Improve T1 parser
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5dead1b1a0
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@ -1,6 +1,8 @@
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local white = (lpeg.S'\0\9\10\12\13\32' + '%' * (1 - lpeg.S'\r\n')^0)^1
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local white = (lpeg.S'\0\9\10\12\13\32' + '%' * (1 - lpeg.S'\r\n')^0)^1 -- Whitespace
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local regular = 1-lpeg.S'()<>[]{}/%\0\9\10\12\13\32'
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local lastbase = '123456789abcdefghiklmnopqrstuvwxyz'
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local number = lpeg.Cmt(lpeg.R'09'^1/tonumber * '#', function(s, p, base)
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if base < 2 then return end
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local pattern
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@ -13,6 +15,7 @@ local number = lpeg.Cmt(lpeg.R'09'^1/tonumber * '#', function(s, p, base)
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return p, num and tonumber(num, base)
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end)
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+ (lpeg.S'+-'^-1 * ('.' * lpeg.R'09'^1 + lpeg.R'09'^1 * lpeg.P'.'^-1 * lpeg.R'09'^0) * (lpeg.S'eE' * lpeg.S'+-'^-1 * lpeg.R'09'^1)^-1)/tonumber
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local literalstring = lpeg.P{'(' * lpeg.Cs((
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lpeg.P'\\n'/'\n'+lpeg.P'\\r'/'\r'+lpeg.P'\\t'/'\t'+lpeg.P'\\b'/'\b'+lpeg.P'\\f'/'\f'
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+'\\'*lpeg.C(lpeg.R'07'*lpeg.R'07'^-2)/function(n)return string.char(tonumber(n, 8))end
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@ -20,16 +23,27 @@ local literalstring = lpeg.P{'(' * lpeg.Cs((
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+'\\'*lpeg.C(1)/1
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+('\n' + ('\r' * lpeg.P'\n'^-1))/'\n'
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+(1-lpeg.S'()\\')+lpeg.V(1))^0) * ')'}
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local hexstring = '<' * lpeg.Cs((
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lpeg.C(lpeg.R'09'+lpeg.R'af'+lpeg.R'AF')*(lpeg.C(lpeg.R'09'+lpeg.R'af'+lpeg.R'AF')+lpeg.Cc'0')/function(a,b)return string.char(tonumber(a..b, 16))end)^0) * '>'
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local name = lpeg.C(regular^1)
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local lname = '/' * name / 1
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local boolean = (lpeg.P'true' + 'false')/{["true"] = true, ["false"] = false}
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-- Everything above this line works pretty reliable and can be understood by reading the PostScript specs.
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-- This is Type1 specific. The only thing which might need adjustment is adding alternative spellings for -|, RD, |-, |, etc.
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local binary_bytes = lpeg.Cmt(number*white^-1*(lpeg.P'-| ' + 'RD '), function(s, p, l)return p+l, s:sub(p, p+l-1) end)*white^-1*(lpeg.P"|-"+"|"+"ND"+"NP")
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-- Attention: The |-, |, ND, NP already contain an implicit `def`
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local function decrypt(key, n, cipher)
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-- Generally you should never implement your own crypto. So we call a well known, peer reviewed,
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-- high-quality cryptographic library. --- Ha-Ha, of course we are implementing by ourselves.
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-- That might be completely unsecure, but given that the encryption keys are well known constants
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-- documented in the T1 Spec, there is no need to worry about it.
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-- Also I do not think any cryptorgraphic library would implement this anyway, it doesn't even
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-- Also I do not think any cryptographic library would implement this anyway, it doesn't even
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-- really deserve the term encryption.
