[libpng16] Changed chunk handler warnings into benign errors, incrementally

load iCCP

scripts/options.awk

@@ -286,15 +286,15 @@ $1 == "option" && NF >= 2{
    # Else fall through to the error handler
 }
 
-# chunk NAME [requires OPT] [on|off|disabled]
+# chunk NAME [requires OPT] [enables LIST] [on|off|disabled]
 #   Expands to the 'option' settings appropriate to the reading and
 #   writing of an ancilliary PNG chunk 'NAME':
 #
 #   option READ_NAME requires READ_ANCILLARY_CHUNKS [READ_OPT]
-#   option READ_NAME enables NAME
+#   option READ_NAME enables NAME LIST
 #   [option READ_NAME off]
 #   option WRITE_NAME requires WRITE_ANCILLARY_CHUNKS [WRITE_OPT]
-#   option WRITE_NAME enables NAME
+#   option WRITE_NAME enables NAME LIST
 #   [option WRITE_NAME off]
 
 pre != 0 && $1 == "chunk" && NF >= 2{
@@ -303,6 +303,7 @@ pre != 0 && $1 == "chunk" && NF >= 2{
    onoff = ""
    reqread = ""
    reqwrite = ""
+   enables = ""
    i = 3 # indicates format error
    if (NF > 2) {
       # read the keywords/additional OPTS
@@ -315,21 +316,25 @@ pre != 0 && $1 == "chunk" && NF >= 2{
                else
                   break # on/off conflict
             }
+            req = 0
          } else if ($(i) == "requires")
             req = 1
-         else if (req != 1)
-            break # bad line: handled below
-         else {
+         else if ($(i) == "enables")
+            req = 2
+         else if (req == 1){
             reqread = reqread " READ_" $(i)
             reqwrite = reqwrite " WRITE_" $(i)
-         }
+         } else if (req == 2)
+            enables = enables " " $(i)
+         else
+            break # bad line: handled below
       }
    }
 
    if (i > NF) {
       # Output new 'option' lines to the intermediate file (out)
-      print "option READ_" $2, "requires READ_ANCILLARY_CHUNKS" reqread, "enables", $2, onoff >out
-      print "option WRITE_" $2, "requires WRITE_ANCILLARY_CHUNKS" reqwrite, "enables", $2, onoff >out
+      print "option READ_" $2, "requires READ_ANCILLARY_CHUNKS" reqread, "enables", $2 enables , onoff >out
+      print "option WRITE_" $2, "requires WRITE_ANCILLARY_CHUNKS" reqwrite, "enables", $2 enables, onoff >out
       next
    }
    # Else hit the error handler below - bad line format!

scripts/pnglibconf.dfa

@@ -32,8 +32,12 @@ file pnglibconf.h scripts/pnglibconf.dfa PNGLCONF_H
 # option <name> [requires ...] [if ...] [enables ...] [disabled]
 #    #define PNG_<name>_SUPPORTED if the requirements are met and
 #    enable the other options listed
-# chunk <name> [requires ...] [disabled]
-#    Enable chunk processing for the given ancillary chunk
+# chunk <name> [requires ...] [enables ...] [disabled]
+#    Enable chunk processing for the given ancillary chunk; any
+#    'requires something' expands to READ_something for read and
+#    WRITE_something for write, but the enables list members are
+#    used as given (e.g. enables GAMMA just expands to that on the
+#    correspond READ_name and WRITE_name lines.)
 #
 # Note that the 'on' and 'off' keywords, while valid on both option
 # and chunk, should not be used in this file because they force the
@@ -461,9 +465,18 @@ option WRITE_TEXT requires WRITE_ANCILLARY_CHUNKS enables TEXT
 #   API is implemented, they get recorded in pnglibconf.h, but
 #   can't be changed by the application.
 
-# Check the correctness of cHRM chunks
+# Colorspace support (enabled as required); just the support for colorant
+# information.  Gamma support, likewise, is just support for the gamma
+# information, READ_GAMMA is required for gamma transformations (so it
+# is possible to read PNG gamma without enabling all the libpng transform
+# code - do this for applications that do their own gamma processing)
+#
+# As of 1.6.0 COLORSPACE is only useful if the application processes the
+# information; this is because the library does not do any colorspace
+# processing, it just validates the data in the PNG file.
 
-option CHECK_cHRM requires cHRM
+option GAMMA disabled
+option COLORSPACE enables GAMMA disabled
 
 #
 # Artificially align memory - the code typically aligns to 8 byte
@@ -560,18 +573,18 @@ setting IDAT_READ_SIZE default PNG_ZBUF_SIZE
 
 # Ancillary chunks
 chunk bKGD
-chunk cHRM
-chunk gAMA
+chunk cHRM enables COLORSPACE
+chunk gAMA enables GAMMA
 chunk hIST
-chunk iCCP
+chunk iCCP enables COLORSPACE GAMMA
 chunk iTXt
 chunk oFFs
 chunk pCAL
-chunk sCAL
 chunk pHYs
 chunk sBIT
+chunk sCAL
 chunk sPLT
-chunk sRGB
+chunk sRGB enables COLORSPACE GAMMA
 chunk tEXt requires TEXT
 chunk tIME
 chunk tRNS

scripts/pnglibconf.h.prebuilt

@@ -3,7 +3,7 @@
 
 /* pnglibconf.h - library build configuration */
 
-/* Libpng 1.6.0beta20 - March 19, 2012 */
+/* Libpng 1.6.0beta20 - March 21, 2012 */
 
 /* Copyright (c) 1998-2012 Glenn Randers-Pehrson */
 
@@ -44,9 +44,9 @@
 /*#undef PNG_BENIGN_WRITE_ERRORS_SUPPORTED*/
 #define PNG_bKGD_SUPPORTED
 #define PNG_BUILD_GRAYSCALE_PALETTE_SUPPORTED
-#define PNG_CHECK_cHRM_SUPPORTED
 #define PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
 #define PNG_cHRM_SUPPORTED
+#define PNG_COLORSPACE_SUPPORTED
 #define PNG_CONSOLE_IO_SUPPORTED
 #define PNG_CONVERT_tIME_SUPPORTED
 #define PNG_EASY_ACCESS_SUPPORTED
@@ -58,6 +58,7 @@
 #define PNG_FORMAT_AFIRST_SUPPORTED
 #define PNG_FORMAT_BGR_SUPPORTED
 #define PNG_gAMA_SUPPORTED
+#define PNG_GAMMA_SUPPORTED
 #define PNG_HANDLE_AS_UNKNOWN_SUPPORTED
 #define PNG_hIST_SUPPORTED
 #define PNG_iCCP_SUPPORTED