Reland "Introduce FX_Number class as a replacement for FX_atonum()."

This reverts commit 29e180342e18873babf1c74f7c5c056f90a191b0.

Reason for revert: probably harmless

Original change's description:
> Revert "Introduce FX_Number class as a replacement for FX_atonum()."
>
> This reverts commit a5d7ad3aa8feb08a14b5cca173d673054c1ade23.
>
> Reason for revert: Speculative revert to get back before flake.
>
> Original change's description:
> > Introduce FX_Number class as a replacement for FX_atonum().
> >
> > The issue with FX_atonum() is that it doesn't return any information
> > about whether it range-checked its integer values as a signed or
> > unsigned type, even though it knows this as part of its processing.
> >
> > Rather than adding another out parameter to that function, create
> > a class to hold all this information together.
> >
> > This is the first place things went astray while diagnosing
> > bug 882959, in that a large positive value was cast to float as a
> > negative value. Unfortunately, this doesn't affect the related bug,
> > but is a step in the right direction.
> >
> > Change-Id: I0977ec8fccf85e2632a962507bdd30a1cbe6d33c
> > Reviewed-on: https://pdfium-review.googlesource.com/42353
> > Reviewed-by: Lei Zhang <thestig@chromium.org>
> > Commit-Queue: Tom Sepez <tsepez@chromium.org>
>
> TBR=thestig@chromium.org,tsepez@chromium.org
>
> Change-Id: Ia56270c3daa80408fc2b23eb4384a77f03f45b82
> Reviewed-on: https://pdfium-review.googlesource.com/42392
> Reviewed-by: Tom Sepez <tsepez@chromium.org>
> Commit-Queue: Tom Sepez <tsepez@chromium.org>

TBR=thestig@chromium.org,tsepez@chromium.org

Change-Id: I83c37aa3040a8890f2117753f19ab1d452d411e7
Reviewed-on: https://pdfium-review.googlesource.com/42410
Commit-Queue: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Tom Sepez <tsepez@chromium.org>

