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libpng/scripts/options.awk

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#!/bin/awk -f
# scripts/options.awk - library build configuration control
#
# last changed in libpng version 1.5.0 - April 25, 2010
#
# Copyright (c) 1998-2010 Glenn Randers-Pehrson
#
# This code is released under the libpng license.
# For conditions of distribution and use, see the disclaimer
# and license in png.h
# The output of this script is written to the file given by
# the variable 'out'. The script is run twice, once with
# an intermediate output file, 'options.tmp' then again on
# that file to produce the final output. Each time the
# output files and whether or not to pre-prrocess must be
# specified:
#
# awk -f scripts/options.awk pre=1 out=options.tmp scripts/options.dat 1>&2
# awk -f scripts/options.awk pre=0 out=options.dfn options.tmp 1>&2
BEGIN{
out="/dev/null" # intermediate, preprocessed, file
pre=-1 # preprocess
start="PNG_DEFN_MAGIC-" # Arbitrary start
end="-PNG_DEFN_END" # Arbitrary end
cx= "/@@@*" # Open C comment for output file
comment=start cx # Comment start
cend="*/" end # Comment end
def=start "#define PNG_@@@" # Arbitrary define
sup="@@@_SUPPORTED" end # end supported option
und=comment "#undef PNG_@@@" # Unsupported option
une="@@@_SUPPORTED" cend # end unsupported option
error=start "ERROR:" # error message
deb=0 # debug - set on command line
logunsupported=0 # write unsupported options too
# Precreate arrays
option[""] = "" # list of all options: default on/off/""
done[""] = 1 # marks option as having been output
requires[""] = "" # requires by option
iffs[""] = "" # if by option
enabledby[""] = "" # options that enable it by option
setting[""] = "" # requires by setting
defaults[""] = "" # used for a defaulted value
doneset[""] = 1 # marks setting as having been output
r[""] = "" # Temporary array
# For decorating the output file
protect = ""
}
# Preprocessing - this just copies the input file with lines
# that need preprocessing (just chunk at present) expanded
pre && $1 != "chunk"{
print >out
next
}
# The first characters of the line determine how it is processed,
# leading spaces are ignored. In general tokens that are not
# keywords are the names of options. An option 'name' is
# controlled by the definition of the corresponding macros:
#
# PNG_name_SUPPORTED The option is turned on
# PNG_NO_name
# PNG_NO_name_SUPPORTED If the first macro is not defined
# either of these will turn the option off
#
# If none of these macros are defined the option is turned on, unless
# the keyword 'off' is given in a line relating to the option. The
# keyword 'on' can also be given, but it will be ignored (since it is
# the default.)
#
# In the syntax below a 'name' is indicated by "NAME", other macro
# values are indicated by "MACRO", as with "NAME" the leading "PNG_"
# is omitted, but in this case the "NO_" prefix and the "_SUPPORTED"
# suffix are never used.
#
# Each line is introduced by a keyword - the first non-space characters
# on the line. A line starting with a '#' is a comment - it is totally
# ignored. Keywords are as follows, a NAME, is simply a macro name
# without the leading PNG_, PNG_NO_ or the trailing _SUPPORTED.
$1 ~ /^#/ || $0 ~ /^[ ]*$/{
next
}
# com <comment>
# The whole line is placed in the output file as a comment with
# the preceding 'com' removed
$1 == "com"{
if (NF > 1) {
sub(/^[ ]*com[ ]*/, "")
print comment, $0, cend >out
} else
print start end >out
next
}
# file output input protect
# Informational: the official name of the input file (without
# make generated local directories), the official name of the
# output file and, if required, a name to use in a protection
# macro for the contents.
$1 == "file" && NF >= 2{
print comment, $2, cend >out
print comment, "Machine generated file: DO NOT EDIT", cend >out
if (NF >= 3)
