accuracy of the prediction.  If you pass in more then
+eight bytes, libpng will only look at the first eight bytes.
+
+(*): If you are not using the standard I/O functions, you will need
+to replace them with custom functions.  See the discussion under
+Customizing libpng.
+
+    FILE *fp = fopen(file_name, "rb");
+    if (!fp)
+    {
+        return;
+    }
+    fread(header, 1, number, fp);
+    is_png = png_check_sig(header, number);
+    if (!is_png)
+    {
+        return;
+    }
+
+Next, png_struct and png_info need to be allocated and initialized.
+As these are both large, you may not want to store these on the stack,
+unless you have stack space to spare.  Of course, you will want to
+check if malloc returns NULL.
 
     png_structp png_ptr = malloc(sizeof (png_struct));
     if (!png_ptr)
@@ -104,22 +116,6 @@ course, you will want to check if malloc returns NULL.
         return;
     }
 
-You may also want to do any i/o initialization here, before
-you get into libpng, so if it doesn't work, you don't have
-much to undo.
-
-	FILE *fp = fopen(file_name, "rb");
-	if (!fp)
-	{
-		free(png_ptr);
-		free(info_ptr);
-		return;
-	}
-
-If you are not using the standard i/o functions, you will need
-to replace them with custom functions.  See the discussion under
-Customizing libpng.
-
 After you have these structures, you will need to set up the
 error handling.  When libpng encounters an error, it expects to
 longjmp back to your routine.  Therefore, you will need to call
@@ -147,19 +143,19 @@ Next, you will need to call png_info_init() and png_read_init().
 These functions make sure all the fields are initialized to useful
 values, and, in the case of png_read_init(), and allocate any memory
 needed for internal uses.  You must call png_info_init() first, as
-png_read_init() could do a longjmp, and if the info is not initialized,
+png_read_init() could do a longjmp, and, if the info is not initialized,
-the png_read_destroy() could try to png_free() random addresses, which
+then png_read_destroy() could try to png_free() random addresses, which
 would be bad.
 
     png_info_init(info_ptr);
     png_read_init(png_ptr);
 
-Now you need to set up the input code.  The default for libpng is
+Now you need to set up the input code.  The default for libpng is to
-to use the C function fread().  If you use this, you will need to
+use the C function fread().  If you use this, you will need to pass a
-pass a valid FILE * in the function png_init_io().  Be sure that
+valid FILE * in the function png_init_io().  Be sure that the file is
-the file is opened in binary mode.  If you wish to handle reading
+opened in binary mode.  Again, if you wish to handle reading data in
-data in another way, see the discussion on png i/o handling in the
+another way, see the discussion on libpng I/O handling in the Customizing
-Customizing Libpng section below.
+Libpng section below.
 
     png_init_io(png_ptr, fp);
 
@@ -177,13 +173,13 @@ to read the file.  Some of the more important parts of the png_info are:
     color_type     - describes the channels and what they mean
                      (see the PNG_COLOR_TYPE_ macros for more information)
     channels       - number of channels of info for the color type
-	pixel_depth    - bits per pixel, the result of multiplying the bit_depth
+    pixel_depth    - bits per pixel, the result of multiplying the 
-						  times the channels
+                     bit_depth times the channels
     rowbytes       - number of bytes needed to hold a row
     interlace_type - currently 0 for none, 1 for interlaced
     valid          - this details which optional chunks were found in the
-						  file to see if a chunk was present, AND valid with the
+                     file to see if a chunk was present, AND valid with
-						  appropriate PNG_INFO_<chunk name> define.
+                     the appropriate PNG_INFO_<chunk name> define.
 
 These are also important, but their validity depends on whether a
 corresponding chunk exists. Use valid (see above) to ensure that what
@@ -193,12 +189,11 @@ you're doing with these values makes sense.
     num_palette    - number of entries in the palette
     gamma          - the gamma the file is written at
     sig_bit        - the number of significant bits
-						  for the gray, red, green, and blue channels, whichever are
+                     for the gray, red, green, and blue channels, whichever
-						  appropriate for the given color type.
+                     are appropriate for the given color type.
-	sig_bit_number - number of channels
     trans_values   - transparent pixel for non-paletted images
     trans          - array of transparent entries for paletted images
-	number_trans   - number of transparent entries
+    num_trans      - number of transparent entries
     hist           - histogram of palette
     text           - text comments in the file.
     num_text       - number of comments
@@ -210,13 +205,13 @@ needed to hold a row (expand, rgbx, xrgb, graph_to_rgb, etc.).
 See png_update_info(), below.
 
 A quick word about text and num_text.  PNG stores comments in
-keyword/text pairs, one pair per chunk.  While there are
+keyword/text pairs, one pair per chunk.  While there are suggested
-suggested keywords, there is no requirement to restrict the use
+keywords, there is no requirement to restrict the use to these
-to these strings.  There is a requirement to have at least one
+strings.  There is a requirement to have at least one character for a
-character for a keyword.  It is strongly suggested that keywords
+keyword.  It is strongly suggested that keywords be sensible to humans
-be sensible to humans (that's the point), so don't use abbreviations.
+(that's the point), so don't use abbreviations.  See the png
-See the png specification for more details.  There is no requirement
+specification for more details.  There is also no requirement to have
-to have text after the keyword.
+text after the keyword.
 
 Keywords are restricted to 80 characters without leading or trailing
 spaces, but spaces are allowed within the keyword  It is possible to
@@ -225,7 +220,7 @@ array of png_text structures, each holding pointer to a keyword
 and a pointer to a text string.  Only the text string may be null.
 The keyword/text pairs are put into the array in the order that
 they are received.  However, some or all of the text chunks may be
-after the image, so to make sure you have read all the text chunks,
+after the image, so, to make sure you have read all the text chunks,
 don't mess with these until after you read the stuff after the image.
 This will be mentioned again below in the discussion that goes with
 png_read_end().
@@ -233,17 +228,17 @@ png_read_end().
 After you've read the file information, you can set up the library to
 handle any special transformations of the image data.  The various
 ways to transform the data will be described in the order that they
-occur.  This is important, as some of these change the color type
+should occur.  This is important, as some of these change the color
-and bit depth of the data, and some others only work on certain
+type and/or bit depth of the data, and some others only work on
-color types and bit depths.  Even though each transformation should
+certain color types and bit depths.  Even though each transformation
-check to see if it has data that it can do somthing with, you should
+checks to see if it has data that it can do somthing with, you should
-make sure to only enable a transformation if it will be valid for
+make sure to only enable a transformation if it will be valid for the
-the data.  For example, don't swap red and blue on grayscale data.
+data.  For example, don't swap red and blue on grayscale data.
 
-This transforms bit depths of less than 8 to 8 bits, changes paletted
+The following code transforms bit depths of less than 8 to 8 bits,
-images to rgb, and adds an alpha channel if there is transparency
+changes paletted images to rgb, and adds an alpha channel if there is
-information in a tRNS chunk.  This is probably most useful on grayscale
+transparency information in a tRNS chunk.  This is probably most
-images with bit depths of 2 or 4 and tRNS chunks.
+useful on grayscale images with bit depths of 2 or 4 and tRNS chunks.
 
    if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
       info_ptr->bit_depth < 8)
@@ -256,15 +251,15 @@ images with bit depths of 2 or 4 and tRNS chunks.
    if (info_ptr->valid & PNG_INFO_tRNS)
       png_set_expand(png_ptr);
 
-This handles alpha and transparency by replacing it with a background
+The following code handles alpha and transparency by replacing it with
-value.  If there was a valid one in the file, you can use it if you
+a background value.  If there was a valid one in the file, you can use
-want.  However, you can replace it with your own if you want also.  If
+it if you want.  However, you can replace it with your own if you want
-there wasn't one in the file, you must supply a color.  If libpng is
+also.  If there wasn't one in the file, you must supply a color.  If
-doing gamma correction, you will need to tell libpng where the
+libpng is doing gamma correction, you will need to tell libpng where
-background came from so it can do the appropriate gamma correction.
+the background came from so it can do the appropriate gamma
-If you are modifying the color data with png_set_expand(), you must
+correction.  If you are telling libpong to modify the color data with
-indicate whether the background needs to be expanded.  See the
+png_set_expand(), you must indicate whether the background needs to be
-function definition in png.h for more details.
+expanded.  See the function definition in png.h for more details.
 
     png_color_16 my_background;
 
@@ -275,12 +270,12 @@ function definition in png.h for more details.
       png_set_background(png_ptr, &my_background,
          PNG_BACKGROUND_GAMMA_SCREEN, 0, 1.0);
 
-This handles gamma transformations of the data.  Pass both the file
+The following code handles gamma transformations of the data.  Pass
-gamma and the desired screen gamma.  If the file does not have a
+both the file gamma and the desired screen gamma.  If the file does
-gamma value, you can pass one anyway if you wish.  Note that file
+not have a gamma value, you can pass one anyway if you wish.  Note
-gammas are inverted from screen gammas.  See the discussions on
+that file gammas are inverted from screen gammas.  See the discussions
-gamma in the PNG specification for more information.  It is strongly
+on gamma in the PNG specification for more information.  It is
-recommended that viewers support gamma correction.
+strongly recommended that viewers support gamma correction.
 
