Don't allocate in SDLTest_GenerateRunSeed

include/SDL3/SDL_test_harness.h

@@ -101,15 +101,15 @@ typedef struct SDLTest_TestSuiteReference {
 
 
 /*
- * Generates a random run seed string for the harness. The generated seed will contain alphanumeric characters (0-9A-Z).
+ * Generates a random run seed string for the harness. The generated seed
+ * will contain alphanumeric characters (0-9A-Z).
  *
- * Note: The returned string needs to be deallocated by the caller.
+ * \param buffer Buffer in which to generate the random seed. Must have a capacity of at least length + 1 characters.
+ * \param length Number of alphanumeric characters to write to buffer, must be >0
  *
- * \param length The length of the seed string to generate
+ * \returns A null-terminated seed string and equal to the in put buffer on success, NULL on failure
- *
- * \returns the generated seed string
  */
-char *SDLTest_GenerateRunSeed(const int length);
+char *SDLTest_GenerateRunSeed(char *buffer, int length);
 
 /*
  * Execute a test suite using the given run seed and execution key.

src/test/SDL_test_harness.c

@@ -50,35 +50,22 @@
 /* ! Timeout for single test case execution */
 static Uint32 SDLTest_TestCaseTimeout = 3600;
 
-/**
+char *SDLTest_GenerateRunSeed(char *buffer, int length)
- * Generates a random run seed string for the harness. The generated seed
- * will contain alphanumeric characters (0-9A-Z).
- *
- * Note: The returned string needs to be deallocated by the caller.
- *
- * \param length The length of the seed string to generate
- *
- * \returns The generated seed string
- */
-char *SDLTest_GenerateRunSeed(const int length)
 {
-    char *seed = NULL;
     Uint64 randomContext = SDL_GetPerformanceCounter();
     int counter;
 
+    if (!buffer) {
+        SDLTest_LogError("Input buffer must not be NULL.");
+        return NULL;
+    }
+
     /* Sanity check input */
     if (length <= 0) {
         SDLTest_LogError("The length of the harness seed must be >0.");
         return NULL;
     }
 
-    /* Allocate output buffer */
-    seed = (char *)SDL_malloc((length + 1) * sizeof(char));
-    if (!seed) {
-        SDLTest_LogError("SDL_malloc for run seed output buffer failed.");
-        return NULL;
-    }
-
     /* Generate a random string of alphanumeric characters */
     for (counter = 0; counter < length; counter++) {
         char ch;
@@ -88,11 +75,11 @@ char *SDLTest_GenerateRunSeed(const int length)
         } else {
             ch = (char)('A' + v - 10);
         }
-        seed[counter] = ch;
+        buffer[counter] = ch;
     }
-    seed[length] = '\0';
+    buffer[length] = '\0';
 
-    return seed;
+    return buffer;
 }
 
 /**
@@ -417,14 +404,11 @@ int SDLTest_RunSuites(SDLTest_TestSuiteReference *testSuites[], const char *user
 
     /* Generate run see if we don't have one already */
     if (!userRunSeed || userRunSeed[0] == '\0') {
-        char *tmp = SDLTest_GenerateRunSeed(16);
+        runSeed = SDLTest_GenerateRunSeed(generatedSeed, 16);
-        if (!tmp) {
+        if (!runSeed) {
             SDLTest_LogError("Generating a random seed failed");
             return 2;
         }
-        SDL_memcpy(generatedSeed, tmp, 16 + 1);
-        SDL_free(tmp);
-        runSeed = generatedSeed;
     } else {
         runSeed = userRunSeed;
     }

test/testautomation_sdltest.c

@@ -16,26 +16,30 @@
  */
 static int sdltest_generateRunSeed(void *arg)
 {
+    char buffer[32];
     char *result;
     size_t i, l;
     int j;
 
     for (i = 1; i <= 10; i += 3) {
-        result = SDLTest_GenerateRunSeed((int)i);
+        result = SDLTest_GenerateRunSeed(buffer, (int)i);
-        SDLTest_AssertPass("Call to SDLTest_GenerateRunSeed()");
+        SDLTest_AssertPass("Call to SDLTest_GenerateRunSeed(<buf>, %" SDL_PRIu64 ")", (Uint64)i);
         SDLTest_AssertCheck(result != NULL, "Verify returned value is not NULL");
         if (result != NULL) {
             l = SDL_strlen(result);
             SDLTest_AssertCheck(l == i, "Verify length of returned value is %d, got: %d", (int)i, (int)l);
-            SDL_free(result);
         }
     }
 
+    result = SDLTest_GenerateRunSeed(NULL, 10);
+    SDLTest_AssertPass("Call to SDLTest_GenerateRunSeed(NULL, 10)");
+    SDLTest_AssertCheck(result == NULL, "Verify returned value is NULL");
+
     /* Negative cases */
     for (j = -2; j <= 0; j++) {
-        result = SDLTest_GenerateRunSeed(j);
+        result = SDLTest_GenerateRunSeed(buffer, j);
-        SDLTest_AssertPass("Call to SDLTest_GenerateRunSeed()");
+        SDLTest_AssertPass("Call to SDLTest_GenerateRunSeed(<buf>, %d)", j);
-        SDLTest_AssertCheck(result == NULL, "Verify returned value is not NULL");
+        SDLTest_AssertCheck(result == NULL, "Verify returned value is NULL");
     }
 
     return TEST_COMPLETED;