/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * Copyright by The HDF Group.                                               *
 * All rights reserved.                                                      *
 *                                                                           *
 * This file is part of HDF5.  The full HDF5 copyright notice, including     *
 * terms governing use, modification, and redistribution, is contained in    *
 * the LICENSE file, which can be found at the root of the source code       *
 * distribution tree, or in https://www.hdfgroup.org/licenses.               *
 * If you do not have access to either file, you may request a copy from     *
 * help@hdfgroup.org.                                                        *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

#include "h5test.h"

#define H5F_FRIEND  /*suppress error about including H5Fpkg	  */
#define H5FD_FRIEND /*suppress error about including H5FDpkg	  */
#define H5FD_TESTING
#include "H5Fpkg.h"
#include "H5FDpkg.h"

#include "H5CXprivate.h" /* API Contexts                         */
#include "H5Iprivate.h"
#include "H5VLprivate.h" /* Virtual Object Layer                     */

/* Filename */
/* (The file names are the same as the define in accum_swmr_reader.c) */
static const char *FILENAME[] = {"accum", "accum_swmr_big", NULL};

/* The reader forked by test_swmr_write_big() */
#define SWMR_READER "accum_swmr_reader"

/* "big" I/O test values */
#define BIG_BUF_SIZE (6 * 1024 * 1024)

/* Random I/O test values */
#define RANDOM_BUF_SIZE     (1 * 1024 * 1024)
#define MAX_RANDOM_SEGMENTS (5 * 1024)
#define RAND_SEG_LEN        (1024)
#define RANDOM_BASE_OFF     (1024 * 1024)

/* Function Prototypes */
unsigned test_write_read(H5F_t *f);
unsigned test_write_read_nonacc_front(H5F_t *f);
unsigned test_write_read_nonacc_end(H5F_t *f);
unsigned test_accum_overlap(H5F_t *f);
unsigned test_accum_overlap_clean(H5F_t *f);
unsigned test_accum_overlap_size(H5F_t *f);
unsigned test_accum_non_overlap_size(H5F_t *f);
unsigned test_accum_adjust(H5F_t *f);
unsigned test_read_after(H5F_t *f);
unsigned test_free(H5F_t *f);
unsigned test_big(H5F_t *f);
unsigned test_random_write(H5F_t *f);
unsigned test_swmr_write_big(bool newest_format);

/* Helper Function Prototypes */
void accum_printf(const H5F_t *f);

/* Private Test H5Faccum Function Wrappers */
#define accum_write(a, s, b) H5F_block_write(f, H5FD_MEM_DEFAULT, (haddr_t)(a), (size_t)(s), (b))
#define accum_read(a, s, b)  H5F_block_read(f, H5FD_MEM_DEFAULT, (haddr_t)(a), (size_t)(s), (b))
#define accum_free(f, a, s)  H5F__accum_free(f->shared, H5FD_MEM_DEFAULT, (haddr_t)(a), (hsize_t)(s))
#define accum_flush(f)       H5F__accum_flush(f->shared)
#define accum_reset(f)       H5F__accum_reset(f->shared, true, false)

/* ================= */
/* Main Test Routine */
/* ================= */

/*-------------------------------------------------------------------------
 * Function:    main
 *
 * Purpose:     Test the metadata accumulator code
 *
 * Return:      Success: SUCCEED
 *              Failure: FAIL
 *
 *-------------------------------------------------------------------------
 */
int
main(void)
{
    unsigned    nerrors        = 0;           /* track errors */
    H5CX_node_t api_ctx        = {{0}, NULL}; /* API context node to push */
    bool        api_ctx_pushed = false;       /* Whether API context pushed */
    hid_t       fid            = H5I_INVALID_HID;
    hid_t       fapl           = H5I_INVALID_HID; /* File access property list */
    char        filename[1024];
    H5F_t      *f = NULL; /* File for all tests */

    /* Test Setup */
    puts("Testing the metadata accumulator");

    /* File access property list */
    h5_test_init();
    if ((fapl = h5_fileaccess()) < 0)
        FAIL_STACK_ERROR;
    h5_fixname(FILENAME[0], fapl, filename, sizeof filename);

    /* Create a test file */
    if ((fid = H5Fcreate(filename, H5F_ACC_TRUNC, H5P_DEFAULT, fapl)) < 0)
        FAIL_STACK_ERROR;

    /* Push API context */
    if (H5CX_push(&api_ctx) < 0)
        FAIL_STACK_ERROR;
    api_ctx_pushed = true;

    /* Get H5F_t * to internal file structure */
    if (NULL == (f = (H5F_t *)H5VL_object(fid)))
        FAIL_STACK_ERROR;

    /* We'll be writing lots of garbage data, so extend the
        file a ways. 10MB should do. */
    if (H5FD_set_eoa(f->shared->lf, H5FD_MEM_DEFAULT, (haddr_t)(1024 * 1024 * 10)) < 0)
        FAIL_STACK_ERROR;

    /* Reset metadata accumulator for the file */
    if (accum_reset(f) < 0)
        FAIL_STACK_ERROR;

    /* Test Functions */
    nerrors += test_write_read(f);
    nerrors += test_write_read_nonacc_front(f);
    nerrors += test_write_read_nonacc_end(f);
    nerrors += test_accum_overlap(f);
    nerrors += test_accum_overlap_clean(f);
    nerrors += test_accum_overlap_size(f);
    nerrors += test_accum_non_overlap_size(f);
    nerrors += test_accum_adjust(f);
    nerrors += test_read_after(f);
    nerrors += test_free(f);
    nerrors += test_big(f);
    nerrors += test_random_write(f);

    /* Pop API context */
    if (api_ctx_pushed && H5CX_pop(false) < 0)
        FAIL_STACK_ERROR;
    api_ctx_pushed = false;

    /* End of test code, close and delete file */
    if (H5Fclose(fid) < 0)
        TEST_ERROR;

    /* This test uses a different file */
    nerrors += test_swmr_write_big(true);
    nerrors += test_swmr_write_big(false);

    if (nerrors)
        goto error;
    puts("All metadata accumulator tests passed.");
    h5_cleanup(FILENAME, fapl);

    return 0;

error:
    if (api_ctx_pushed)
        H5CX_pop(false);

    puts("*** TESTS FAILED ***");
    return 1;
} /* end main() */

/* ============================= */
/* Individual Unit Test Routines */
/* ============================= */

/*-------------------------------------------------------------------------
 * Function:    test_write_read
 *
 * Purpose:     Simple test to write to then read from metadata accumulator.
 *
 * Return:      Success: SUCCEED
 *              Failure: FAIL
 *
 *-------------------------------------------------------------------------
 */
unsigned
test_write_read(H5F_t *f)
{
    int  i = 0;
    int *write_buf, *read_buf;

    TESTING("simple write/read to/from metadata accumulator");

    /* Allocate buffers */
    write_buf = (int *)malloc(1024 * sizeof(int));
    assert(write_buf);
    read_buf = (int *)calloc((size_t)1024, sizeof(int));
    assert(read_buf);

    /* Fill buffer with data, zero out read buffer */
    for (i = 0; i < 1024; i++)
        write_buf[i] = i + 1;

    /* Do a simple write/read/verify of data */
    /* Write 1KB at Address 0 */
    if (accum_write(0, 1024, write_buf) < 0)
        FAIL_STACK_ERROR;
    if (accum_read(0, 1024, read_buf) < 0)
        FAIL_STACK_ERROR;
    if (memcmp(write_buf, read_buf, (size_t)1024) != 0)
        TEST_ERROR;

    if (accum_reset(f) < 0)
        FAIL_STACK_ERROR;

    PASSED();

    /* Release memory */
    free(write_buf);
    free(read_buf);

    return 0;

error:
    /* Release memory */
    free(write_buf);
    free(read_buf);

    return 1;
} /* test_write_read */

/*-------------------------------------------------------------------------
 * Function:    test_write_read_nonacc_front
 *
 * Purpose:     Simple test to write to then read from before metadata accumulator.
 *
 * Return:      Success: SUCCEED
 *              Failure: FAIL
 *
 *-------------------------------------------------------------------------
 */
unsigned
test_write_read_nonacc_front(H5F_t *f)
{
    int  i = 0;
    int *write_buf, *read_buf;

    TESTING("simple write/read to/from before metadata accumulator");

    /* Allocate buffers */
    write_buf = (int *)malloc(2048 * sizeof(int));
    assert(write_buf);
    read_buf = (int *)calloc((size_t)2048, sizeof(int));
    assert(read_buf);

    /* Fill buffer with data, zero out read buffer */
    for (i = 0; i < 2048; i++)
        write_buf[i] = i + 1;

    /* Do a simple write/read/verify of data */
    /* Write 1KB at Address 0 */
    if (accum_write(0, 1024, write_buf) < 0)
        FAIL_STACK_ERROR;
    if (accum_flush(f) < 0)
        FAIL_STACK_ERROR;
    if (accum_reset(f) < 0)
        FAIL_STACK_ERROR;
    if (accum_write(1024, 1024, write_buf) < 0)
        FAIL_STACK_ERROR;
    if (accum_read(0, 1024, read_buf) < 0)
        FAIL_STACK_ERROR;
    if (memcmp(write_buf, read_buf, (size_t)1024) != 0)
        TEST_ERROR;

    if (accum_reset(f) < 0)
        FAIL_STACK_ERROR;

    PASSED();

    /* Release memory */
    free(write_buf);
    free(read_buf);

    return 0;

error:
    /* Release memory */
    free(write_buf);
    free(read_buf);

    return 1;
} /* test_write_read */

/*-------------------------------------------------------------------------
 * Function:    test_write_read_nonacc_end
 *
 * Purpose:     Simple test to write to then read from after metadata accumulator.
 *
 * Return:      Success: SUCCEED
 *              Failure: FAIL
 *
 *-------------------------------------------------------------------------
 */
unsigned
test_write_read_nonacc_end(H5F_t *f)
{
    int  i = 0;
    int *write_buf, *read_buf;

    TESTING("simple write/read to/from after metadata accumulator");

    /* Allocate buffers */
    write_buf = (int *)malloc(2048 * sizeof(int));
    assert(write_buf);
    read_buf = (int *)calloc((size_t)2048, sizeof(int));
    assert(read_buf);

    /* Fill buffer with data, zero out read buffer */
    for (i = 0; i < 2048; i++)
        write_buf[i] = i + 1;

    /* Do a simple write/read/verify of data */
    /* Write 1KB at Address 0 */
    if (accum_write(1024, 1024, write_buf) < 0)
        FAIL_STACK_ERROR;
    if (accum_flush(f) < 0)
        FAIL_STACK_ERROR;
    if (accum_reset(f) < 0)
        FAIL_STACK_ERROR;
    if (accum_write(0, 1024, write_buf) < 0)
        FAIL_STACK_ERROR;
    if (accum_read(1024, 1024, read_buf) < 0)
        FAIL_STACK_ERROR;
    if (memcmp(write_buf, read_buf, (size_t)1024) != 0)
        TEST_ERROR;

    if (accum_reset(f) < 0)
        FAIL_STACK_ERROR;

    PASSED();