    if (info_ptr->valid & PNG_INFO_gAMA)
       png_set_gamma(png_ptr, screen_gamma, info_ptr->gamma);
@@ -293,42 +288,46 @@ PNG can have files with 16 bits per channel.  If you only can handle
    if (info_ptr->bit_depth == 16)
       png_set_strip_16(png_ptr);
 
-If you need to reduce an rgb file to a paletted file, or if a
+If you need to reduce an rgb file to a paletted file, or if a paletted
-paletted file has more entries then will fit on your screen,
+file has more entries then will fit on your screen, png_set_dither()
-png_set_dither() will do that.  Note that this is a simple match
+will do that.  Note that this is a simple match dither that merely
-dither, that merely finds the closest color available.  This should
+finds the closest color available.  This should work fairly well with
-work fairly well with optimized palettes, and fairly badly with linear
+optimized palettes, and fairly badly with linear color cubes.  If you
-color cubes.  If you pass a palette that is larger then
+pass a palette that is larger then maximum_colors, the file will
-maximum_colors, the file will reduce the number of colors in the
+reduce the number of colors in the palette so it will fit into
-palette so it will fit into maximum_colors.  If there is a histogram,
+maximum_colors.  If there is a histogram, it will use it to make
-it will use it to make intelligent choices when reducing the palette.
+intelligent choices when reducing the palette.  If there is no
-If there is no histogram, it may not do as good a job.
+histogram, it may not do as good a job.
 
-This function will be rewritten and/or replaced in libpng 0.9, which
+It should be noted that this function will be rewritten and/or
-will have full two pass dithering with optimized palettes.
+replaced in libpng 0.9, which will have full two pass dithering with
+optimized palettes.
 
    if (info_ptr->color_type & PNG_COLOR_MASK_COLOR)
    {
       if (info_ptr->valid & PNG_INFO_PLTE)
+      {
          png_set_dither(png_ptr, info_ptr->palette,
             info_ptr->num_palette, max_screen_colors,
-               info_ptr->histogram);
+            info_ptr->histogram, 1);
+      }
       else
       {
          png_color std_color_cube[MAX_SCREEN_COLORS] =
             { ... colors ... };
 
          png_set_dither(png_ptr, std_color_cube, MAX_SCREEN_COLORS,
-            MAX_SCREEN_COLORS, NULL);
+            MAX_SCREEN_COLORS, NULL,0);
       }
    }
 
-PNG files describe monocrome as black is zero and white is one.  The
+PNG files describe monochrome as black being zero and white being one.
-following code will reverse this (make black be one and white be zero):
+The following code will reverse this (make black be one and white be
+zero):
 
    if (info_ptr->bit_depth == 1 &&
       info_ptr->color_type == PNG_COLOR_GRAY)
-      png_set_invert(png_ptr);
+      png_set_invert_mono(png_ptr);
 
 PNG files have possible bit depths of 1, 2, 4, 8, and 16.  However,
 they also provide a way to describe the true bit depth of the image.
@@ -428,43 +427,43 @@ where row_pointers is:
 
 You can point to void or char or whatever you use for pixels.
 
-If you don't want to read the whole image in at once, you can
+If you don't want to read int the whole image at once, you can
 use png_read_rows() instead.  If there is no interlacing (check
 info_ptr->interlace_type), this is simple:
 
     png_read_rows(png_ptr, row_pointers, NULL, number_of_rows);
 
-row_pointers is the same as in the png_read_image() call.
+where row_pointers is the same as in the png_read_image() call.
 
-If you are just calling one row at a time, you can do this for
+If you are doing this just one row at a time, you can do this with
 row_pointers:
 
     png_bytep row_pointers = row;
-
     png_read_rows(png_ptr, &row_pointers, NULL, 1);
 
 If the file is interlaced (info_ptr->interlace_type != 0), things get
-a good deal harder.  The only currently (as of 12/95) defined
+a good deal harder.  The only currently (as of 1/96 -- PNG
-interlacing scheme for PNG files (info_ptr->interlace_type == 1) is a
+Specification version 0.92) defined interlacing scheme for PNG files
-complicated interlace scheme, known as Adam7, that breaks down an
+(info_ptr->interlace_type == 1) is a complicated interlace scheme,
-image into seven smaller images of varying size.  libpng will fill out
+known as Adam7, that breaks down an image into seven smaller images of
-those images or it will give them to you "as is".  If you want to fill
+varying size.  libpng will fill out those images or it will give them
-them out, there are two ways to do that.  The one mentioned in the PNG
+to you "as is".  If you want them filled out, there are two ways to
-specification is to expand each pixel to cover those pixels that have
+do that.  The one mentioned in the PNG specification is to expand each
-not been read yet.  This results in a blocky image for the first pass,
+pixel to cover those pixels that have not been read yet.  This results
-which gradually smoothes out as more pixels are read.  The other
+in a blocky image for the first pass, which gradually smoothes out as
-method is the "sparkle" method, where pixels are draw only in their
+more pixels are read.  The other method is the "sparkle" method, where
-final locations, with the rest of the image remaining whatever colors
+pixels are draw only in their final locations, with the rest of the
-they were initialized to before the start of the read.  The first
+image remaining whatever colors they were initialized to before the
-method usually looks better, but tends to be slower, as there are more
+start of the read.  The first method usually looks better, but tends
-pixels to put in the rows.
+to be slower, as there are more pixels to put in the rows.
 
 If you don't want libpng to handle the interlacing details, just
 call png_read_rows() the correct number of times to read in all
 seven images.  See the PNG specification for more details on the
 interlacing scheme.
 
-If you want libpng to expand the images, call this above:
+If you want libpng to expand the images, call this before calling
+png_start_read_image() or png_read_update_info():
 
     if (info_ptr->interlace_type)
         number_passes = png_set_interlace_handling(png_ptr);
@@ -521,7 +520,7 @@ callbacks when it has the info, a row, or the end of the image.  You
 set up these callbacks with png_set_progressive_read_fn().  You don't
 have to worry about the input/output functions of libpng, as you are
 giving the library the data directly in png_process_data().  I will
-assume that you have read the second on reading PNG files above,
+assume that you have read the section on reading PNG files above,
 so I will only highlight the differences (although I will show
 all of the code).
 
@@ -553,11 +552,13 @@ initialize_png_reader()
     png_info_init(info_ptr);
     png_read_init(png_ptr);
 
-	/* this one's new.  You will need to provide all three
+    /*
+        This one's new.  You will need to provide all three
         function callbacks, even if you aren't using them all.
         You can use any void pointer as the user_ptr, and
         retrieve the pointer from inside the callbacks using
-      the function png_get_progressive_ptr(png_ptr); */
+        the function png_get_progressive_ptr(png_ptr);        
+    */
      png_set_progressive_read_fn(png_ptr, user_ptr,
         info_callback, row_callback, end_callback);
 
@@ -575,33 +576,39 @@ process_data(png_bytep buffer, png_uint_32 length)
         return -1;
     }
 
-	/* this one's new also.  Simply give it a chunk of data
+    /* 
-		from the file stream (in order, of course).  On Segmented
+        This one's new also.  Simply give it a chunk of data
-		machines, don't give it any more then 64K.  The library
+        from the file stream (in order, of course).  On machines
-		seems to run fine with sizes of 4K, although you can give
+        with segmented memory models machines, don't give it any 
-		it much less if necessary (I assume you can give it chunks
+        more than 64K.  The library seems to run fine with sizes 
-		of 1 byte, but I haven't tried less then 256 bytes yet).
+        of 4K. Although you can give it much less if necessary 
-		When this function returns, you may want to display any
+        (I assume you can give it chunks of 1 byte, I haven't
-		rows that were generated in the row callback. */
+        tried less then 256 bytes yet).  When this function returns,
+        you may want to display any rows that were generated in the
+        row callback. 
+    */
     png_process_data(png_ptr, info_ptr, buffer, length);
     return 0;
 }
 
 info_callback(png_structp png_ptr, png_infop info)
 {
-	do any setup here, including setting any of the transformations
+    /*
+        Do any setup here, including setting any of the transformations
         mentioned in the Reading PNG files section.  For now, you _must_
         call either png_start_read_image() or png_read_update_info()
         after all the transformations are set (even if you don't set
         any).  You may start getting rows before png_process_data()
         returns, so this is your last chance to prepare for that.
+    */
 }
 
 row_callback(png_structp png_ptr, png_bytep new_row,
     png_uint_32 row_num, int pass)
 {
-	this function is called for every row in the image.  If the
+    /* 
-	image is interlacing, and you turned on the interlace handler,
+        This function is called for every row in the image.  If the
+        image is interlaced, and you turned on the interlace handler,
         this function will be called for every row in every pass.
         Some of these rows will not be changed from the previous pass.
         When the row is not changed, the new_row variable will be NULL.
@@ -619,16 +626,18 @@ row_callback(png_structp png_ptr, png_bytep new_row,
         png_progressive_combine_row(png_ptr, old_row, new_row);
 
         where old_row is what was displayed for previous rows.  Note
-	that the first pass (pass == 0 really) will completely cover
+        that the first pass (pass == 0, really) will completely cover
         the old row, so the rows do not have to be initialized.  After
         the first pass (and only for interlaced images), you will have
         to pass the current row, and the function will combine the
         old row and the new row.
+    */  
 }
 
 end_callback(png_structp png_ptr, png_infop info)
 {
-	this function is called when the whole image has been read,
+    /*  
+        This function is called after the whole image has been read,
         including any chunks after the image (up to and including
         the IEND).  You will usually have the same info chunk as you
         had in the header, although some data may have been added
@@ -636,19 +645,32 @@ end_callback(png_structp png_ptr, png_infop info)
 
         Most people won't do much here, perhaps setting a flag that
         marks the image as finished.
+    */
 }
 
 
+
 IV. Writing
 
 Much of this is very similar to reading.  However, everything of
-importance is repeated here, so you don't have to constantly look
+importance is repeated here, so you won't have to constantly look
 back up in the reading section to understand writing.
 