print comment, "Derived from:", $3, cend >out
protect = $4
if (protect != "") {
print start "#ifndef", protect end >out
print start "#define", protect end >out
}
next
}
# option NAME ( (requires|enables|if) NAME* | on | off )*
# Declares an option 'NAME' and describes its default setting (on|off)
# and its relationship to other options. The option is disabled
# unless *all* the options listed after 'requires' are set and at
# least one of the options listed after 'if' is set. If the
# option is set then it turns on all the options listed after 'enables'.
$1 == "option" && NF >= 2{
onoff = option[$2] # records default on or default off
key = ""
for (i=3; i<=NF; ++i) {
if ($(i) == "on" || $(i) == "off") {
key = ""
if (onoff != $(i)) {
if (onoff == "")
onoff = $(i)
else {
# Print a message, otherwise the error
# below is incomprehensible
print $2 ": currently", onoff ": attempt to turn", $(i)
break
}
}
} else if ($(i) == "requires" || $(i) == "if" || $(i) == "enables") {
key = $(i)
} else if (key == "requires") {
requires[$2] = requires[$2] " " $(i)
} else if (key == "if") {
iffs[$2] = iffs[$2] " " $(i)
} else if (key == "enables") {
enabledby[$(i)] = enabledby[$(i)] " " $2
} else
break # bad line format
}
if (i > NF) {
# Set the option - this may explicitly set it to "", that's good
# becaue we need to ensure it exists and we can't rely on some
# actually quite sensible awk implementation not optimising the
# read above away (gawk doesn't)
option[$2] = onoff
next
}
# Else fall through to the error handler
}
# chunk NAME [requires OPT] [off]
# 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 off]
# option WRITE_NAME requires WRITE_ANCILLARY_CHUNKS [WRITE_OPT]
# option WRITE_NAME enables NAME
# [option WRITE_NAME off]
pre && $1 == "chunk" && NF >= 2{
# 'chunk' is handled on the first pass by writing appropriate
# 'option' lines into the intermediate file.
onoff = ""
reqread = ""
reqwrite = ""
i = 3 # indicates format error
if (NF > 2) {
# read the keywords/additional OPTS
req = 0
for (i=3; i<=NF; ++i) {
if ($(i) == "on" || $(i) == "off") {
if (onoff != $(i)) {
if (onoff == "")
onoff = $(i)
else
break # on/off conflict
}
} else if ($(i) == "requires")
req = 1
else if (req != 1)
break # bad line: handled below
else {
reqread = reqread " READ_" $(i)
reqwrite = reqwrite " WRITE_" $(i)
}
}
}
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
next
}
# Else hit the error handler below - bad line format!
}
# setting MACRO ( requires MACRO* )* [ default VALUE ]
# Behaves in a similar way to 'option' without looking for NO_ or
# _SUPPORTED; the macro is enabled if it is defined so long as all
# the 'requires' macros are also defined. The definitions may be
# empty, an error will be issued if the 'requires' macros are
# *not* defined. If given the 'default' value is used if the
# macro is not defined. The default value will be re-tokenised.
# (BTW: this is somewhat restrictive, it mainly exists for the
# support of non-standard configurations and numeric parameters,
# see the uses in scripts/options.dat
$1 == "setting" && (NF == 2 || NF >= 3 && ($3 == "requires" || $3 == "default")){
reqs = ""
deflt = ""
isdef = 0
key = ""
for (i=3; i<=NF; ++i)
if ($(i) == "requires" || $(i) == "default") {
key = $(i)
if (key == "default") isdef = 1
} else if (key == "requires")
reqs = reqs " " $(i)
else if (key == "default")
deflt = deflt " " $(i)
else
break # Format error, handled below
setting[$2] = reqs
if (isdef && deflt == "")
