bittests.c

/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * 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.                                                        *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

/*
 * Purpose:	Tests functions in H5Tbit.c
 */
#include "h5test.h"

#define H5T_FRIEND /*suppress error about including H5Tpkg	  */
#include "H5Tpkg.h"

#define NTESTS 100000

/*-------------------------------------------------------------------------
 * Function:	test_find
 *
 * Purpose:	Test bit find operations.  This is just the basic stuff; more
 *		rigorous testing will be performed by the other test
 *		functions.
 *
 * Return:	Success:	0
 *
 *		Failure:	-1
 *
 *-------------------------------------------------------------------------
 */
static herr_t
test_find(void)
{
    uint8_t v1[8];
    int     i;
    ssize_t n;

    TESTING("bit search operations");

    /* The zero length buffer */
    memset(v1, 0xaa, sizeof v1);
    n = H5T__bit_find(v1, (size_t)0, (size_t)0, H5T_BIT_LSB, true);
    if (-1 != n) {
        H5_FAILED();
        puts("    Zero length test failed (lsb)!");
        goto failed;
    }
    n = H5T__bit_find(v1, (size_t)0, (size_t)0, H5T_BIT_MSB, true);
    if (-1 != n) {
        H5_FAILED();
        puts("    Zero length test failed (msb)!");
        goto failed;
    }

    /* The zero buffer */
    memset(v1, 0, sizeof v1);
    n = H5T__bit_find(v1, (size_t)0, 8 * sizeof(v1), H5T_BIT_LSB, true);
    if (-1 != n) {
        H5_FAILED();
        puts("    Zero buffer test failed (lsb)!");
        goto failed;
    }
    n = H5T__bit_find(v1, (size_t)0, 8 * sizeof(v1), H5T_BIT_MSB, true);
    if (-1 != n) {
        H5_FAILED();
        puts("    Zero buffer test failed (msb)!");
        goto failed;
    }

    /* Try all combinations of one byte */
    for (i = 0; i < 8 * (int)sizeof(v1); i++) {
        memset(v1, 0, sizeof v1);
        v1[i / 8] = (uint8_t)(1 << (i % 8));
        n         = H5T__bit_find(v1, (size_t)0, 8 * sizeof(v1), H5T_BIT_LSB, true);
        if ((ssize_t)i != n) {
            H5_FAILED();
            printf("    Test for set bit %d failed (lsb)!\n", i);
            goto failed;
        }
        n = H5T__bit_find(v1, (size_t)0, 8 * sizeof(v1), H5T_BIT_MSB, true);
        if ((ssize_t)i != n) {
            H5_FAILED();
            printf("    Test for set bit %d failed (msb)!\n", i);
            goto failed;
        }
    }

    /* The one buffer */
    memset(v1, 0xff, sizeof v1);
    n = H5T__bit_find(v1, (size_t)0, 8 * sizeof(v1), H5T_BIT_LSB, false);
    if (-1 != n) {
        H5_FAILED();
        puts("    One buffer test failed (lsb)!");
        goto failed;
    }
    n = H5T__bit_find(v1, (size_t)0, 8 * sizeof(v1), H5T_BIT_MSB, false);
    if (-1 != n) {
        H5_FAILED();
        puts("    One buffer test failed (msb)!");
        goto failed;
    }

    /* Try all combinations of one byte */
    for (i = 0; i < 8 * (int)sizeof(v1); i++) {
        memset(v1, 0xff, sizeof v1);
        v1[i / 8] &= (uint8_t) ~(1 << (i % 8));
        n = H5T__bit_find(v1, (size_t)0, 8 * sizeof(v1), H5T_BIT_LSB, false);
        if ((ssize_t)i != n) {
            H5_FAILED();
            printf("    Test for clear bit %d failed (lsb)!\n", i);
            goto failed;
        }
        n = H5T__bit_find(v1, (size_t)0, 8 * sizeof(v1), H5T_BIT_MSB, false);
        if ((ssize_t)i != n) {
            H5_FAILED();
            printf("    Test for clear bit %d failed (lsb)!\n", i);
            goto failed;
        }
    }