-The first thing you need to do while writing a PNG file is to allocate
+You will want to do the I/O initialization before you get into libpng,
-and initialize png_struct and png_info.  As these are both large, you
+so if it doesn't work, you don't have much to undo. If you are not
-may not want to store these on the stack, unless you have stack space
+using the standard I/O functions, you will need to replace them with
-to spare.
+custom functions.  See the discussion under Customizing libpng.
+    
+    FILE *fp = fopen(file_name, "wb");
+    if (!fp)
+    {
+        return;
+    }
+
+Next, png_struct and png_info need to be allocated and initialized.
+As these are both large, you may not want to store these on the stack,
+unless you have stack space to spare.  Of course, you will want to
+check if malloc returns NULL.
 
     png_structp png_ptr = malloc(sizeof (png_struct));
     if (!png_ptr)
@@ -660,18 +682,6 @@ to spare.
         return;
     }
 
-You may also want to do any i/o initialization here, before
-you get into libpng, so if it doesn't work, you don't have
-much to undo.
-
-   FILE *fp = fopen(file_name, "wb");
-   if (!fp)
-   {
-      free(png_ptr);
-		free(info_ptr);
-      return;
-   }
-
 After you have these structures, you will need to set up the
 error handling.  When libpng encounters an error, it expects to
 longjmp back to your routine.  Therefore, you will need to call
@@ -694,7 +704,7 @@ section below for more information on the libpng error handling.
         return;
     }
 
-Next, you will need to call png_info_init() and png_write_init().
+Then, you will need to call png_info_init() and png_write_init().
 These functions make sure all the fields are initialized to useful
 values, and, in the case of png_write_init(), allocate any memory
 needed for internal uses.  Do png_info_init() first, so if
@@ -704,12 +714,12 @@ don't free random memory pointers, which would be bad.
     png_info_init(info_ptr);
     png_write_init(png_ptr);
 
-Now you need to set up the input code.  The default for libpng is
+Now you need to set up the input code.  The default for libpng is to
-to use the C function fwrite().  If you use this, you will need to
+use the C function fwrite().  If you use this, you will need to pass a
-pass a valid FILE * in the function png_init_io().  Be sure that
+valid FILE * in the function png_init_io().  Be sure that the file is
-the file is opened in binary mode.  If you wish to handle writing
+opened in binary mode.  Again, if you wish to handle writing data in
-data in another way, see the discussion on png i/o handling in the
+another way, see the discussion on libpng I/O handling in the Customizing
-Customizing Libpng section below.
+Libpng section below.
 
     png_init_io(png_ptr, fp);
 
@@ -733,10 +743,11 @@ See the compression library for more details.
     png_set_compression_window_bits(png_ptr, 15);
     png_set_compression_method(png_ptr, 8);
 
-You now need to fill in the png_info structure with all the data
+You now need to fill in the png_info structure with all the data you
-you wish to write before the actual image.  Note that the only thing
+wish to write before the actual image.  Note that the only thing you
-you are allowed to write after the image is the text chunks and the
+are allowed to write after the image is the text chunks and the time
-time chunk.  See png_write_end() for more information on that.  If you
+chunk (as of PNG Specification 0.92, anyway).  See png_write_end() and
+the latest PNG specification for more information on that.  If you
 wish to write them before the image, fill them in now.  If you want to
 wait until after the data, don't fill them until png_write_end().  For
 all the fields in png_info, see png.h.  For explanations of what the
@@ -754,18 +765,17 @@ Some of the more important parts of the png_info are:
                      file.  Note that if you are writing a
                      PNG_COLOR_TYPE_PALETTE file, the PLTE chunk is not
                      optional, but must still be marked for writing.  To
-						  mark chunks for writing, OR valid with the appropriate
+                     mark chunks for writing, OR valid with the 
-						  PNG_INFO_<chunk name> define.
+                     appropriate PNG_INFO_<chunk name> define.
     palette        - the palette for the file
     num_palette    - number of entries in the palette
     gamma          - the gamma the file is written at
-	sig_bit        - the number of significant bits
+    sig_bit        - the number of significant bits for the gray, red, 
-						  for the gray, red, green, and blue channels, whichever are
+                     green, and blue channels, whichever are appropriate
-						  appropriate for the given color type.
+                     for the given color type.
-   sig_bit_number - number of channels
     trans_values   - transparent pixel for non-paletted images
     trans          - array of transparent entries for paletted images
-	number_trans   - number of transparent entries
+    num_trans      - number of transparent entries
     hist           - histogram of palette
     text           - text comments in the file.
     num_text       - number of comments
@@ -836,12 +846,12 @@ image data.  You do this with a call to png_write_info().
 After you've read the file information, you can set up the library to
 handle any special transformations of the image data.  The various
 ways to transform the data will be described in the order that they
-occur.  This is important, as some of these change the color type
+should occur.  This is important, as some of these change the color
-and bit depth of the data, and some others only work on certain
+type and/or bit depth of the data, and some others only work on
-color types and bit depths.  Even though each transformation should
+certain color types and bit depths.  Even though each transformation
-check to see if it has data that it can do somthing with, you should
+checks to see if it has data that it can do somthing with, you should
-make sure to only enable a transformation if it will be valid for
+make sure to only enable a transformation if it will be valid for the
-the data.  For example, don't swap red and blue on grayscale data.
+data.  For example, don't swap red and blue on grayscale data.
 
 PNG files store rgb pixels packed into 3 bytes.  This code tells
 the library to use 4 bytes per pixel
@@ -865,10 +875,10 @@ this will scale the values to appear to be the correct bit depth.
 Make sure you write a sBIT chunk when you do this, so others, if
 they want, can reduce the values down to their true depth.
     
-	/* do this before png_write_info() */
+    /* Do this before png_write_info() */
     info_ptr->valid |= PNG_INFO_sBIT;
 
-	/* note that you can cheat and set all the values of
+    /* Note that you can cheat and set all the values of
        sig_bit to true_bit_depth if you want */
     if (info_ptr->color_type & PNG_COLOR_MASK_COLOR)
     {
@@ -889,19 +899,19 @@ they want, can reduce the values down to their true depth.
     png_set_shift(png_ptr, &(info_ptr->sig_bit));
 
 PNG files store 16 bit pixels in network byte order (big-endian,
-ie. most significant bits first).  This code would be used to supply
+ie. most significant bits first).  This code would be used if they are
-them the other way (little-endian, ie. least significant bits first,
+supplied the other way (little-endian, ie. least significant bits
-eg. the way PCs store them):
+first, eg. the way PCs store them):
 
     png_set_swap(png_ptr);
 
 PNG files store 3 color pixels in red, green, blue order.  This code
-would be used to supply the pixels as blue, green, red:
+would be used if they are supplied as blue, green, red:
 
     png_set_bgr(png_ptr);
 
 PNG files describe monochrome as black being zero and white being
-one. This code would be used to supply the pixels with this reversed
+one. This code would be used if the pixels are supplied with this reversed
 (black being one and white being zero):
 
     png_set_invert(png_ptr);
@@ -930,7 +940,7 @@ this is simple:
 
 row_pointers is the same as in the png_write_image() call.
 
-If you are just calling one row at a time, you can do this for
+If you are just writing one row at a time, you can do this with
 row_pointers:
 
     png_bytep row_pointers = row;
@@ -938,12 +948,13 @@ row_pointers:
     png_write_rows(png_ptr, &row_pointers, 1);
 
 When the file is interlaced, things can get a good deal more
-complicated.  The only currently (as of 12/95) defined interlacing
+complicated.  The only currently (as of 1/96 -- PNG Specification
-scheme for PNG files is a compilcated interlace scheme, known as
+version 0.92) defined interlacing scheme for PNG files is a
-Adam7, that breaks down an image into seven smaller images of varying
+compilcated interlace scheme, known as Adam7, that breaks down an
-size.  libpng will build these images for you, or you can do them
+image into seven smaller images of varying size.  libpng will build
-yourself.  If you want to build them yourself, see the PNG
+these images for you, or you can do them yourself.  If you want to
-specification for details of which pixels to write when.
+build them yourself, see the PNG specification for details of which
+pixels to write when.
 
 If you don't want libpng to handle the interlacing details, just
 call png_write_rows() the correct number of times to write all
@@ -991,10 +1002,10 @@ standard things like memory allocation, input/output, and error handling.
 The second deals with more complicated things like adding new chunks,
 adding new transformations, and generally changing how libpng works.
 
