pdfjs-dist/lib/core/function.js

/* Copyright 2017 Mozilla Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
'use strict';
var sharedUtil = require('../shared/util.js');
var corePrimitives = require('./primitives.js');
var corePsParser = require('./ps_parser.js');
var error = sharedUtil.error;
var info = sharedUtil.info;
var isArray = sharedUtil.isArray;
var isBool = sharedUtil.isBool;
var isDict = corePrimitives.isDict;
var isStream = corePrimitives.isStream;
var PostScriptLexer = corePsParser.PostScriptLexer;
var PostScriptParser = corePsParser.PostScriptParser;
var PDFFunction = function PDFFunctionClosure() {
 var CONSTRUCT_SAMPLED = 0;
 var CONSTRUCT_INTERPOLATED = 2;
 var CONSTRUCT_STICHED = 3;
 var CONSTRUCT_POSTSCRIPT = 4;
 return {
  getSampleArray: function PDFFunction_getSampleArray(size, outputSize, bps, str) {
   var i, ii;
   var length = 1;
   for (i = 0, ii = size.length; i < ii; i++) {
    length *= size[i];
   }
   length *= outputSize;
   var array = new Array(length);
   var codeSize = 0;
   var codeBuf = 0;
   var sampleMul = 1.0 / (Math.pow(2.0, bps) - 1);
   var strBytes = str.getBytes((length * bps + 7) / 8);
   var strIdx = 0;
   for (i = 0; i < length; i++) {
    while (codeSize < bps) {
     codeBuf <<= 8;
     codeBuf |= strBytes[strIdx++];
     codeSize += 8;
    }
    codeSize -= bps;
    array[i] = (codeBuf >> codeSize) * sampleMul;
    codeBuf &= (1 << codeSize) - 1;
   }
   return array;
  },
  getIR: function PDFFunction_getIR(xref, fn) {
   var dict = fn.dict;
   if (!dict) {
    dict = fn;
   }
   var types = [
    this.constructSampled,
    null,
    this.constructInterpolated,
    this.constructStiched,
    this.constructPostScript
   ];
   var typeNum = dict.get('FunctionType');
   var typeFn = types[typeNum];
   if (!typeFn) {
    error('Unknown type of function');
   }
   return typeFn.call(this, fn, dict, xref);
  },
  fromIR: function PDFFunction_fromIR(IR) {
   var type = IR[0];
   switch (type) {
   case CONSTRUCT_SAMPLED:
    return this.constructSampledFromIR(IR);
   case CONSTRUCT_INTERPOLATED:
    return this.constructInterpolatedFromIR(IR);
   case CONSTRUCT_STICHED:
    return this.constructStichedFromIR(IR);
   default:
    return this.constructPostScriptFromIR(IR);
   }
  },
  parse: function PDFFunction_parse(xref, fn) {
   var IR = this.getIR(xref, fn);
   return this.fromIR(IR);
  },
  parseArray: function PDFFunction_parseArray(xref, fnObj) {
   if (!isArray(fnObj)) {
    return this.parse(xref, fnObj);
   }
   var fnArray = [];
   for (var j = 0, jj = fnObj.length; j < jj; j++) {
    var obj = xref.fetchIfRef(fnObj[j]);
    fnArray.push(PDFFunction.parse(xref, obj));
   }
   return function (src, srcOffset, dest, destOffset) {
    for (var i = 0, ii = fnArray.length; i < ii; i++) {
     fnArray[i](src, srcOffset, dest, destOffset + i);
    }
   };
  },
  constructSampled: function PDFFunction_constructSampled(str, dict) {
   function toMultiArray(arr) {
    var inputLength = arr.length;
    var out = [];
    var index = 0;
    for (var i = 0; i < inputLength; i += 2) {
     out[index] = [
      arr[i],
      arr[i + 1]
     ];
     ++index;
    }
    return out;
   }
   var domain = dict.getArray('Domain');
   var range = dict.getArray('Range');
   if (!domain || !range) {
    error('No domain or range');
   }
   var inputSize = domain.length / 2;
   var outputSize = range.length / 2;
   domain = toMultiArray(domain);
   range = toMultiArray(range);
   var size = dict.get('Size');
   var bps = dict.get('BitsPerSample');
   var order = dict.get('Order') || 1;
   if (order !== 1) {
    info('No support for cubic spline interpolation: ' + order);
   }
   var encode = dict.getArray('Encode');
   if (!encode) {
    encode = [];