    /* Release memory */
    free(write_buf);
    free(read_buf);

    return 0;

error:
    /* Release memory */
    free(write_buf);
    free(read_buf);

    return 1;
} /* test_write_read */

/*-------------------------------------------------------------------------
 * Function:    test_free
 *
 * Purpose:     Simple test to free metadata accumulator.
 *
 * Return:      Success: SUCCEED
 *              Failure: FAIL
 *
 *-------------------------------------------------------------------------
 */
unsigned
test_free(H5F_t *f)
{
    int      i      = 0;
    int32_t *wbuf   = NULL;
    int32_t *rbuf   = NULL;
    int32_t *expect = NULL;

    TESTING("simple freeing metadata accumulator");

    /* Write and free the whole accumulator. */
    wbuf = (int32_t *)malloc(256 * sizeof(int32_t));
    assert(wbuf);
    rbuf = (int32_t *)malloc(256 * sizeof(int32_t));
    assert(rbuf);
    expect = (int32_t *)malloc(256 * sizeof(int32_t));
    assert(expect);

    /* Fill buffer with data */
    for (i = 0; i < 256; i++)
        wbuf[i] = (int32_t)(i + 1);

    if (accum_write(0, 256 * sizeof(int32_t), wbuf) < 0)
        FAIL_STACK_ERROR;

    if (accum_free(f, 0, 256 * sizeof(int32_t)) < 0)
        FAIL_STACK_ERROR;

    /* Free an empty accumulator */
    if (accum_free(f, 0, 256 * 1024 * sizeof(int32_t)) < 0)
        FAIL_STACK_ERROR;

    /* Write second quarter of the accumulator */
    if (accum_write(64 * sizeof(int32_t), 64 * sizeof(int32_t), wbuf) < 0)
        FAIL_STACK_ERROR;

    /* Free the second quarter of the accumulator, the requested area
     * is bigger than the data region on the right side. */
    if (accum_free(f, 64 * sizeof(int32_t), 65 * sizeof(int32_t)) < 0)
        FAIL_STACK_ERROR;

    /* Write half of the accumulator. */
    if (accum_write(0, 128 * sizeof(int32_t), wbuf) < 0)
        FAIL_STACK_ERROR;

    /* Free the first block of 4B */
    if (accum_free(f, 0, sizeof(int32_t)) < 0)
        FAIL_STACK_ERROR;

    /* Check that the accumulator still contains the correct data */
    if (accum_read(1 * sizeof(int32_t), 127 * sizeof(int32_t), rbuf) < 0)
        FAIL_STACK_ERROR;
    if (memcmp(wbuf + 1, rbuf, 127 * sizeof(int32_t)) != 0)
        TEST_ERROR;

    /* Free the block of 4B at 127*4B */
    if (accum_free(f, 127 * sizeof(int32_t), sizeof(int32_t)) < 0)
        FAIL_STACK_ERROR;

    /* Check that the accumulator still contains the correct data */
    if (accum_read(1 * sizeof(int32_t), 126 * sizeof(int32_t), rbuf) < 0)
        FAIL_STACK_ERROR;
    if (memcmp(wbuf + 1, rbuf, 126 * sizeof(int32_t)) != 0)
        TEST_ERROR;

    /* Free the block of 4B at 2*4B */
    if (accum_free(f, 2 * sizeof(int32_t), sizeof(int32_t)) < 0)
        FAIL_STACK_ERROR;

    /* Check that the accumulator still contains the correct data */
    if (accum_read(1 * sizeof(int32_t), 1 * sizeof(int32_t), rbuf) < 0)
        FAIL_STACK_ERROR;
    if (memcmp(wbuf + 1, rbuf, 1 * sizeof(int32_t)) != 0)
        TEST_ERROR;
    if (accum_read(3 * sizeof(int32_t), 124 * sizeof(int32_t), rbuf) < 0)
        FAIL_STACK_ERROR;
    if (memcmp(wbuf + 3, rbuf, 124 * sizeof(int32_t)) != 0)
        TEST_ERROR;

    /* Test freeing section that overlaps the start of the accumulator and is
     * entirely before dirty section */
    if (accum_write(64 * sizeof(int32_t), 128 * sizeof(int32_t), wbuf) < 0)
        FAIL_STACK_ERROR;
    memcpy(expect + 64, wbuf, 128 * sizeof(int32_t));
    if (accum_flush(f) < 0)
        FAIL_STACK_ERROR;
    if (accum_write(68 * sizeof(int32_t), 4 * sizeof(int32_t), wbuf) < 0)
        FAIL_STACK_ERROR;
    memcpy(expect + 68, wbuf, 4 * sizeof(int32_t));
    if (accum_free(f, 62 * sizeof(int32_t), 4 * sizeof(int32_t)) < 0)
        FAIL_STACK_ERROR;

    /* Check that the accumulator still contains the correct data */
    if (accum_read(66 * sizeof(int32_t), 126 * sizeof(int32_t), rbuf) < 0)
        FAIL_STACK_ERROR;
    if (memcmp(expect + 66, rbuf, 126 * sizeof(int32_t)) != 0)
        TEST_ERROR;

    /* Test freeing section that overlaps the start of the accumulator and
     * completely contains dirty section */
    if (accum_write(64 * sizeof(int32_t), 128 * sizeof(int32_t), wbuf) < 0)
        FAIL_STACK_ERROR;
    memcpy(expect + 64, wbuf, 128 * sizeof(int32_t));
    if (accum_flush(f) < 0)
        FAIL_STACK_ERROR;
    if (accum_write(68 * sizeof(int32_t), 4 * sizeof(int32_t), wbuf) < 0)
        FAIL_STACK_ERROR;
    memcpy(expect + 68, wbuf, 4 * sizeof(int32_t));
    if (accum_free(f, 62 * sizeof(int32_t), 16 * sizeof(int32_t)) < 0)
        FAIL_STACK_ERROR;

    /* Check that the accumulator still contains the correct data */
    if (accum_read(78 * sizeof(int32_t), 114 * sizeof(int32_t), rbuf) < 0)
        FAIL_STACK_ERROR;
    if (memcmp(expect + 78, rbuf, 114 * sizeof(int32_t)) != 0)
        TEST_ERROR;

    /* Test freeing section completely contained in accumulator and is entirely
     * before dirty section */
    if (accum_write(64 * sizeof(int32_t), 128 * sizeof(int32_t), wbuf) < 0)
        FAIL_STACK_ERROR;
    memcpy(expect + 64, wbuf, 128 * sizeof(int32_t));
    if (accum_flush(f) < 0)
        FAIL_STACK_ERROR;
    if (accum_write(72 * sizeof(int32_t), 4 * sizeof(int32_t), wbuf) < 0)
        FAIL_STACK_ERROR;
    memcpy(expect + 72, wbuf, 4 * sizeof(int32_t));
    if (accum_free(f, 66 * sizeof(int32_t), 4 * sizeof(int32_t)) < 0)
        FAIL_STACK_ERROR;

    /* Check that the accumulator still contains the correct data */
    if (accum_read(70 * sizeof(int32_t), 122 * sizeof(int32_t), rbuf) < 0)
        FAIL_STACK_ERROR;
    if (memcmp(expect + 70, rbuf, 122 * sizeof(int32_t)) != 0)
        TEST_ERROR;

    /* Test freeing section completely contained in accumulator, starts before
     * dirty section, and ends in dirty section */
    if (accum_write(64 * sizeof(int32_t), 128 * sizeof(int32_t), wbuf) < 0)
        FAIL_STACK_ERROR;
    memcpy(expect + 64, wbuf, 128 * sizeof(int32_t));
    if (accum_flush(f) < 0)
        FAIL_STACK_ERROR;
    if (accum_write(72 * sizeof(int32_t), 4 * sizeof(int32_t), wbuf) < 0)
        FAIL_STACK_ERROR;
    memcpy(expect + 72, wbuf, 4 * sizeof(int32_t));
    if (accum_free(f, 70 * sizeof(int32_t), 4 * sizeof(int32_t)) < 0)
        FAIL_STACK_ERROR;

    /* Check that the accumulator still contains the correct data */
    if (accum_read(74 * sizeof(int32_t), 118 * sizeof(int32_t), rbuf) < 0)
        FAIL_STACK_ERROR;
    if (memcmp(expect + 74, rbuf, 118 * sizeof(int32_t)) != 0)
        TEST_ERROR;

    /* Test freeing section completely contained in accumulator and completely
     * contains dirty section */
    if (accum_write(64 * sizeof(int32_t), 128 * sizeof(int32_t), wbuf) < 0)
        FAIL_STACK_ERROR;
    memcpy(expect + 64, wbuf, 128 * sizeof(int32_t));
    if (accum_flush(f) < 0)
        FAIL_STACK_ERROR;
    if (accum_write(72 * sizeof(int32_t), 4 * sizeof(int32_t), wbuf) < 0)
        FAIL_STACK_ERROR;
    memcpy(expect + 72, wbuf, 4 * sizeof(int32_t));
    if (accum_free(f, 70 * sizeof(int32_t), 8 * sizeof(int32_t)) < 0)
        FAIL_STACK_ERROR;

    /* Check that the accumulator still contains the correct data */
    if (accum_read(78 * sizeof(int32_t), 114 * sizeof(int32_t), rbuf) < 0)
        FAIL_STACK_ERROR;
    if (memcmp(expect + 78, rbuf, 114 * sizeof(int32_t)) != 0)
        TEST_ERROR;

    /* Test freeing section completely contained in accumulator, starts at start
     * of dirty section, and ends in dirty section */
    if (accum_write(64 * sizeof(int32_t), 128 * sizeof(int32_t), wbuf) < 0)
        FAIL_STACK_ERROR;
    memcpy(expect + 64, wbuf, 128 * sizeof(int32_t));
    if (accum_flush(f) < 0)
        FAIL_STACK_ERROR;
    if (accum_write(72 * sizeof(int32_t), 8 * sizeof(int32_t), wbuf) < 0)
        FAIL_STACK_ERROR;
    memcpy(expect + 72, wbuf, 8 * sizeof(int32_t));
    if (accum_free(f, 72 * sizeof(int32_t), 4 * sizeof(int32_t)) < 0)
        FAIL_STACK_ERROR;

    /* Check that the accumulator still contains the correct data */
    if (accum_read(76 * sizeof(int32_t), 116 * sizeof(int32_t), rbuf) < 0)
        FAIL_STACK_ERROR;
    if (memcmp(expect + 76, rbuf, 116 * sizeof(int32_t)) != 0)
        TEST_ERROR;

    free(wbuf);
    wbuf = NULL;
    free(rbuf);
    rbuf = NULL;
    free(expect);
    expect = NULL;

    if (accum_reset(f) < 0)
        FAIL_STACK_ERROR;

    PASSED();

    return 0;

error:
    if (wbuf)
        free(wbuf);
    if (rbuf)
        free(rbuf);
    if (expect)
        free(expect);

    return 1;
} /* test_free */

/*-------------------------------------------------------------------------
 * Function:    test_accum_overlap
 *
 * Purpose:     This test will write a series of pieces of data
 *              to the accumulator with the goal of overlapping
 *              the writes in various different ways.
 *
 * Return:      Success: SUCCEED
 *              Failure: FAIL
 *
 *-------------------------------------------------------------------------
 */
unsigned
test_accum_overlap(H5F_t *f)
{
    int      i = 0;
    int32_t *wbuf, *rbuf;

    TESTING("overlapping write to metadata accumulator");

    /* Allocate buffers */
    wbuf = (int32_t *)malloc(4096 * sizeof(int32_t));
    assert(wbuf);
    rbuf = (int32_t *)calloc((size_t)4096, sizeof(int32_t));
    assert(rbuf);

