#!/bin/awk -f
# Check a list of symbols against the master definition
# (official) list.  Arguments:
#
# awk -f checksym.awk official-def list-to-check
#
# Output is a file in the current directory called 'symbols.new',
# stdout holds error messages.  Error code indicates success or
# failure.
#
# NOTE: this is a pure, old fashioned, awk script.  It will
# work with any awk

BEGIN{
    err=0
    master=""         # master file
    official[1] = ""  # defined symbols from master file
    symbol[1] = ""    # defined symbols from png.h
    removed[1] = ""   # removed symbols from png.h
    lasto = 0         # last ordinal value from png.h
    mastero = 0       # highest ordinal in master file
    symbolo = 0       # highest ordinal in png.h
}

# Read existing definitions from the master file (the first
# file on the command line.)  This must be a def file and it
# has definition lines (others are ignored) of the form:
#
#   symbol @ordinal
#
master == "" {
    master = FILENAME;
}
FILENAME==master && NF==2 && $2~/^@/ && $1!~/^;/ {
    o=0+substr($2,2)
    if (o > 0) {
	if (official[o] == "") {
	    official[o] = $1
	    if (o > mastero) mastero = o
	    next
	} else
	    print master ": duplicated symbol:", official[o] ":", $0
    } else
	print master ": bad export line format:", $0
    err = 1
}
FILENAME==master {
    next
}

# Read new definitions, these are free form but the lines must
# just be symbol definitions.  Lines will be commented out for
# 'removed' symbols, introduced in png.h using PNG_REMOVED rather
# than PNG_EXPORT.  Use symbols.dfn or pngwin.dfn to generate the
# input file.
#
#  symbol @ordinal     # two fields, exported symbol
#  ; symbol @ordinal   # three fields, removed symbol
#  ; @ordinal          # two fields, the last ordinal
NF==2 && $1 == ";" && $2 ~ /^@[1-9][0-9]*$/ { # last ordinal
    o=0+substr($2,2)
    if (lasto == 0 || lasto == o)
	lasto=o
    else {
 	print "png.h: duplicated last ordinal:", lasto, o
	err = 1
    }
    next
}
NF==3 && $1 == ";" && $3 ~ /^@[1-9][0-9]*$/ { # removed symbol
    o=0+substr($3,2)
    if (removed[o] == "" || removed[o] == $2) {
	removed[o] = $2
	if (o > symbolo) symbolo = o
    } else {
	print "png.h: duplicated removed symbol",
		o ": '" removed[o] "' != '" $2 "'"
	err = 1
    }
    next
}
NF==2 && $2 ~ /^@[1-9][0-9]*$/ { # exported symbol
    o=0+substr($2,2)
    if (symbol[o] == "" || symbol[o] == $1) {
    	symbol[o] = $1
	if (o > symbolo) symbolo = o
    } else {
	print "png.h: duplicated symbol",
		o ": '" symbol[o] "' != '" $1 "'"
	err = 1
    }
}
{
    next # skip all other lines
}

# At the end check for symbols marked as both duplicated and removed
END{
    if (symbolo > lasto) {
    	print "highest symbol ordinal in png.h,",
		symbolo ", exceeds last ordinal from png.h", lasto
	err = 1
    }
    if (mastero > lasto) {
    	print "highest symbol ordinal in", master ",",
		mastero ", exceeds last ordinal from png.h", lasto
	err = 1
    }
    unexported=0
    for (o=1; o<=lasto; ++o) {
	if (symbol[o] == "" && removed[o] == "") {
	    if (unexported == 0) unexported = o
	    if (official[o] == "") {
	    	# missing in export list too, so ok
		if (o < lasto) continue
	    }
	}
	if (unexported != 0) {
	    # Symbols in the .def but not in the new file are errors
	    if (o-1 > unexported)
		print "png.h: warning: unexported symbol definitions:",
		    unexported "-" o-1
	    else
		print "png.h: warning: unexported symbol definition:",
		    unexported
	    unexported = 0
	}
	if (symbol[o] != "" && removed[o] != "") {
	    print "png.h: symbol", o,
	      "both exported as '" symbol[o] "' and removed as '" removed[o] "'"
	    err = 1
	} else if (symbol[o] != official[o]) {
	    # either the symbol is missing somewhere or it changed
	    err = 1
	    if (symbol[o] == "")
		print "png.h: symbol", o,
		    "is exported as '" official[o] "' in", master
	    else if (official[o] == "")
		print "png.h: exported symbol", o,
		    "'" symbol[o] "' not present in", master
	    else
		print "png.h: exported symbol", o,
		    "'" symbol[o] "' exists as '" official[o] "' in", master
	}

	# Finally generate symbols.new
	if (symbol[o] != "")
	    print " " symbol[o], "@" o > "symbols.new"
    }

    if (err != 0) {
	print "*** A new list is in symbols.new ***"
	exit 1
    }
}