add check and tests for bad offset in getAgentDataFromBuffer

src/test/util.test.ts

@@ -1,3 +1,4 @@
+import { FrontEndError } from "../simularium";
 import {
     checkAndSanitizePath,
     compareTimes,
@@ -214,6 +215,49 @@ describe("util", () => {
                     subpoints: [63, 64], //"subpoint-1", "subpoint-2"
                 });
             });
+            test("it throws an error if the data doesn't have the right shape", () => {
+                // Test with not enough data for the agent object keys
+                const invalidTestData = [
+                    10,
+                    15,
+                    20,
+                    30,
+                    31,
+                    32,
+                    40,
+                    41, // Missing other values like zrot, cr, nSubPoints, etc.
+                ];
+                const view = new Float32Array(invalidTestData);
+
+                // Expect the function to throw an error when trying to parse this invalid data
+                expect(() => getAgentDataFromBuffer(view, 0)).toThrow(
+                    FrontEndError
+                );
+            });
+
+            test("it throws an error if the subpoints exceed available data", () => {
+                const incompleteSubpointsTestData = [
+                    10, //"visType",
+                    15, //"instanceId",
+                    20, //"type",
+                    30, //"x",
+                    31, //"y",
+                    32, //"z",
+                    40, //"xrot",
+                    41, //"yrot",
+                    42, //"zrot",
+                    50, //"cr",
+                    3, //"nSubPoints"
+                    60, //"subpoint-1",
+                    61, // Missing "subpoint-3"
+                ];
+                const view = new Float32Array(incompleteSubpointsTestData);
+
+                // Expect the function to throw an error because there aren't enough subpoints
+                expect(() => getAgentDataFromBuffer(view, 0)).toThrow(
+                    FrontEndError
+                );
+            });
         });
     });
 });

src/util.ts

@@ -3,6 +3,7 @@ import JsonFileReader from "./simularium/JsonFileReader";
 import BinaryFileReader from "./simularium/BinaryFileReader";
 import { AGENT_OBJECT_KEYS, AgentData, CachedFrame } from "./simularium/types";
 import { BYTES_PER_AGENT, BYTE_SIZE_64_BIT_NUM, nullAgent } from "./constants";
+import { FrontEndError } from "./simularium";
 
 export const compareTimes = (
     time1: number,
@@ -104,11 +105,27 @@ export const getAgentDataFromBuffer = (
     view: Float32Array,
     offset: number
 ): AgentData => {
+    // Check if the buffer has enough data for the AGENT_OBJECT_KEYS
+    if (offset + AGENT_OBJECT_KEYS.length > view.length) {
+        throw new FrontEndError(
+            "Invalid offset: Not enough data in the buffer for agent data."
+        );
+    }
     const agentData: AgentData = nullAgent();
     for (let i = 0; i < AGENT_OBJECT_KEYS.length; i++) {
         agentData[AGENT_OBJECT_KEYS[i]] = view[offset + i];
     }
     const nSubPoints = agentData["nSubPoints"];
+
+    // Check if the buffer has enough data for subpoints
+    const subpointsStart = offset + AGENT_OBJECT_KEYS.length;
+    const subpointsEnd = subpointsStart + nSubPoints;
+
+    if (subpointsEnd > view.length) {
+        throw new FrontEndError(
+            "Invalid offset: Not enough data in the buffer for subpoints."
+        );
+    }
     agentData.subpoints = Array.from(
         view.subarray(
             offset + AGENT_OBJECT_KEYS.length,