    /* Case 1: No metadata in accumulator */
    /* Write 10 1's at address 40 */
    /* @0:|          1111111111| */
    /* Put some data in the accumulator initially */
    for (i = 0; i < 10; i++)
        wbuf[i] = 1;
    if (accum_write(40, 10 * sizeof(int32_t), wbuf) < 0)
        FAIL_STACK_ERROR;
    if (accum_read(40, 10 * sizeof(int32_t), rbuf) < 0)
        FAIL_STACK_ERROR;
    if (memcmp(wbuf, rbuf, 10 * sizeof(int32_t)) != 0)
        TEST_ERROR;

    /* Case 2: End of new piece aligns with start of accumulated data */
    /* Write 5 2's at address 20 */
    /* @0:|     222221111111111| */
    for (i = 0; i < 5; i++)
        wbuf[i] = 2;
    if (accum_write(20, 5 * sizeof(int32_t), wbuf) < 0)
        FAIL_STACK_ERROR;
    if (accum_read(20, 5 * sizeof(int32_t), rbuf) < 0)
        FAIL_STACK_ERROR;
    if (memcmp(wbuf, rbuf, 5 * sizeof(int32_t)) != 0)
        TEST_ERROR;

    /* Case 3: Start of new piece aligns with start of accumulated data */
    /* Write 3 3's at address 20 */
    /* @0:|     333221111111111| */
    for (i = 0; i < 3; i++)
        wbuf[i] = 3;
    if (accum_write(20, 3 * sizeof(int32_t), wbuf) < 0)
        FAIL_STACK_ERROR;
    if (accum_read(20, 3 * sizeof(int32_t), rbuf) < 0)
        FAIL_STACK_ERROR;
    if (memcmp(wbuf, rbuf, 3 * sizeof(int32_t)) != 0)
        TEST_ERROR;

    /* Case 4: New piece overlaps start of accumulated data */
    /* Write 5 4's at address 8 */
    /* @0:|  444443221111111111| */
    for (i = 0; i < 5; i++)
        wbuf[i] = 4;
    if (accum_write(8, 5 * sizeof(int32_t), wbuf) < 0)
        FAIL_STACK_ERROR;
    if (accum_read(8, 5 * sizeof(int32_t), rbuf) < 0)
        FAIL_STACK_ERROR;
    if (memcmp(wbuf, rbuf, 5 * sizeof(int32_t)) != 0)
        TEST_ERROR;

    /* Case 5: New piece completely within accumulated data */
    /* Write 4 5's at address 48 */
    /* @0:|  444443221155551111| */
    for (i = 0; i < 4; i++)
        wbuf[i] = 5;
    if (accum_write(48, 4 * sizeof(int32_t), wbuf) < 0)
        FAIL_STACK_ERROR;
    if (accum_read(48, 4 * sizeof(int32_t), rbuf) < 0)
        FAIL_STACK_ERROR;
    if (memcmp(wbuf, rbuf, 4 * sizeof(int32_t)) != 0)
        TEST_ERROR;

    /* Case 6: End of new piece aligns with end of accumulated data */
    /* Write 3 6's at address 68 */
    /* @0:|  444443221155551666| */
    for (i = 0; i < 3; i++)
        wbuf[i] = 6;
    if (accum_write(68, 3 * sizeof(int32_t), wbuf) < 0)
        FAIL_STACK_ERROR;
    if (accum_read(68, 3 * sizeof(int32_t), rbuf) < 0)
        FAIL_STACK_ERROR;
    if (memcmp(wbuf, rbuf, 3 * sizeof(int32_t)) != 0)
        TEST_ERROR;

    /* Case 7: New piece overlaps end of accumulated data */
    /* Write 5 7's at address 76 */
    /* @0:|  4444432211555516677777| */
    for (i = 0; i < 5; i++)
        wbuf[i] = 7;
    if (accum_write(76, 5 * sizeof(int32_t), wbuf) < 0)
        FAIL_STACK_ERROR;
    if (accum_read(76, 5 * sizeof(int32_t), rbuf) < 0)
        FAIL_STACK_ERROR;
    if (memcmp(wbuf, rbuf, 5 * sizeof(int32_t)) != 0)
        TEST_ERROR;

    /* Case 8: Start of new piece aligns with end of accumulated data */
    /* Write 3 8's at address 96 */
    /* @0:|  4444432211555516677777888| */
    for (i = 0; i < 3; i++)
        wbuf[i] = 8;
    if (accum_write(96, 3 * sizeof(int32_t), wbuf) < 0)
        FAIL_STACK_ERROR;
    if (accum_read(96, 3 * sizeof(int32_t), rbuf) < 0)
        FAIL_STACK_ERROR;
    if (memcmp(wbuf, rbuf, 3 * sizeof(int32_t)) != 0)
        TEST_ERROR;

    /* Set up expected data buffer and verify contents of
        accumulator as constructed by cases 1-8, above */
    for (i = 0; i < 5; i++)
        wbuf[i] = 4;
    for (i = 5; i < 6; i++)
        wbuf[i] = 3;
    for (i = 6; i < 8; i++)
        wbuf[i] = 2;
    for (i = 8; i < 10; i++)
        wbuf[i] = 1;
    for (i = 10; i < 14; i++)
        wbuf[i] = 5;
    for (i = 14; i < 15; i++)
        wbuf[i] = 1;
    for (i = 15; i < 17; i++)
        wbuf[i] = 6;
    for (i = 17; i < 22; i++)
        wbuf[i] = 7;
    for (i = 22; i < 25; i++)
        wbuf[i] = 8;
    if (accum_read(8, 25 * sizeof(int32_t), rbuf) < 0)
        FAIL_STACK_ERROR;
    if (memcmp(wbuf, rbuf, 25 * sizeof(int32_t)) != 0)
        TEST_ERROR;

    /* Case 9: New piece completely before accumulated data */
    /* Write 1 9 at address 0 */
    /* @0:|9 4444432211555516677777888| */
    for (i = 0; i < 1; i++)
        wbuf[i] = 9;
    if (accum_write(0, 1 * sizeof(int32_t), wbuf) < 0)
        FAIL_STACK_ERROR;
    if (accum_read(0, 1 * sizeof(int32_t), rbuf) < 0)
        FAIL_STACK_ERROR;
    if (memcmp(wbuf, rbuf, 1 * sizeof(int32_t)) != 0)
        TEST_ERROR;

    /* Case 10: New piece completely after accumulated data */
    /* Write 4 3's at address 116 */
    /* @0:|9 4444432211555516677777888  3333| */
    for (i = 0; i < 4; i++)
        wbuf[i] = 3;
    if (accum_write(116, 4 * sizeof(int32_t), wbuf) < 0)
        FAIL_STACK_ERROR;
    if (accum_read(116, 4 * sizeof(int32_t), rbuf) < 0)
        FAIL_STACK_ERROR;
    if (memcmp(wbuf, rbuf, 4 * sizeof(int32_t)) != 0)
        TEST_ERROR;

    /* Case 11: New piece completely overlaps accumulated data */
    /* Write 6 4's at address 112 */
    /* @0:|9 4444432211555516677777888 444444| */
    for (i = 0; i < 6; i++)
        wbuf[i] = 4;
    if (accum_write(112, 6 * sizeof(int32_t), wbuf) < 0)
        FAIL_STACK_ERROR;
    if (accum_read(112, 6 * sizeof(int32_t), rbuf) < 0)
        FAIL_STACK_ERROR;
    if (memcmp(wbuf, rbuf, 6 * sizeof(int32_t)) != 0)
        TEST_ERROR;

    if (accum_reset(f) < 0)
        FAIL_STACK_ERROR;

    PASSED();

    /* Release memory */
    free(wbuf);
    free(rbuf);

    return 0;

error:
    /* Release memory */
    free(wbuf);
    free(rbuf);

    return 1;
} /* test_accum_overlap */

/*-------------------------------------------------------------------------
 * Function:    test_accum_overlap_clean
 *
 * Purpose:     This test will write a series of pieces of data
 *              to the accumulator with the goal of overlapping
 *              the writes in various different ways, with clean
 *              areas in the accumulator.
 *
 * Return:      Success: SUCCEED
 *              Failure: FAIL
 *
 *-------------------------------------------------------------------------
 */
unsigned
test_accum_overlap_clean(H5F_t *f)
{
    int      i = 0;
    int32_t *wbuf, *rbuf;

    TESTING("overlapping write to partially clean metadata accumulator");

    /* Allocate buffers */
    wbuf = (int32_t *)malloc(4096 * sizeof(int32_t));
    assert(wbuf);
    rbuf = (int32_t *)calloc((size_t)4096, sizeof(int32_t));
    assert(rbuf);

    /* Case 1: No metadata in accumulator */
    /* Write 10 1's at address 40 */
    /* @0:|          1111111111| */
    /* Put some data in the accumulator initially */
    for (i = 0; i < 10; i++)
        wbuf[i] = 1;
    if (accum_write(40, 10 * sizeof(int32_t), wbuf) < 0)
        FAIL_STACK_ERROR;
    if (accum_read(40, 10 * sizeof(int32_t), rbuf) < 0)
        FAIL_STACK_ERROR;
    if (memcmp(wbuf, rbuf, 10 * sizeof(int32_t)) != 0)
        TEST_ERROR;

    /* Case 2: End of new piece aligns with start of clean accumulated data */
    /* Write 5 2's at address 20 */
    /* @0:|     222221111111111| */
    if (accum_flush(f) < 0)
        FAIL_STACK_ERROR;
    for (i = 0; i < 5; i++)
        wbuf[i] = 2;
    if (accum_write(20, 5 * sizeof(int32_t), wbuf) < 0)
        FAIL_STACK_ERROR;
    if (accum_read(20, 5 * sizeof(int32_t), rbuf) < 0)
        FAIL_STACK_ERROR;
    if (memcmp(wbuf, rbuf, 5 * sizeof(int32_t)) != 0)
        TEST_ERROR;

    /* Case 3: Start of new piece aligns with start of accumulated data,
     * completely encloses dirty section of accumulator */
    /* Write 6 3's at address 20 */
    /* @0:|  333333111111111| */
    for (i = 0; i < 6; i++)
        wbuf[i] = 3;
    if (accum_write(20, 6 * sizeof(int32_t), wbuf) < 0)
        FAIL_STACK_ERROR;
    if (accum_read(20, 6 * sizeof(int32_t), rbuf) < 0)
        FAIL_STACK_ERROR;
    if (memcmp(wbuf, rbuf, 6 * sizeof(int32_t)) != 0)
        TEST_ERROR;

    /* Case 4: New piece completely within accumulated data, overlaps
     * end of dirty section of accumulator */
    /* Write 2 4's at address 40 */
    /* @0:|  333334411111111| */
    for (i = 0; i < 2; i++)
        wbuf[i] = 4;
    if (accum_write(40, 2 * sizeof(int32_t), wbuf) < 0)
        FAIL_STACK_ERROR;
    if (accum_read(40, 2 * sizeof(int32_t), rbuf) < 0)
        FAIL_STACK_ERROR;
    if (memcmp(wbuf, rbuf, 2 * sizeof(int32_t)) != 0)
        TEST_ERROR;