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local decoded = {string.byte(cipher, 1,-1)}
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for i=1,#decoded do
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@ -40,66 +54,77 @@ local function decrypt(key, n, cipher)
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return string.char(table.unpack(decoded, n+1))
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end
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-- io.stdout:write(decrypt(55665, 4, string.sub(io.stdin:read'a', 7)))
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local boolean = (lpeg.P'true' + 'false')/{["true"] = true, ["false"] = false}
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local anytype = {hexstring + literalstring + number + lname + boolean + lpeg.V(2) + name, lpeg.Ct('[' * (white^-1 * lpeg.V(1))^0 * white^-1 * ']' + '{' * (white^-1 * lpeg.V(1))^0 * white^-1 * '}' * white^-1 * lpeg.P"executeonly"^-1)}
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local dict = lpeg.Cf(lpeg.Carg(1) * lpeg.Cg(white^-1*lname*white^-1*(anytype)*white^-1*lpeg.P"readonly"^-1*white^-1*lpeg.P"noaccess"^-1*white^-1*(lpeg.P"def"+"ND"+"|-"))^0, rawset)
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local encoding = (white+anytype-("dup"*white))^0/0
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local anytype = {
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hexstring
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+ literalstring
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+ number
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+ lname
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+ boolean
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+ lpeg.V'array'
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+ name,
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array = lpeg.Ct( '[' * (white^-1 * lpeg.V(1))^0 * white^-1 * ']' -- Arrays have two possible syntaxes
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+ '{' * (white^-1 * lpeg.V(1))^0 * white^-1 * '}') * (white * "executeonly")^-1
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}
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local function skip_until(p)
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if type(p) == 'string' then p = p * -name end
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return (white + anytype - p)^0/0
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end
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local skip_to_begin = skip_until'begin' * 'begin'
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local def_like = (lpeg.P'def' + 'ND' + '|-') * -name
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local encoding = '/' * lpeg.C'Encoding' * -name
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* skip_until'dup'
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* lpeg.Cf(lpeg.Ct''
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* lpeg.Cg("dup"*white*number*white^-1*lname*white^-1*"put"*white)^0
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, rawset)
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* lpeg.P"readonly"^-1*white*"def"
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local function parse_encoding(offset, str)
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local found
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found, offset = (encoding*lpeg.Cp()):match(str, offset)
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return found, offset
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end
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local function parse_fontinfo(offset, str)
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local found
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repeat
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found, offset = ((white+(anytype-name))^0/0*name*lpeg.Cp()):match(str, offset)
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until found == 'begin'
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found, offset = (dict*lpeg.Cp()):match(str, offset, {})
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offset = (white^-1*"end"*white^-1*lpeg.P"readonly"^-1*white^-1*"def"):match(str, offset)
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return found, offset
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end
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local binary_bytes = lpeg.Cmt(number*white^-1*(lpeg.P'-| ' + 'RD '), function(s, p, l)return p+l, s:sub(p, p+l-1) end)*white^-1*(lpeg.P"|-"+"|"+"ND"+"NP")
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local charstr = white^-1*lname*(white^-1*(anytype-lname))^0/0*white^-1
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* ("readonly"*white)^-1 * "def"
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local charstr = '/' * lpeg.C'CharStrings' * -name
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* skip_until(lname) -- sometimes we get weird stuff in between. Just make sure that we don't swallow a charname
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* lpeg.Cf(lpeg.Ct''
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* lpeg.Cg(lname*white^-1*binary_bytes*white)^0
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* lpeg.Cg(lname*white^-1*binary_bytes*white)^0 -- Remember: binary_bytes includes a `def`
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, rawset)
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* lpeg.P"end"*white
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local subrs = (white^-1*(anytype-("dup"*white)))^0/0*white^-1
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local subrs = '/' * lpeg.C'Subrs' * -name
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* skip_until'dup'
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* lpeg.Cf(lpeg.Ct''
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* lpeg.Cg("dup"*white^-1*number*white^-1*binary_bytes*white)^0
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, rawset)
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* (lpeg.P"readonly"*white)^-1 * (lpeg.P"noaccess"*white)^-1*(lpeg.P"def"+"ND"+"|-")
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-- lpeg.V(2) == dict_entries
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local dict = skip_to_begin * lpeg.V(2) * white^-1 * 'end' * white * ('readonly' * white)^-1 * ('noaccess' * white)^-1 * def_like
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local dict_entry = encoding + subrs +
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'/' * lpeg.C'FontInfo' * dict +
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lname -- key
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* white^-1
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* anytype -- value
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* ((white + anytype - (def_like + 'dict' + 'array') * -name)/0 * white^-1)^0 -- Sometimes we get Postscript code in between.