    for (var i = 0; i < inputSize; ++i) {
     encode.push(0);
     encode.push(size[i] - 1);
    }
   }
   encode = toMultiArray(encode);
   var decode = dict.getArray('Decode');
   if (!decode) {
    decode = range;
   } else {
    decode = toMultiArray(decode);
   }
   var samples = this.getSampleArray(size, outputSize, bps, str);
   return [
    CONSTRUCT_SAMPLED,
    inputSize,
    domain,
    encode,
    decode,
    samples,
    size,
    outputSize,
    Math.pow(2, bps) - 1,
    range
   ];
  },
  constructSampledFromIR: function PDFFunction_constructSampledFromIR(IR) {
   function interpolate(x, xmin, xmax, ymin, ymax) {
    return ymin + (x - xmin) * ((ymax - ymin) / (xmax - xmin));
   }
   return function constructSampledFromIRResult(src, srcOffset, dest, destOffset) {
    var m = IR[1];
    var domain = IR[2];
    var encode = IR[3];
    var decode = IR[4];
    var samples = IR[5];
    var size = IR[6];
    var n = IR[7];
    var range = IR[9];
    var cubeVertices = 1 << m;
    var cubeN = new Float64Array(cubeVertices);
    var cubeVertex = new Uint32Array(cubeVertices);
    var i, j;
    for (j = 0; j < cubeVertices; j++) {
     cubeN[j] = 1;
    }
    var k = n, pos = 1;
    for (i = 0; i < m; ++i) {
     var domain_2i = domain[i][0];
     var domain_2i_1 = domain[i][1];
     var xi = Math.min(Math.max(src[srcOffset + i], domain_2i), domain_2i_1);
     var e = interpolate(xi, domain_2i, domain_2i_1, encode[i][0], encode[i][1]);
     var size_i = size[i];
     e = Math.min(Math.max(e, 0), size_i - 1);
     var e0 = e < size_i - 1 ? Math.floor(e) : e - 1;
     var n0 = e0 + 1 - e;
     var n1 = e - e0;
     var offset0 = e0 * k;
     var offset1 = offset0 + k;
     for (j = 0; j < cubeVertices; j++) {
      if (j & pos) {
       cubeN[j] *= n1;
       cubeVertex[j] += offset1;
      } else {
       cubeN[j] *= n0;
       cubeVertex[j] += offset0;
      }
     }
     k *= size_i;
     pos <<= 1;
    }
    for (j = 0; j < n; ++j) {
     var rj = 0;
     for (i = 0; i < cubeVertices; i++) {
      rj += samples[cubeVertex[i] + j] * cubeN[i];
     }
     rj = interpolate(rj, 0, 1, decode[j][0], decode[j][1]);
     dest[destOffset + j] = Math.min(Math.max(rj, range[j][0]), range[j][1]);
    }
   };
  },
  constructInterpolated: function PDFFunction_constructInterpolated(str, dict) {
   var c0 = dict.getArray('C0') || [0];
   var c1 = dict.getArray('C1') || [1];
   var n = dict.get('N');
   if (!isArray(c0) || !isArray(c1)) {
    error('Illegal dictionary for interpolated function');
   }
   var length = c0.length;
   var diff = [];
   for (var i = 0; i < length; ++i) {
    diff.push(c1[i] - c0[i]);
   }
   return [
    CONSTRUCT_INTERPOLATED,
    c0,
    diff,
    n
   ];
  },
  constructInterpolatedFromIR: function PDFFunction_constructInterpolatedFromIR(IR) {
   var c0 = IR[1];
   var diff = IR[2];
   var n = IR[3];
   var length = diff.length;
   return function constructInterpolatedFromIRResult(src, srcOffset, dest, destOffset) {
    var x = n === 1 ? src[srcOffset] : Math.pow(src[srcOffset], n);
    for (var j = 0; j < length; ++j) {
     dest[destOffset + j] = c0[j] + x * diff[j];
    }
   };
  },
  constructStiched: function PDFFunction_constructStiched(fn, dict, xref) {
   var domain = dict.getArray('Domain');
   if (!domain) {
    error('No domain');
   }
   var inputSize = domain.length / 2;
   if (inputSize !== 1) {
    error('Bad domain for stiched function');
   }
   var fnRefs = dict.get('Functions');
   var fns = [];
   for (var i = 0, ii = fnRefs.length; i < ii; ++i) {
    fns.push(PDFFunction.getIR(xref, xref.fetchIfRef(fnRefs[i])));
   }
   var bounds = dict.getArray('Bounds');
   var encode = dict.getArray('Encode');
   return [
    CONSTRUCT_STICHED,
    domain,
    bounds,