    /* Case 5: New piece completely within accumulated data, completely
     * after dirty section of accumulator */
    /* Write 2 5's at address 52 */
    /* @0:|  333334415511111| */
    for (i = 0; i < 2; i++)
        wbuf[i] = 5;
    if (accum_write(52, 2 * sizeof(int32_t), wbuf) < 0)
        FAIL_STACK_ERROR;
    if (accum_read(52, 2 * sizeof(int32_t), rbuf) < 0)
        FAIL_STACK_ERROR;
    if (memcmp(wbuf, rbuf, 2 * sizeof(int32_t)) != 0)
        TEST_ERROR;

    /* Case 6: New piece completely within clean accumulated data */
    /* Write 3 6's at address 44 */
    /* @0:|  333334666511111| */
    if (accum_flush(f) < 0)
        FAIL_STACK_ERROR;
    for (i = 0; i < 3; i++)
        wbuf[i] = 6;
    if (accum_write(44, 3 * sizeof(int32_t), wbuf) < 0)
        FAIL_STACK_ERROR;
    if (accum_read(44, 3 * sizeof(int32_t), rbuf) < 0)
        FAIL_STACK_ERROR;
    if (memcmp(wbuf, rbuf, 3 * sizeof(int32_t)) != 0)
        TEST_ERROR;

    /* Case 7: New piece overlaps start of clean accumulated data */
    /* Write 2 7's at address 16 */
    /* @0:|  7733334666511111| */
    if (accum_flush(f) < 0)
        FAIL_STACK_ERROR;
    for (i = 0; i < 2; i++)
        wbuf[i] = 7;
    if (accum_write(16, 2 * sizeof(int32_t), wbuf) < 0)
        FAIL_STACK_ERROR;
    if (accum_read(16, 2 * sizeof(int32_t), rbuf) < 0)
        FAIL_STACK_ERROR;
    if (memcmp(wbuf, rbuf, 2 * sizeof(int32_t)) != 0)
        TEST_ERROR;

    /* Case 8: New piece overlaps start of accumulated data, completely
     * encloses dirty section of accumulator */
    /* Write 4 8's at address 12 */
    /* @0:|  88883334666511111| */
    for (i = 0; i < 4; i++)
        wbuf[i] = 8;
    if (accum_write(12, 4 * sizeof(int32_t), wbuf) < 0)
        FAIL_STACK_ERROR;
    if (accum_read(12, 4 * sizeof(int32_t), rbuf) < 0)
        FAIL_STACK_ERROR;
    if (memcmp(wbuf, rbuf, 4 * sizeof(int32_t)) != 0)
        TEST_ERROR;

    /* Case 9: Start of new piece aligns with end of clean accumulated data */
    /* Write 3 9's at address 80 */
    /* @0:|  88883334666511111999| */
    if (accum_flush(f) < 0)
        FAIL_STACK_ERROR;
    for (i = 0; i < 3; i++)
        wbuf[i] = 9;
    if (accum_write(80, 3 * sizeof(int32_t), wbuf) < 0)
        FAIL_STACK_ERROR;
    if (accum_read(80, 3 * sizeof(int32_t), rbuf) < 0)
        FAIL_STACK_ERROR;
    if (memcmp(wbuf, rbuf, 3 * sizeof(int32_t)) != 0)
        TEST_ERROR;

    /* Case 10: New piece overlaps end of clean accumulated data */
    /* Write 3 2's at address 88 */
    /* @0:|  888833346665111119922| */
    if (accum_flush(f) < 0)
        FAIL_STACK_ERROR;
    for (i = 0; i < 2; i++)
        wbuf[i] = 2;
    if (accum_write(88, 2 * sizeof(int32_t), wbuf) < 0)
        FAIL_STACK_ERROR;
    if (accum_read(88, 2 * sizeof(int32_t), rbuf) < 0)
        FAIL_STACK_ERROR;
    if (memcmp(wbuf, rbuf, 2 * sizeof(int32_t)) != 0)
        TEST_ERROR;

    /* Case 11: New piece overlaps end of accumulated data, completely encloses
     * dirty section of accumulator */
    /* Write 4 7's at address 84 */
    /* @0:|  8888333466651111197777| */
    for (i = 0; i < 4; i++)
        wbuf[i] = 7;
    if (accum_write(84, 4 * sizeof(int32_t), wbuf) < 0)
        FAIL_STACK_ERROR;
    if (accum_read(84, 4 * sizeof(int32_t), rbuf) < 0)
        FAIL_STACK_ERROR;
    if (memcmp(wbuf, rbuf, 4 * sizeof(int32_t)) != 0)
        TEST_ERROR;

    /* Set up expected data buffer and verify contents of
        accumulator as constructed by cases 1-11, above */
    for (i = 0; i < 4; i++)
        wbuf[i] = 8;
    for (i = 4; i < 7; i++)
        wbuf[i] = 3;
    for (i = 7; i < 8; i++)
        wbuf[i] = 4;
    for (i = 8; i < 11; i++)
        wbuf[i] = 6;
    for (i = 11; i < 12; i++)
        wbuf[i] = 5;
    for (i = 12; i < 17; i++)
        wbuf[i] = 1;
    for (i = 17; i < 18; i++)
        wbuf[i] = 9;
    for (i = 18; i < 22; i++)
        wbuf[i] = 7;
    if (accum_read(12, 22 * sizeof(int32_t), rbuf) < 0)
        FAIL_STACK_ERROR;
    if (memcmp(wbuf, rbuf, 22 * sizeof(int32_t)) != 0)
        TEST_ERROR;

    if (accum_reset(f) < 0)
        FAIL_STACK_ERROR;

    PASSED();

    /* Release memory */
    free(wbuf);
    free(rbuf);

    return 0;

error:
    /* Release memory */
    free(wbuf);
    free(rbuf);

    return 1;
} /* test_accum_overlap_clean */

/*-------------------------------------------------------------------------
 * Function:    test_accum_non_overlap_size
 *
 * Purpose:     This test will write a series of pieces of data
 *              to the accumulator with the goal of not overlapping
 *              the writes with a data size larger then the accum size.
 *
 * Return:      Success: SUCCEED
 *              Failure: FAIL
 *
 *-------------------------------------------------------------------------
 */
unsigned
test_accum_non_overlap_size(H5F_t *f)
{
    int      i = 0;
    int32_t *wbuf, *rbuf;

    TESTING("non-overlapping write to accumulator larger then accum_size");

    /* Allocate buffers */
    wbuf = (int *)malloc(4096 * sizeof(int32_t));
    assert(wbuf);
    rbuf = (int *)calloc((size_t)4096, sizeof(int32_t));
    assert(rbuf);

    /* Case 1: No metadata in accumulator */
    /* Write 10 1's at address 140 */
    /* @0:|     1111111111| */
    /* Put some data in the accumulator initially */
    for (i = 0; i < 10; i++)
        wbuf[i] = 1;
    if (accum_write(140, 10 * sizeof(int32_t), wbuf) < 0)
        FAIL_STACK_ERROR;
    if (accum_read(140, 10 * sizeof(int32_t), rbuf) < 0)
        FAIL_STACK_ERROR;
    if (memcmp(wbuf, rbuf, 10 * sizeof(int32_t)) != 0)
        TEST_ERROR;

    /* Case 9: New piece completely before accumulated data */
    /* Write 20 9 at address 0 */
    /* @0:|9   1111111111| */
    for (i = 0; i < 20; i++)
        wbuf[i] = 9;
    if (accum_write(0, 20 * sizeof(int32_t), wbuf) < 0)
        FAIL_STACK_ERROR;
    if (accum_read(0, 20 * sizeof(int32_t), rbuf) < 0)
        FAIL_STACK_ERROR;
    if (memcmp(wbuf, rbuf, 20 * sizeof(int32_t)) != 0)
        TEST_ERROR;

    if (accum_reset(f) < 0)
        FAIL_STACK_ERROR;

    PASSED();

    /* Release memory */
    free(wbuf);
    free(rbuf);

    return 0;

error:
    /* Release memory */
    free(wbuf);
    free(rbuf);

    return 1;
} /* test_accum_non_overlap_size */

/*-------------------------------------------------------------------------
 * Function:    test_accum_overlap_size
 *
 * Purpose:     This test will write a series of pieces of data
 *              to the accumulator with the goal of overlapping
 *              the writes with a data size completely overlapping
 *              the accumulator at both ends.
 *
 * Return:      Success: SUCCEED
 *              Failure: FAIL
 *
 *-------------------------------------------------------------------------
 */
unsigned
test_accum_overlap_size(H5F_t *f)
{
    int      i = 0;
    int32_t *wbuf, *rbuf;

    TESTING("overlapping write to accumulator larger then accum_size");

    /* Allocate buffers */
    wbuf = (int32_t *)malloc(4096 * sizeof(int32_t));
    assert(wbuf);
    rbuf = (int32_t *)calloc((size_t)4096, sizeof(int32_t));
    assert(rbuf);

    /* Case 1: No metadata in accumulator */
    /* Write 10 1's at address 64 */
    /* @0:|     1111111111| */
    /* Put some data in the accumulator initially */
    for (i = 0; i < 10; i++)
        wbuf[i] = 1;
    if (accum_write(64, 10 * sizeof(int32_t), wbuf) < 0)
        FAIL_STACK_ERROR;
    if (accum_read(64, 10 * sizeof(int32_t), rbuf) < 0)
        FAIL_STACK_ERROR;
    if (memcmp(wbuf, rbuf, 10 * sizeof(int32_t)) != 0)
        TEST_ERROR;

    /* Case 9: New piece completely before accumulated data */
    /* Write 72 9 at address 60  */
    /* @0:|9   1111111111| */
    for (i = 0; i < 72; i++)
        wbuf[i] = 9;
    if (accum_write(60, 72 * sizeof(int32_t), wbuf) < 0)
        FAIL_STACK_ERROR;
    if (accum_read(60, 72 * sizeof(int32_t), rbuf) < 0)
        FAIL_STACK_ERROR;
    if (memcmp(wbuf, rbuf, 72 * sizeof(int32_t)) != 0)
        TEST_ERROR;

    if (accum_reset(f) < 0)
        FAIL_STACK_ERROR;

    PASSED();

    /* Release memory */
    free(wbuf);
    free(rbuf);

    return 0;

error:
    /* Release memory */
    free(wbuf);
    free(rbuf);

    return 1;
} /* test_accum_overlap_size */

/*-------------------------------------------------------------------------
 * Function:    test_accum_adjust
 *
 * Purpose:     This test examines the various ways the accumulator might
 *              adjust itself as a result of data appending or prepending
 *              to it.
 *
 *              This test program covers all the code in H5F_accum_adjust,
 *              but NOT all possible paths through said code. It only covers
 *              six potential paths through the function. (Again, though, each
 *              piece of code within an if/else statement in H5F_accum_adjust is
 *              covered by one of the paths in this test function). Since there
 *              are a ridiculous number of total possible paths through this
 *              function due to its large number of embedded if/else statements,
 *              that's certainly a lot of different test cases to write by hand.
 *              (Though if someone comes across this code and has some free
 *              time, go for it).
 *
 * Return:      Success: SUCCEED
 *              Failure: FAIL
 *
 *-------------------------------------------------------------------------
 */
unsigned
test_accum_adjust(H5F_t *f)
{
    int      i = 0;
    int      s = 1048576; /* size of buffer */
    int32_t *wbuf, *rbuf;

    TESTING("accumulator adjustments after append/prepend of data");

    /* Allocate buffers */
    wbuf = (int32_t *)malloc((size_t)s * sizeof(int32_t));
    assert(wbuf);
    rbuf = (int32_t *)calloc((size_t)s, sizeof(int32_t));
    assert(rbuf);

