made Ascii85Stream be a child of DecodeStream

pdf.js

@@ -171,15 +171,22 @@ var DecodeStream = (function() {
         getBytes: function(length) {
             var pos = this.pos;
 
+            if (length) {
                 this.ensureBuffer(pos + length);
-            while (!this.eof && this.bufferLength < pos + length)
+                var end = pos + length;
+
+                while (!this.eof && this.bufferLength < end)
                     this.readBlock();
 
-            var end = pos + length;
                 var bufEnd = this.bufferLength;
-
                 if (end > bufEnd)
                     end = bufEnd;
+            } else {
+                while (!this.eof)
+                    this.readBlock();
+
+                var end = this.bufferLength;
+            }
 
             this.pos = end;
             return this.buffer.subarray(pos, end)
@@ -763,79 +770,12 @@ var Ascii85Stream = (function() {
     function constructor(str) {
         this.str = str;
         this.dict = str.dict;
-        this.eof = false;
-        this.pos = 0;
-        this.bufferLength = 0;
-        this.buffer = null;
-    }
-    constructor.prototype = {
-        ensureBuffer: function(requested) {
-            var buffer = this.buffer;
-            var current = buffer ? buffer.byteLength : 0;
-            if (requested < current)
-                return buffer;
-            var size = 512;
-            while (size < requested)
-                size <<= 1;
-            var buffer2 = Uint8Array(size);
-            for (var i = 0; i < current; ++i)
-                buffer2[i] = buffer[i];
-            return this.buffer = buffer2;
-        },
-        getByte: function() {
-            var pos = this.pos;
-            while (this.bufferLength <= pos) {
-                if (this.eof)
-                    return;
-                this.readBlock();
-            }
-            return this.buffer[this.pos++];
-        },
-       getBytes: function(length) {
-            var pos = this.pos;
-
-            this.ensureBuffer(pos + length);
-            if (length) {
-                while (!this.eof && this.bufferLength < pos + length)
-                    this.readBlock();
-
-                var end = pos + length;
-                var bufEnd = this.bufferLength;
         
-                if (end > bufEnd)
-                    end = bufEnd;
-            } else {
-                while(!this.eof)
-                    this.readBlock();
-                var end = this.bufferLength;
-            }
-            this.pos = end;
-            return this.buffer.subarray(pos, end)
-        },
-        lookChar: function() {
-            var pos = this.pos;
-            while (this.bufferLength <= pos) {
-                if (this.eof)
-                    return;
-                this.readBlock();
-            }
-            return String.fromCharCode(this.buffer[this.pos]);
-        },
-        getChar: function() {
-            var pos = this.pos;
-            while (this.bufferLength <= pos) {
-                if (this.eof)
-                    return;
-                this.readBlock();
+        DecodeStream.call(this);
     }
-            return String.fromCharCode(this.buffer[this.pos++]);
-        },
-        skip: function(n) {
-            if (!n)
-                n = 1;
-            this.pos += n;
-        },
-        readBlock: function() {
+
+    constructor.prototype = Object.create(DecodeStream.prototype);
+    constructor.prototype.readBlock = function() {
         const tildaCode = "~".charCodeAt(0);
         const zCode = "z".charCodeAt(0);
         var str = this.str;
@@ -843,6 +783,7 @@ var Ascii85Stream = (function() {
         var c = str.getByte();
         while (Lexer.isSpace(String.fromCharCode(c)))
             c = str.getByte();
+
         if (!c || c === tildaCode) {
             this.eof = true;
             return;
@@ -854,10 +795,8 @@ var Ascii85Stream = (function() {
         if (c == zCode) {
             this.ensureBuffer(bufferLength + 4);
             var buffer = this.buffer;
-                buffer[bufferLength++] = 0;
-                buffer[bufferLength++] = 0;
-                buffer[bufferLength++] = 0;
-                buffer[bufferLength++] = 0;
+            for (var i = 0; i < 4; ++i)
+                buffer[bufferLength + i] = 0;
             this.bufferLength += 4;
         } else {
             var input = new Uint8Array(5);
@@ -875,9 +814,10 @@ var Ascii85Stream = (function() {
             this.ensureBuffer(bufferLength + i - 1);
             var buffer = this.buffer;
             this.bufferLength += i - 1;
+
             // partial ending;
             if (i < 5) {
-                    for (++i; i < 5; ++i)
+                for (; i < 5; ++i)
                     input[i] = 0x21 + 84;
                 this.eof = true;
             }
@@ -890,7 +830,6 @@ var Ascii85Stream = (function() {
                 t >>= 8;
             }
         }
-        }
     };
 
     return constructor;
@@ -2402,6 +2341,7 @@ var CanvasGraphics = (function() {
 
     constructor.prototype = {
         translateFont: function(fontDict, xref, resources) {
+            return;
             var descriptor = xref.fetch(fontDict.get("FontDescriptor"));
 
             var fontName = descriptor.get("FontName");