    PASSED();
    return 0;

failed:
    printf("    v = 0x");
    for (i = 0; i < (int)sizeof(v1); i++)
        printf("%02x", v1[i]);
    printf("\n");
    return -1;
}

/*-------------------------------------------------------------------------
 * Function:	test_copy
 *
 * Purpose:	Test bit copy operations.
 *
 * Return:	Success:	0
 *
 *		Failure:	-1
 *
 *-------------------------------------------------------------------------
 */
static herr_t
test_copy(void)
{
    uint8_t v1[8], v2[8];
    size_t  s_offset, d_offset, size;
    int     i, j;
    ssize_t n;

    TESTING("bit copy operations");

    for (i = 0; i < NTESTS; i++) {
        s_offset = (size_t)rand() % (8 * sizeof v1);
        d_offset = (size_t)rand() % (8 * sizeof v2);
        size     = (unsigned)rand() % MIN(8 * sizeof(v1), 8 * sizeof(v2));
        size     = MIN3(size, 8 * sizeof(v1) - s_offset, 8 * sizeof(v2) - d_offset);
        memset(v1, 0xff, sizeof v1);
        memset(v2, 0x00, sizeof v2);

        /* Copy some bits to v2 and make sure something was copied */
        H5T__bit_copy(v2, d_offset, v1, s_offset, size);
        for (j = 0; j < (int)sizeof(v2); j++)
            if (v2[j])
                break;
        if (size > 0 && j >= (int)sizeof(v2)) {
            H5_FAILED();
            puts("    Unable to find copied region in destination");
            goto failed;
        }
        if (0 == size && j < (int)sizeof(v2)) {
            H5_FAILED();
            puts("    Found copied bits when we shouldn't have");
            goto failed;
        }

        /* Look for the zeros and ones */
        n = H5T__bit_find(v2, (size_t)0, 8 * sizeof(v2), H5T_BIT_LSB, 1);
        if (size > 0 && n != (ssize_t)d_offset) {
            H5_FAILED();
            printf("    Unable to find first copied bit in destination "
                   "(n=%d)\n",
                   (int)n);
            goto failed;
        }
        if (0 == size && n >= 0) {
            H5_FAILED();
            puts("    Found copied bits and shouldn't have!");
            goto failed;
        }
        n = H5T__bit_find(v2, d_offset, 8 * sizeof(v2) - d_offset, H5T_BIT_LSB, 0);
        if (d_offset + size < 8 * sizeof(v2) && n != (ssize_t)size) {
            H5_FAILED();
            printf("    Unable to find last copied bit in destination "
                   "(n=%d)\n",
                   (int)n);
            goto failed;
        }
        if (d_offset + size == 8 * sizeof(v2) && n >= 0) {
            H5_FAILED();
            puts("    High-order zeros are present and shouldn't be!");
            goto failed;
        }

        /*
         * Look for zeros and ones in reverse order.  This is only to test
         * that reverse searches work as expected.
         */
        n = H5T__bit_find(v2, (size_t)0, 8 * sizeof(v2), H5T_BIT_MSB, 1);
        if (size > 0 && (size_t)(n + 1) != d_offset + size) {
            H5_FAILED();
            printf("    Unable to find last copied bit in destination "
                   "(reverse, n=%d)\n",
                   (int)n);
            goto failed;
        }
        if (0 == size && n >= 0) {
            H5_FAILED();
            puts("    Found copied bits but shouldn't have (reverse)!");
            goto failed;
        }
        n = H5T__bit_find(v2, (size_t)0, d_offset + size, H5T_BIT_MSB, 0);
        if (d_offset > 0 && n + 1 != (ssize_t)d_offset) {
            H5_FAILED();
            printf("    Unable to find beginning of copied data "
                   "(reverse, n=%d)\n",
                   (int)n);
            goto failed;
        }
        if (0 == d_offset && n >= 0) {
            H5_FAILED();
            puts("    Found leading original data but shouldn't have!");
            goto failed;
        }
    }

    PASSED();
    return 0;

failed:
    printf("    i=%d, s_offset=%lu, d_offset=%lu, size=%lu\n", i, (unsigned long)s_offset,
           (unsigned long)d_offset, (unsigned long)size);
    printf("    s = 0x");
    for (j = sizeof(v1) - 1; j >= 0; --j)
        printf("%02x", v1[j]);
    printf("\n    d = 0x");
    for (j = sizeof(v2) - 1; j >= 0; --j)
        printf("%02x", v2[j]);
    printf("\n");
    return -1;
}

