GIF decode: optional error messages and fault tolerance.

tests/GifTest.cpp

+/*
+ * Copyright 2013 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+// This tests out GIF decoder (SkImageDecoder_libgif.cpp)
+// It is not used on these platforms:
+#if (!defined(SK_BUILD_FOR_WIN32)) &&           \
+    (!defined(SK_BUILD_FOR_IOS)) &&             \
+    (!defined(SK_BUILD_FOR_MAC))
+
+#include "SkBitmap.h"
+#include "SkData.h"
+#include "SkForceLinking.h"
+#include "SkImageDecoder.h"
+#include "SkImage.h"
+#include "SkStream.h"
+#include "Test.h"
+
+__SK_FORCE_IMAGE_DECODER_LINKING;
+
+namespace {
+    unsigned char gifData[] = {
+        0x47, 0x49, 0x46, 0x38, 0x37, 0x61, 0x03, 0x00,
+        0x03, 0x00, 0xe3, 0x08, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0xff, 0xff, 0x00, 0x00, 0xff, 0x00,
+        0xff, 0x80, 0x80, 0x80, 0x00, 0xff, 0x00, 0x00,
+        0xff, 0xff, 0xff, 0xff, 0x00, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0x2c, 0x00, 0x00,
+        0x00, 0x00, 0x03, 0x00, 0x03, 0x00, 0x00, 0x04,
+        0x07, 0x50, 0x1c, 0x43, 0x40, 0x41, 0x23, 0x44,
+        0x00, 0x3b};
+    unsigned char gifDataNoColormap[] = {
+        0x47, 0x49, 0x46, 0x38, 0x39, 0x61, 0x01, 0x00,
+        0x01, 0x00, 0x00, 0x00, 0x00, 0x21, 0xf9, 0x04,
+        0x01, 0x0a, 0x00, 0x01, 0x00, 0x2c, 0x00, 0x00,
+        0x00, 0x00, 0x01, 0x00, 0x01, 0x00, 0x00, 0x02,
+        0x02, 0x4c, 0x01, 0x00, 0x3b};
+    unsigned char interlacedGif[] = {
+        0x47, 0x49, 0x46, 0x38, 0x37, 0x61, 0x09, 0x00,
+        0x09, 0x00, 0xe3, 0x08, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0xff, 0xff, 0x00, 0x00, 0xff, 0x00,
+        0xff, 0x80, 0x80, 0x80, 0x00, 0xff, 0x00, 0x00,
+        0xff, 0xff, 0xff, 0xff, 0x00, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0x2c, 0x00, 0x00,
+        0x00, 0x00, 0x09, 0x00, 0x09, 0x00, 0x40, 0x04,
+        0x1b, 0x50, 0x1c, 0x23, 0xe9, 0x44, 0x23, 0x60,
+        0x9d, 0x09, 0x28, 0x1e, 0xf8, 0x6d, 0x64, 0x56,
+        0x9d, 0x53, 0xa8, 0x7e, 0xa8, 0x65, 0x94, 0x5c,
+        0xb0, 0x8a, 0x45, 0x04, 0x00, 0x3b};
+};  // namespace
+
+static void test_gif_data_no_colormap(skiatest::Reporter* r,
+                                  void* data, size_t size) {
+    SkBitmap bm;
+    bool imageDecodeSuccess = SkImageDecoder::DecodeMemory(
+        data, size, &bm);
+    REPORTER_ASSERT(r, imageDecodeSuccess);
+    REPORTER_ASSERT(r, bm.width() == 1);
+    REPORTER_ASSERT(r, bm.height() == 1);
+    REPORTER_ASSERT(r, !(bm.empty()));
+    if (!(bm.empty())) {
+        REPORTER_ASSERT(r, bm.getColor(0, 0) == 0x00000000);
+    }
+}
+static void test_gif_data(skiatest::Reporter* r, void* data, size_t size) {
+    SkBitmap bm;
+    bool imageDecodeSuccess = SkImageDecoder::DecodeMemory(
+        data, size, &bm);
+    REPORTER_ASSERT(r, imageDecodeSuccess);
+    REPORTER_ASSERT(r, bm.width() == 3);
+    REPORTER_ASSERT(r, bm.height() == 3);
+    REPORTER_ASSERT(r, !(bm.empty()));
+    if (!(bm.empty())) {