-All of the memory allocation, input/output, and error handling in libpng
+All of the memory allocation, input/output, and error handling in
-goes through callbacks which are user setable.  The default routines
+libpng goes through callbacks which are user setable.  The default
-are in pngerror.c, pngmem.c, and pngio.c.  To change these functions,
+routines are in pngmem.c, pngio.c, and pngerror.c respectively.  To
-call the approprate _fn function.
+change these functions, call the approprate _fn function.
 
 Memory allocation is done through the functions png_large_malloc(),
 png_malloc(), png_realloc(), png_large_free(), and png_free().
@@ -1066,16 +1077,16 @@ If you need to read or write custom chunks, you will need to get deeper
 into the libpng code.  First, read the PNG specification, and have
 a first level of understanding of how it works.  Pay particular
 attention to the sections that describe chunk names, and look
-at how other chunks were designed, so you can do things similar.
+at how other chunks were designed, so you can do things similarly.
 Second, check out the sections of libpng that read and write chunks.
-Try to find a chunk that is similar to yours, and copy off of it.
+Try to find a chunk that is similar to yours and copy off of it.
 More details can be found in the comments inside the code.
 
 If you wish to write your own transformation for the data, look
 through the part of the code that does the transformations, and check
-out some of the more simple ones to get an idea of how they work.  Try
+out some of the simpler ones to get an idea of how they work.  Try to
-to find a similar transformation to the one you want to add, and copy
+find a similar transformation to the one you want to add and copy off
-off of it.  More details can be found in the comments inside the code
+of it.  More details can be found in the comments inside the code
 itself.
 
 Configuring for 16 bit platforms:

makefile

@@ -2,15 +2,15 @@
 # Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
 # For conditions of distribution and use, see copyright notice in png.h
 
-CC=gcc
+CC=cc
-CFLAGS=-I../zlib -O2 -Wall
+CFLAGS=-I../zlib -O
 LDFLAGS=-L. -L../zlib/ -lpng -lz -lm
 
-RANLIB=ranlib
+#RANLIB=ranlib
-#RANLIB=echo
+RANLIB=echo
 
 # where make install puts libpng.a and png.h
-prefix=/home/munet-d2/sun/local
+prefix=/usr/local
 
 OBJS = png.o pngrcb.o pngrutil.o pngtrans.o pngwutil.o \
 	pngread.o pngio.o pngwrite.o pngrtran.o pngwtran.o \
@@ -31,12 +31,11 @@ test: pngtest
 install: libpng.a
 	-@mkdir $(prefix)/include
 	-@mkdir $(prefix)/lib
-	cp png.h pngconf.h $(prefix)/include
+	cp png.h $(prefix)/include
-	rcp png.h pngconf.h vlsi:bin/include
+	cp pngconf.h $(prefix)/include
 	chmod 644 $(prefix)/include/png.h
 	chmod 644 $(prefix)/include/pngconf.h
 	cp libpng.a $(prefix)/lib
-	rcp libpng.a vlsi:bin/lib
 	chmod 644 $(prefix)/lib/libpng.a
 
 clean:

makefile.ama

@@ -0,0 +1,42 @@
+# Commodore Amiga Makefile
+# makefile for libpng and SAS C V6.55 compiler
+# Copyright (C) 1995 Wolf Faust
+
+#compiler
+CC=sc
+#compiler flags
+# WARNING: a bug in V6.51 causes bad code with OPTGO
+#          So use V6.55 or set NOOPTGO!!!!!!!!!
+CFLAGS= NOSTKCHK PARMS=REG OPTIMIZE OPTGO OPTPEEP OPTINLOCAL OPTINL\
+        OPTLOOP OPTRDEP=4 OPTDEP=4 OPTCOMP=4 DEFINE=PNG_INTERNAL
+#linker flags
+LDFLAGS= SD ND BATCH
+#link libs
+LDLIBS= libpng.lib libgz.lib LIB:scm.lib LIB:sc.lib Lib:amiga.lib
+# linker
+LN= slink
+# file deletion command
+RM= delete quiet
+# library (.lib) file creation command
+AR= oml
+# make directory command
+MKDIR= makedir
+
+OBJS = png.o pngrcb.o pngrutil.o pngtrans.o pngwutil.o pngpread.o \
+pngread.o pngerror.o pngwrite.o pngrtran.o pngwtran.o pngio.o pngmem.o
+
+all: libpng.lib pngtest
+
+libpng.lib: $(OBJS)
+-$(RM) libpng.lib
+$(AR) libpng.lib r $(OBJS)
+
+pngtest: pngtest.o libpng.lib
+$(LN) <WITH <
+$(LDFLAGS)
+TO pngtest
+FROM LIB:c.o pngtest.o
+LIB $(LDLIBS)
+<
+
+

makefile.atr

@@ -0,0 +1,31 @@
+# makefile for libpng
+# Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
+# For conditions of distribution and use, see copyright notice in png.h
+# modified for LC56/ATARI assumes libz.lib is in same dir and uses default
+# rules for library management
+#
+CFLAGS=-I..\zlib -O
+LBR = png.lib
+LDFLAGS=-lpng -lz -lm
+
+# where make install puts libpng.a and png.h
+
+OBJS = $(LBR)(png.o) $(LBR)(pngrcb.o) $(LBR)(pngrutil.o)\
+	$(LBR)(pngtrans.o) $(LBR)(pngwutil.o)\
+	$(LBR)(pngread.o) $(LBR)(pngerror.o) $(LBR)(pngwrite.o)\
+	$(LBR)(pngrtran.o) $(LBR)(pngwtran.o)\
+   $(LBR)(pngmem.o) $(LBR)(pngio.o) $(LBR)(pngpread.o)
+
+all: $(LBR) pngtest.ttp
+
+$(LBR): $(OBJS)
+
+pngtest.ttp: pngtest.o $(LBR)
+	$(CC) $(CFLAGS) $(LDFLAGS) -o$@ pngtest.o
+
+install: libpng.a
+	-@mkdir $(prefix)/include
+	-@mkdir $(prefix)/lib
+	cp png.h $(prefix)/include
+	cp pngconf.h $(prefix)/include
+	chmod 644 $(prefix)/include/p

makefile.bor

@@ -0,0 +1,165 @@
+# Makefile for libpng
+# Borland C++ 4.5 (Note: All modules are compiled in C mode)
+# Will work with C++ 4.02 also
+# To build the library, do: 
+#       "make -fmakefile.bor -DMODEL=m"
+# or:   "make -fmakefile.bor -DMODEL=l"
+#
+# ------------- Borland C++ 4.5 -------------
+
+### Absolutely necessary for this makefile to work
+.AUTODEPEND
+
+## Useful user options
+
+# Usually defined in builtins.mak or the environment
+# Currently unused.
+!ifndef BCROOT
+BCROOT=N:\BC45
+!endif
+
+# Where zlib.h and zconf.h and zlib.lib are
+ZLIB_PATH=..\zlib
+
+!ifndef MODEL
+MODEL=l
+!endif
+
+#TARGET_CPU=3
+# 2 = 286, 3 = 386, etc.
+!ifndef TARGET_CPU
+TARGET_CPU=2
+!endif
+
+
+# Use this if you don't want Borland's fancy exception handling.
+NOEHLIB=noeh$(MODEL).lib
+
+!ifdef DEBUG
+CDEBUG=-v
+LDEBUG=-v
+!else
+CDEBUG=
+LDEBUG=
+!endif
+
+# STACKOFLOW=1
+!ifdef STACKOFLOW
+CDEBUG=$(CDEBUG) -N
+LDEBUG=$(LDEBUG) -N
+!endif
+
+
+## Compiler, linker, and lib stuff
+CC=bcc
+LD=bcc
+LIB=tlib
+
+MODELARG=-m$(MODEL)
+
+# -X- turns on dependency generation in the object file
+# -w  sets all warnings on
+# -O2 optimize for speed
+# -Z  global optimization
+CFLAGS=-O2 -Z -X- -w -I$(ZLIB_PATH) -$(TARGET_CPU) $(MODELARG) $(CDEBUG)
+
+# -M  generate map file
+LDFLAGS=-M $(LDEBUG)
+
+O=obj
+
+## variables
+OBJS = \
+ png.$(O) \
+ pngrcb.$(O) \
+ pngrutil.$(O) \
+ pngtrans.$(O) \
+ pngwutil.$(O) \
+ pngmem.$(O) \
+ pngread.$(O) \
+ pngpread.$(O) \
+ pngerror.$(O) \
+ pngwrite.$(O) \
+ pngrtran.$(O) \
+ pngwtran.$(O) \
+ pngzlib.$(O) \
+ pngio.$(O)
+
+LIBOBJS = \
+ +png.$(O) \
+ +pngrcb.$(O) \
+ +pngrutil.$(O) \
+ +pngtrans.$(O) \
+ +pngwutil.$(O) \
+ +pngmem.$(O) \
+ +pngpread.$(O) \
+ +pngread.$(O) \
+ +pngerror.$(O) \
+ +pngwrite.$(O) \
+ +pngrtran.$(O) \
+ +pngwtran.$(O) \
+ +pngzlib.$(O) \
+ +pngio.$(O)
+
+LIBNAME=libpng$(MODEL).lib
+
+
+## Implicit rules
+# Braces let make "batch" calls to the compiler,
+# 2 calls instead of 12; space is important.
+.c.obj:
+	$(CC) $(CFLAGS) -c {$*.c }
+
+.c.exe:
+	$(CC) $(CFLAGS) $(LDFLAGS) $*.c
+
+
+## Major targets
+libpng: $(LIBNAME)
+
+pngtest: pngtest$(MODEL).exe
+
+test:
+	pngtest$(MODEL)
+
+
+## Minor Targets
+
+png.obj: png.c
+pngrcb.obj: pngrcb.c
+pngread.obj: pngread.c
+pngpread.obj: pngpread.c
+pngrtran.obj: pngrtran.c
+pngrutil.obj: pngrutil.c
+pngerror.obj: pngerror.c
+pngmem.obj: pngmem.c
+pngio.obj: pngio.c
+pngtrans.obj: pngtrans.c
+pngwrite.obj: pngwrite.c
+pngwtran.obj: pngwtran.c
+pngwutil.obj: pngwutil.c
+pngzlib.obj: pngzlib.c
+
+
+$(LIBNAME): $(OBJS)
+	-del $(LIBNAME)
+        $(LIB) $(LIBNAME) @&&|
+$(LIBOBJS), libpng$(MODEL)
+|
+
+
+pngtest$(MODEL).obj: pngtest.c
+	$(CC) $(CFLAGS) -opngtest$(MODEL) -c pngtest.c
+
+pngtest$(MODEL).exe: pngtest$(MODEL).obj
+	$(CC) $(MODELARG) $(LDFLAGS) -L$(ZLIB_PATH) pngtest$(MODEL).obj $(LIBNAME) zlib$(MODEL).lib $(NOEHLIB)
+
+
+# Clean up anything else you want
+clean:
+	-del *.obj
+	-del *.lib
+	-del *.lst
+
+
+# End of makefile for libpng