/*-------------------------------------------------------------------------
 * Function:	test_shift
 *
 * Purpose:	Test bit shifting operations.
 *
 * Return:	Success:	0
 *
 *		Failure:	-1
 *
 *-------------------------------------------------------------------------
 */
static herr_t
test_shift(void)
{
    uint8_t vector[8];
    size_t  offset, size;
    int     i, j;
    ssize_t shift_dist, n;

    TESTING("bit shift operations");

    for (i = 0; i < NTESTS; i++) {
        offset = (size_t)rand() % (8 * sizeof vector);
        size   = (size_t)rand() % (8 * sizeof(vector) - offset);
        /* Don't want size to be 0 */
        if (size == 0)
            continue;
        shift_dist = (ssize_t)((size_t)rand() % size);

        /*-------- LEFT-shift some bits and make sure something was shifted --------*/
        memset(vector, 0x00, sizeof vector);
        H5T__bit_set(vector, offset, size, 1);

        H5T__bit_shift(vector, shift_dist, offset, size);

        /* Look for the ones */
        n = H5T__bit_find(vector, (size_t)0, 8 * sizeof(vector), H5T_BIT_LSB, 1);
        if (n != (ssize_t)offset + shift_dist) {
            H5_FAILED();
            printf("    Unable to find first bit in destination "
                   "(n=%d)\n",
                   (int)n);
            goto failed;
        }

        /*
         * Look for zeros and ones in reverse order.  This is only to test
         * that reverse searches work as expected.
         */
        n = H5T__bit_find(vector, (size_t)0, 8 * sizeof(vector), H5T_BIT_MSB, 1);
        if (n != (ssize_t)(offset + size - 1)) {
            H5_FAILED();
            printf("    Unable to find last bit in destination "
                   "(reverse, n=%d)\n",
                   (int)n);
            goto failed;
        }

        /*-------- RIGHT-shift some bits and make sure something was shifted --------*/
        memset(vector, 0x00, sizeof vector);
        H5T__bit_set(vector, offset, size, 1);

        H5T__bit_shift(vector, -shift_dist, offset, size);

        /* Look for the ones */
        n = H5T__bit_find(vector, (size_t)0, 8 * sizeof(vector), H5T_BIT_LSB, 1);
        if ((size_t)n != offset) {
            H5_FAILED();
            printf("    Unable to find first bit in destination "
                   "(n=%d)\n",
                   (int)n);
            goto failed;
        }

        /*
         * Look for zeros and ones in reverse order.  This is only to test
         * that reverse searches work as expected.
         */
        n = H5T__bit_find(vector, (size_t)0, 8 * sizeof(vector), H5T_BIT_MSB, 1);
        if (n != (ssize_t)(offset + size) - shift_dist - 1) {
            H5_FAILED();
            printf("    Unable to find last bit in destination "
                   "(reverse, n=%d)\n",
                   (int)n);
            goto failed;
        }

        /*-------- Shift the bits out of sight --------*/
        /* A sequence 111111 will be 000000 if shift_dist=6 */

        /* Randomly decide shift direction */
        if (size % 2 == 0)
            shift_dist = (ssize_t)size;
        else
            shift_dist = -((ssize_t)size);

        memset(vector, 0x00, sizeof vector);
        H5T__bit_set(vector, offset, size, 1);

        H5T__bit_shift(vector, shift_dist, offset, size);

        /* Supposed to fail to find any ones */
        n = H5T__bit_find(vector, (size_t)0, 8 * sizeof(vector), H5T_BIT_LSB, 1);
        if (n >= 0) {
            H5_FAILED();
            printf("    Unable to verify all bits are zero in destination(LSB) "
                   "(n=%d)\n",
                   (int)n);
            goto failed;
        }

        /* Look from the other direction */
        n = H5T__bit_find(vector, (size_t)0, 8 * sizeof(vector), H5T_BIT_MSB, 1);
        if (n >= 0) {
            H5_FAILED();
            printf("    Unable to verify all bits are zero in destination(MSB) "
                   "(n=%d)\n",
                   (int)n);
            goto failed;
        }
    }