    encode,
    fns
   ];
  },
  constructStichedFromIR: function PDFFunction_constructStichedFromIR(IR) {
   var domain = IR[1];
   var bounds = IR[2];
   var encode = IR[3];
   var fnsIR = IR[4];
   var fns = [];
   var tmpBuf = new Float32Array(1);
   for (var i = 0, ii = fnsIR.length; i < ii; i++) {
    fns.push(PDFFunction.fromIR(fnsIR[i]));
   }
   return function constructStichedFromIRResult(src, srcOffset, dest, destOffset) {
    var clip = function constructStichedFromIRClip(v, min, max) {
     if (v > max) {
      v = max;
     } else if (v < min) {
      v = min;
     }
     return v;
    };
    var v = clip(src[srcOffset], domain[0], domain[1]);
    for (var i = 0, ii = bounds.length; i < ii; ++i) {
     if (v < bounds[i]) {
      break;
     }
    }
    var dmin = domain[0];
    if (i > 0) {
     dmin = bounds[i - 1];
    }
    var dmax = domain[1];
    if (i < bounds.length) {
     dmax = bounds[i];
    }
    var rmin = encode[2 * i];
    var rmax = encode[2 * i + 1];
    tmpBuf[0] = dmin === dmax ? rmin : rmin + (v - dmin) * (rmax - rmin) / (dmax - dmin);
    fns[i](tmpBuf, 0, dest, destOffset);
   };
  },
  constructPostScript: function PDFFunction_constructPostScript(fn, dict, xref) {
   var domain = dict.getArray('Domain');
   var range = dict.getArray('Range');
   if (!domain) {
    error('No domain.');
   }
   if (!range) {
    error('No range.');
   }
   var lexer = new PostScriptLexer(fn);
   var parser = new PostScriptParser(lexer);
   var code = parser.parse();
   return [
    CONSTRUCT_POSTSCRIPT,
    domain,
    range,
    code
   ];
  },
  constructPostScriptFromIR: function PDFFunction_constructPostScriptFromIR(IR) {
   var domain = IR[1];
   var range = IR[2];
   var code = IR[3];
   var compiled = new PostScriptCompiler().compile(code, domain, range);
   if (compiled) {
    return new Function('src', 'srcOffset', 'dest', 'destOffset', compiled);
   }
   info('Unable to compile PS function');
   var numOutputs = range.length >> 1;
   var numInputs = domain.length >> 1;
   var evaluator = new PostScriptEvaluator(code);
   var cache = Object.create(null);
   var MAX_CACHE_SIZE = 2048 * 4;
   var cache_available = MAX_CACHE_SIZE;
   var tmpBuf = new Float32Array(numInputs);
   return function constructPostScriptFromIRResult(src, srcOffset, dest, destOffset) {
    var i, value;
    var key = '';
    var input = tmpBuf;
    for (i = 0; i < numInputs; i++) {
     value = src[srcOffset + i];
     input[i] = value;
     key += value + '_';
    }
    var cachedValue = cache[key];
    if (cachedValue !== undefined) {
     dest.set(cachedValue, destOffset);
     return;
    }
    var output = new Float32Array(numOutputs);
    var stack = evaluator.execute(input);
    var stackIndex = stack.length - numOutputs;
    for (i = 0; i < numOutputs; i++) {
     value = stack[stackIndex + i];
     var bound = range[i * 2];
     if (value < bound) {
      value = bound;
     } else {
      bound = range[i * 2 + 1];
      if (value > bound) {
       value = bound;
      }
     }
     output[i] = value;
    }
    if (cache_available > 0) {
     cache_available--;
     cache[key] = output;
    }
    dest.set(output, destOffset);
   };
  }
 };
}();
function isPDFFunction(v) {
 var fnDict;
 if (typeof v !== 'object') {
  return false;
 } else if (isDict(v)) {
  fnDict = v;
 } else if (isStream(v)) {
  fnDict = v.dict;
 } else {
  return false;
 }
 return fnDict.has('FunctionType');
}
var PostScriptStack = function PostScriptStackClosure() {
 var MAX_STACK_SIZE = 100;
 function PostScriptStack(initialStack) {
  this.stack = !initialStack ? [] : Array.prototype.slice.call(initialStack, 0);
 }
 PostScriptStack.prototype = {
  push: function PostScriptStack_push(value) {
   if (this.stack.length >= MAX_STACK_SIZE) {