makefile.elf

@@ -9,7 +9,7 @@ LDFLAGS=-L. -L../zlib/ -lpng -lz -lm
 RANLIB=ranlib
 #RANLIB=echo
 
-PNGVER = 0.87
+PNGVER = 0.86
 
 # where make install puts libpng.a, libpng.so*, and png.h
 prefix=/usr/local

makefile.gcc

@@ -0,0 +1,50 @@
+# gcc/DOS makefile for libpng
+# Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
+# For conditions of distribution and use, see copyright notice in png.h
+
+CC=gcc
+CFLAGS=-I../zlib -O
+LDFLAGS=-L. -L../zlib/ -lpng -lz -lm
+
+RANLIB=ranlib
+
+# where make install puts libpng.a and png.h
+#prefix=/usr/local
+prefix=.
+
+OBJS = png.o pngrcb.o pngrutil.o pngtrans.o pngwutil.o \
+	pngread.o pngio.o pngwrite.o pngrtran.o pngwtran.o \
+	pngmem.o pngerror.o pngpread.o
+
+all: libpng.a pngtest
+
+libpng.a: $(OBJS)
+	ar rc $@  $(OBJS)
+	$(RANLIB) $@
+
+pngtest: pngtest.o libpng.a
+	$(CC) -o pngtest $(CCFLAGS) pngtest.o $(LDFLAGS)
+	coff2exe pngtest
+
+test: pngtest
+	./pngtest
+clean:
+	rm -f *.o libpng.a pngtest pngout.png
+
+# DO NOT DELETE THIS LINE -- make depend depends on it.
+
+png.o: png.h pngconf.h
+pngerror.o: png.h pngconf.h
+pngio.o: png.h pngconf.h
+pngmem.o: png.h pngconf.h
+pngrcb.o: png.h pngconf.h
+pngread.o: png.h pngconf.h
+pngpread.o: png.h pngconf.h
+pngrtran.o: png.h pngconf.h
+pngrutil.o: png.h pngconf.h
+pngtest.o: png.h pngconf.h
+pngtrans.o: png.h pngconf.h
+pngwrite.o: png.h pngconf.h
+pngwtran.o: png.h pngconf.h
+pngwutil.o: png.h pngconf.h
+

makefile.knr

@@ -0,0 +1,71 @@
+# makefile for libpng
+# Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
+# For conditions of distribution and use, see copyright notice in png.h
+
+CC=cc
+CFLAGS=-I../zlib -O
+LDFLAGS=-L. -L../zlib/ -lpng -lz -lm
+# flags for ansi2knr
+ANSI2KNRFLAGS=
+
+RANLIB=ranlib
+#RANLIB=echo
+
+# where make install puts libpng.a and png.h
+prefix=/usr/local
+
+OBJS = png.o pngrcb.o pngrutil.o pngtrans.o pngwutil.o \
+	pngread.o pngio.o pngwrite.o pngrtran.o pngwtran.o \
+   pngmem.o pngerror.o pngpread.o
+
+all: ansi2knr libpng.a pngtest
+
+# general rule to allow ansi2knr to work
+.c.o:
+	./ansi2knr $*.c T$*.c
+	$(CC) $(CFLAGS) -c T$*.c
+	rm -f T$*.c $*.o
+	mv T$*.o $*.o
+
+ansi2knr: ansi2knr.c
+	$(CC) $(CFLAGS) $(ANSI2KNRFLAGS) -o ansi2knr ansi2knr.c
+
+libpng.a: ansi2knr $(OBJS)
+	ar rc $@  $(OBJS)
+	$(RANLIB) $@
+
+pngtest: pngtest.o libpng.a ansi2knr
+	cc -o pngtest $(CCFLAGS) pngtest.o $(LDFLAGS)
+
+test: pngtest
+	./pngtest
+
+install: libpng.a
+	-@mkdir $(prefix)/include
+	-@mkdir $(prefix)/lib
+	cp png.h $(prefix)/include
+	cp pngconf.h $(prefix)/include
+	chmod 644 $(prefix)/include/png.h
+	chmod 644 $(prefix)/include/pngconf.h
+	cp libpng.a $(prefix)/lib
+	chmod 644 $(prefix)/lib/libpng.a
+
+clean:
+	rm -f *.o libpng.a pngtest pngout.png ansi2knr
+
+# DO NOT DELETE THIS LINE -- make depend depends on it.
+
+png.o: png.h pngconf.h
+pngerror.o: png.h pngconf.h
+pngio.o: png.h pngconf.h
+pngmem.o: png.h pngconf.h
+pngrcb.o: png.h pngconf.h
+pngread.o: png.h pngconf.h
+pngpread.o: png.h pngconf.h
+pngrtran.o: png.h pngconf.h
+pngrutil.o: png.h pngconf.h
+pngtest.o: png.h pngconf.h
+pngtrans.o: png.h pngconf.h
+pngwrite.o: png.h pngconf.h
+pngwtran.o: png.h pngconf.h
+pngwutil.o: png.h pngconf.h

makefile.mip

@@ -0,0 +1,60 @@
+# makefile for libpng
+# Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
+# For conditions of distribution and use, see copyright notice in png.h
+
+CC=cc
+CFLAGS=-I../zlib -O -systype sysv -DSYSV -w -Dmips
+#CFLAGS=-O
+LDFLAGS=-L. -L../zlib/ -lpng -lz -lm
+
+#RANLIB=ranlib
+RANLIB=echo
+
+# where make install puts libpng.a and png.h
+prefix=/usr/local
+
+OBJS = png.o pngrcb.o pngrutil.o pngtrans.o pngwutil.o \
+	pngread.o pngio.o pngwrite.o pngrtran.o pngwtran.o \
+   pngmem.o pngerror.o pngpread.o
+
+all: libpng.a pngtest
+
+libpng.a: $(OBJS)
+	ar rc $@  $(OBJS)
+	$(RANLIB) $@
+
+pngtest: pngtest.o libpng.a
+	cc -o pngtest $(CCFLAGS) pngtest.o $(LDFLAGS)
+
+test: pngtest
+	./pngtest
+
+install: libpng.a
+	-@mkdir $(prefix)/include
+	-@mkdir $(prefix)/lib
+	cp png.h $(prefix)/include
+	cp pngconf.h $(prefix)/include
+	chmod 644 $(prefix)/include/png.h
+	chmod 644 $(prefix)/include/pngconf.h
+	cp libpng.a $(prefix)/lib
+	chmod 644 $(prefix)/lib/libpng.a
+
+clean:
+	rm -f *.o libpng.a pngtest pngout.png
+
+# DO NOT DELETE THIS LINE -- make depend depends on it.
+
+png.o: png.h pngconf.h
+pngerror.o: png.h pngconf.h
+pngio.o: png.h pngconf.h
+pngmem.o: png.h pngconf.h
+pngrcb.o: png.h pngconf.h
+pngread.o: png.h pngconf.h
+pngpread.o: png.h pngconf.h
+pngrtran.o: png.h pngconf.h
+pngrutil.o: png.h pngconf.h
+pngtest.o: png.h pngconf.h
+pngtrans.o: png.h pngconf.h
+pngwrite.o: png.h pngconf.h
+pngwtran.o: png.h pngconf.h
+pngwutil.o: png.h pngconf.h