    /* Fill up write buffer */
    for (i = 0; i < s; i++)
        wbuf[i] = i + 1;

    /* ================================================================ */
    /* CASE 1: Prepending small block to large, fully dirty accumulator */
    /* ================================================================ */

    /* Write data to the accumulator to fill it just under 1MB (max size),
     * but not quite full. This will force the accumulator to, on subsequent
     * writes, a) have to adjust since it's nearly full, and b) prevent
     * an increase in size because it's already at it's maximum size */
    if (accum_write((1024 * 1024), (1024 * 1024) - 1, wbuf) < 0)
        FAIL_STACK_ERROR;

    /* Write a small (1KB) block that prepends to the front of the accumulator. */
    /* ==> Accumulator will need more buffer space */
    /* ==> Accumulator will try to resize, but see that it's getting too big */
    /* ==> Size of new block is less than half maximum size of accumulator */
    /* ==> New block is being prepended to accumulator */
    /* ==> Accumulator is dirty, it will be flushed. */
    /* ==> Dirty region overlaps region to eliminate from accumulator */
    if (accum_write((1024 * 1024) - 1024, 1024, wbuf) < 0)
        FAIL_STACK_ERROR;

    /* Read back and verify first write */
    if (accum_read((1024 * 1024), (1024 * 1024) - 1, rbuf) < 0)
        FAIL_STACK_ERROR;
    if (memcmp(wbuf, rbuf, (size_t)((1024 * 1024) - 1)) != 0)
        TEST_ERROR;

    /* Read back and verify second write */
    if (accum_read((1024 * 1024) - 1024, 1024, rbuf) < 0)
        FAIL_STACK_ERROR;
    if (memcmp(wbuf, rbuf, (size_t)1024) != 0)
        TEST_ERROR;

    /* Reset accumulator for next case */
    if (accum_reset(f) < 0)
        FAIL_STACK_ERROR;

    /* ================================================================ */
    /* Case 2: Prepending large block to large, fully dirty accumulator */
    /* ================================================================ */

    /* Write data to the accumulator to fill it just under 1MB (max size),
     * but not quite full. This will force the accumulator to, on subsequent
     * writes, a) have to adjust since it's nearly full, and b) prevent
     * an increase in size because it's already at it's maximum size */
    if (accum_write((1024 * 1024), (1024 * 1024) - 1, wbuf) < 0)
        FAIL_STACK_ERROR;

    /* Write a large (just under 1MB) block to the front of the accumulator. */
    /* ==> Accumulator will need more buffer space */
    /* ==> Accumulator will try to resize, but see that it's getting too big */
    /* ==> Size of new block is larger than half maximum size of accumulator */
    /* ==> New block is being prepended to accumulator */
    /* ==> Accumulator is dirty, it will be flushed. */
    /* ==> Dirty region overlaps region to eliminate from accumulator */
    if (accum_write(5, (1024 * 1024) - 5, wbuf) < 0)
        FAIL_STACK_ERROR;

    /* Read back and verify both pieces of data */
    if (accum_read(1048576, 1048575, rbuf) < 0)
        FAIL_STACK_ERROR;
    if (memcmp(wbuf, rbuf, (size_t)1048576) != 0)
        TEST_ERROR;

    if (accum_read(5, 1048571, rbuf) < 0)
        FAIL_STACK_ERROR;
    if (memcmp(wbuf, rbuf, (size_t)1048571) != 0)
        TEST_ERROR;

    /* Reset accumulator for next case */
    if (accum_reset(f) < 0)
        FAIL_STACK_ERROR;

    /* ========================================================= */
    /* Case 3: Appending small block to large, clean accumulator */
    /* ========================================================= */

    /* Write data to the accumulator to fill it just under 1MB (max size),
     * but not quite full. This will force the accumulator to, on subsequent
     * writes, a) have to adjust since it's nearly full, and b) prevent
     * an increase in size because it's already at it's maximum size */
    if (accum_write(0, (1024 * 1024) - 1, wbuf) < 0)
        FAIL_STACK_ERROR;

    /* Flush the accumulator -- we want to test the case when
        accumulator contains clean data */
    if (accum_flush(f) < 0)
        FAIL_STACK_ERROR;

    /* Write a small (1KB) block to the end of the accumulator */
    /* ==> Accumulator will need more buffer space */
    /* ==> Accumulator will try to resize, but see that it's getting too big */
    /* ==> Size of new block is larger than half maximum size of accumulator */
    /* ==> New block being appended to accumulator */
    /* ==> Accumulator is NOT dirty */
    /* ==> Since we're appending, need to adjust location of accumulator */
    if (accum_write((1024 * 1024) - 1, 1024, wbuf) < 0)
        FAIL_STACK_ERROR;

    /* Write a piece of metadata outside current accumulator to force write
        to disk */
    if (accum_write(0, 1, wbuf) < 0)
        FAIL_STACK_ERROR;

    /* Read in the piece we wrote to disk above, and then verify that
        the data is as expected */
    if (accum_read((1024 * 1024) - 1, 1024, rbuf) < 0)
        FAIL_STACK_ERROR;
    if (memcmp(wbuf, rbuf, (size_t)1024) != 0)
        TEST_ERROR;

    /* Reset accumulator for next case */
    if (accum_reset(f) < 0)
        FAIL_STACK_ERROR;

    /* ==================================================================== */
    /* Case 4: Appending small block to large, partially dirty accumulator, */
    /*         with existing dirty region NOT aligning with the new block   */
    /* ==================================================================== */

    /* Write data to the accumulator to fill it just under 1MB (max size),
     * but not quite full. This will force the accumulator to, on subsequent
     * writes, a) have to adjust since it's nearly full, and b) prevent
     * an increase in size because it's already at it's maximum size */
    if (accum_write(0, (1024 * 1024) - 5, wbuf) < 0)
        FAIL_STACK_ERROR;

    /* Flush the accumulator to clean it */
    if (accum_flush(f) < 0)
        FAIL_STACK_ERROR;

    /* write to part of the accumulator so just the start of it is dirty */
    if (accum_write(0, 5, wbuf) < 0)
        FAIL_STACK_ERROR;

    /* Write a small (~340KB) piece of data to the other end of the accumulator */
    /* ==> Accumulator will need more buffer space */
    /* ==> Accumulator will try to resize, but see that it's getting too big */
    /* ==> Size of new block is less than than half maximum size of accumulator */
    /* ==> New block being appended to accumulator */
    /* ==> We can slide the dirty region down, to accommodate the request */
    /* ==> Max Buffer Size - (dirty offset + adjust size) >= 2 * size) */
    /* ==> Need to adjust location of accumulator while appending */
    /* ==> Accumulator will need to be reallocated */
    if (accum_write(1048571, 349523, wbuf) < 0)
        FAIL_STACK_ERROR;

    /* Write a piece of metadata outside current accumulator to force write
        to disk */
    if (accum_write(1398900, 1, wbuf) < 0)
        FAIL_STACK_ERROR;

    /* Read in the piece we wrote to disk above, and then verify that
        the data is as expected */
    if (accum_read(1048571, 349523, rbuf) < 0)
        FAIL_STACK_ERROR;
    if (memcmp(wbuf, rbuf, (size_t)349523) != 0)
        TEST_ERROR;

    /* Reset accumulator for next case */
    if (accum_reset(f) < 0)
        FAIL_STACK_ERROR;

    /* ==================================================================== */
    /* Case 5: Appending small block to large, partially dirty accumulator, */
    /*         with existing dirty region aligning with new block           */
    /* ==================================================================== */

    /* Write data to the accumulator to fill it just under max size (but not full) */
    if (accum_write(0, (1024 * 1024) - 5, wbuf) < 0)
        FAIL_STACK_ERROR;

    /* Flush the accumulator to clean it */
    if (accum_flush(f) < 0)
        FAIL_STACK_ERROR;

    /* write to part of the accumulator so it's dirty, but not entirely dirty */
    /* (just the begging few bytes will be clean) */
    if (accum_write(10, (1024 * 1024) - 15, wbuf) < 0)
        FAIL_STACK_ERROR;

    /* Write a small piece of data to the dirty end of the accumulator */
    /* ==> Accumulator will need more buffer space */
    /* ==> Accumulator will try to resize, but see that it's getting too big */
    /* ==> Size of new block is less than than half maximum size of accumulator */
    /* ==> New block being appended to accumulator */
    /* ==> We can slide the dirty region down, to accommodate the request */
    /* ==> Max Buffer Size - (dirty offset + adjust size) < 2 * size) */
    /* ==> Need to adjust location of accumulator while appending */
    if (accum_write((1024 * 1024) - 5, 10, wbuf) < 0)
        FAIL_STACK_ERROR;

    /* Write a piece of metadata outside current accumulator to force write
        to disk */
    if (accum_write(0, 1, wbuf) < 0)
        FAIL_STACK_ERROR;

    /* Read in the piece we wrote to disk above, and then verify that
        the data is as expected */
    if (accum_read((1024 * 1024) - 5, 10, rbuf) < 0)
        FAIL_STACK_ERROR;
    if (memcmp(wbuf, rbuf, (size_t)10) != 0)
        TEST_ERROR;

    /* Reset accumulator for next case */
    if (accum_reset(f) < 0)
        FAIL_STACK_ERROR;

    /* ================================================================= */
    /* Case 6: Appending small block to large, fully dirty accumulator   */
    /* ================================================================= */

    /* Write data to the accumulator to fill it just under 1MB (max size),
     * but not quite full. This will force the accumulator to, on subsequent
     * writes, a) have to adjust since it's nearly full, and b) prevent
     * an increase in size because it's already at it's maximum size */
    if (accum_write(0, (1024 * 1024) - 5, wbuf) < 0)
        FAIL_STACK_ERROR;

    /* Write a small (~340KB) piece of data to the end of the accumulator */
    /* ==> Accumulator will need more buffer space */
    /* ==> Accumulator will try to resize, but see that it's getting too big */
    /* ==> Size of new block is less than than half maximum size of accumulator */
    /* ==> New block being appended to accumulator */
    /* ==> We cannot slide dirty region down, it's all dirty */
    /* ==> Dirty region overlaps region to eliminate from accumulator */
    /* ==> Need to adjust location of accumulator while appending */
    if (accum_write(1048571, 349523, wbuf) < 0)
        FAIL_STACK_ERROR;

    /* Write a piece of metadata outside current accumulator to force write
        to disk */
    if (accum_write(1398900, 1, wbuf) < 0)
        FAIL_STACK_ERROR;

    /* Read in the piece we wrote to disk above, and then verify that
        the data is as expected */
    if (accum_read(1048571, 349523, rbuf) < 0)
        FAIL_STACK_ERROR;
    if (memcmp(wbuf, rbuf, (size_t)349523) != 0)
        TEST_ERROR;

    if (accum_reset(f) < 0)
        FAIL_STACK_ERROR;

    PASSED();

    /* Release memory */
    free(wbuf);
    free(rbuf);

    return 0;

error:
    /* Release memory */
    free(wbuf);
    free(rbuf);

    return 1;
} /* test_accum_adjust */

/*-------------------------------------------------------------------------
 * Function:    test_read_after
 *
 * Purpose:     This test will verify the case when metadata is read partly
 *              from the accumulator and partly from disk.  The test will
 *              write a block of data at address 512, force the data to be
 *              written to disk, write new data partially overlapping the
 *              original block from below, then read data at address 512.
 *              The data read should be partly new and partly original.
 *
 * Return:      Success: SUCCEED
 *              Failure: FAIL
 *
 *-------------------------------------------------------------------------
 */
unsigned
test_read_after(H5F_t *f)
{
    int      i = 0;
    int      s = 128; /* size of buffer */
    int32_t *wbuf, *rbuf;

