libpng/scripts/dfn.awk

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#!/bin/awk -f
# scripts/dfn.awk - process a .dfn file
#
# last changed in libpng version 1.5.14 - February 4, 2013
#
# Copyright (c) 2013-2013 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', which should be set on the command line.
# Error messages are printed to stdout and if any are printed
# the script will exit with error code 1.
BEGIN{
out="/dev/null" # as a flag
out_count=0 # count of output lines
err=0 # set if an error occured
sort=0 # sort the output
array[""]=""
}
# The output file must be specified before any input:
NR==1 && out == "/dev/null" {
print "out=output.file must be given on the command line"
# but continue without setting the error code, this allows the
# script to be checked easily
}
# Output can be sorted; two lines are recognized
$1 == "PNG_DFN_START_SORT"{
sort=$2
next
}
$1 == "PNG_DFN_END_SORT"{
# Do a very simple, slow, sort; notice that blank lines won't be
# output by this
for (entry in array) {
while (array[entry] != "") {
key = entry
value = array[key]
array[key] = ""
for (alt in array) {
if (array[alt] != "" && alt < key) {
array[key] = value
value = array[alt]
key = alt
array[alt] = ""
}
}
print value >out
}
}
sort=0
next
}
/^[^"]*PNG_DFN *".*"[^"]*$/{
# A definition line, apparently correctly formated, extract the
# definition then replace any doubled "" that remain with a single
# double quote. Notice that the original doubled double quotes
# may have been split by tokenization
orig=$0
if (gsub(/^[^"]*PNG_DFN *"/,"") != 1 || gsub(/"[^"]*$/, "") != 1) {
print "line", NR, "processing failed:"
print orig
print $0
err=1
} else {
++out_count
}
# Now examine quotes within the value:
#
# @" - delete this and any following spaces
# "@ - delete this and any original spaces
# @' - replace this by a double quote
#
# This allows macro substitution by the C compiler thus:
#
# #define first_name John
# #define last_name Smith
#
# PNG_DFN"#define name @'@" first_name "@ @" last_name "@@'"
#
# Might get C preprocessed to:
#
# PNG_DFN "#define foo @'@" John "@ @" Smith "@@'"
#
# Which this script reduces to:
#
# #define name "John Smith"
#
while (sub(/@" */, "")) {
if (!sub(/ *"@/, "")) {
print "unbalanced @\" ... \"@ pair"
err=1
break
}
}
# Put any needed double quotes in
gsub(/@'/,"\"")
# Remove any trailing spaces (not really required, but for
# editorial consistency
sub(/ *$/, "")
if (sort)
array[$(sort)] = $0
else
print $0 >out
next
}
/PNG_DFN/{
print "line", NR, "incorrectly formated PNG_DFN line:"
print $0
err = 1
}
END{
if (out_count > 0 || err > 0)
exit err
print "no definition lines found"
exit 1
}