Experimental parsing expression grammar (PEG) template library

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2271743002

Review-Url: https://codereview.chromium.org/2271743002

1 files changed, 300 insertions, 0 deletions

diff --git a/tests/SkPEGTest.cpp b/tests/SkPEGTest.cpp
new file mode 100644
index 0000000000..68a47776e8
--- /dev/null
+++ b/tests/SkPEGTest.cpp
@@ -0,0 +1,300 @@
+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkPEG.h"
+#include "Test.h"
+
+using namespace skpeg;
+
+namespace {
+
+struct Alpha {
+    using V = char;
+    using MatchT = MatchResult<V>;
+
+    static MatchT Match(const char* in) {
+        static constexpr unsigned kAlphaRange = 'z' - 'a';
+        return static_cast<unsigned>(*in - 'a') <= kAlphaRange
+            || static_cast<unsigned>(*in - 'A') <= kAlphaRange
+            ? MatchT(in + 1, *in)
+            : nullptr;
+    }
+};
+
+struct Digit {
+    using V = uint8_t;
+    using MatchT = MatchResult<V>;
+
+    static MatchT Match(const char* in) {
+        static constexpr unsigned kDigitRange = '9' - '0';
+        return static_cast<unsigned>(*in - '0') <= kDigitRange
+            ? MatchT(in + 1, SkTo<uint8_t>(*in - '0'))
+            : nullptr;
+    }
+};
+
+void test_EOS(skiatest::Reporter* r) {
+    static const struct {
+        const char* fInput;
+        bool        fMatch;
+    } gTests[] = {
+        { ""   , true  },
+        { " "  , false },
+        { "\0" , true  },
+        { "foo", false },
+    };
+
+    for (size_t i = 0; i < SK_ARRAY_COUNT(gTests); ++i) {
+        const auto match = EOS::Match(gTests[i].fInput);
+        REPORTER_ASSERT(r, match == gTests[i].fMatch);
+        REPORTER_ASSERT(r, match.fNext == (match ? gTests[i].fInput : nullptr));
+    }
+}
+
+void test_LIT(skiatest::Reporter* r) {
+    static const struct {
+        const char* fInput;
+        bool        fMatch;
+    } gTests[] = {
+        { ""  , false },
+        { " " , false },
+        { "x" , false },
+        { "X" , true  },
+        { "xX", false },
+        { "Xx", true  },
+    };
+
+    for (size_t i = 0; i < SK_ARRAY_COUNT(gTests); ++i) {
+        const auto match = LIT<'X'>::Match(gTests[i].fInput);
+        REPORTER_ASSERT(r, match == gTests[i].fMatch);
+        REPORTER_ASSERT(r, match.fNext == (match ? gTests[i].fInput + 1 : nullptr));
+    }
+
+    REPORTER_ASSERT(r, !(LIT<'F', 'o', 'o'>::Match("")));
+    REPORTER_ASSERT(r, !(LIT<'F', 'o', 'o'>::Match("Fo")));
+    REPORTER_ASSERT(r, !(LIT<'F', 'o', 'o'>::Match("FoO")));
+    REPORTER_ASSERT(r,  (LIT<'F', 'o', 'o'>::Match("Foo")));
+    REPORTER_ASSERT(r,  (LIT<'F', 'o', 'o'>::Match("Foobar")));
+}
+
+void test_Alpha(skiatest::Reporter* r) {
+    static const struct {
+        const char* fInput;
+        bool        fMatch;
+        char        fMatchValue;
+    } gTests[] = {
+        { ""  , false,  0  },
+        { "\r", false,  0  },
+        { "\n", false,  0  },
+        { "\t", false,  0  },
+        { "0" , false,  0  },
+        { "9" , false,  0  },
+        { "a" , true , 'a' },
+        { "a" , true , 'a' },
+        { "z" , true , 'z' },
+        { "A" , true , 'A' },
+        { "Z" , true , 'Z' },
+        { "az", true , 'a' },
