/*

 * Copyright (c) 2016, 2018, 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 "memory/resourceArea.hpp"

#include "runtime/os.hpp"

#include "utilities/ostream.hpp"

#include "unittest.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 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

  ResourceMark rm;

  outputStream* out = &ss;

//  outputStream* out = tty; // enable for printout

  for (int c = 0; c < 100; c++) {

    arr[c] = c;

  }

}

//////////////////////////////////////////////////////////////////////////////

// Test os::vsnprintf and friends.

static void check_snprintf_result(int expected, size_t limit, int actual, bool expect_count) {

  if (expect_count || ((size_t)expected < limit)) {

    ASSERT_EQ(expected, actual);

  } else {

    ASSERT_GT(0, actual);

  }

}

// PrintFn is expected to be int (*)(char*, size_t, const char*, ...).

// But jio_snprintf is a C-linkage function with that signature, which

// has a different type on some platforms (like Solaris).

template<typename PrintFn>

static void test_snprintf(PrintFn pf, bool expect_count) {

  const char expected[] = "abcdefghijklmnopqrstuvwxyz";

  const int expected_len = sizeof(expected) - 1;

  const size_t padding_size = 10;

  char buffer[2 * (sizeof(expected) + padding_size)];

  char check_buffer[sizeof(buffer)];

  const char check_char = '1';  // Something not in expected.

  memset(check_buffer, check_char, sizeof(check_buffer));

  const size_t sizes_to_test[] = {

    sizeof(buffer) - padding_size,       // Fits, with plenty of space to spare.

    sizeof(buffer)/2,                    // Fits, with space to spare.

    sizeof(buffer)/4,                    // Doesn't fit.

    sizeof(expected) + padding_size + 1, // Fits, with a little room to spare

    sizeof(expected) + padding_size,     // Fits exactly.

    sizeof(expected) + padding_size - 1, // Doesn't quite fit.

    2,                                   // One char + terminating NUL.

    1,                                   // Only space for terminating NUL.

    0 };                                 // No space at all.

  for (unsigned i = 0; i < ARRAY_SIZE(sizes_to_test); ++i) {

    memset(buffer, check_char, sizeof(buffer)); // To catch stray writes.

    size_t test_size = sizes_to_test[i];

    ResourceMark rm;

    stringStream s;

    s.print("test_size: " SIZE_FORMAT, test_size);

    SCOPED_TRACE(s.as_string());

    size_t prefix_size = padding_size;

    guarantee(test_size <= (sizeof(buffer) - prefix_size), "invariant");

    size_t write_size = MIN2(sizeof(expected), test_size);

    size_t suffix_size = sizeof(buffer) - prefix_size - write_size;

    char* write_start = buffer + prefix_size;

    char* write_end = write_start + write_size;

    int result = pf(write_start, test_size, "%s", expected);

    check_snprintf_result(expected_len, test_size, result, expect_count);

    // Verify expected output.

    if (test_size > 0) {

      ASSERT_EQ(0, strncmp(write_start, expected, write_size - 1));

      // Verify terminating NUL of output.

      ASSERT_EQ('\0', write_start[write_size - 1]);

    } else {

      guarantee(test_size == 0, "invariant");

      guarantee(write_size == 0, "invariant");

      guarantee(prefix_size + suffix_size == sizeof(buffer), "invariant");

      guarantee(write_start == write_end, "invariant");

    }

    // Verify no scribbling on prefix or suffix.

    ASSERT_EQ(0, strncmp(buffer, check_buffer, prefix_size));

    ASSERT_EQ(0, strncmp(write_end, check_buffer, suffix_size));

  }

  // Special case of 0-length buffer with empty (except for terminator) output.

  check_snprintf_result(0, 0, pf(NULL, 0, "%s", ""), expect_count);

  check_snprintf_result(0, 0, pf(NULL, 0, ""), expect_count);

}

// This is probably equivalent to os::snprintf, but we're being

// explicit about what we're testing here.

static int vsnprintf_wrapper(char* buf, size_t len, const char* fmt, ...) {

  va_list args;

  va_start(args, fmt);

  int result = os::vsnprintf(buf, len, fmt, args);

  va_end(args);

  return result;

}

TEST_VM(os, vsnprintf) {

  test_snprintf(vsnprintf_wrapper, true);

}

TEST_VM(os, snprintf) {

  test_snprintf(os::snprintf, true);

}

// These are declared in jvm.h; test here, with related functions.

extern "C" {

int jio_vsnprintf(char*, size_t, const char*, va_list);

int jio_snprintf(char*, size_t, const char*, ...);

}

// This is probably equivalent to jio_snprintf, but we're being

// explicit about what we're testing here.

static int jio_vsnprintf_wrapper(char* buf, size_t len, const char* fmt, ...) {

  va_list args;

  va_start(args, fmt);

  int result = jio_vsnprintf(buf, len, fmt, args);

  va_end(args);

  return result;

}

TEST_VM(os, jio_vsnprintf) {

  test_snprintf(jio_vsnprintf_wrapper, false);

}

TEST_VM(os, jio_snprintf) {

  test_snprintf(jio_snprintf, false);

}