share/png/scripts/dfn.awk

   1 #!/bin/awk -f
   2 # scripts/dfn.awk - process a .dfn file
   3 #
   4 # last changed in libpng version 1.5.14 - February 4, 2013
   5 #
   6 # Copyright (c) 2013-2013 Glenn Randers-Pehrson
   7 #
   8 # This code is released under the libpng license.
   9 # For conditions of distribution and use, see the disclaimer
  10 # and license in png.h
  11
  12 # The output of this script is written to the file given by
  13 # the variable 'out', which should be set on the command line.
  14 # Error messages are printed to stdout and if any are printed
  15 # the script will exit with error code 1.
  16
  17 BEGIN{
  18    out="/dev/null"       # as a flag
  19    out_count=0           # count of output lines
  20    err=0                 # set if an error occured
  21    sort=0                # sort the output
  22    array[""]=""
  23 }
  24
  25 # The output file must be specified before any input:
  26 NR==1 && out == "/dev/null" {
  27    print "out=output.file must be given on the command line"
  28    # but continue without setting the error code, this allows the
  29    # script to be checked easily
  30 }
  31
  32 # Output can be sorted; two lines are recognized
  33 $1 == "PNG_DFN_START_SORT"{
  34    sort=0+$2
  35    next
  36 }
  37
  38 $1 ~ /^PNG_DFN_END_SORT/{
  39    # Do a very simple, slow, sort; notice that blank lines won't be
  40    # output by this
  41    for (entry in array) {
  42       while (array[entry] != "") {
  43          key = entry
  44          value = array[key]
  45          array[key] = ""
  46
  47          for (alt in array) {
  48             if (array[alt] != "" && alt < key) {
  49                array[key] = value
  50                value = array[alt]
  51                key = alt
  52                array[alt] = ""
  53             }
  54          }
  55
  56          print value >out
  57       }
  58    }
  59    sort=0
  60    next
  61 }
  62
  63 /^[^"]*PNG_DFN *".*"[^"]*$/{
  64    # A definition line, apparently correctly formated, extract the
  65    # definition then replace any doubled "" that remain with a single
  66    # double quote.  Notice that the original doubled double quotes
  67    # may have been split by tokenization
  68    #
  69    # Sometimes GCC splits the PNG_DFN lines, we know this has happened
  70    # if the quotes aren't closed and must read another line.  In this
  71    # case it is essential to reject lines that start '#' because those
  72    # are introduced #line directives.
  73    orig=$0
  74    line=$0
  75    lineno=FNR
  76    if (lineno == "") lineno=NR
  77
  78    if (sub(/^[^"]*PNG_DFN *"/,"",line) != 1) {
  79         print "line", lineno ": processing failed:"
  80         print orig
  81         err=1
  82        next
  83    } else {
  84         ++out_count
  85    }
  86
  87    # Now examine quotes within the value:
  88    #
  89    #   @" - delete this and any following spaces
  90    #   "@ - delete this and any preceding spaces
  91    #   @' - replace this by a double quote
  92    #
  93    # This allows macro substitution by the C compiler thus:
  94    #
  95    #   #define first_name John
  96    #   #define last_name Smith
  97    #
  98    #    PNG_DFN"#define name @'@" first_name "@ @" last_name "@@'"
  99    #
 100    # Might get C preprocessed to:
 101    #
 102    #   PNG_DFN "#define foo @'@" John "@ @" Smith "@@'"
 103    #
 104    # Which this script reduces to:
 105    #
 106    #    #define name "John Smith"
 107    #
 108    while (1) {
 109       # While there is an @" remove it and the next "@
 110       if (line ~ /@"/) {
 111          if (line ~ /@".*"@/) {
 112             # Do this special case first to avoid swallowing extra spaces
 113             # before or after the @ stuff:
 114             if (!sub(/@" *"@/, "", line)) {
 115                # Ok, do it in pieces - there has to be a non-space between the
 116                # two.  NOTE: really weird things happen if a leading @" is
 117                # lost - the code will error out below (I believe).
 118                if (!sub(/@" */, "", line) || !sub(/ *"@/, "", line)) {
 119                   print "line", lineno, ": internal error:", orig
 120                   exit 1
 121                }
 122             }
 123          }
 124
 125          # There is no matching "@.  Assume a split line
 126          else while (1) {
 127             if (getline nextline) {
 128                # If the line starts with '#' it is a preprocesor line directive
 129                # from cc -E, skip it:
 130                if (nextline !~ /^#/) {
 131                   line = line " " nextline
 132                   break
 133                }
 134             } else {
 135                # This is end-of-input - probably a missig "@ on the first line:
 136                print "line", lineno ": unbalanced @\" ... \"@ pair"
 137                err=1
 138                next
 139             }
 140          }
 141
 142          # Keep going until all the @" have gone
 143          continue
 144       }
 145
 146       # Attempt to remove a trailing " (not preceded by '@') - if this can
 147       # be done stop now, if not assume a split line again
 148       if (sub(/"[^"]*$/, "", line))
 149          break
 150
 151       # Read another line
 152       while (1) {
 153          if (getline nextline) {
 154             if (nextline !~ /^#/) {
 155                line = line " " nextline
 156                # Go back to stripping @" "@ pairs
 157                break
 158             }
 159          } else {
 160             print "line", lineno ": unterminated PNG_DFN string"
 161             err=1
 162             next
 163          }
 164       }
 165    }
 166
 167    # Put any needed double quotes in (at the end, because these would otherwise
 168    # interfere with the processing above.)
 169    gsub(/@'/,"\"", line)
 170
 171    # Remove any trailing spaces (not really required, but for
 172    # editorial consistency
 173    sub(/ *$/, "", line)
 174
 175    # Remove trailing CR
 176    sub(/$/, "", line)
 177
 178    if (sort) {
 179       if (split(line, parts) < sort) {
 180          print "line", lineno ": missing sort field:", line
 181          err=1
 182       } else
 183          array[parts[sort]] = line
 184    }
 185
 186    else
 187       print line >out
 188    next
 189 }
 190
 191 /PNG_DFN/{
 192    print "line", NR, "incorrectly formated PNG_DFN line:"
 193    print $0
 194    err = 1
 195 }
 196
 197 END{
 198    if (out_count > 0 || err > 0)
 199         exit err
 200
 201    print "no definition lines found"
 202    exit 1
 203 }