+        { "a0", true , 'a' },
+        { "0a", false,  0  },
+    };
+
+    for (size_t i = 0; i < SK_ARRAY_COUNT(gTests); ++i) {
+        const auto match = Alpha::Match(gTests[i].fInput);
+        REPORTER_ASSERT(r, match == gTests[i].fMatch);
+        REPORTER_ASSERT(r, match.fNext == (match ? gTests[i].fInput + 1 : nullptr));
+        if (match) {
+            REPORTER_ASSERT(r, *match == gTests[i].fMatchValue);
+        }
+    }
+}
+
+void test_Digit(skiatest::Reporter* r) {
+    static const struct {
+        const char* fInput;
+        bool        fMatch;
+        uint8_t     fMatchValue;
+    } gTests[] = {
+        { ""   , false, 0 },
+        { "/"  , false, 0 },
+        { ":"  , false, 0 },
+        { "x"  , false, 0 },
+        { "x0" , false, 0 },
+        { "0"  , true , 0 },
+        { "1x" , true , 1 },
+        { "9 a", true , 9 },
+    };
+
+    for (size_t i = 0; i < SK_ARRAY_COUNT(gTests); ++i) {
+        const auto match = Digit::Match(gTests[i].fInput);
+        REPORTER_ASSERT(r, match == gTests[i].fMatch);
+        REPORTER_ASSERT(r, match.fNext == (match ? gTests[i].fInput + 1 : nullptr));
+        if (match) {
+            REPORTER_ASSERT(r, *match == gTests[i].fMatchValue);
+        }
+    }
+}
+
+void test_Opt(skiatest::Reporter* r) {
+    static const struct {
+        const char* fInput;
+        bool        fMatch;
+    } gTests[] = {
+        { ""       , false },
+        { "fo"     , false },
+        { " foo"   , false },
+        { "foo"    , true },
+        { "foobar" , true },
+    };
+
+    for (size_t i = 0; i < SK_ARRAY_COUNT(gTests); ++i) {
+        const auto m = Opt<LIT<'f', 'o', 'o'>>::Match(gTests[i].fInput);
+        REPORTER_ASSERT(r, m);
+        REPORTER_ASSERT(r, m->fValue.isValid() == gTests[i].fMatch);
+    }
+}
+
+void test_Seq(skiatest::Reporter* r) {
+    REPORTER_ASSERT(r,  (Seq<LIT<'X'>, EOS>::Match("X")));
+    REPORTER_ASSERT(r, !(Seq<LIT<'X'>, EOS>::Match("x")));
+    REPORTER_ASSERT(r, !(Seq<LIT<'X'>, EOS>::Match("xX")));
+    REPORTER_ASSERT(r, !(Seq<LIT<'X'>, EOS>::Match("XX")));
+    REPORTER_ASSERT(r,  (Seq<LIT<'X'>, Seq<LIT<'X'>, EOS>>::Match("XX")));
+    REPORTER_ASSERT(r,  (Seq<LIT<'X'>, Seq<LIT<'X'>, EOS>>::Match("XX")));
+
+    REPORTER_ASSERT(r, !(Seq<LIT<'F', 'o', 'o'>, EOS>::Match("FooBar")));
+    REPORTER_ASSERT(r,  (Seq<LIT<'F', 'o', 'o'>, EOS>::Match("Foo")));
+
+    {
+        const auto m = Seq<LIT<'x'>, Digit>::Match("x5");
+        REPORTER_ASSERT(r, m);
+        REPORTER_ASSERT(r, m->get<1>() == 5);
+    }
+    {
+        const auto m = Seq<Digit, Digit>::Match("42");
+        REPORTER_ASSERT(r, m);
+        REPORTER_ASSERT(r, m->get<0>() == 4);
+        REPORTER_ASSERT(r, m->get<1>() == 2);
+    }
+}
+
+void test_Choice(skiatest::Reporter* r) {
+    REPORTER_ASSERT(r, !(Choice<Digit,Alpha>::Match("")));
+    REPORTER_ASSERT(r, !(Choice<Digit,Alpha>::Match("\t")));
+    REPORTER_ASSERT(r, !(Choice<Digit,Alpha>::Match(" ")));
+    REPORTER_ASSERT(r,  (Choice<Digit,Alpha>::Match("a")));
+    REPORTER_ASSERT(r,  (Choice<Digit,Alpha>::Match("3")));
+    REPORTER_ASSERT(r,  (Choice<Digit,Alpha>::Match("a ")));
+    REPORTER_ASSERT(r,  (Choice<Digit,Alpha>::Match("3 ")));