makefile.msc

@@ -0,0 +1,78 @@
+# makefile for libpng
+# Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
+# For conditions of distribution and use, see copyright notice in png.h
+# Assumes that zlib.lib, zconf.h, and zlib.h have been copied to ..\zlib
+
+# ------------- Microsoft C 5.1 and later -------------
+MODEL=-AL
+CFLAGS=-Oait -Gs -nologo -W2 $(MODEL) -I..\zlib
+#-Ox generates bad code with MSC 5.1
+CC=cl
+LD=link
+LDFLAGS=/e/st:0x1500/noe 
+O=.obj
+
+#uncomment next to put error messages in a file
+ERRFILE= >> pngerrs
+
+# variables
+OBJS1 = png$(O) pngrcb$(O) pngrutil$(O) pngtrans$(O) pngwutil$(O) pngmem$(O) pngpread$(O)
+OBJS2 = pngread$(O) pngerror$(O) pngwrite$(O) pngrtran$(O) pngwtran$(O) pngio$(O)
+
+all: libpng.lib
+
+png$(O): png.h pngconf.h
+		  $(CC) -c $(CFLAGS) $*.c $(ERRFILE)
+
+pngrcb$(O): png.h pngconf.h
+        $(CC) -c $(CFLAGS) $*.c $(ERRFILE)
+
+pngread$(O): png.h pngconf.h
+        $(CC) -c $(CFLAGS) $*.c $(ERRFILE)
+
+pngpread$(O): png.h pngconf.h
+		  $(CC) -c $(CFLAGS) $*.c $(ERRFILE)
+
+pngrtran$(O): png.h pngconf.h
+        $(CC) -c $(CFLAGS) $*.c $(ERRFILE)
+
+pngrutil$(O): png.h pngconf.h
+        $(CC) -c $(CFLAGS) $*.c $(ERRFILE)
+
+pngerror$(O): png.h pngconf.h
+        $(CC) -c $(CFLAGS) $*.c $(ERRFILE)
+
+pngmem$(O): png.h pngconf.h
+        $(CC) -c $(CFLAGS) $*.c $(ERRFILE)
+
+pngio$(O): png.h pngconf.h
+        $(CC) -c $(CFLAGS) $*.c $(ERRFILE)
+
+pngtest$(O): png.h pngconf.h
+        $(CC) -c $(CFLAGS) $*.c $(ERRFILE)
+
+pngtrans$(O): png.h pngconf.h
+        $(CC) -c $(CFLAGS) $*.c $(ERRFILE)
+
+pngwrite$(O): png.h pngconf.h
+        $(CC) -c $(CFLAGS) $*.c $(ERRFILE)
+
+pngwtran$(O): png.h pngconf.h
+        $(CC) -c $(CFLAGS) $*.c $(ERRFILE)
+
+pngwutil$(O): png.h pngconf.h
+        $(CC) -c $(CFLAGS) $*.c $(ERRFILE)
+
+libpng.lib: $(OBJS1) $(OBJS2)
+        del libpng.lib
+	lib libpng $(OBJS1);
+	lib libpng $(OBJS2);
+
+pngtest.exe: pngtest.obj libpng.lib 
+	$(LD) $(LDFLAGS) pngtest.obj,,,libpng.lib ..\zlib\zlib.lib ;
+
+test: pngtest.exe
+	pngtest
+
+# End of makefile for libpng
+

makefile.std

@@ -0,0 +1,60 @@
+# makefile for libpng
+# Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
+# For conditions of distribution and use, see copyright notice in png.h
+
+CC=cc
+CFLAGS=-I../zlib -O
+LDFLAGS=-L. -L../zlib/ -lpng -lz -lm
+
+#RANLIB=ranlib
+RANLIB=echo
+
+# where make install puts libpng.a and png.h
+prefix=/usr/local
+
+OBJS = png.o pngrcb.o pngrutil.o pngtrans.o pngwutil.o \
+	pngread.o pngio.o pngwrite.o pngrtran.o pngwtran.o \
+   pngmem.o pngerror.o pngpread.o
+
+all: libpng.a pngtest
+
+libpng.a: $(OBJS)
+	ar rc $@  $(OBJS)
+	$(RANLIB) $@
+
+pngtest: pngtest.o libpng.a
+	$(CC) -o pngtest $(CCFLAGS) pngtest.o $(LDFLAGS)
+
+test: pngtest
+	./pngtest
+
+install: libpng.a
+	-@mkdir $(prefix)/include
+	-@mkdir $(prefix)/lib
+	cp png.h $(prefix)/include
+	cp pngconf.h $(prefix)/include
+	chmod 644 $(prefix)/include/png.h
+	chmod 644 $(prefix)/include/pngconf.h
+	cp libpng.a $(prefix)/lib
+	chmod 644 $(prefix)/lib/libpng.a
+
+clean:
+	rm -f *.o libpng.a pngtest pngout.png
+
+# DO NOT DELETE THIS LINE -- make depend depends on it.
+
+png.o: png.h pngconf.h
+pngerror.o: png.h pngconf.h
+pngio.o: png.h pngconf.h
+pngmem.o: png.h pngconf.h
+pngrcb.o: png.h pngconf.h
+pngread.o: png.h pngconf.h
+pngrtran.o: png.h pngconf.h
+pngrutil.o: png.h pngconf.h
+pngtest.o: png.h pngconf.h
+pngtrans.o: png.h pngconf.h
+pngwrite.o: png.h pngconf.h
+pngwtran.o: png.h pngconf.h
+pngwutil.o: png.h pngconf.h
+pngpread.o: png.h pngconf.h
+

makefile.tc

@@ -0,0 +1,69 @@
+# Makefile for libpng
+# TurboC++ 3.0 (Note: All modules are compiled in C mode)
+
+# To use, do "make -fmakefile.tc"
+
+# ------------- Turbo C++ 3.0 -------------
+MODEL=-ml
+CFLAGS=-O2 -Z $(MODEL) -I..\zlib
+CC=tcc
+LD=tcc
+LIB=tlib
+LDFLAGS=$(MODEL)
+O=.obj
+
+# variables
+OBJS1 = png$(O) pngrcb$(O) pngrutil$(O) pngtrans$(O) pngwutil$(O) pngmem$(O) pngpread$(O)
+OBJS2 = pngread$(O) pngerror$(O) pngwrite$(O) pngrtran$(O) pngwtran$(O) pngio$(O)
+OBJSL1 = +png$(O) +pngrcb$(O) +pngrutil$(O) +pngtrans$(O) +pngwutil$(O) +pngmem$(O) +pngpread$(O)
+OBJSL2 = +pngread$(O) +pngerror$(O) +pngwrite$(O) +pngrtran$(O) +pngwtran$(O) pngio$(O)
+
+all: libpng.lib
+
+png$(O): png.h pngconf.h
+		  $(CC) -c $(CFLAGS) $*.c
+
+pngrcb$(O): png.h pngconf.h
+		  $(CC) -c $(CFLAGS) $*.c
+
+pngread$(O): png.h pngconf.h
+		  $(CC) -c $(CFLAGS) $*.c
+
+pngpread$(O): png.h pngconf.h
+		  $(CC) -c $(CFLAGS) $*.c
+
+pngrtran$(O): png.h pngconf.h
+		  $(CC) -c $(CFLAGS) $*.c
+
+pngrutil$(O): png.h pngconf.h
+		  $(CC) -c $(CFLAGS) $*.c
+
+pngerror$(O): png.h pngconf.h
+        $(CC) -c $(CFLAGS) $*.c
+
+pngmem$(O): png.h pngconf.h
+        $(CC) -c $(CFLAGS) $*.c
+
+pngio$(O): png.h pngconf.h
+        $(CC) -c $(CFLAGS) $*.c
+
+pngtest$(O): png.h pngconf.h
+        $(CC) -c $(CFLAGS) $*.c
+
+pngtrans$(O): png.h pngconf.h
+        $(CC) -c $(CFLAGS) $*.c
+
+pngwrite$(O): png.h pngconf.h
+        $(CC) -c $(CFLAGS) $*.c
+
+pngwtran$(O): png.h pngconf.h
+        $(CC) -c $(CFLAGS) $*.c
+
+pngwutil$(O): png.h pngconf.h
+        $(CC) -c $(CFLAGS) $*.c
+
+libpng.lib: $(OBJS1) $(OBJS2)
+        $(LIB) libpng +$(OBJSL1)
+        $(LIB) libpng +$(OBJSL2)
+
+# End of makefile for libpng

