mirror of
https://github.com/zen-browser/pdf.js.git
synced 2025-07-12 19:25:47 +02:00
260 lines
8.1 KiB
JavaScript
260 lines
8.1 KiB
JavaScript
|
||
var Type1Parser = function(aAsciiStream, aBinaryStream) {
|
||
var lexer = new Lexer(aAsciiStream);
|
||
|
||
// Turn on this flag for additional debugging logs
|
||
var debug = false;
|
||
|
||
var dump = function(aData) {
|
||
if (debug)
|
||
log(aData);
|
||
};
|
||
|
||
/*
|
||
* Decrypt a Sequence of Ciphertext Bytes to Produce the Original Sequence
|
||
* of Plaintext Bytes. The function took a key as a parameter which can be
|
||
* for decrypting the eexec block of for decoding charStrings.
|
||
*/
|
||
var kEexecEncryptionKey = 55665;
|
||
var kCharStringsEncryptionKey = 4330;
|
||
|
||
function decrypt(aStream, aKey, aDiscardNumber) {
|
||
var r = aKey, c1 = 52845, c2 = 22719;
|
||
|
||
var decryptedString = [];
|
||
var value = null;
|
||
|
||
var count = aStream.length;
|
||
for (var i = 0; i < count; i++) {
|
||
value = aStream.getByte();
|
||
decryptedString[i] = String.fromCharCode(value ^ (r >> 8));
|
||
r = ((value + r) * c1 + c2) & ((1 << 16) - 1);
|
||
}
|
||
return decryptedString.slice(aDiscardNumber);
|
||
}
|
||
|
||
/*
|
||
* The operand stack holds arbitrary PostScript objects that are the operands
|
||
* and results of PostScript operators being executed. The interpreter pushes
|
||
* objects on the operand stack when it encounters them as literal data in a
|
||
* program being executed. When an operator requires one or more operands, it
|
||
* obtains them by popping them off the top of the operand stack. When an
|
||
* operator returns one or more results, it does so by pushing them on the
|
||
* operand stack.
|
||
*/
|
||
var operandStack = {
|
||
__innerStack__: [],
|
||
|
||
push: function(aOperand) {
|
||
this.__innerStack__.push(aOperand);
|
||
},
|
||
|
||
pop: function() {
|
||
return this.__innerStack__.pop();
|
||
},
|
||
|
||
peek: function() {
|
||
return this.__innerStack__[this.__innerStack__.length - 1];
|
||
},
|
||
|
||
get length() {
|
||
return this.__innerStack__.length;
|
||
}
|
||
};
|
||
|
||
// Flag indicating if the topmost operand of the operandStack is an array
|
||
var operandIsArray = false;
|
||
|
||
/*
|
||
* The dictionary stack holds only dictionary objects. The current set of
|
||
* dictionaries on the dictionary stack defines the environment for all
|
||
* implicit name searches, such as those that occur when the interpreter
|
||
* encounters an executable name. The role of the dictionary stack is
|
||
* introduced in Section 3.3, “Data Types and Objects,” and is further
|
||
* explained in Section 3.5, “Execution.” of the PostScript Language
|
||
* Reference.
|
||
*/
|
||
var systemDict = new Dict(),
|
||
globalDict = new Dict(),
|
||
userDict = new Dict();
|
||
|
||
var dictionaryStack = {
|
||
__innerStack__: [systemDict, globalDict],
|
||
|
||
push: function(aDictionary) {
|
||
this.__innerStack__.push(aDictionary);
|
||
},
|
||
|
||
pop: function() {
|
||
if (this.__innerStack__.length == 2)
|
||
return null;
|
||
|
||
return this.__innerStack__.pop();
|
||
},
|
||
|
||
peek: function() {
|
||
return this.__innerStack__[this.__innerStack__.length - 1];
|
||
},
|
||
|
||
get length() {
|
||
return this.__innerStack__.length;
|
||
}
|
||
}
|
||
|
||
/*
|
||
* The execution stack holds executable objects (mainly procedures and files)
|
||
* that are in intermediate stages of execution. At any point in the
|
||
* execution of a PostScript program, this stack represents the program’s
|
||
* call stack. Whenever the interpreter suspends execution of an object to
|
||
* execute some other object, it pushes the new object on the execution
|
||
* stack. When the interpreter finishes executing an object, it pops that
|
||
* object off the execution stack and resumes executing the suspended object
|
||
* beneath it.