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* def_like
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local dict_entries = lpeg.P{
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lpeg.Cf(lpeg.Carg(1) * lpeg.Cg(white^-1*lpeg.V(3))^0, rawset),
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lpeg.Cf(lpeg.Ct'' * lpeg.Cg(white^-1*lpeg.V(3))^0, rawset),
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dict_entry,
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}
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local function parse_private(offset, str)
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local mydict, found
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repeat
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found, offset = ((white+(anytype-name))^0/0*name*lpeg.Cp()):match(str, offset)
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until found == 'begin'
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mydict, offset = (dict*lpeg.Cp()):match(str, offset, {})
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found = (white^-1*lname):match(str, offset)
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if found == "Subrs" then
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mydict.Subrs, offset = (subrs*lpeg.Cp()):match(str, offset)
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end
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offset = (skip_to_begin * lpeg.Cp()):match(str, offset)
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-- Scan the dictionary
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mydict, offset = (dict_entries*lpeg.Cp()):match(str, offset, {})
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return mydict, offset
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end
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local function continue_maintable(offset, str, mydict)
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mydict, offset = (dict*lpeg.Cp()):match(str, offset, mydict)
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mydict, offset = (dict_entries*lpeg.Cp()):match(str, offset, mydict)
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local found = (white^-1*lname):match(str, offset)
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if found == "FontInfo" then
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mydict.FontInfo, offset = parse_fontinfo(offset, str)
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return continue_maintable(offset, str, mydict)
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elseif found == "Encoding" then
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mydict.Encoding, offset = parse_encoding(offset, str)
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return continue_maintable(offset, str, mydict)
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elseif found == "Private" then
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if found == "Private" then -- Scanned separatly because it isn't always ended in a regular way
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mydict.Private, offset = parse_private(offset, str)
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return continue_maintable(offset, str, mydict)
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elseif found == "CharStrings" then
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mydict.CharStrings, offset = (charstr*lpeg.Cp()):match(str, offset)
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elseif found == "CharStrings" then -- This could be included in normal scanning, but it is our signal to terminate
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found, mydict.CharStrings, offset = (charstr*lpeg.Cp()):match(str, offset)
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return mydict
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else
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local newoffset = ((white+name)^1/0*lpeg.Cp()):match(str, offset)
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@ -107,23 +132,18 @@ local function continue_maintable(offset, str, mydict)
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return continue_maintable(newoffset, str, mydict)
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end
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end
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print(str:sub(offset))
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error[[Unable to read Type 1 font]]
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end
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local function parse_maintable(offset, str)
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local found
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repeat
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found, offset = ((white+(anytype-name))^0/0*name*lpeg.Cp()):match(str, offset)
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until found == 'begin'
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offset = (skip_to_begin * lpeg.Cp()):match(str, offset)
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return continue_maintable(offset, str, {})
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end
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return function(filename)
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local file = io.open(filename, 'rb')
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local _, length = string.unpack("<I2I4", file:read(6))
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local preface = file:read(length)
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_, length = string.unpack("<I2I4", file:read(6))
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local private = decrypt(55665, 4, file:read(length))
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local preface, private = string.unpack("<xxs4xxs4", file:read'a')
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private = decrypt(55665, 4, private)
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file:close()
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local after = parse_maintable(1, preface .. private)
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local lenIV = after.Private.lenIV or 4
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