allow NULL in writeString/readString

tests/Writer32Test.cpp

 
 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 
 #include "SkRandom.h"
 #include "SkReader32.h"
 #include "SkWriter32.h"
 #include "Test.h"
 
 static void check_contents(skiatest::Reporter* reporter, const SkWriter32& writer,
                            const void* expected, size_t size) {
     SkAutoSMalloc<256> storage(size);
     REPORTER_ASSERT(reporter, writer.bytesWritten() == size);
     writer.flatten(storage.get());
     REPORTER_ASSERT(reporter, !memcmp(storage.get(), expected, size));
 }
 
+static void test_string_null(skiatest::Reporter* reporter) {
+    uint8_t storage[8];
+    SkWriter32 writer(0, storage, sizeof(storage));
+    SkReader32 reader(storage, sizeof(storage));
+
+    const char* str;
+    size_t len;
+
+    // Can we write NULL?
+    writer.writeString(NULL);
+    const int32_t null[] = { 0xFFFF };
+    check_contents(reporter, writer, null, sizeof(null));
+    str = reader.readString(&len);
+    REPORTER_ASSERT(reporter, NULL == str);
+    REPORTER_ASSERT(reporter, 0 == len);
+
+    writer.reset(storage, sizeof(storage));
+    reader.rewind();
+
+    // Is NULL distinct from ""?
+    writer.writeString("");
+    const int32_t empty[] = { 0x0, 0x0 };
+    check_contents(reporter, writer, empty, sizeof(empty));
+    str = reader.readString(&len);
+    REPORTER_ASSERT(reporter, 0 == strcmp("", str));
+    REPORTER_ASSERT(reporter, 0 == len);
+}
+
 static void test_rewind(skiatest::Reporter* reporter) {
     SkSWriter32<32> writer(32);
     int32_t array[3] = { 1, 2, 4 };
 
     REPORTER_ASSERT(reporter, 0 == writer.bytesWritten());
     for (size_t i = 0; i < SK_ARRAY_COUNT(array); ++i) {
         writer.writeInt(array[i]);
     }
     check_contents(reporter, writer, array, sizeof(array));
 
@@ skipping 187 matching lines @@
     {
         SkSWriter32<1024 * sizeof(intptr_t)> writer(100);
         test1(reporter, &writer);
         writer.reset(); // should just rewind our storage
         test2(reporter, &writer);
 
         writer.reset();
         testWritePad(reporter, &writer);
     }
 
+    test_string_null(reporter);
     test_ptr(reporter);
     test_rewind(reporter);
 }
 
 #include "TestClassDef.h"
 DEFINE_TESTCLASS("Writer32", Writer32Class, Tests)