    error('PostScript function stack overflow.');
   }
   this.stack.push(value);
  },
  pop: function PostScriptStack_pop() {
   if (this.stack.length <= 0) {
    error('PostScript function stack underflow.');
   }
   return this.stack.pop();
  },
  copy: function PostScriptStack_copy(n) {
   if (this.stack.length + n >= MAX_STACK_SIZE) {
    error('PostScript function stack overflow.');
   }
   var stack = this.stack;
   for (var i = stack.length - n, j = n - 1; j >= 0; j--, i++) {
    stack.push(stack[i]);
   }
  },
  index: function PostScriptStack_index(n) {
   this.push(this.stack[this.stack.length - n - 1]);
  },
  roll: function PostScriptStack_roll(n, p) {
   var stack = this.stack;
   var l = stack.length - n;
   var r = stack.length - 1, c = l + (p - Math.floor(p / n) * n), i, j, t;
   for (i = l, j = r; i < j; i++, j--) {
    t = stack[i];
    stack[i] = stack[j];
    stack[j] = t;
   }
   for (i = l, j = c - 1; i < j; i++, j--) {
    t = stack[i];
    stack[i] = stack[j];
    stack[j] = t;
   }
   for (i = c, j = r; i < j; i++, j--) {
    t = stack[i];
    stack[i] = stack[j];
    stack[j] = t;
   }
  }
 };
 return PostScriptStack;
}();
var PostScriptEvaluator = function PostScriptEvaluatorClosure() {
 function PostScriptEvaluator(operators) {
  this.operators = operators;
 }
 PostScriptEvaluator.prototype = {
  execute: function PostScriptEvaluator_execute(initialStack) {
   var stack = new PostScriptStack(initialStack);
   var counter = 0;
   var operators = this.operators;
   var length = operators.length;
   var operator, a, b;
   while (counter < length) {
    operator = operators[counter++];
    if (typeof operator === 'number') {
     stack.push(operator);
     continue;
    }
    switch (operator) {
    case 'jz':
     b = stack.pop();
     a = stack.pop();
     if (!a) {
      counter = b;
     }
     break;
    case 'j':
     a = stack.pop();
     counter = a;
     break;
    case 'abs':
     a = stack.pop();
     stack.push(Math.abs(a));
     break;
    case 'add':
     b = stack.pop();
     a = stack.pop();
     stack.push(a + b);
     break;
    case 'and':
     b = stack.pop();
     a = stack.pop();
     if (isBool(a) && isBool(b)) {
      stack.push(a && b);
     } else {
      stack.push(a & b);
     }
     break;
    case 'atan':
     a = stack.pop();
     stack.push(Math.atan(a));
     break;
    case 'bitshift':
     b = stack.pop();
     a = stack.pop();
     if (a > 0) {
      stack.push(a << b);
     } else {
      stack.push(a >> b);
     }
     break;
    case 'ceiling':
     a = stack.pop();
     stack.push(Math.ceil(a));
     break;
    case 'copy':
     a = stack.pop();
     stack.copy(a);
     break;
    case 'cos':
     a = stack.pop();
     stack.push(Math.cos(a));
     break;
    case 'cvi':
     a = stack.pop() | 0;
     stack.push(a);
     break;
    case 'cvr':
     break;
    case 'div':
     b = stack.pop();
     a = stack.pop();
     stack.push(a / b);
     break;
    case 'dup':
     stack.copy(1);
     break;
    case 'eq':
     b = stack.pop();
     a = stack.pop();
     stack.push(a === b);
     break;
    case 'exch':
     stack.roll(2, 1);
     break;
    case 'exp':
     b = stack.pop();
     a = stack.pop();
     stack.push(Math.pow(a, b));
     break;
    case 'false':
     stack.push(false);
     break;
    case 'floor':
     a = stack.pop();
     stack.push(Math.floor(a));
     break;
    case 'ge':
     b = stack.pop();
     a = stack.pop();
     stack.push(a >= b);
     break;
    case 'gt':
     b = stack.pop();
     a = stack.pop();
     stack.push(a > b);
     break;
    case 'idiv':
     b = stack.pop();
     a = stack.pop();
     stack.push(a / b | 0);
     break;
    case 'index':
     a = stack.pop();
