Fixup integer conversion logic.

core/fxcrt/fx_basic_util_unittest.cpp

 // Copyright 2016 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 "core/fxcrt/include/fx_basic.h"
 #include "testing/fx_string_testhelpers.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace {
 
@@ skipping 10 matching lines @@
 
 TEST(fxge, GetBits32) {
   unsigned char data[] = {0xDE, 0x3F, 0xB1, 0x7C, 0x12, 0x9A, 0x04, 0x56};
   for (int nbits = 1; nbits <= 32; ++nbits) {
     for (int bitpos = 0; bitpos < (int)sizeof(data) * 8 - nbits; ++bitpos) {
       EXPECT_EQ(ReferenceGetBits32(data, bitpos, nbits),
                 GetBits32(data, bitpos, nbits));
     }
   }
 }
+
+TEST(fxcrt, FX_atonum) {
+  int i;
+  EXPECT_TRUE(FX_atonum("10", &i));
+  EXPECT_EQ(10, i);
+
+  EXPECT_TRUE(FX_atonum("-10", &i));
+  EXPECT_EQ(-10, i);
+
+  EXPECT_TRUE(FX_atonum("+10", &i));
+  EXPECT_EQ(10, i);
+
+  // Value overflows.
+  EXPECT_TRUE(FX_atonum("4223423494965252", &i));
+  EXPECT_EQ(0, i);
+
+  // No explicit sign will allow the number to go negative. This is for things
+  // like the encryption Permissions flag (Table 3.20 PDF 1.7 spec)
+  EXPECT_TRUE(FX_atonum("4294965252", &i));
+  EXPECT_EQ(-2044, i);
+
+  EXPECT_TRUE(FX_atonum("-4294965252", &i));
+  EXPECT_EQ(0, i);
+
+  EXPECT_TRUE(FX_atonum("+4294965252", &i));
+  EXPECT_EQ(0, i);
+
+  float f;
+  EXPECT_FALSE(FX_atonum("3.24", &f));
+  EXPECT_FLOAT_EQ(3.24f, f);
+}