/*
 * Copyright (c) 2016, 2017, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

#include "precompiled.hpp"
#include "runtime/os.hpp"
#include "unittest.hpp"
#include "utilities/decoder.hpp"

static size_t small_page_size() {
  return os::vm_page_size();
}

static size_t large_page_size() {
  const size_t large_page_size_example = 4 * M;
  return os::page_size_for_region_aligned(large_page_size_example, 1);
}

TEST_VM(os, page_size_for_region) {
  size_t large_page_example = 4 * M;
  size_t large_page = os::page_size_for_region_aligned(large_page_example, 1);

  size_t small_page = os::vm_page_size();
  if (large_page > small_page) {
    size_t num_small_in_large = large_page / small_page;
    size_t page = os::page_size_for_region_aligned(large_page, num_small_in_large);
    ASSERT_EQ(page, small_page) << "Did not get a small page";
  }
}

TEST_VM(os, page_size_for_region_aligned) {
  if (UseLargePages) {
    const size_t small_page = small_page_size();
    const size_t large_page = large_page_size();

    if (large_page > small_page) {
      size_t num_small_pages_in_large = large_page / small_page;
      size_t page = os::page_size_for_region_aligned(large_page, num_small_pages_in_large);

      ASSERT_EQ(page, small_page);
    }
  }
}

TEST_VM(os, page_size_for_region_alignment) {
  if (UseLargePages) {
    const size_t small_page = small_page_size();
    const size_t large_page = large_page_size();
    if (large_page > small_page) {
      const size_t unaligned_region = large_page + 17;
      size_t page = os::page_size_for_region_aligned(unaligned_region, 1);
      ASSERT_EQ(page, small_page);

      const size_t num_pages = 5;
      const size_t aligned_region = large_page * num_pages;
      page = os::page_size_for_region_aligned(aligned_region, num_pages);
      ASSERT_EQ(page, large_page);
    }
  }
}

TEST_VM(os, page_size_for_region_unaligned) {
  if (UseLargePages) {
    // Given exact page size, should return that page size.
    for (size_t i = 0; os::_page_sizes[i] != 0; i++) {
      size_t expected = os::_page_sizes[i];
      size_t actual = os::page_size_for_region_unaligned(expected, 1);
      ASSERT_EQ(expected, actual);
    }

    // Given slightly larger size than a page size, return the page size.
    for (size_t i = 0; os::_page_sizes[i] != 0; i++) {
      size_t expected = os::_page_sizes[i];
      size_t actual = os::page_size_for_region_unaligned(expected + 17, 1);
      ASSERT_EQ(expected, actual);
    }

    // Given a slightly smaller size than a page size,
    // return the next smaller page size.
    if (os::_page_sizes[1] > os::_page_sizes[0]) {
      size_t expected = os::_page_sizes[0];
      size_t actual = os::page_size_for_region_unaligned(os::_page_sizes[1] - 17, 1);
      ASSERT_EQ(actual, expected);
    }

    // Return small page size for values less than a small page.
    size_t small_page = small_page_size();
    size_t actual = os::page_size_for_region_unaligned(small_page - 17, 1);
    ASSERT_EQ(small_page, actual);
  }
}

TEST(os, test_random) {
  const double m = 2147483647;
  double mean = 0.0, variance = 0.0, t;
  const int reps = 10000;
  unsigned int seed = 1;

  // tty->print_cr("seed %ld for %ld repeats...", seed, reps);
  os::init_random(seed);
  int num;
  for (int k = 0; k < reps; k++) {
    num = os::random();
    double u = (double)num / m;
    ASSERT_TRUE(u >= 0.0 && u <= 1.0) << "bad random number!";

    // calculate mean and variance of the random sequence
    mean += u;
    variance += (u*u);
  }
  mean /= reps;
  variance /= (reps - 1);

  ASSERT_EQ(num, 1043618065) << "bad seed";
  // tty->print_cr("mean of the 1st 10000 numbers: %f", mean);
  int intmean = mean*100;
  ASSERT_EQ(intmean, 50);
  // tty->print_cr("variance of the 1st 10000 numbers: %f", variance);
  int intvariance = variance*100;
  ASSERT_EQ(intvariance, 33);
  const double eps = 0.0001;
  t = fabsd(mean - 0.5018);
  ASSERT_LT(t, eps) << "bad mean";
  t = (variance - 0.3355) < 0.0 ? -(variance - 0.3355) : variance - 0.3355;
  ASSERT_LT(t, eps) << "bad variance";
}

#ifdef _WIN32
TEST(os, dll_addr_to_function_valid) {
  char buf[128] = "";
  int offset = -1;
  address valid_function_pointer = (address) JNI_CreateJavaVM;
  ASSERT_TRUE(os::dll_address_to_function_name(valid_function_pointer,
                                          buf, sizeof(buf), &offset, true) == true);
  ASSERT_TRUE(strstr(buf, "JNI_CreateJavaVM") != NULL);
  ASSERT_TRUE(offset >= 0);
}