+        REPORTER_ASSERT(r, bm.getColor(0, 0) == 0xffff0000);
+        REPORTER_ASSERT(r, bm.getColor(1, 0) == 0xffffff00);
+        REPORTER_ASSERT(r, bm.getColor(2, 0) == 0xff00ffff);
+        REPORTER_ASSERT(r, bm.getColor(0, 1) == 0xff808080);
+        REPORTER_ASSERT(r, bm.getColor(1, 1) == 0xff000000);
+        REPORTER_ASSERT(r, bm.getColor(2, 1) == 0xff00ff00);
+        REPORTER_ASSERT(r, bm.getColor(0, 2) == 0xffffffff);
+        REPORTER_ASSERT(r, bm.getColor(1, 2) == 0xffff00ff);
+        REPORTER_ASSERT(r, bm.getColor(2, 2) == 0xff0000ff);
+    }
+}
+static void test_interlaced_gif_data(skiatest::Reporter* r,
+                                     void* data,
+                                     size_t size) {
+    SkBitmap bm;
+    bool imageDecodeSuccess = SkImageDecoder::DecodeMemory(
+        data, size, &bm);
+    REPORTER_ASSERT(r, imageDecodeSuccess);
+    REPORTER_ASSERT(r, bm.width() == 9);
+    REPORTER_ASSERT(r, bm.height() == 9);
+    REPORTER_ASSERT(r, !(bm.empty()));
+    if (!(bm.empty())) {
+        REPORTER_ASSERT(r, bm.getColor(0, 0) == 0xffff0000);
+        REPORTER_ASSERT(r, bm.getColor(1, 0) == 0xffffff00);
+        REPORTER_ASSERT(r, bm.getColor(2, 0) == 0xff00ffff);
+
+        REPORTER_ASSERT(r, bm.getColor(0, 2) == 0xffffffff);
+        REPORTER_ASSERT(r, bm.getColor(1, 2) == 0xffff00ff);
+        REPORTER_ASSERT(r, bm.getColor(2, 2) == 0xff0000ff);
+
+        REPORTER_ASSERT(r, bm.getColor(0, 4) == 0xff808080);
+        REPORTER_ASSERT(r, bm.getColor(1, 4) == 0xff000000);
+        REPORTER_ASSERT(r, bm.getColor(2, 4) == 0xff00ff00);
+
+        REPORTER_ASSERT(r, bm.getColor(0, 6) == 0xffff0000);
+        REPORTER_ASSERT(r, bm.getColor(1, 6) == 0xffffff00);
+        REPORTER_ASSERT(r, bm.getColor(2, 6) == 0xff00ffff);
+
+        REPORTER_ASSERT(r, bm.getColor(0, 8) == 0xffffffff);
+        REPORTER_ASSERT(r, bm.getColor(1, 8) == 0xffff00ff);
+        REPORTER_ASSERT(r, bm.getColor(2, 8) == 0xff0000ff);
+    }
+}
+
+static void test_gif_data_short(skiatest::Reporter* r,
+                                void* data,
+                                size_t size) {
+    SkBitmap bm;
+    bool imageDecodeSuccess = SkImageDecoder::DecodeMemory(
+        data, size, &bm);
+    REPORTER_ASSERT(r, imageDecodeSuccess);
+    REPORTER_ASSERT(r, bm.width() == 3);
+    REPORTER_ASSERT(r, bm.height() == 3);
+    REPORTER_ASSERT(r, !(bm.empty()));
+    if (!(bm.empty())) {
+        REPORTER_ASSERT(r, bm.getColor(0, 0) == 0xffff0000);
+        REPORTER_ASSERT(r, bm.getColor(1, 0) == 0xffffff00);
+        REPORTER_ASSERT(r, bm.getColor(2, 0) == 0xff00ffff);
+        REPORTER_ASSERT(r, bm.getColor(0, 1) == 0xff808080);
+        REPORTER_ASSERT(r, bm.getColor(1, 1) == 0xff000000);
+        REPORTER_ASSERT(r, bm.getColor(2, 1) == 0xff00ff00);
+    }
+}
+
+/**
+  This test will test the ability of the SkImageDecoder to deal with
+  GIF files which have been mangled somehow.  We want to display as
+  much of the GIF as possible.