deflt = " " # as a flag to force output
defaults[$2] = deflt
next
}
# The order of the dependency lines (option, chunk, setting) is irrelevant
# - the 'enables', 'requires' and 'if' settings will be used to determine
# the correct order in the output and the final values in pnglibconf.h are
# not order dependent. 'requires' and 'if' entries take precedence over
# 'enables' from other options; if an option requires another option it
# won't be set regardless of any options that enable it unless the other
# option is also enabled.
#
# Similarly 'enables' trumps a NO_ definition in CFLAGS or pngusr.h
#
# For simplicity cycles in the definitions are regarded as errors,
# even if they are not ambiguous.
# A given NAME can be specified in as many 'option' lines as required, the
# definitions are additive.
# For backwards compatibility equivalent macros may be listed thus:
#
# = [NO_]NAME MACRO
# Makes -DMACRO equivalent to -DPNG_NO_NAME or -DPNG_NAME_SUPPORTED
# as appropriate.
#
# The definition is injected into the C compiler input when encountered
# in the second pass (so all these definitions appear *after* the @
# lines!)
#
# 'NAME' is as above, but 'MACRO' is the full text of the equivalent
# old, deprecated, macro.
$1 == "=" && NF == 3{
print "#ifdef PNG_" $3 >out
if ($2 ~ /^NO_/)
print "# define PNG_" $2 >out
else
print "# define PNG_" $2 "_SUPPORTED" >out
print "#endif" >out
next
}
# Lines may be injected into the C compiler input by preceding them
# with an "@" character. The line is copied with just the leading
# @ removed.
$1 ~ /^@/{
sub(/^[ ]*@/, "")
print >out
next
}
# Check for unreognized lines, because of the preprocessing chunk
# format errors will be detected on the first pass independent of
# any other format errors.
{
print "options.awk: bad line (" NR "):", $0
exit 1
}
# For checking purposes names that start with "ok_" or "fail_" are
# not output to pnglibconf.h and must be either enabled or disabled
# respectively for the build to succeed. This allows interdependencies
# between options of the form "at least one of" or "at most one of"
# to be checked. For example:
#
# option FLOATING_POINT enables ok_math
# option FIXED_POINT enables ok_math
# This ensures that at least one of FLOATING_POINT and FIXED_POINT
# must be set for the build to succeed.
#
# option fail_math requires FLOATING_POINT FIXED_POINT
# This means the build will fail if *both* FLOATING_POINT and
# FIXED_POINT are set (this is an example; in fact both are allowed.)
#
# If all these options were given the build would require exactly one
# of the names to be enabled.
END{
if (out == "/dev/null") {
print "out=output.file must be given on the command line"
exit 1
}
if (pre) {
if (pre != 1) {
print "pre=0 or pre=1 must be given on command line"
exit 1
}
exit 0
}
# Do the 'setting' values first, the algorithm the standard
# tree walk (O(1)) done in an O(2) while/for loop; interations
# settings x depth, outputing the deepest required macros
# first.
print "" >out
print "/* SETTINGS */" >out
print comment, "settings", cend >out
finished = 0
while (!finished) {
finished = 1
movement = 0 # done nothing
for (i in setting) if (!doneset[i]) {
nreqs = split(setting[i], r)
if (nreqs > 0) {
for (j=1; j<=nreqs; ++j) if (!doneset[r[j]])
break
if (j<=nreqs) {
finished = 0
continue # try a different setting
}
}
# All the requirements have been processed, output
# this setting.
if (deb) print "setting", i
print "" >out
print "/* setting: ", i >out
print " * requires:" setting[i] >out
print " * default: ", defaults[i], "*/" >out
if (defaults[i] == "") # no default, only check if defined
print "#ifdef PNG_" i >out
for (j=1; j<=nreqs; ++j) {
print "# ifndef PNG_" r[j] >out
print error, i, "requires", r[j] end >out
print "# endif" >out
}
if (defaults[i] != "") # default handling
print "#ifdef PNG_" i >out
print def i, "PNG_" i end >out
if (defaults[i] != "") {
print "#else /*default*/" >out
print def i defaults[i] end >out
}
print "#endif" >out
doneset[i] = 1
++movement
}
if (!finished && !movement) {
print "setting: loop or missing setting in 'requires', cannot process:"
for (i in setting) if (!doneset[i])
print " setting", i, "requires" setting[i]
exit 1
}
}
print comment, "end of settings", cend >out
# Now do the options - somewhat more complex. The dependency
# tree is thus:
#
# name > name
# name requires name
# name if name
# name enabledby name
#
# First build a list 'tree' by option of all the things on which
# it depends.
print "" >out
print "/* OPTIONS */" >out
print comment, "options", cend >out
for (opt in enabledby) tree[opt] = 1 # may not be explicit options
for (opt in option) tree[opt] = "" # so unlisted options marked
for (opt in tree) {
if (tree[opt] == 1) {
tree[opt] = ""
if (option[opt] != "") {
print "internal error (1)"
exit 1
}
# Macros only listed in 'enables' remain off unless
# one of the enabling macros is on.
option[opt] = "off"
}
split("", list) # clear 'list'
# Now add every requires, iffs or enabledby entry to 'list'
# so that we can add a unique list of requirements to tree[i]
split(requires[opt] iffs[opt] enabledby[opt], r)
for (i in r) list[r[i]] = 1
for (i in list) tree[opt] = tree[opt] " " i
}
# print the tree for extreme debugging
if (deb > 2) for (i in tree) if (i != "") print i, "depends-on" tree[i]