|
||
*/
|
||
var executionStack = [];
|
||
|
||
this.getObj = function() {
|
||
var obj = lexer.getObj();
|
||
|
||
if (operandIsArray && !IsCmd(obj, "}") && !IsCmd(obj, "]")) {
|
||
operandStack.peek().push(obj);
|
||
this.getObj();
|
||
} else if (IsCmd(obj, "{") || IsCmd(obj, "[")) {
|
||
dump("Start Array: " + obj);
|
||
operandStack.push([]);
|
||
operandIsArray = true;
|
||
this.getObj();
|
||
} else if (IsCmd(obj, "}") || IsCmd(obj, "]")) {
|
||
dump("End Array: " + obj);
|
||
operandIsArray = false;
|
||
this.getObj();
|
||
} else if (IsBool(obj) || IsInt(obj) || IsNum(obj) || IsString(obj)) {
|
||
dump("Value: " + obj);
|
||
operandStack.push(obj);
|
||
this.getObj();
|
||
} else if (IsCmd(obj, "dup")) {
|
||
dump("Duplicate");
|
||
operandStack.push(operandStack.peek());
|
||
this.getObj();
|
||
} else if (IsCmd(obj, "currentdict")) {
|
||
dump("currentdict");
|
||
operandStack.push(dictionaryStack.peek());
|
||
this.getObj();
|
||
} else if (IsCmd(obj, "systemdict")) {
|
||
dump("systemdict");
|
||
operandStack.push(systemDict);
|
||
this.getObj();
|
||
} else if (IsCmd(obj, "readonly") || IsCmd(obj, "executeonly") ||
|
||
IsCmd(obj, "currentfile")) {
|
||
// Do nothing for the moment
|
||
this.getObj();
|
||
} else if (IsName(obj)) {
|
||
dump("Name: " + obj.name);
|
||
operandStack.push(obj.name);
|
||
this.getObj();
|
||
} else if (IsCmd(obj, "dict")) {
|
||
dump("Dict: " + obj);
|
||
var size = operandStack.pop();
|
||
var dict = new Dict(size);
|
||
operandStack.push(dict);
|
||
this.getObj();
|
||
} else if (IsCmd(obj, "begin")) {
|
||
dump("begin a dictionary");
|
||
dictionaryStack.push(operandStack.pop());
|
||
this.getObj();
|
||
} else if (IsCmd(obj, "end")) {
|
||
dump("Ending a dictionary");
|
||
dictionaryStack.pop();
|
||
this.getObj();
|
||
} else if (IsCmd(obj, "def")) {
|
||
var value = operandStack.pop();
|
||
var key = operandStack.pop();
|
||
dump("def: " + key + " = " + value);
|
||
dictionaryStack.peek().set(key, value);
|
||
this.getObj();
|
||
} else if (IsCmd(obj, "eexec")) {
|
||
// All the first segment data has been read, decrypt the second segment
|
||
// and start interpreting it in order to decode it
|
||
var eexecString = decrypt(aBinaryStream, kEexecEncryptionKey, 4).join("");
|
||
lexer = new Lexer(new StringStream(eexecString));
|
||
|
||
this.getObj();
|
||
} else if (IsCmd(obj, "known")) {
|
||
dump("known");
|
||
var name = operandStack.pop();
|
||
var dict = operandStack.pop();
|
||
// returns dict.hasKey(name);
|
||
|
||
this.getObj();
|
||
} else if (IsCmd(obj, "RD")) {
|
||
dump("RD");
|
||
var size = operandStack.pop();
|
||
var key = operandStack.pop();
|
||
|
||
var stream = lexer.stream.makeSubStream(lexer.stream.pos, size);
|
||
var charString = decrypt(stream, kCharStringsEncryptionKey, 4).join("");
|
||
|
||
// XXX do we want to store that on the top dictionary or somewhere else
|
||
dictionaryStack.peek().set(key, new StringStream(charString));
|
||
log (new StringStream(charString));
|
||
this.getObj();
|
||
} else if (IsCmd(obj, "LenIV")) {
|
||
error("LenIV: argh! we need to modify the length of discard characters for charStrings");
|
||
} else {
|
||
dump("Getting an unknow token, adding it to the stack just in case");
|
||
dump(obj);
|
||
operandStack.push(obj);
|
||
this.getObj();
|
||
}
|
||
|
||
return operandStack.peek();
|
||
}
|
||
};
|
||
|
||
var hack = false;
|
||
|
||
var Type1Font = function(aFontName, aFontFile) {
|
||
// All Type1 font program should begin with the comment %!
|
||
var validHeader = aFontFile.getByte() == 0x25 && aFontFile.getByte() == 0x21;
|
||
if (!validHeader)
|
||
error("Invalid file header");
|
||
|
||
var programType = "PS-AdobeFont";
|
||
for (var i = 0; i < programType.length; i++)
|
||
aFontFile.getChar();
|
||
|
||
// Ignore the '-' separator
|
||
aFontFile.getChar();
|
||
|
||
var version = parseFloat(aFontFile.getChar() + aFontFile.getChar() + aFontFile.getChar());
|
||
|
||
if (!hack) {
|
||
log(aFontName);
|
||
log("Version is: " + version);
|
||
|
||
var ASCIIStream = aFontFile.makeSubStream(0, aFontFile.dict.get("Length1"), aFontFile.dict);
|
||
var binaryStream = aFontFile.makeSubStream(aFontFile.dict.get("Length1"), aFontFile.dict.get("Length2"), aFontFile.dict);
|
||
|
||
this.parser = new Type1Parser(ASCIIStream, binaryStream);
|
||
|
||
var fontDictionary = this.parser.getObj();
|
||
log(fontDictionary + "\t" + "fontInfo: " + fontDictionary.get("FontInfo"));
|
||
hack = true;
|
||
}
|
||
|
||
|
||
this.info = {};
|
||
this.name = aFontName;
|
||
this.encoding = [];
|
||
this.paintType = 0;
|
||
this.fontType = 0;
|
||
this.fontMatrix = [];
|
||
this.fontBBox = [];
|
||
this.uniqueID = 0;
|
||
this.metrics = {};
|
||
this.strokeWidth = 0.0;
|
||
this.private = {};
|
||
this.charStrings = {}
|
||
this.FID = 0;
|
||
};
|
||
|