makevms.com

@@ -0,0 +1,121 @@
+$! make libpng under VMS
+$!
+$!
+$! Look for the compiler used
+$!
+$ zlibsrc = "[-.zlib]"
+$ ccopt="/include=''zlibsrc'"
+$ if f$getsyi("HW_MODEL").ge.1024
+$ then
+$  ccopt = "/prefix=all"+ccopt
+$  comp  = "__decc__=1"
+$  if f$trnlnm("SYS").eqs."" then define sys sys$library:
+$ else
+$  if f$search("SYS$SYSTEM:DECC$COMPILER.EXE").eqs.""
+$   then
+$    if f$trnlnm("SYS").eqs."" then define sys sys$library:
+$    if f$search("SYS$SYSTEM:VAXC.EXE").eqs.""
+$     then
+$      comp  = "__gcc__=1"
+$      CC :== GCC
+$     else
+$      comp = "__vaxc__=1"
+$     endif
+$   else
+$    if f$trnlnm("SYS").eqs."" then define sys decc$library_include:
+$    ccopt = "/decc/prefix=all"+ccopt
+$    comp  = "__decc__=1"
+$  endif
+$ endif
+$!
+$! Build the thing plain or with mms
+$!
+$ write sys$output "Compiling Libpng sources ..."
+$ if f$search("SYS$SYSTEM:MMS.EXE").eqs.""
+$  then
+$   dele pngtest.obj;*
+$   CALL MAKE png.OBJ "cc ''CCOPT' png" -
+                png.c png.h pngconf.h   
+$   CALL MAKE pngpread.OBJ "cc ''CCOPT' pngpread" -
+					 pngpread.c png.h pngconf.h
+$   CALL MAKE pngrcb.OBJ "cc ''CCOPT' pngrcb" -
+                pngrcb.c png.h pngconf.h
+$   CALL MAKE pngread.OBJ "cc ''CCOPT' pngread" -
+                pngread.c png.h pngconf.h
+$   CALL MAKE pngpread.OBJ "cc ''CCOPT' pngpread" -
+					 pngpread.c png.h pngconf.h
+$   CALL MAKE pngrtran.OBJ "cc ''CCOPT' pngrtran" -
+                pngrtran.c png.h pngconf.h
+$   CALL MAKE pngrutil.OBJ "cc ''CCOPT' pngrutil" -
+                pngrutil.c png.h pngconf.h
+$   CALL MAKE pngerror.OBJ "cc ''CCOPT' pngerror" -
+                pngerror.c png.h pngconf.h
+$   CALL MAKE pngmem.OBJ "cc ''CCOPT' pngmem" -
+                pngmem.c png.h pngconf.h
+$   CALL MAKE pngio.OBJ "cc ''CCOPT' pngio" -
+                pngio.c png.h pngconf.h
+$   CALL MAKE pngtrans.OBJ "cc ''CCOPT' pngtrans" -
+                pngtrans.c png.h pngconf.h
+$   CALL MAKE pngwrite.OBJ "cc ''CCOPT' pngwrite" -
+                pngwrite.c png.h pngconf.h
+$   CALL MAKE pngwtran.OBJ "cc ''CCOPT' pngwtran" -
+                pngwtran.c png.h pngconf.h
+$   CALL MAKE pngwutil.OBJ "cc ''CCOPT' pngwutil" -
+                pngwutil.c png.h pngconf.h
+$   write sys$output "Building Libpng ..."
+$   CALL MAKE libpng.OLB "lib/crea libpng.olb *.obj" *.OBJ
+$   write sys$output "Building pngtest..."
+$   CALL MAKE pngtest.OBJ "cc ''CCOPT' pngtest" -
+                pngtest.c png.h pngconf.h
+$   call make pngtest.exe - 
+                "LINK pngtest,libpng.olb/lib,''zlibsrc'libgz.olb/lib" - 
+                pngtest.obj libpng.olb
+$   write sys$output "Testing Libpng..."
+$   run pngtest
+$  else
+$   mms/macro=('comp',zlibsrc='zlibsrc')
+$  endif
+$ write sys$output "Libpng build completed"
+$ exit
+$!
+$!
+$MAKE: SUBROUTINE   !SUBROUTINE TO CHECK DEPENDENCIES
+$ V = 'F$Verify(0)
+$! P1 = What we are trying to make
+$! P2 = Command to make it
+$! P3 - P8  What it depends on
+$
+$ If F$Search(P1) .Eqs. "" Then Goto Makeit
+$ Time = F$CvTime(F$File(P1,"RDT"))
+$arg=3
+$Loop:
+$       Argument = P'arg
+$       If Argument .Eqs. "" Then Goto Exit
+$       El=0
+$Loop2:
+$       File = F$Element(El," ",Argument)
+$       If File .Eqs. " " Then Goto Endl
+$       AFile = ""
+$Loop3:
+$       OFile = AFile
+$       AFile = F$Search(File)
+$       If AFile .Eqs. "" .Or. AFile .Eqs. OFile Then Goto NextEl
+$       If F$CvTime(F$File(AFile,"RDT")) .Ges. Time Then Goto Makeit
+$       Goto Loop3
+$NextEL:
+$       El = El + 1
+$       Goto Loop2
+$EndL:
+$ arg=arg+1
+$ If arg .Le. 8 Then Goto Loop
+$ Goto Exit
+$
+$Makeit:
+$ VV=F$VERIFY(0)
+$ write sys$output P2
+$ 'P2
+$ VV='F$Verify(VV)
+$Exit:
+$ If V Then Set Verify
+$ENDSUBROUTINE
+

png.c

@@ -1,10 +1,10 @@
 
 /* png.c - location for general purpose png functions
 
-	libpng 1.0 beta 2 - version 0.87
+   libpng 1.0 beta 2 - version 0.88
    For conditions of distribution and use, see copyright notice in png.h
    Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
-   January 15, 1996
+   January 25, 1996
    */
 
 #define PNG_INTERNAL
@@ -13,7 +13,7 @@
 
 /* version information for c files.  This better match the version
    string defined in png.h */
-char png_libpng_ver[] = "0.87";
+char png_libpng_ver[] = "0.88";
 
 /* place to hold the signiture string for a png file. */
 png_byte FARDATA png_sig[8] = {137, 80, 78, 71, 13, 10, 26, 10};

png.h

@@ -1,8 +1,8 @@
 
 /* png.h - header file for png reference library
 
-   libpng 1.0 beta 2 - version 0.87
+   libpng 1.0 beta 2 - version 0.88
-   Jan 15, 1996
+   Jan 25, 1996
 
    Note: This is a beta version.  It reads and writes valid files
    on the platforms I have, but it has had limited portability
@@ -27,7 +27,7 @@
    with testing, bug fixes, and patience.  You know who you are.  This
    wouldn't have been possible without all of you.
 
-   Thanks to Frank J. T. Wojcik for reviewing the documentation
+   Thanks to Frank J. T. Wojcik for helping with the documentation
 
    The PNG Reference Library is supplied "AS IS". The Contributing Authors
    and Group 42, Inc. disclaim all warranties, expressed or implied,
@@ -74,10 +74,10 @@
 
 /* version information for png.h - this should match the version
    number in png.c */
-#define PNG_LIBPNG_VER_STRING "0.87"
+#define PNG_LIBPNG_VER_STRING "0.88"
-/* careful here.  I wanted to use 087, but that would be octal.  Version
+/* careful here.  I wanted to use 088, but that would be octal.  Version
    1.0 will be 100 here, etc. */
-#define PNG_LIBPNG_VER 87
+#define PNG_LIBPNG_VER 88
 
 /* variables defined in png.c - only it needs to define PNG_NO_EXTERN */
 #ifndef PNG_NO_EXTERN

pngchang.txt

@@ -54,7 +54,8 @@ version 0.8
    changed external functions passing floats to doubles (k&r problems?)
    put all the configurable stuff in pngconf.h
    enabled png_set_shift to work with paletted images on read
-   added png_read_update_info() - updates info structure with transformations
+   added png_read_update_info() - updates info structure with
+      transformations
 version 0.81
    incorporated Tim Wegner's medium model code (thanks, Tim)
 version 0.85
@@ -69,4 +70,7 @@ version 0.87
    fixed medium model bugs
    fixed other bugs introduced in 0.85 and 0.86
    added some minor documentation
-
+version 0.88
+   fixed progressive bugs
+   replaced tabs with spaces
+   cleaned up documentation

pngconf.h

@@ -1,10 +1,10 @@
 
 /* pngconf.c - machine configurable file for libpng
 
-	libpng 1.0 beta 2 - version 0.87
+   libpng 1.0 beta 2 - version 0.88
    For conditions of distribution and use, see copyright notice in png.h
    Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
-   January 15, 1996
+   January 25, 1996
    */
 
 /* Any machine specific code is near the front of this file, so if you
@@ -27,7 +27,7 @@
    Unless this gets smaller then the size of a row (compressed),
    it should not make much difference how big this is.  */
 
-#define PNG_ZBUF_SIZE 32768
+#define PNG_ZBUF_SIZE 8192
 
 /* While libpng currently uses zlib for it's compression, it has been designed
    to stand on it's own.  Towards this end, there are two defines that are

pngerror.c

@@ -1,10 +1,10 @@
 
 /* pngerror.c - stub functions for i/o and memory allocation
 
-	libpng 1.0 beta 2 - version 0.87
+   libpng 1.0 beta 2 - version 0.88
    For conditions of distribution and use, see copyright notice in png.h
    Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
-   January 15, 1996
+   January 25, 1996
 
    This file provides a location for all error handling.  Users which
    need special error handling are expected to write replacement functions

pngio.c

@@ -1,10 +1,10 @@
 
 /* pngio.c - stub functions for i/o and memory allocation
 
-	libpng 1.0 beta 2 - version 0.87
+   libpng 1.0 beta 2 - version 0.88
    For conditions of distribution and use, see copyright notice in png.h
    Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
-   January 15, 1996
+   January 25, 1996
 