    TESTING("reading data from both accumulator and disk");

    /* Allocate buffers */
    wbuf = (int32_t *)malloc((size_t)s * sizeof(int32_t));
    assert(wbuf);
    rbuf = (int32_t *)calloc((size_t)s, sizeof(int32_t));
    assert(rbuf);

    /* Fill up write buffer with 1s */
    for (i = 0; i < s; i++)
        wbuf[i] = 1;

    /* Write data to the accumulator to fill it. */
    if (accum_write(512, 512, wbuf) < 0)
        FAIL_STACK_ERROR;

    /* Write a piece of metadata outside current accumulator to force write
        to disk */
    if (accum_write(0, 1, wbuf) < 0)
        FAIL_STACK_ERROR;

    /* Fill up write buffer with 2s */
    for (i = 0; i < s; i++)
        wbuf[i] = 2;

    /* Write a block of 2s of the original size that will overlap the lower half
        of the original block */
    if (accum_write(256, 512, wbuf) < 0)
        FAIL_STACK_ERROR;

    /* Read 128 bytes at the original address, and then  */
    if (accum_read(512, 512, rbuf) < 0)
        FAIL_STACK_ERROR;

    /* Set the second half of wbuf back to 1s */
    for (i = 64; i < s; i++)
        wbuf[i] = 1;

    /* Read in the piece we wrote to disk above, and then verify that
        the data is as expected */
    if (accum_read(512, 512, rbuf) < 0)
        FAIL_STACK_ERROR;
    if (memcmp(wbuf, rbuf, (size_t)128) != 0)
        TEST_ERROR;

    if (accum_reset(f) < 0)
        FAIL_STACK_ERROR;

    PASSED();

    /* Release memory */
    free(wbuf);
    free(rbuf);

    return 0;

error:
    /* Release memory */
    free(wbuf);
    free(rbuf);

    return 1;
} /* end test_read_after */

/*-------------------------------------------------------------------------
 * Function:    test_big
 *
 * Purpose:     This test exercises writing large pieces of metadata to the
 *		file.
 *
 * Return:      Success: SUCCEED
 *              Failure: FAIL
 *
 *-------------------------------------------------------------------------
 */
unsigned
test_big(H5F_t *f)
{
    uint8_t *wbuf, *wbuf2, *rbuf, *zbuf; /* Buffers for reading & writing, etc */
    unsigned u;                          /* Local index variable */

    /* Allocate space for the write & read buffers */
    wbuf = (uint8_t *)malloc((size_t)BIG_BUF_SIZE);
    assert(wbuf);
    wbuf2 = (uint8_t *)malloc((size_t)BIG_BUF_SIZE);
    assert(wbuf2);
    rbuf = (uint8_t *)calloc((size_t)(BIG_BUF_SIZE + 1536), (size_t)1);
    assert(rbuf);
    zbuf = (uint8_t *)calloc((size_t)(BIG_BUF_SIZE + 1536), (size_t)1);
    assert(zbuf);

    /* Initialize write buffers */
    for (u = 0; u < BIG_BUF_SIZE; u++) {
        wbuf[u]  = (uint8_t)u;
        wbuf2[u] = (uint8_t)(u + 1);
    } /* end for */

    TESTING("large metadata I/O operations");

    /* Write large data segment to file */
    if (accum_write(0, BIG_BUF_SIZE, wbuf) < 0)
        FAIL_STACK_ERROR;

    /* Read entire segment back from file */
    if (accum_read(0, BIG_BUF_SIZE, rbuf) < 0)
        FAIL_STACK_ERROR;

    /* Verify data read */
    if (memcmp(wbuf, rbuf, (size_t)BIG_BUF_SIZE) != 0)
        TEST_ERROR;

    /* Reset data in file back to zeros & reset the read buffer */
    if (accum_write(0, BIG_BUF_SIZE, zbuf) < 0)
        FAIL_STACK_ERROR;
    memset(rbuf, 0, (size_t)BIG_BUF_SIZE);
    if (accum_reset(f) < 0)
        FAIL_STACK_ERROR;

    /* Write small section to middle of accumulator */
    if (accum_write(1024, 1024, wbuf) < 0)
        FAIL_STACK_ERROR;

    /* Read entire segment back from file */
    /* (Read covers entire dirty region) */
    if (accum_read(0, BIG_BUF_SIZE, rbuf) < 0)
        FAIL_STACK_ERROR;

    /* Verify data read */
    if (memcmp(zbuf, rbuf, (size_t)1024) != 0)
        TEST_ERROR;
    if (memcmp(wbuf, rbuf + 1024, (size_t)1024) != 0)
        TEST_ERROR;
    if (memcmp(zbuf, rbuf + 2048, (size_t)(BIG_BUF_SIZE - 2048)) != 0)
        TEST_ERROR;

    /* Reset data in file back to zeros & reset the read buffer */
    if (accum_write(1024, 1024, zbuf) < 0)
        FAIL_STACK_ERROR;
    memset(rbuf, 0, (size_t)BIG_BUF_SIZE);
    if (accum_reset(f) < 0)
        FAIL_STACK_ERROR;

    /* Write small section to overlap with end of "big" region */
    if (accum_write(BIG_BUF_SIZE - 512, 1024, wbuf) < 0)
        FAIL_STACK_ERROR;

    /* Read entire segment back from file */
    /* (Read covers bottom half of dirty region) */
    if (accum_read(0, BIG_BUF_SIZE, rbuf) < 0)
        FAIL_STACK_ERROR;

    /* Verify data read */
    if (memcmp(zbuf, rbuf, (size_t)(BIG_BUF_SIZE - 512)) != 0)
        TEST_ERROR;
    if (memcmp(wbuf, rbuf + (BIG_BUF_SIZE - 512), (size_t)512) != 0)
        TEST_ERROR;

    /* Reset data in file back to zeros & reset the read buffer */
    if (accum_write(BIG_BUF_SIZE - 512, 1024, zbuf) < 0)
        FAIL_STACK_ERROR;
    memset(rbuf, 0, (size_t)BIG_BUF_SIZE);
    if (accum_reset(f) < 0)
        FAIL_STACK_ERROR;

    /* Write small section to overlap with beginning of "big" region */
    if (accum_write(0, 1024, wbuf) < 0)
        FAIL_STACK_ERROR;

    /* Read entire segment back from file */
    /* (Read covers bottom half of dirty region) */
    if (accum_read(512, BIG_BUF_SIZE, rbuf) < 0)
        FAIL_STACK_ERROR;

    /* Verify data read */
    if (memcmp(wbuf + 512, rbuf, (size_t)512) != 0)
        TEST_ERROR;
    if (memcmp(zbuf, rbuf + 512, (size_t)(BIG_BUF_SIZE - 512)) != 0)
        TEST_ERROR;

    /* Reset data in file back to zeros & reset the read buffer */
    if (accum_write(0, 1024, zbuf) < 0)
        FAIL_STACK_ERROR;
    memset(rbuf, 0, (size_t)BIG_BUF_SIZE);
    if (accum_reset(f) < 0)
        FAIL_STACK_ERROR;

    /* Write small section to middle of accumulator */
    /* (With write buffer #1) */
    if (accum_write(1024, 1024, wbuf) < 0)
        FAIL_STACK_ERROR;

    /* Write entire segment to from file */
    /* (With write buffer #2) */
    /* (Write covers entire dirty region) */
    if (accum_write(0, BIG_BUF_SIZE, wbuf2) < 0)
        FAIL_STACK_ERROR;

    /* Read entire segment back from file */
    if (accum_read(0, BIG_BUF_SIZE, rbuf) < 0)
        FAIL_STACK_ERROR;

    /* Verify data read */
    if (memcmp(wbuf2, rbuf, (size_t)BIG_BUF_SIZE) != 0)
        TEST_ERROR;

    /* Reset data in file back to zeros & reset the read buffer */
    if (accum_write(0, BIG_BUF_SIZE, zbuf) < 0)
        FAIL_STACK_ERROR;
    memset(rbuf, 0, (size_t)BIG_BUF_SIZE);
    if (accum_reset(f) < 0)
        FAIL_STACK_ERROR;

    /* Write small section to overlap with end of "big" region */
    /* (With write buffer #1) */
    if (accum_write(BIG_BUF_SIZE - 512, 1024, wbuf) < 0)
        FAIL_STACK_ERROR;

    /* Write entire segment to from file */
    /* (With write buffer #2) */
    /* (Read covers bottom half of dirty region) */
    if (accum_write(0, BIG_BUF_SIZE, wbuf2) < 0)
        FAIL_STACK_ERROR;

    /* Read both segments back from file */
    if (accum_read(0, BIG_BUF_SIZE + 512, rbuf) < 0)
        FAIL_STACK_ERROR;

    /* Verify data read */
    if (memcmp(wbuf2, rbuf, (size_t)BIG_BUF_SIZE) != 0)
        TEST_ERROR;
    if (memcmp(wbuf + 512, rbuf + BIG_BUF_SIZE, (size_t)512) != 0)
        TEST_ERROR;

    /* Reset data in file back to zeros & reset the read buffer */
    if (accum_write(0, BIG_BUF_SIZE + 512, zbuf) < 0)
        FAIL_STACK_ERROR;
    memset(rbuf, 0, (size_t)(BIG_BUF_SIZE + 512));
    if (accum_reset(f) < 0)
        FAIL_STACK_ERROR;

    /* Write small section to be past "big" region */
    /* (With write buffer #1) */
    if (accum_write(BIG_BUF_SIZE + 512, 1024, wbuf) < 0)
        FAIL_STACK_ERROR;

    /* Read section before "big" region */
    /* (To enlarge accumulator, to it will intersect with big write) */
    if (accum_read(BIG_BUF_SIZE - 512, 1024, rbuf) < 0)
        FAIL_STACK_ERROR;

    /* Write entire segment to from file */
    /* (With write buffer #2) */
    /* (Doesn't overlap with small section) */
    if (accum_write(0, BIG_BUF_SIZE, wbuf2) < 0)
        FAIL_STACK_ERROR;

    /* Read both segments & gap back from file */
    if (accum_read(0, BIG_BUF_SIZE + 1024, rbuf) < 0)
        FAIL_STACK_ERROR;

    /* Verify data read */
    if (memcmp(wbuf2, rbuf, (size_t)BIG_BUF_SIZE) != 0)
        TEST_ERROR;
    if (memcmp(zbuf, rbuf + BIG_BUF_SIZE, (size_t)512) != 0)
        TEST_ERROR;
    if (memcmp(wbuf, rbuf + BIG_BUF_SIZE + 512, (size_t)512) != 0)
        TEST_ERROR;

    /* Reset data in file back to zeros & reset the read buffer */
    if (accum_write(0, BIG_BUF_SIZE + 1536, zbuf) < 0)
        FAIL_STACK_ERROR;
    memset(rbuf, 0, (size_t)(BIG_BUF_SIZE + 1024));
    if (accum_reset(f) < 0)
        FAIL_STACK_ERROR;