# option[i] is now the complete list of all the tokens we may
# need to output, go through it as above, depth first.
finished = 0
while (!finished) {
finished = 1
movement = 0 # done nothing
for (i in option) if (!done[i]) {
nreqs = split(tree[i], r)
if (nreqs > 0) {
for (j=1; j<=nreqs; ++j) if (!done[r[j]])
break
if (j<=nreqs) {
finished = 0
continue # next option
}
}
# All the requirements have been processed, output
# this option. An option is _SUPPORTED if:
#
# all 'requires' are _SUPPORTED AND
# at least one of the 'if' options are _SUPPORTED AND
# EITHER:
# The name is _SUPPORTED (on the command line)
# OR:
# an 'enabledby' is _SUPPORTED
# OR:
# NO_name is not defined AND
# the option is not marked "off"
if (deb) print "option", i
print "" >out
print "/* option:", i, option[i] >out
print " * requires: " requires[i] >out
print " * if: " iffs[i] >out
print " * enabled-by:" enabledby[i], "*/" >out
print "#undef PNG_on" >out
print "#define PNG_on 1" >out
# requires
nreqs = split(requires[i], r)
for (j=1; j<=nreqs; ++j) {
print "#ifndef PNG_" r[j] "_SUPPORTED" >out
print "# undef PNG_on /*!" r[j] "*/" >out
print "#endif" >out
}
# if
nreqs = split(iffs[i], r)
print "#undef PNG_no_if" >out
if (nreqs > 0) {
print "/* if" iffs[i], "*/" >out
print "#define PNG_no_if 1" >out
for (j=1; j<=nreqs; ++j) {
print "#ifdef PNG_" r[j] "_SUPPORTED" >out
print "# undef PNG_no_if /*" r[j] "*/" >out
print "#endif" >out
}
print "#ifdef PNG_no_if /*missing if*/" >out
print "# undef PNG_on" >out
print "#endif" >out
}
print "#ifdef PNG_on /*requires, if*/" >out
# enables
print "# undef PNG_not_enabled" >out
print "# define PNG_not_enabled 1" >out
print " /* enabled by" enabledby[i], "*/" >out
nreqs = split(enabledby[i], r)
for (j=1; j<=nreqs; ++j) {
print "#ifdef PNG_" r[j] "_SUPPORTED" >out
print "# undef PNG_not_enabled /*" r[j] "*/" >out
print "#endif" >out
}
print "# ifndef PNG_" i "_SUPPORTED /*!command line*/" >out
print "# ifdef PNG_not_enabled /*!enabled*/" >out
if (option[i] == "off") {
print "# undef PNG_on /*default off*/" >out
} else {
print "# ifdef PNG_NO_" i >out
print "# undef PNG_on /*turned off*/" >out
print "# endif" >out
print "# ifdef PNG_NO_" i "_SUPPORTED" >out
print "# undef PNG_on /*turned off*/" >out
print "# endif" >out
}
print "# endif /*!enabled*/" >out
print "# ifdef PNG_on" >out
# The _SUPPORTED macro must be defined so that dependent
# options output later work.
print "# define PNG_" i "_SUPPORTED" >out
print "# endif" >out
print "# endif /*!command line*/" >out
# If PNG_on is still set the option should be defined in
# pnglibconf.h
print "# ifdef PNG_on" >out
if (i ~ /^fail_/)
print error, i, "if" iffs[i], "requires" requires[i] end >out
else if (i !~ /^ok_/)
print def i sup >out
print "# endif /* definition */" >out
print "#endif /*requires, if*/" >out
if (logunsupported || i ~ /^ok_/) {
print "#ifndef PNG_on" >out
if (logunsupported)
print und i une >out
if (i ~ /^ok_/)
print error, i, "if" iffs[i], "requires" requires[i] end >out
print "#endif" >out
}
done[i] = 1
++movement
}
if (!finished && !movement) {
print "option: loop or missing option in dependency tree, cannot process:"
for (i in option) if (!done[i]) {
print " option", i, "depends on" tree[i], "needs:"
nreqs = split(tree[i], r)
if (nreqs > 0) for (j=1; j<=nreqs; ++j) if (!done[r[j]])
print " " r[j]
}
exit 1
}
}
print comment, "end of options", cend >out
# Regular end - everything looks ok
if (protect != "")
print start "#endif", cx, protect, "*/" end >out
}
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