    This file provides a location for all input/output.  Users which need
    special handling are expected to write functions which have the same

pngmem.c

@@ -1,10 +1,10 @@
 
 /* pngmem.c - stub functions for memory allocation
 
-	libpng 1.0 beta 2 - version 0.87
+   libpng 1.0 beta 2 - version 0.88
    For conditions of distribution and use, see copyright notice in png.h
    Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
-   January 15, 1996
+   January 25, 1996
 
    This file provides a location for all memory allocation.  Users which
    need special memory handling are expected to modify the code in this file

pngpread.c

@@ -1,10 +1,10 @@
 
 /* pngpread.c - read a png file in push mode
 
-	libpng 1.0 beta 2 - version 0.87
+   libpng 1.0 beta 2 - version 0.88
    For conditions of distribution and use, see copyright notice in png.h
    Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
-   January 15, 1996
+   January 25, 1996
    */
 
 #define PNG_INTERNAL
@@ -55,6 +55,13 @@ png_process_some_data(png_structp png_ptr, png_infop info)
          png_push_read_text(png_ptr, info);
          break;
       }
+#endif
+#if defined(PNG_READ_zTXt_SUPPORTED)
+      case PNG_READ_zTXt_MODE:
+      {
+         png_push_read_ztxt(png_ptr, info);
+         break;
+      }
 #endif
       case PNG_READ_END_MODE:
       {
@@ -173,7 +180,7 @@ png_push_read_chunk(png_structp png_ptr, png_infop info)
       }
 
       if (png_ptr->mode != PNG_HAVE_IHDR)
-			png_error(png_ptr, "Out of Place PLTE");
+         png_error(png_ptr, "Out of Place gAMA");
 
       png_handle_gAMA(png_ptr, info, png_ptr->push_length);
       png_push_check_crc(png_ptr);
@@ -396,8 +403,13 @@ png_push_skip(png_structp png_ptr)
       png_ptr->current_buffer_size -= save_size;
       png_ptr->current_buffer_ptr += (png_size_t)save_size;
    }
-	if (!png_ptr->skip_length && png_ptr->buffer_size >= 4)
+   if (!png_ptr->skip_length)
    {
+      if (png_ptr->buffer_size < 4)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
       png_push_check_crc(png_ptr);
       png_ptr->process_mode = PNG_READ_CHUNK_MODE;
    }
@@ -564,8 +576,14 @@ png_push_read_idat(png_structp png_ptr)
       png_ptr->current_buffer_size -= save_size;
       png_ptr->current_buffer_ptr += (png_size_t)save_size;
    }
-	if (!png_ptr->idat_size && png_ptr->buffer_size >= 4)
+   if (!png_ptr->idat_size)
    {
+      if (png_ptr->buffer_size < 4)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+
       png_push_check_crc(png_ptr);
       png_ptr->have_chunk_header = 0;
    }
@@ -861,11 +879,17 @@ png_push_read_text(png_structp png_ptr, png_infop info)
       png_ptr->current_text_left -= text_size;
       png_ptr->current_text_ptr += (png_size_t)text_size;
    }
-	if (!(png_ptr->current_text_left) && png_ptr->buffer_size >= 4)
+   if (!(png_ptr->current_text_left))
    {
       png_charp text;
       png_charp key;
 
+      if (png_ptr->buffer_size < 4)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+
       png_push_check_crc(png_ptr);
 
       key = png_ptr->current_text;
@@ -879,8 +903,17 @@ png_push_read_text(png_structp png_ptr, png_infop info)
 
       png_read_tEXt(png_ptr, info, key, text,
          png_ptr->current_text_size - (text - key));
+
+      if (png_ptr->mode == PNG_AT_LAST_IDAT ||
+         png_ptr->mode == PNG_AFTER_IDAT)
+      {
+         png_ptr->process_mode = PNG_READ_END_MODE;
+      }
+      else
+      {
          png_ptr->process_mode = PNG_READ_CHUNK_MODE;
       }
+   }
 }
 #endif
 
@@ -915,13 +948,19 @@ png_push_read_ztxt(png_structp png_ptr, png_infop info)
       png_ptr->current_text_left -= text_size;
       png_ptr->current_text_ptr += (png_size_t)text_size;
    }
-	if (!(png_ptr->current_text_left) && png_ptr->buffer_size >= 4)
+   if (!(png_ptr->current_text_left))
    {
       png_charp text;
       png_charp key;
       int ret;
       png_uint_32 text_size, key_size;
 
+      if (png_ptr->buffer_size < 4)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+
       png_push_check_crc(png_ptr);
 
       key = png_ptr->current_text;
@@ -1028,6 +1067,15 @@ png_push_read_ztxt(png_structp png_ptr, png_infop info)
       text_size -= key_size;
 
       png_read_zTXt(png_ptr, info, key, text, text_size, 0);
+      if (png_ptr->mode == PNG_AT_LAST_IDAT ||
+         png_ptr->mode == PNG_AFTER_IDAT)
+      {
+         png_ptr->process_mode = PNG_READ_END_MODE;
+      }
+      else
+      {
+         png_ptr->process_mode = PNG_READ_CHUNK_MODE;
+      }
    }
 }
 #endif
@@ -1098,6 +1146,11 @@ png_push_read_end(png_structp png_ptr, png_infop info)
    {
       if (png_ptr->push_length)
          png_error(png_ptr, "Invalid IEND chunk");
+      if (png_ptr->buffer_size < 4)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
       png_push_check_crc(png_ptr);
       png_ptr->mode = PNG_AFTER_IEND;
       png_ptr->process_mode = PNG_READ_DONE_MODE;

pngrcb.c

@@ -1,9 +1,9 @@
 /* pngrcb.c - callbacks while reading a png file
 
-	libpng 1.0 beta 2 - version 0.87
+   libpng 1.0 beta 2 - version 0.88
    For conditions of distribution and use, see copyright notice in png.h
    Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
-   January 15, 1996
+   January 25, 1996
    */
 
 #define PNG_INTERNAL

pngread.c

@@ -1,10 +1,10 @@
 
 /* pngread.c - read a png file
 
-   libpng 1.0 beta 2 - version 0.87
+   libpng 1.0 beta 2 - version 0.88
    For conditions of distribution and use, see copyright notice in png.h
    Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
-   January 15, 1996
+   January 25, 1996
    */
 
 #define PNG_INTERNAL

pngrtran.c

@@ -1,10 +1,10 @@
 
 /* pngrtran.c - transforms the data in a row for png readers
 
-	libpng 1.0 beta 2 - version 0.87
+   libpng 1.0 beta 2 - version 0.88
    For conditions of distribution and use, see copyright notice in png.h
    Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
-   January 15, 1996
+   January 25, 1996
    */
 
 #define PNG_INTERNAL

pngrutil.c

@@ -1,10 +1,10 @@
 
 /* pngrutil.c - utilities to read a png file
 
-	libpng 1.0 beta 2 - version 0.87
+   libpng 1.0 beta 2 - version 0.88
    For conditions of distribution and use, see copyright notice in png.h
    Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
-   January 15, 1996
+   January 25, 1996
    */
 
 #define PNG_INTERNAL

pngtrans.c

@@ -2,10 +2,10 @@
 /* pngtrans.c - transforms the data in a row
    routines used by both readers and writers
 
-	libpng 1.0 beta 2 - version 0.87
+   libpng 1.0 beta 2 - version 0.88
    For conditions of distribution and use, see copyright notice in png.h
    Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
-   January 15, 1996
+   January 25, 1996
    */
 
 #define PNG_INTERNAL

pngwrite.c

@@ -1,10 +1,10 @@
 
 /* pngwrite.c - general routines to write a png file
 
-	libpng 1.0 beta 2 - version 0.87
+   libpng 1.0 beta 2 - version 0.88
    For conditions of distribution and use, see copyright notice in png.h
    Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
-   January 15, 1996
+   January 25, 1996
    */
 
 /* get internal access to png.h */

pngwtran.c

@@ -1,10 +1,10 @@
 
 /* pngwtran.c - transforms the data in a row for png writers
 
-	libpng 1.0 beta 2 - version 0.87
+   libpng 1.0 beta 2 - version 0.88
    For conditions of distribution and use, see copyright notice in png.h
    Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
-   January 15, 1996
+   January 25, 1996
    */
 
 #define PNG_INTERNAL

pngwutil.c

@@ -1,10 +1,10 @@
 
 /* pngwutil.c - utilities to write a png file
 
-	libpng 1.0 beta 2 - version 0.87
+   libpng 1.0 beta 2 - version 0.88
    For conditions of distribution and use, see copyright notice in png.h
    Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
-   January 15, 1996
+   January 25, 1996
    */
 #define PNG_INTERNAL
 #include "png.h"

readme.txt

@@ -1,8 +1,8 @@
-readme.txt - for libpng 0.87
+readme.txt - for libpng 0.88
 
 This is a bug fix for the second beta version of libpng 1.0, and
-a first try at a progressive (push) reader.  It hasn't been
+a more secure progressive (push) reader.  The progressive reader
-tested as much as the pull reader, but seems to work ok.
+hasn't been tested as much as the pull reader, but seems to work ok.
 
 I've implemented the callback functions for the error/warning
 messages and the input/output.  See the libpng.txt