     stack.index(a);
     break;
    case 'le':
     b = stack.pop();
     a = stack.pop();
     stack.push(a <= b);
     break;
    case 'ln':
     a = stack.pop();
     stack.push(Math.log(a));
     break;
    case 'log':
     a = stack.pop();
     stack.push(Math.log(a) / Math.LN10);
     break;
    case 'lt':
     b = stack.pop();
     a = stack.pop();
     stack.push(a < b);
     break;
    case 'mod':
     b = stack.pop();
     a = stack.pop();
     stack.push(a % b);
     break;
    case 'mul':
     b = stack.pop();
     a = stack.pop();
     stack.push(a * b);
     break;
    case 'ne':
     b = stack.pop();
     a = stack.pop();
     stack.push(a !== b);
     break;
    case 'neg':
     a = stack.pop();
     stack.push(-a);
     break;
    case 'not':
     a = stack.pop();
     if (isBool(a)) {
      stack.push(!a);
     } else {
      stack.push(~a);
     }
     break;
    case 'or':
     b = stack.pop();
     a = stack.pop();
     if (isBool(a) && isBool(b)) {
      stack.push(a || b);
     } else {
      stack.push(a | b);
     }
     break;
    case 'pop':
     stack.pop();
     break;
    case 'roll':
     b = stack.pop();
     a = stack.pop();
     stack.roll(a, b);
     break;
    case 'round':
     a = stack.pop();
     stack.push(Math.round(a));
     break;
    case 'sin':
     a = stack.pop();
     stack.push(Math.sin(a));
     break;
    case 'sqrt':
     a = stack.pop();
     stack.push(Math.sqrt(a));
     break;
    case 'sub':
     b = stack.pop();
     a = stack.pop();
     stack.push(a - b);
     break;
    case 'true':
     stack.push(true);
     break;
    case 'truncate':
     a = stack.pop();
     a = a < 0 ? Math.ceil(a) : Math.floor(a);
     stack.push(a);
     break;
    case 'xor':
     b = stack.pop();
     a = stack.pop();
     if (isBool(a) && isBool(b)) {
      stack.push(a !== b);
     } else {
      stack.push(a ^ b);
     }
     break;
    default:
     error('Unknown operator ' + operator);
     break;
    }
   }
   return stack.stack;
  }
 };
 return PostScriptEvaluator;
}();
var PostScriptCompiler = function PostScriptCompilerClosure() {
 function AstNode(type) {
  this.type = type;
 }
 AstNode.prototype.visit = function (visitor) {
  throw new Error('abstract method');
 };
 function AstArgument(index, min, max) {
  AstNode.call(this, 'args');
  this.index = index;
  this.min = min;
  this.max = max;
 }
 AstArgument.prototype = Object.create(AstNode.prototype);
 AstArgument.prototype.visit = function (visitor) {
  visitor.visitArgument(this);
 };
 function AstLiteral(number) {
  AstNode.call(this, 'literal');
  this.number = number;
  this.min = number;
  this.max = number;
 }
 AstLiteral.prototype = Object.create(AstNode.prototype);
 AstLiteral.prototype.visit = function (visitor) {
  visitor.visitLiteral(this);
 };
 function AstBinaryOperation(op, arg1, arg2, min, max) {
  AstNode.call(this, 'binary');
  this.op = op;
  this.arg1 = arg1;
  this.arg2 = arg2;
  this.min = min;
  this.max = max;
 }
 AstBinaryOperation.prototype = Object.create(AstNode.prototype);
 AstBinaryOperation.prototype.visit = function (visitor) {
  visitor.visitBinaryOperation(this);
 };
 function AstMin(arg, max) {
  AstNode.call(this, 'max');
  this.arg = arg;
  this.min = arg.min;
  this.max = max;
 }
 AstMin.prototype = Object.create(AstNode.prototype);
 AstMin.prototype.visit = function (visitor) {
  visitor.visitMin(this);
 };
 function AstVariable(index, min, max) {
  AstNode.call(this, 'var');
  this.index = index;
  this.min = min;
  this.max = max;
 }
 AstVariable.prototype = Object.create(AstNode.prototype);
 AstVariable.prototype.visit = function (visitor) {
  visitor.visitVariable(this);
 };
 function AstVariableDefinition(variable, arg) {
  AstNode.call(this, 'definition');