    /* Write small section to be past "big" region */
    /* (With write buffer #1) */
    if (accum_write(BIG_BUF_SIZE + 512, 1024, wbuf) < 0)
        FAIL_STACK_ERROR;

    /* Read section before "big" region */
    /* (To enlarge accumulator, so it will intersect with big write) */
    if (accum_read(BIG_BUF_SIZE - 512, 1024, rbuf) < 0)
        FAIL_STACK_ERROR;
    if (accum_read(BIG_BUF_SIZE + 1536, 1024, rbuf) < 0)
        FAIL_STACK_ERROR;

    /* Write entire segment to from file */
    /* (With write buffer #2) */
    /* (Overwriting dirty region, but not invalidating entire accumulator) */
    if (accum_write(1536, BIG_BUF_SIZE, wbuf2) < 0)
        FAIL_STACK_ERROR;

    /* Read both segments & gap back from file */
    if (accum_read(0, BIG_BUF_SIZE + 1536, rbuf) < 0)
        FAIL_STACK_ERROR;

    /* Verify data read */
    if (memcmp(zbuf, rbuf, (size_t)1536) != 0)
        TEST_ERROR;
    if (memcmp(wbuf2, rbuf + 1536, (size_t)BIG_BUF_SIZE) != 0)
        TEST_ERROR;

    /* Reset data in file back to zeros & reset the read buffer */
    if (accum_write(1536, BIG_BUF_SIZE, zbuf) < 0)
        FAIL_STACK_ERROR;
    memset(rbuf, 0, (size_t)(BIG_BUF_SIZE + 1536));
    if (accum_reset(f) < 0)
        FAIL_STACK_ERROR;

    /* Write small section before "big" region */
    /* (With write buffer #1) */
    if (accum_write(1024, 1024, wbuf) < 0)
        FAIL_STACK_ERROR;

    /* Read section before "big" region */
    /* (To enlarge accumulator, so it will intersect with big write) */
    if (accum_read(0, 1024, rbuf) < 0)
        FAIL_STACK_ERROR;

    /* Write entire segment to from file */
    /* (With write buffer #2) */
    /* (Overwriting dirty region, but not invalidating entire accumulator) */
    if (accum_write(512, BIG_BUF_SIZE, wbuf2) < 0)
        FAIL_STACK_ERROR;

    /* Read both segments & gap back from file */
    if (accum_read(0, BIG_BUF_SIZE + 512, rbuf) < 0)
        FAIL_STACK_ERROR;

    /* Verify data read */
    if (memcmp(zbuf, rbuf, (size_t)512) != 0)
        TEST_ERROR;
    if (memcmp(wbuf2, rbuf + 512, (size_t)BIG_BUF_SIZE) != 0)
        TEST_ERROR;

    /* Reset data in file back to zeros & reset the read buffer */
    if (accum_write(512, BIG_BUF_SIZE, zbuf) < 0)
        FAIL_STACK_ERROR;
    memset(rbuf, 0, (size_t)(BIG_BUF_SIZE + 512));
    if (accum_reset(f) < 0)
        FAIL_STACK_ERROR;

    /* Write small section before "big" region */
    /* (With write buffer #1) */
    if (accum_write(0, 1024, wbuf) < 0)
        FAIL_STACK_ERROR;

    /* Read section before "big" region */
    /* (To enlarge accumulator, so it will intersect with big write) */
    if (accum_read(1024, 1024, rbuf) < 0)
        FAIL_STACK_ERROR;

    /* Write entire segment to from file */
    /* (With write buffer #2) */
    /* (Avoiding dirty region, and not invalidating entire accumulator) */
    if (accum_write(1536, BIG_BUF_SIZE, wbuf2) < 0)
        FAIL_STACK_ERROR;

    /* Read both segments & gap back from file */
    if (accum_read(0, BIG_BUF_SIZE + 1536, rbuf) < 0)
        FAIL_STACK_ERROR;

    /* Verify data read */
    if (memcmp(wbuf, rbuf, (size_t)1024) != 0)
        TEST_ERROR;
    if (memcmp(zbuf, rbuf + 1024, (size_t)512) != 0)
        TEST_ERROR;
    if (memcmp(wbuf2, rbuf + 1536, (size_t)BIG_BUF_SIZE) != 0)
        TEST_ERROR;

    /* Reset data in file back to zeros & reset the read buffer */
    if (accum_write(0, BIG_BUF_SIZE + 1536, zbuf) < 0)
        FAIL_STACK_ERROR;
    memset(rbuf, 0, (size_t)(BIG_BUF_SIZE + 1536));
    if (accum_reset(f) < 0)
        FAIL_STACK_ERROR;

    /* Write small section before "big" region */
    /* (With write buffer #1) */
    if (accum_write(0, 1024, wbuf) < 0)
        FAIL_STACK_ERROR;

    /* Read section before "big" region */
    /* (To enlarge accumulator, so it will intersect with big write) */
    if (accum_read(1024, 1024, rbuf) < 0)
        FAIL_STACK_ERROR;

    /* Write entire segment to from file */
    /* (With write buffer #2) */
    /* (Partially overwriting dirty region, and not invalidating entire accumulator) */
    if (accum_write(512, BIG_BUF_SIZE, wbuf2) < 0)
        FAIL_STACK_ERROR;

    /* Read both segments back from file */
    if (accum_read(0, BIG_BUF_SIZE + 512, rbuf) < 0)
        FAIL_STACK_ERROR;

    /* Verify data read */
    if (memcmp(wbuf, rbuf, (size_t)512) != 0)
        TEST_ERROR;
    if (memcmp(wbuf2, rbuf + 512, (size_t)BIG_BUF_SIZE) != 0)
        TEST_ERROR;

    if (accum_reset(f) < 0)
        FAIL_STACK_ERROR;

    PASSED();

    /* Release memory */
    free(wbuf);
    free(wbuf2);
    free(rbuf);
    free(zbuf);

    return 0;

error:
    free(wbuf);
    free(wbuf2);
    free(rbuf);
    free(zbuf);

    return 1;
} /* end test_big() */

/*-------------------------------------------------------------------------
 * Function:    test_random_write
 *
 * Purpose:     This test writes random pieces of data to the file and
 *		then reads it all back.
 *
 * Return:      Success: SUCCEED
 *              Failure: FAIL
 *
 *-------------------------------------------------------------------------
 */
unsigned
test_random_write(H5F_t *f)
{
    uint8_t *wbuf, *rbuf; /* Buffers for reading & writing */
    unsigned seed = 0;    /* Random # seed */
    size_t  *off;         /* Offset of buffer segments to write */
    size_t  *len;         /* Size of buffer segments to write */
    size_t   cur_off;     /* Current offset */
    size_t   nsegments;   /* Number of segments to write */
    size_t   swap;        /* Position to swap with */
    unsigned u;           /* Local index variable */

    /* Allocate space for the write & read buffers */
    wbuf = (uint8_t *)malloc((size_t)RANDOM_BUF_SIZE);
    assert(wbuf);
    rbuf = (uint8_t *)calloc((size_t)RANDOM_BUF_SIZE, (size_t)1);
    assert(rbuf);

    /* Initialize write buffer */
    for (u = 0; u < RANDOM_BUF_SIZE; u++)
        wbuf[u] = (uint8_t)u;

    TESTING("random writes to accumulator");

    /* Choose random # seed */
    seed = (unsigned)time(NULL);
#if 0
/* seed = (unsigned)1155438845; */
fprintf(stderr, "Random # seed was: %u\n", seed);
#endif
    srand(seed);

    /* Allocate space for the segment length buffer */
    off = (size_t *)malloc(MAX_RANDOM_SEGMENTS * sizeof(size_t));
    assert(off);
    len = (size_t *)malloc(MAX_RANDOM_SEGMENTS * sizeof(size_t));
    assert(len);

    /* Randomly choose lengths of segments */
    cur_off = 0;
    for (u = 0; u < MAX_RANDOM_SEGMENTS;) {
        size_t length = 0; /* Length of current segment */

        /* Choose random length of segment, allowing for variance */
        do {
            length += (size_t)(rand() % RAND_SEG_LEN) + 1;
        } while ((rand() & 256) >= 128); /* end while */

        /* Check for going off end of buffer */
        if ((cur_off + length) > RANDOM_BUF_SIZE)
            length = RANDOM_BUF_SIZE - cur_off;

        /* Set offset & length of segment */
        off[u] = cur_off;
        len[u] = length;

        /* Advance array offset */
        u++;

        /* Advance current offset */
        cur_off += length;

        /* If we've used up entire buffer before hitting limit of segments, get out */
        if (cur_off >= RANDOM_BUF_SIZE)
            break;
    } /* end for */
    nsegments = u;

    /* Increase length of last segment, if it doesn't reach end of buffer */
    if (nsegments < MAX_RANDOM_SEGMENTS)
        len[nsegments - 1] = RANDOM_BUF_SIZE - off[nsegments - 1];

    /* Shuffle order of segments, to randomize positions to write */
    for (u = 0; u < nsegments; u++) {
        size_t tmp; /* Temporary holder for offset & length values */

        /* Choose value within next few elements to to swap with */
        swap = ((size_t)rand() % 8) + u;
        if (swap >= nsegments)
            swap = nsegments - 1;

        /* Swap values */
        tmp       = off[u];
        off[u]    = off[swap];
        off[swap] = tmp;
        tmp       = len[u];
        len[u]    = len[swap];
        len[swap] = tmp;
    } /* end for */

    /* Write data segments to file */
    for (u = 0; u < nsegments; u++) {
        if (accum_write(RANDOM_BASE_OFF + off[u], len[u], wbuf + off[u]) < 0)
            FAIL_STACK_ERROR;

        /* Verify individual reads */
        if (accum_read(RANDOM_BASE_OFF + off[u], len[u], rbuf) < 0)
            FAIL_STACK_ERROR;
        if (memcmp(wbuf + off[u], rbuf, len[u]) != 0)
            TEST_ERROR;
    } /* end for */

    /* Read entire region back from file */
    if (accum_read(RANDOM_BASE_OFF, RANDOM_BUF_SIZE, rbuf) < 0)
        FAIL_STACK_ERROR;

    /* Verify data read back in */
    if (memcmp(wbuf, rbuf, (size_t)RANDOM_BUF_SIZE) != 0)
        TEST_ERROR;

    if (accum_reset(f) < 0)
        FAIL_STACK_ERROR;

    PASSED();

    /* Release memory */
    free(wbuf);
    free(rbuf);
    free(off);
    free(len);

    return 0;

error:
    /* Release memory */
    free(wbuf);
    free(rbuf);
    free(off);
    free(len);

    fprintf(stderr, "Random # seed was: %u\n", seed);
    return 1;
} /* end test_random_write() */

/*-------------------------------------------------------------------------
 * Function:    test_swmr_write_big
 *
 * Purpose:     A SWMR test: verifies that writing "large" metadata to a file
 *              opened with SWMR_WRITE will flush the existing metadata in the
 *              accumulator to disk first before writing the "large" metadata
 *              to disk.
 *
 *              This test will fork and exec a reader "accum_swmr_reader" which
 *              opens the same file with SWMR_READ and verifies that the correct
 *              metadata is read from disk.
 *
 * Return:      Success: 0
 *              Failure: 1
 *
 *-------------------------------------------------------------------------
 */
unsigned
test_swmr_write_big(bool newest_format)
{
    const char *driver_name = NULL;            /* VFD string (from env variable) */
    hid_t       fid         = H5I_INVALID_HID; /* File ID */
    hid_t       fapl        = H5I_INVALID_HID; /* File access property list */
    H5F_t      *rf          = NULL;            /* File pointer */
    char        filename[1024];
    uint8_t    *wbuf2 = NULL, *rbuf = NULL; /* Buffers for reading & writing */
    uint8_t     wbuf[1024];                 /* Buffer for reading & writing */
    unsigned    u;                          /* Local index variable */
    bool        process_success = false;
    H5CX_node_t api_ctx         = {{0}, NULL}; /* API context node to push */
    bool        api_ctx_pushed  = false;       /* Whether API context pushed */

    if (newest_format)
        TESTING("SWMR write of large metadata: with latest format");
    else
        TESTING("SWMR write of large metadata: with non-latest-format");