    PASSED();
    return 0;

failed:
    printf("    i=%d, offset=%lu, size=%lu, shift_dist=%lu\n", i, (unsigned long)offset, (unsigned long)size,
           (unsigned long)shift_dist);
    for (j = sizeof(vector) - 1; j >= 0; --j)
        printf("%02x", vector[j]);
    printf("\n");
    return -1;
}

/*-------------------------------------------------------------------------
 * Function:	test_increment
 *
 * Purpose:	Test operation to increment bit vector by 1.
 *
 * Return:	Success:	0
 *
 *		Failure:	-1
 *
 *-------------------------------------------------------------------------
 */
static herr_t
test_increment(void)
{
    uint8_t vector[8];
    size_t  offset, size;
    int     i, j;
    ssize_t n;

    TESTING("bit increment operations");

    for (i = 0; i < NTESTS; i++) {
        offset = (size_t)rand() % (8 * sizeof vector);
        size   = (size_t)rand() % (8 * sizeof(vector) - offset);
        /* Don't want size to be 0 */
        if (size == 0)
            continue;

        memset(vector, 0x00, sizeof vector);
        if (size > 1) /* if size=6, make a sequence like 011111 */
            H5T__bit_set(vector, offset, size - 1, 1);
        else /* if size=1, just set this one bit to 1 */
            H5T__bit_set(vector, offset, size, 1);

        /* Increment the sequence by one */
        H5T__bit_inc(vector, offset, size);

        /* Look for the one */
        n = H5T__bit_find(vector, (size_t)0, 8 * sizeof(vector), H5T_BIT_LSB, 1);
        if (size != 1 && (size_t)n != offset + size - 1) {
            H5_FAILED();
            printf("    Unable to find first bit in destination "
                   "(n=%d)\n",
                   (int)n);
            goto failed;
        }
        if (size == 1 && n >= 0) {
            H5_FAILED();
            printf("    Unable to verify all-zero bit in destination "
                   "(n=%d)\n",
                   (int)n);
            goto failed;
        }

        /*
         * Look for one in reverse order.  This is only to test
         * that reverse searches work as expected.
         */
        n = H5T__bit_find(vector, (size_t)0, 8 * sizeof(vector), H5T_BIT_MSB, 1);
        if (size != 1 && n != (ssize_t)(offset + size - 1)) {
            H5_FAILED();
            printf("    Unable to find last bit in destination "
                   "(reverse, n=%d)\n",
                   (int)n);
            goto failed;
        }
        if (size == 1 && n >= 0) {
            H5_FAILED();
            printf("    Unable to verify all-zero bit in destination "
                   "(reverse, n=%d)\n",
                   (int)n);
            goto failed;
        }
    }

    PASSED();
    return 0;

failed:
    printf("    i=%d, offset=%lu, size=%lu\n", i, (unsigned long)offset, (unsigned long)size);
    for (j = sizeof(vector) - 1; j >= 0; --j)
        printf("%02x", vector[j]);
    printf("\n");
    return -1;
}

/*-------------------------------------------------------------------------
 * Function:	test_decrement
 *
 * Purpose:	Test operation to decrement bit vector by 1.
 *
 * Return:	Success:	0
 *
 *		Failure:	-1
 *
 *-------------------------------------------------------------------------
 */
static herr_t
test_decrement(void)
{
    uint8_t vector[8];
    size_t  offset, size;
    int     i, j;
    ssize_t n;

    TESTING("bit decrement operations");

    for (i = 0; i < NTESTS; i++) {
        offset = (size_t)rand() % (8 * sizeof vector);
        size   = (size_t)rand() % (8 * sizeof(vector) - offset);
        /* Don't want size to be 0 */
        if (size == 0)
            continue;

        /* All-zero sequence will become 111111(size=6) after decrement */
        memset(vector, 0x00, sizeof vector);

        /* decrement the sequence by one */
        H5T__bit_dec(vector, offset, size);