// Test that handing down a too-small output buffer will truncate the output
// string correctly but cause no harm otherwise.
TEST(os, dll_addr_to_function_valid_truncated) {
  char buf[128] = "";
  int offset = -1;
  memset(buf, 'X', sizeof(buf));
  address valid_function_pointer = (address) JNI_CreateJavaVM;
  ASSERT_TRUE(os::dll_address_to_function_name(valid_function_pointer,
                                          buf, 10, &offset, true) == true);
  ASSERT_TRUE(buf[10 - 1] == '\0');
  ASSERT_TRUE(buf[10] == 'X');
  // Note: compare the first (sizeof buf - 2) bytes only because Windows decoder
  // (actually UndecorateSymbolName()) seems to have a bug where it uses one byte less than
  // the buffer would offer.
  ASSERT_TRUE(strncmp(buf, "JNI_Crea", 8) == 0);
  ASSERT_TRUE(offset >= 0);
}

// Test that handing down invalid addresses will cause no harm and output buffer
// and offset will contain "" and -1, respectively.
TEST(os, dll_addr_to_function_invalid) {
  char buf[128];
  int offset;
  address invalid_function_pointers[] = { NULL, (address)1, (address)&offset };

  for (int i = 0;
       i < sizeof(invalid_function_pointers) / sizeof(address);
       i ++)
  {
    address addr = invalid_function_pointers[i];
    strcpy(buf, "blabla");
    offset = 12;
    ASSERT_TRUE(os::dll_address_to_function_name(addr, buf, sizeof(buf),
                                            &offset, true) == false);
    ASSERT_TRUE(buf[0] == '\0');
    ASSERT_TRUE(offset == -1);
  }
}

TEST(os, decoder_get_source_info_valid) {
  char buf[128] = "";
  int line = -1;
  address valid_function_pointer = (address) JNI_CreateJavaVM;
  ASSERT_TRUE(Decoder::get_source_info(valid_function_pointer, buf, sizeof(buf), &line) == true);
  ASSERT_TRUE(strcmp(buf, "jni.cpp") == 0);
  ASSERT_TRUE(line >= 0);
}

// Test that handing down a too-small output buffer will truncate the output
// string correctly but cause no harm otherwise.
TEST(os, decoder_get_source_info_valid_truncated) {
  char buf[128] = "";
  int line = -1;
  memset(buf, 'X', sizeof(buf));
  address valid_function_pointer = (address) JNI_CreateJavaVM;
  ASSERT_TRUE(Decoder::get_source_info(valid_function_pointer, buf, 7, &line) == true);
  ASSERT_TRUE(buf[7 - 1] == '\0');
  ASSERT_TRUE(buf[7] == 'X');
  ASSERT_TRUE(strcmp(buf, "jni.cp") == 0);
  ASSERT_TRUE(line > 0);
}

// Test that handing down invalid addresses will cause no harm and output buffer
// and line will contain "" and -1, respectively.
TEST(os, decoder_get_source_info_invalid) {
  char buf[128] = "";
  int line = -1;
  address invalid_function_pointers[] = { NULL, (address)1, (address)&line };

  for (int i = 0;
       i < sizeof(invalid_function_pointers) / sizeof(address);
       i ++)
  {
    address addr = invalid_function_pointers[i];
    // We should fail but not crash
    strcpy(buf, "blabla");
    line = 12;
    ASSERT_TRUE(Decoder::get_source_info(addr, buf, sizeof(buf), &line) == false);
    // buffer should contain "", offset should contain -1
    ASSERT_TRUE(buf[0] == '\0');
    ASSERT_TRUE(line == -1);
  }
}

#ifdef PLATFORM_PRINT_NATIVE_STACK
TEST(os, platform_print_native_stack) {
  bufferedStream bs;
  // Note: scratch buffer argument to os::platform_print_native_stack is not
  // optional!
  char scratch_buffer [255];
  for (int i = 0; i < 3; i ++) {
    ASSERT_TRUE(os::platform_print_native_stack(&bs, NULL, scratch_buffer,
                                                sizeof(scratch_buffer)));
    ASSERT_TRUE(bs.size() > 0);
    // This may depend on debug information files being generated and available
    // (e.g. not zipped).
    ASSERT_TRUE(::strstr(bs.base(), "platform_print_native_stack") != NULL);
#ifdef _WIN32
    // We have source information on Windows.
    ASSERT_TRUE(::strstr(bs.base(), "os_windows_x86.cpp") != NULL);
#endif
  }
}
#endif
#endif

#ifdef ASSERT
TEST_VM_ASSERT_MSG(os, page_size_for_region_with_zero_min_pages, "sanity") {
  size_t region_size = 16 * os::vm_page_size();
  os::page_size_for_region_aligned(region_size, 0); // should assert
}
#endif