  this.variable = variable;
  this.arg = arg;
 }
 AstVariableDefinition.prototype = Object.create(AstNode.prototype);
 AstVariableDefinition.prototype.visit = function (visitor) {
  visitor.visitVariableDefinition(this);
 };
 function ExpressionBuilderVisitor() {
  this.parts = [];
 }
 ExpressionBuilderVisitor.prototype = {
  visitArgument: function (arg) {
   this.parts.push('Math.max(', arg.min, ', Math.min(', arg.max, ', src[srcOffset + ', arg.index, ']))');
  },
  visitVariable: function (variable) {
   this.parts.push('v', variable.index);
  },
  visitLiteral: function (literal) {
   this.parts.push(literal.number);
  },
  visitBinaryOperation: function (operation) {
   this.parts.push('(');
   operation.arg1.visit(this);
   this.parts.push(' ', operation.op, ' ');
   operation.arg2.visit(this);
   this.parts.push(')');
  },
  visitVariableDefinition: function (definition) {
   this.parts.push('var ');
   definition.variable.visit(this);
   this.parts.push(' = ');
   definition.arg.visit(this);
   this.parts.push(';');
  },
  visitMin: function (max) {
   this.parts.push('Math.min(');
   max.arg.visit(this);
   this.parts.push(', ', max.max, ')');
  },
  toString: function () {
   return this.parts.join('');
  }
 };
 function buildAddOperation(num1, num2) {
  if (num2.type === 'literal' && num2.number === 0) {
   return num1;
  }
  if (num1.type === 'literal' && num1.number === 0) {
   return num2;
  }
  if (num2.type === 'literal' && num1.type === 'literal') {
   return new AstLiteral(num1.number + num2.number);
  }
  return new AstBinaryOperation('+', num1, num2, num1.min + num2.min, num1.max + num2.max);
 }
 function buildMulOperation(num1, num2) {
  if (num2.type === 'literal') {
   if (num2.number === 0) {
    return new AstLiteral(0);
   } else if (num2.number === 1) {
    return num1;
   } else if (num1.type === 'literal') {
    return new AstLiteral(num1.number * num2.number);
   }
  }
  if (num1.type === 'literal') {
   if (num1.number === 0) {
    return new AstLiteral(0);
   } else if (num1.number === 1) {
    return num2;
   }
  }
  var min = Math.min(num1.min * num2.min, num1.min * num2.max, num1.max * num2.min, num1.max * num2.max);
  var max = Math.max(num1.min * num2.min, num1.min * num2.max, num1.max * num2.min, num1.max * num2.max);
  return new AstBinaryOperation('*', num1, num2, min, max);
 }
 function buildSubOperation(num1, num2) {
  if (num2.type === 'literal') {
   if (num2.number === 0) {
    return num1;
   } else if (num1.type === 'literal') {
    return new AstLiteral(num1.number - num2.number);
   }
  }
  if (num2.type === 'binary' && num2.op === '-' && num1.type === 'literal' && num1.number === 1 && num2.arg1.type === 'literal' && num2.arg1.number === 1) {
   return num2.arg2;
  }
  return new AstBinaryOperation('-', num1, num2, num1.min - num2.max, num1.max - num2.min);
 }
 function buildMinOperation(num1, max) {
  if (num1.min >= max) {
   return new AstLiteral(max);
  } else if (num1.max <= max) {
   return num1;
  }
  return new AstMin(num1, max);
 }
 function PostScriptCompiler() {
 }
 PostScriptCompiler.prototype = {
  compile: function PostScriptCompiler_compile(code, domain, range) {
   var stack = [];
   var i, ii;
   var instructions = [];
   var inputSize = domain.length >> 1, outputSize = range.length >> 1;
   var lastRegister = 0;
   var n, j;
   var num1, num2, ast1, ast2, tmpVar, item;
   for (i = 0; i < inputSize; i++) {
    stack.push(new AstArgument(i, domain[i * 2], domain[i * 2 + 1]));
   }
   for (i = 0, ii = code.length; i < ii; i++) {
    item = code[i];
    if (typeof item === 'number') {
     stack.push(new AstLiteral(item));
     continue;
    }
    switch (item) {
    case 'add':
     if (stack.length < 2) {
      return null;