#if !defined(H5_HAVE_UNISTD_H) && !defined(H5_HAVE_WIN32_API)

    /* Not a Windows or POSIX system */
    SKIPPED();
    puts("    Test skipped: Not a Windows or POSIX system.");
    return 0;

#else
    /* Skip this test if SWMR I/O is not supported for the VFD specified
     * by the environment variable.
     */
    driver_name = h5_get_test_driver_name();
    if (!H5FD__supports_swmr_test(driver_name)) {
        SKIPPED();
        puts("    Test skipped due to VFD not supporting SWMR I/O.");
        return 0;
    }

    /* File access property list */
    if ((fapl = h5_fileaccess()) < 0)
        FAIL_STACK_ERROR;
    h5_fixname(FILENAME[1], fapl, filename, sizeof filename);

    /* Both cases will result in v3 superblock and version 2 object header for SWMR */
    if (newest_format) { /* latest format */
        if (H5Pset_libver_bounds(fapl, H5F_LIBVER_LATEST, H5F_LIBVER_LATEST) < 0)
            FAIL_STACK_ERROR;

        if ((fid = H5Fcreate(filename, H5F_ACC_TRUNC, H5P_DEFAULT, fapl)) < 0)
            FAIL_STACK_ERROR;
    }
    else { /* non-latest-format */
        if ((fid = H5Fcreate(filename, H5F_ACC_TRUNC | H5F_ACC_SWMR_WRITE, H5P_DEFAULT, fapl)) < 0)
            FAIL_STACK_ERROR;
    } /* end if */

    /* Close the file */
    if (H5Fclose(fid) < 0)
        FAIL_STACK_ERROR;

    /* Open the file with SWMR_WRITE */
    if ((fid = H5Fopen(filename, H5F_ACC_RDWR | H5F_ACC_SWMR_WRITE, fapl)) < 0)
        FAIL_STACK_ERROR;

    /* Push API context */
    if (H5CX_push(&api_ctx) < 0)
        FAIL_STACK_ERROR;
    api_ctx_pushed = true;

    /* Get H5F_t * to internal file structure */
    if (NULL == (rf = (H5F_t *)H5VL_object(fid)))
        FAIL_STACK_ERROR;

    /* We'll be writing lots of garbage data, so extend the
        file a ways. 10MB should do. */
    if (H5FD_set_eoa(rf->shared->lf, H5FD_MEM_DEFAULT, (haddr_t)(1024 * 1024 * 10)) < 0)
        FAIL_STACK_ERROR;

    if (H5Fflush(fid, H5F_SCOPE_GLOBAL) < 0)
        FAIL_STACK_ERROR;

    /* Reset metadata accumulator for the file */
    if (accum_reset(rf) < 0)
        FAIL_STACK_ERROR;

    /* Allocate space for the write & read buffers */
    if ((wbuf2 = (uint8_t *)malloc((size_t)BIG_BUF_SIZE)) == NULL)
        FAIL_STACK_ERROR;
    if ((rbuf = (uint8_t *)malloc((size_t)BIG_BUF_SIZE)) == NULL)
        FAIL_STACK_ERROR;

    /* Initialize wbuf with "0, 1, 2...1024"*/
    for (u = 0; u < 1024; u++)
        wbuf[u] = (uint8_t)u;

    /* Write [1024, 1024] bytes with wbuf */
    if (H5F_block_write(rf, H5FD_MEM_DEFAULT, (haddr_t)1024, (size_t)1024, wbuf) < 0)
        FAIL_STACK_ERROR;
    /* Read the data */
    if (H5F_block_read(rf, H5FD_MEM_DEFAULT, (haddr_t)1024, (size_t)1024, rbuf) < 0)
        FAIL_STACK_ERROR;
    /* Verify the data read is correct */
    if (memcmp(wbuf, rbuf, (size_t)1024) != 0)
        TEST_ERROR;
    /* Flush the data to disk */
    if (accum_reset(rf) < 0)
        FAIL_STACK_ERROR;

    /* Initialize wbuf with all 1s */
    for (u = 0; u < 1024; u++)
        wbuf[u] = (uint8_t)1;

    /* Initialize wbuf2 */
    for (u = 0; u < BIG_BUF_SIZE; u++)
        wbuf2[u] = (uint8_t)(u + 1);

    /* Write [1024,1024] with wbuf--all 1s */
    if (H5F_block_write(rf, H5FD_MEM_DEFAULT, (haddr_t)1024, (size_t)1024, wbuf) < 0)
        FAIL_STACK_ERROR;
    /* Read the data */
    if (H5F_block_read(rf, H5FD_MEM_DEFAULT, (haddr_t)1024, (size_t)1024, rbuf) < 0)
        FAIL_STACK_ERROR;
    /* Verify the data read is correct */
    if (memcmp(wbuf, rbuf, (size_t)1024) != 0)
        TEST_ERROR;
    /* The data stays in the accumulator */

    /* Write a large piece of metadata [2048, BIG_BUF_SIZE] with wbuf2 */
    if (H5F_block_write(rf, H5FD_MEM_DEFAULT, (haddr_t)2048, (size_t)BIG_BUF_SIZE, wbuf2) < 0)
        FAIL_STACK_ERROR;
    /* Read the data */
    if (H5F_block_read(rf, H5FD_MEM_DEFAULT, (haddr_t)2048, (size_t)BIG_BUF_SIZE, rbuf) < 0)
        FAIL_STACK_ERROR;
    /* Verify the data read is correct */
    if (memcmp(wbuf2, rbuf, (size_t)BIG_BUF_SIZE) != 0)
        TEST_ERROR;

#if defined(H5_HAVE_WIN32_API)
    {
        STARTUPINFO         si;
        PROCESS_INFORMATION pi;
        DWORD               exit_code = EXIT_FAILURE;

        ZeroMemory(&si, sizeof(si));
        si.cb = sizeof(si);
        ZeroMemory(&pi, sizeof(pi));

        if (0 == CreateProcess(NULL, SWMR_READER, NULL, NULL, false, 0, NULL, NULL, &si, &pi)) {
            printf("CreateProcess failed (%lu).\n", GetLastError());
            FAIL_STACK_ERROR;
        }

        (void)WaitForSingleObject(pi.hProcess, INFINITE);

        if (false == GetExitCodeProcess(pi.hProcess, &exit_code) || EXIT_FAILURE == exit_code)
            process_success = false;
        else
            process_success = true;

        CloseHandle(pi.hProcess);
        CloseHandle(pi.hThread);
    }
#else  /* defined(H5_HAVE_WIN32_API) */
    {
        pid_t pid;    /* Process ID */
        int   status; /* Status returned from child process */

        /* Fork child process to verify that the data at [1024, 2014] does get written to disk */
        if ((pid = fork()) < 0) {
            perror("fork");
            FAIL_STACK_ERROR;
        }
        else if (0 == pid) { /* Child process */
            /* By convention, argv[0] tells the name of program invoked.
             *
             * execv on NetBSD 8 will actually return EFAULT if there is a
             * NULL at argv[0], so we follow the convention unconditionally.
             */
            char        swmr_reader[] = SWMR_READER;
            char *const new_argv[]    = {swmr_reader, NULL};
            /* Run the reader */
            status = execv(SWMR_READER, new_argv);
            printf("errno from execv = %s\n", strerror(errno));
            FAIL_STACK_ERROR;
        } /* end if */

        /* Parent process -- wait for the child process to complete */
        while (pid != waitpid(pid, &status, 0))
            /*void*/;

        /* Check if child process terminates normally and its return value */
        if (WIFEXITED(status) && !WEXITSTATUS(status))
            process_success = true;
    }
#endif /* defined(H5_HAVE_WIN32_API) */

    /* Check if the process terminated correctly */
    if (!process_success)
        FAIL_PUTS_ERROR("child process exited abnormally");

    /* Flush the accumulator */
    if (accum_reset(rf) < 0)
        FAIL_STACK_ERROR;

    /* Close and remove the file */
    if (H5Fclose(fid) < 0)
        FAIL_STACK_ERROR;

    /* Close the property list */
    if (H5Pclose(fapl) < 0)
        FAIL_STACK_ERROR;

    /* Pop API context */
    if (api_ctx_pushed && H5CX_pop(false) < 0)
        FAIL_STACK_ERROR;
    api_ctx_pushed = false;

    /* Release memory */
    if (wbuf2)
        free(wbuf2);
    if (rbuf)
        free(rbuf);

    PASSED();
    return 0;

error:
    /* Closing and remove the file */
    H5Fclose(fid);

    if (api_ctx_pushed)
        H5CX_pop(false);

    H5Pclose(fapl);

    /* Release memory */
    if (wbuf2)
        free(wbuf2);
    if (rbuf)
        free(rbuf);

    return 1;

#endif /* !defined(H5_HAVE_UNISTD_H) && !defined(H5_HAVE_WIN32_API) */

} /* end test_swmr_write_big() */

/*-------------------------------------------------------------------------
 * Function:    accum_printf
 *
 * Purpose:     Debug function to print some stats about the accumulator
 *
 * Return:      Success: SUCCEED
 *              Failure: FAIL
 *
 *-------------------------------------------------------------------------
 */
void
accum_printf(const H5F_t *f)
{
    H5F_meta_accum_t *accum = &f->shared->accum;

    printf("\n");
    printf("Current contents of accumulator:\n");
    if (accum->alloc_size == 0) {
        printf("=====================================================\n");
        printf(" No accumulator allocated.\n");
        printf("=====================================================\n");
    }
    else {
        printf("=====================================================\n");
        printf(" accumulator allocated size == %zu\n", accum->alloc_size);
        printf(" accumulated data size      == %zu\n", accum->size);
        fprintf(stdout, " accumulator dirty?         == %s\n", accum->dirty ? "true" : "false");
        printf("=====================================================\n");
        fprintf(stdout, " start of accumulated data, loc = %" PRIuHADDR "\n", accum->loc);
        if (accum->dirty) {
            fprintf(stdout, " start of dirty region, loc = %" PRIuHADDR "\n",
                    (haddr_t)(accum->loc + accum->dirty_off));
            fprintf(stdout, " end of dirty region,   loc = %" PRIuHADDR "\n",
                    (haddr_t)(accum->loc + accum->dirty_off + accum->dirty_len));
        } /* end if */
        fprintf(stdout, " end of accumulated data,   loc = %" PRIuHADDR "\n",
                (haddr_t)(accum->loc + accum->size));
        fprintf(stdout, " end of accumulator allocation,   loc = %" PRIuHADDR "\n",
                (haddr_t)(accum->loc + accum->alloc_size));
        printf("=====================================================\n");
    }
    printf("\n\n");
} /* accum_printf() */
