Merge pull request #7407 from Snuffleupagus/issue-7406

Assign the `quantizationTables` after parsing the entire JPEG image, to prevent issues when the DQT (Define Quantization Tables) marker is encountered after SOF{n} (Start of Frame) markers (issue 7406)

src/core/jpg.js

@@ -387,6 +387,10 @@ var JpegImage = (function jpegImage() {
     var p0, p1, p2, p3, p4, p5, p6, p7;
     var t;
 
+    if (!qt) {
+      throw 'missing required Quantization Table.';
+    }
+
     // inverse DCT on rows
     for (var row = 0; row < 64; row += 8) {
       // gather block data
@@ -738,7 +742,8 @@ var JpegImage = (function jpegImage() {
               l = frame.components.push({
                 h: h,
                 v: v,
-                quantizationTable: quantizationTables[qId]
+                quantizationId: qId,
+                quantizationTable: null, // See comment below.
               });
               frame.componentIds[componentId] = l - 1;
               offset += 3;
@@ -822,6 +827,15 @@ var JpegImage = (function jpegImage() {
       this.components = [];
       for (i = 0; i < frame.components.length; i++) {
         component = frame.components[i];
+
+        // Prevent errors when DQT markers are placed after SOF{n} markers,
+        // by assigning the `quantizationTable` entry after the entire image
+        // has been parsed (fixes issue7406.pdf).
+        var quantizationTable = quantizationTables[component.quantizationId];
+        if (quantizationTable) {
+          component.quantizationTable = quantizationTable;
+        }
+
         this.components.push({
           output: buildComponentData(frame, component),
           scaleX: component.h / frame.maxH,

test/pdfs/.gitignore

@@ -30,6 +30,7 @@
 !issue7200.pdf
 !issue7229.pdf
 !issue7403.pdf
+!issue7406.pdf
 !issue7426.pdf
 !issue7439.pdf
 !issue7446.pdf

test/test_manifest.json

@@ -999,6 +999,13 @@
        "rounds": 1,
        "type": "eq"
     },
+    {  "id": "issue7406",
+       "file": "pdfs/issue7406.pdf",
+       "md5": "7a3d322d7c595a36b4470cfb6a54a2b7",
+       "link": false,
+       "rounds": 1,
+       "type": "eq"
+    },
     {  "id": "protectip",
        "file": "pdfs/protectip.pdf",
        "md5": "676e7a7b8f96d04825361832b1838a93",