        /* Look for the ones */
        n = H5T__bit_find(vector, (size_t)0, 8 * sizeof(vector), H5T_BIT_LSB, 1);
        if ((size_t)n != offset) {
            H5_FAILED();
            printf("    Unable to find first bit in destination "
                   "(n=%d)\n",
                   (int)n);
            goto failed;
        }

        /*
         * Look for zeros and ones in reverse order.  This is only to test
         * that reverse searches work as expected.
         */
        n = H5T__bit_find(vector, (size_t)0, 8 * sizeof(vector), H5T_BIT_MSB, 1);
        if (n != (ssize_t)(offset + size - 1)) {
            H5_FAILED();
            printf("    Unable to find last bit in destination "
                   "(reverse, n=%d)\n",
                   (int)n);
            goto failed;
        }
    }

    PASSED();
    return 0;

failed:
    printf("    i=%d, offset=%lu, size=%lu\n", i, (unsigned long)offset, (unsigned long)size);
    for (j = sizeof(vector) - 1; j >= 0; --j)
        printf("%02x", vector[j]);
    printf("\n");
    return -1;
}

/*-------------------------------------------------------------------------
 * Function:	test_negate
 *
 * Purpose:	Test operation to negate bit vector.
 *
 * Return:	Success:	0
 *
 *		Failure:	-1
 *
 *-------------------------------------------------------------------------
 */
static herr_t
test_negate(void)
{
    uint8_t vector[8];
    size_t  offset, size;
    int     i, j;
    ssize_t n;

    TESTING("bit negate operations");

    for (i = 0; i < NTESTS; i++) {
        offset = (size_t)rand() % (8 * sizeof vector);
        size   = (size_t)rand() % (8 * sizeof(vector) - offset);
        /* Don't want size to be 0 */
        if (size == 0)
            continue;

        /* All-zero sequence will become 111111(size=6) after negating */
        memset(vector, 0x00, sizeof vector);

        /* negate the sequence */
        H5T__bit_neg(vector, offset, size);

        /* Look for the ones */
        n = H5T__bit_find(vector, (size_t)0, 8 * sizeof(vector), H5T_BIT_LSB, 1);
        if ((size_t)n != offset) {
            H5_FAILED();
            printf("    Unable to find first bit in destination "
                   "(n=%d)\n",
                   (int)n);
            goto failed;
        }

        /*
         * Look for zeros and ones in reverse order.  This is only to test
         * that reverse searches work as expected.
         */
        n = H5T__bit_find(vector, (size_t)0, 8 * sizeof(vector), H5T_BIT_MSB, 1);
        if (n != (ssize_t)(offset + size - 1)) {
            H5_FAILED();
            printf("    Unable to find last bit in destination "
                   "(reverse, n=%d)\n",
                   (int)n);
            goto failed;
        }

        /* All-one sequence will become 000000(size=6) after negating */
        memset(vector, 0x00, sizeof vector);
        H5T__bit_set(vector, offset, size, 1);

        /* negate the sequence */
        H5T__bit_neg(vector, offset, size);

        /* Look for the ones */
        n = H5T__bit_find(vector, (size_t)0, 8 * sizeof(vector), H5T_BIT_LSB, 1);
        if (n >= 0) {
            H5_FAILED();
            printf("    Unable to verify all-zero bits in destination "
                   "(n=%d)\n",
                   (int)n);
            goto failed;
        }

        /*
         * Look for ones in reverse order.  This is only to test
         * that reverse searches work as expected.
         */
        n = H5T__bit_find(vector, (size_t)0, 8 * sizeof(vector), H5T_BIT_MSB, 1);
        if (n >= 0) {
            H5_FAILED();
            printf("    Unable to verify all-zero bits in destination "
                   "(reverse, n=%d)\n",
                   (int)n);
            goto failed;
        }
    }

    PASSED();
    return 0;

failed:
    printf("    i=%d, offset=%lu, size=%lu\n", i, (unsigned long)offset, (unsigned long)size);
    for (j = sizeof(vector) - 1; j >= 0; --j)
        printf("%02x", vector[j]);
    printf("\n");
    return -1;
}

/*-------------------------------------------------------------------------
 * Function:	test_set
 *
 * Purpose:	Test bit set operations
 *
 * Return:	Success:	0
 *
 *		Failure:	-1
 *
 *-------------------------------------------------------------------------
 */
static herr_t
test_set(void)
{
    uint8_t v2[8];
    size_t  d_offset, size;
    int     i, j;
    ssize_t n;