+    REPORTER_ASSERT(r, !(Choice<Digit,Alpha>::Match(" a ")));
+    REPORTER_ASSERT(r, !(Choice<Digit,Alpha>::Match(" 3 ")));
+
+    {
+        const auto m = Choice<Alpha, Digit>::Match("x");
+        REPORTER_ASSERT(r,  m);
+        REPORTER_ASSERT(r,  m->v1.isValid());
+        REPORTER_ASSERT(r, !m->v2.isValid());
+        REPORTER_ASSERT(r, *m->v1.get() == 'x');
+    }
+
+    {
+        const auto m = Choice<Alpha, Digit>::Match("7");
+        REPORTER_ASSERT(r,  m);
+        REPORTER_ASSERT(r, !m->v1.isValid());
+        REPORTER_ASSERT(r,  m->v2.isValid());
+        REPORTER_ASSERT(r, *m->v2.get() == 7);
+    }
+}
+
+void test_AnySome(skiatest::Reporter* r) {
+    static const struct {
+        const char* fInput;
+        int         fCount;
+    } gTests[] = {
+        { ""      , 0 },
+        { "fo"    , 0 },
+        { "Foo"   , 0 },
+        { "foo"   , 1 },
+        { "foofoo", 2 },
+    };
+
+    for (size_t i = 0; i < SK_ARRAY_COUNT(gTests); ++i) {
+        const auto matchAny = Any<LIT<'f', 'o', 'o'>>::Match(gTests[i].fInput);
+        REPORTER_ASSERT(r, matchAny);
+        REPORTER_ASSERT(r, matchAny->fValues.count() == gTests[i].fCount);
+
+        const auto matchSome = Some<LIT<'f', 'o', 'o'>>::Match(gTests[i].fInput);
+        REPORTER_ASSERT(r,  matchSome == (gTests[i].fCount > 0));
+        REPORTER_ASSERT(r, !matchSome ||
+                            matchSome->get<1>().fValues.count() == gTests[i].fCount - 1);
+    }
+
+    {
+        const auto m = Any<Digit>::Match("0123456789foo");
+        REPORTER_ASSERT(r, m);
+        REPORTER_ASSERT(r, m->fValues.count() == 10);
+        for (int i = 0; i < m->fValues.count(); ++i) {
+            REPORTER_ASSERT(r, m->fValues[i] == i);
+        }
+    }
+}
+
+void test_Complex(skiatest::Reporter* r) {
+    // [0-9]+(,[0-9]+)?$
+    using P0 =
+        Seq<
+          Some<Digit>,
+          Opt<Seq<
+            LIT<','>,
+            Some<Digit>>>,
+          EOS>;
+
+    REPORTER_ASSERT(r, !P0::Match(""));
+    REPORTER_ASSERT(r, !P0::Match(","));
+    REPORTER_ASSERT(r, !P0::Match("1,"));
+    REPORTER_ASSERT(r, !P0::Match(",1"));
+    REPORTER_ASSERT(r,  P0::Match("1"));
+    REPORTER_ASSERT(r,  P0::Match("1,2"));
+    REPORTER_ASSERT(r, !P0::Match("1,2 "));
+    REPORTER_ASSERT(r,  P0::Match("123,456"));
+
+    // [ ]*[Ff]oo([Bb]ar)+[Bb]az[ ]*$
+    using P1 =
+        Seq<
+          Any<LIT<' '>>,
+          Choice<LIT<'F'>, LIT<'f'>>,
+          LIT<'o', 'o'>,
+          Some<Seq<
+            Choice<LIT<'B'>, LIT<'b'>>,
+            LIT<'a', 'r'>>>,
+          Choice<LIT<'B'>, LIT<'b'>>,
+          LIT<'a', 'z'>,
+          Any<LIT<' '>>,
+          EOS>;
+
+    REPORTER_ASSERT(r, !P1::Match(""));
+    REPORTER_ASSERT(r, !P1::Match("FooBar"));
+    REPORTER_ASSERT(r, !P1::Match("FooBaz"));
+    REPORTER_ASSERT(r,  P1::Match("FooBarBaz"));
+    REPORTER_ASSERT(r,  P1::Match("foobarbaz"));
+    REPORTER_ASSERT(r,  P1::Match("  FooBarbaz     "));
+    REPORTER_ASSERT(r,  P1::Match(" FooBarbarbarBaz "));
+}
+
+} // anonymous ns
+
+DEF_TEST(SkPEG, r) {
+    test_EOS(r);
+    test_LIT(r);
+    test_Alpha(r);
+    test_Digit(r);
+    test_Opt(r);
+    test_Seq(r);
+    test_Choice(r);
+    test_AnySome(r);
+    test_Complex(r);
+}