     }
     num2 = stack.pop();
     num1 = stack.pop();
     stack.push(buildAddOperation(num1, num2));
     break;
    case 'cvr':
     if (stack.length < 1) {
      return null;
     }
     break;
    case 'mul':
     if (stack.length < 2) {
      return null;
     }
     num2 = stack.pop();
     num1 = stack.pop();
     stack.push(buildMulOperation(num1, num2));
     break;
    case 'sub':
     if (stack.length < 2) {
      return null;
     }
     num2 = stack.pop();
     num1 = stack.pop();
     stack.push(buildSubOperation(num1, num2));
     break;
    case 'exch':
     if (stack.length < 2) {
      return null;
     }
     ast1 = stack.pop();
     ast2 = stack.pop();
     stack.push(ast1, ast2);
     break;
    case 'pop':
     if (stack.length < 1) {
      return null;
     }
     stack.pop();
     break;
    case 'index':
     if (stack.length < 1) {
      return null;
     }
     num1 = stack.pop();
     if (num1.type !== 'literal') {
      return null;
     }
     n = num1.number;
     if (n < 0 || (n | 0) !== n || stack.length < n) {
      return null;
     }
     ast1 = stack[stack.length - n - 1];
     if (ast1.type === 'literal' || ast1.type === 'var') {
      stack.push(ast1);
      break;
     }
     tmpVar = new AstVariable(lastRegister++, ast1.min, ast1.max);
     stack[stack.length - n - 1] = tmpVar;
     stack.push(tmpVar);
     instructions.push(new AstVariableDefinition(tmpVar, ast1));
     break;
    case 'dup':
     if (stack.length < 1) {
      return null;
     }
     if (typeof code[i + 1] === 'number' && code[i + 2] === 'gt' && code[i + 3] === i + 7 && code[i + 4] === 'jz' && code[i + 5] === 'pop' && code[i + 6] === code[i + 1]) {
      num1 = stack.pop();
      stack.push(buildMinOperation(num1, code[i + 1]));
      i += 6;
      break;
     }
     ast1 = stack[stack.length - 1];
     if (ast1.type === 'literal' || ast1.type === 'var') {
      stack.push(ast1);
      break;
     }
     tmpVar = new AstVariable(lastRegister++, ast1.min, ast1.max);
     stack[stack.length - 1] = tmpVar;
     stack.push(tmpVar);
     instructions.push(new AstVariableDefinition(tmpVar, ast1));
     break;
    case 'roll':
     if (stack.length < 2) {
      return null;
     }
     num2 = stack.pop();
     num1 = stack.pop();
     if (num2.type !== 'literal' || num1.type !== 'literal') {
      return null;
     }
     j = num2.number;
     n = num1.number;
     if (n <= 0 || (n | 0) !== n || (j | 0) !== j || stack.length < n) {
      return null;
     }
     j = (j % n + n) % n;
     if (j === 0) {
      break;
     }
     Array.prototype.push.apply(stack, stack.splice(stack.length - n, n - j));
     break;
    default:
     return null;
    }
   }
   if (stack.length !== outputSize) {
    return null;
   }
   var result = [];
   instructions.forEach(function (instruction) {
    var statementBuilder = new ExpressionBuilderVisitor();
    instruction.visit(statementBuilder);
    result.push(statementBuilder.toString());
   });
   stack.forEach(function (expr, i) {
    var statementBuilder = new ExpressionBuilderVisitor();
    expr.visit(statementBuilder);
    var min = range[i * 2], max = range[i * 2 + 1];
    var out = [statementBuilder.toString()];
    if (min > expr.min) {
     out.unshift('Math.max(', min, ', ');
     out.push(')');
    }
    if (max < expr.max) {
     out.unshift('Math.min(', max, ', ');
     out.push(')');
    }
    out.unshift('dest[destOffset + ', i, '] = ');
    out.push(';');
    result.push(out.join(''));
   });
   return result.join('\n');
  }
 };
 return PostScriptCompiler;
}();
exports.isPDFFunction = isPDFFunction;
exports.PDFFunction = PDFFunction;
exports.PostScriptEvaluator = PostScriptEvaluator;
exports.PostScriptCompiler = PostScriptCompiler;