1 files changed, 165 insertions, 0 deletions

diff --git a/core/fxcrt/fx_number_unittest.cpp b/core/fxcrt/fx_number_unittest.cpp
new file mode 100644
index 0000000000..83702dadcf
--- /dev/null
+++ b/core/fxcrt/fx_number_unittest.cpp
@@ -0,0 +1,165 @@
+// Copyright 2018 PDFium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include <limits>
+
+#include "core/fxcrt/fx_number.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+TEST(fxnumber, Default) {
+  FX_Number number;
+  EXPECT_TRUE(number.IsInteger());
+  EXPECT_FALSE(number.IsSigned());
+  EXPECT_EQ(0u, number.GetUnsigned());
+  EXPECT_EQ(0, number.GetSigned());
+  EXPECT_FLOAT_EQ(0.0f, number.GetFloat());
+}
+
+TEST(fxnumber, FromUnsigned) {
+  FX_Number number(42u);
+  EXPECT_TRUE(number.IsInteger());
+  EXPECT_FALSE(number.IsSigned());
+  EXPECT_EQ(42u, number.GetUnsigned());
+  EXPECT_EQ(42, number.GetSigned());
+  EXPECT_FLOAT_EQ(42.0f, number.GetFloat());
+
+  // Show that assignment works.
+  FX_Number number2 = number;
+  EXPECT_TRUE(number2.IsInteger());
+  EXPECT_FALSE(number2.IsSigned());
+  EXPECT_EQ(42u, number2.GetUnsigned());
+  EXPECT_EQ(42, number2.GetSigned());
+  EXPECT_FLOAT_EQ(42.0F, number2.GetFloat());
+}
+
+TEST(fxnumber, FromSigned) {
+  FX_Number number(-128);
+  EXPECT_TRUE(number.IsInteger());
+  EXPECT_TRUE(number.IsSigned());
+  EXPECT_EQ(4294967168u, number.GetUnsigned());
+  EXPECT_EQ(-128, number.GetSigned());
+  EXPECT_FLOAT_EQ(-128.0f, number.GetFloat());
+
+  // Show that assignment works.
+  FX_Number number2 = number;
+  EXPECT_TRUE(number2.IsInteger());
+  EXPECT_TRUE(number2.IsSigned());
+  EXPECT_EQ(4294967168u, number2.GetUnsigned());
+  EXPECT_EQ(-128, number2.GetSigned());
+  EXPECT_FLOAT_EQ(-128.0f, number2.GetFloat());
+}
+
+TEST(fxnumber, FromFloat) {
+  FX_Number number(-100.001f);
+  EXPECT_FALSE(number.IsInteger());
+  EXPECT_TRUE(number.IsSigned());
+  EXPECT_EQ(4294967196u, number.GetUnsigned());
+  EXPECT_EQ(-100, number.GetSigned());
+  EXPECT_FLOAT_EQ(-100.001f, number.GetFloat());
+
+  // Show that assignment works.
+  FX_Number number2 = number;
+  EXPECT_FALSE(number2.IsInteger());
+  EXPECT_TRUE(number2.IsSigned());
+  EXPECT_EQ(4294967196u, number2.GetUnsigned());
+  EXPECT_EQ(-100, number2.GetSigned());
+  EXPECT_FLOAT_EQ(-100.001f, number2.GetFloat());
+}
+
+TEST(fxnumber, FromStringUnsigned) {
+  {
+    FX_Number number("");
+    EXPECT_TRUE(number.IsInteger());
+    EXPECT_FALSE(number.IsSigned());
+    EXPECT_EQ(0u, number.GetUnsigned());
+  }
+  {
+    FX_Number number("0");
+    EXPECT_TRUE(number.IsInteger());
+    EXPECT_FALSE(number.IsSigned());
+    EXPECT_EQ(0u, number.GetUnsigned());
+  }
+  {
+    FX_Number number("10");
+    EXPECT_TRUE(number.IsInteger());
+    EXPECT_FALSE(number.IsSigned());
+    EXPECT_EQ(10u, number.GetUnsigned());
+  }
+  {
+    FX_Number number("4294967295");
+    EXPECT_TRUE(number.IsInteger());
+    EXPECT_FALSE(number.IsSigned());
+    EXPECT_EQ(std::numeric_limits<uint32_t>::max(), number.GetUnsigned());
+  }
+  {
+    // Value overflows.
+    FX_Number number("4223423494965252");
+    EXPECT_TRUE(number.IsInteger());
+    EXPECT_FALSE(number.IsSigned());
+    EXPECT_EQ(0u, number.GetUnsigned());
+  }
+  {
+    // No explicit sign will allow the number to go negative if we retrieve
+    // it as a signed value. This is needed for things like the encryption
+    // Permissions flag (Table 3.20 PDF 1.7 spec)
+    FX_Number number("4294965252");
+    EXPECT_EQ(-2044, number.GetSigned());
+  }
+}
+
+TEST(fxnumber, FromStringSigned) {
+  {
+    FX_Number number("-0");
+    EXPECT_TRUE(number.IsInteger());
+    EXPECT_TRUE(number.IsSigned());
+    EXPECT_EQ(0, number.GetSigned());
+  }
+  {
+    FX_Number number("+0");
+    EXPECT_TRUE(number.IsInteger());
+    EXPECT_TRUE(number.IsSigned());
+    EXPECT_EQ(0, number.GetSigned());
+  }
+  {
+    FX_Number number("-10");
+    EXPECT_TRUE(number.IsInteger());
+    EXPECT_TRUE(number.IsSigned());
+    EXPECT_EQ(-10, number.GetSigned());
+  }
+  {
+    FX_Number number("+10");
+    EXPECT_TRUE(number.IsInteger());
+    EXPECT_TRUE(number.IsSigned());
+    EXPECT_EQ(10, number.GetSigned());
+  }
+  {
+    FX_Number number("-2147483648");
+    EXPECT_TRUE(number.IsInteger());
+    EXPECT_TRUE(number.IsSigned());
+    EXPECT_EQ(std::numeric_limits<int32_t>::min(), number.GetSigned());
+  }
+  {
+    FX_Number number("+2147483647");
+    EXPECT_TRUE(number.IsInteger());
+    EXPECT_TRUE(number.IsSigned());
+    EXPECT_EQ(std::numeric_limits<int32_t>::max(), number.GetSigned());
+  }
+  {
+    // Value underflows.
+    FX_Number number("-2147483649");
+    EXPECT_EQ(0u, number.GetUnsigned());
+    EXPECT_EQ(0, number.GetSigned());
+  }
+  {
+    // Value overflows.
+    FX_Number number("+2147483648");
+    EXPECT_EQ(0u, number.GetUnsigned());
+    EXPECT_EQ(0, number.GetSigned());
+  }
+}
+
+TEST(fxnumber, FromStringFloat) {
+  FX_Number number("3.24");
+  EXPECT_FLOAT_EQ(3.24f, number.GetFloat());
+}