+*/
+static void TestGif(skiatest::Reporter* reporter) {
+    // test perfectly good images.
+    test_gif_data(reporter, static_cast<void *>(gifData), sizeof(gifData));
+    test_interlaced_gif_data(reporter, static_cast<void *>(interlacedGif),
+                          sizeof(interlacedGif));
+
+    unsigned char badData[sizeof(gifData)];
+
+    /* If you set the environment variable
+       skia_images_gif_suppressDecoderWarnings to 'false', you will
+       see warnings on stderr.  This is a feature.  */
+
+    memcpy(badData, gifData, sizeof(gifData));
+    badData[6] = 0x01;  // image too wide
+    test_gif_data(reporter, static_cast<void *>(badData), sizeof(gifData));
+    // "libgif warning [image too wide, expanding output to size]"
+
+    memcpy(badData, gifData, sizeof(gifData));
+    badData[8] = 0x01;  // image too tall
+    test_gif_data(reporter, static_cast<void *>(badData), sizeof(gifData));
+    // "libgif warning [image too tall,  expanding output to size]"
+
+    memcpy(badData, gifData, sizeof(gifData));
+    badData[62] = 0x01;  // image shifted right
+    test_gif_data(reporter, static_cast<void *>(badData), sizeof(gifData));
+    // "libgif warning [shifting image left to fit]"
+
+    memcpy(badData, gifData, sizeof(gifData));
+    badData[64] = 0x01;  // image shifted down
+    test_gif_data(reporter, static_cast<void *>(badData), sizeof(gifData));
+    // "libgif warning [shifting image up to fit]"
+
+    memcpy(badData, gifData, sizeof(gifData));
+    badData[62] = 0xff;  // image shifted left
+    badData[63] = 0xff;  // 2's complement -1 short
+    test_gif_data(reporter, static_cast<void *>(badData), sizeof(gifData));
+    // "libgif warning [shifting image left to fit]"
+
+    memcpy(badData, gifData, sizeof(gifData));
+    badData[64] = 0xff;  // image shifted up
+    badData[65] = 0xff;  // 2's complement -1 short
+    test_gif_data(reporter, static_cast<void *>(badData), sizeof(gifData));
+    // "libgif warning [shifting image up to fit]"
+
+    test_gif_data_no_colormap(reporter, static_cast<void *>(gifDataNoColormap),
+                              sizeof(gifDataNoColormap));
+    // "libgif warning [missing colormap]"
+
+    // test short Gif.  80 is missing a few bytes.
+    test_gif_data_short(reporter, static_cast<void *>(gifData), 80);
+    // "libgif warning [DGifGetLine]"
+
+    test_interlaced_gif_data(reporter, static_cast<void *>(interlacedGif),
+                             100);  // 100 is missing a few bytes
+    // "libgif warning [interlace DGifGetLine]"
+}
+
+#include "TestClassDef.h"
+DEFINE_TESTCLASS("GifTest", GifTestClass, TestGif)
+
+#endif  // !(SK_BUILD_FOR_WIN32||SK_BUILD_FOR_IOS||SK_BUILD_FOR_MAC)