    TESTING("bit set operations");

    for (i = 0; i < NTESTS; i++) {
        d_offset = (size_t)rand() % (8 * sizeof v2);
        size     = (size_t)rand() % (8 * sizeof(v2));
        size     = MIN(size, 8 * sizeof(v2) - d_offset);
        memset(v2, 0x00, sizeof v2);

        /* Set some bits in v2 */
        H5T__bit_set(v2, d_offset, size, true);
        for (j = 0; j < (int)sizeof(v2); j++)
            if (v2[j])
                break;
        if (size > 0 && j >= (int)sizeof(v2)) {
            H5_FAILED();
            puts("    Unable to find set region in buffer");
            goto failed;
        }
        if (0 == size && j < (int)sizeof(v2)) {
            H5_FAILED();
            puts("    Found set bits when we shouldn't have");
            goto failed;
        }

        /* Look for the zeros and ones */
        n = H5T__bit_find(v2, (size_t)0, 8 * sizeof(v2), H5T_BIT_LSB, 1);
        if (size > 0 && n != (ssize_t)d_offset) {
            H5_FAILED();
            printf("    Unable to find first set bit in destination "
                   "(n=%d)\n",
                   (int)n);
            goto failed;
        }
        if (0 == size && n >= 0) {
            H5_FAILED();
            puts("    Found set bits and shouldn't have!");
            goto failed;
        }
        n = H5T__bit_find(v2, d_offset, 8 * sizeof(v2) - d_offset, H5T_BIT_LSB, 0);
        if (d_offset + size < 8 * sizeof(v2) && n != (ssize_t)size) {
            H5_FAILED();
            printf("    Unable to find last set bit in destination "
                   "(n=%d)\n",
                   (int)n);
            goto failed;
        }
        if (d_offset + size == 8 * sizeof(v2) && n >= 0) {
            H5_FAILED();
            puts("    High-order zeros are present and shouldn't be!");
            goto failed;
        }

        /*
         * Look for zeros and ones in reverse order.  This is only to test
         * that reverse searches work as expected.
         */
        n = H5T__bit_find(v2, (size_t)0, 8 * sizeof(v2), H5T_BIT_MSB, 1);
        if (size > 0 && (size_t)(n + 1) != d_offset + size) {
            H5_FAILED();
            printf("    Unable to find last set bit in destination "
                   "(reverse, n=%d)\n",
                   (int)n);
            goto failed;
        }
        if (0 == size && n >= 0) {
            H5_FAILED();
            puts("    Found set bits but shouldn't have (reverse)!");
            goto failed;
        }
        n = H5T__bit_find(v2, (size_t)0, d_offset + size, H5T_BIT_MSB, 0);
        if (d_offset > 0 && n + 1 != (ssize_t)d_offset) {
            H5_FAILED();
            printf("    Unable to find beginning of set bit region "
                   "(reverse, n=%d)\n",
                   (int)n);
            goto failed;
        }
        if (0 == d_offset && n >= 0) {
            H5_FAILED();
            puts("    Found leading zeros but shouldn't have!");
            goto failed;
        }
    }

    PASSED();
    return 0;

failed:
    printf("    i=%d, d_offset=%lu, size=%lu\n", i, (unsigned long)d_offset, (unsigned long)size);
    printf("    d = 0x");
    for (j = sizeof(v2) - 1; j >= 0; --j)
        printf("%02x", v2[j]);
    printf("\n");
    return -1;
}

/*-------------------------------------------------------------------------
 * Function:	test_clear
 *
 * Purpose:	Test bit clear operations
 *
 * Return:	Success:	0
 *
 *		Failure:	-1
 *
 *-------------------------------------------------------------------------
 */
static herr_t
test_clear(void)
{
    uint8_t v2[8];
    size_t  d_offset, size;
    int     i, j;
    ssize_t n;

    TESTING("bit clear operations");

    for (i = 0; i < NTESTS; i++) {
        d_offset = (size_t)rand() % (8 * sizeof v2);
        size     = (size_t)rand() % (8 * sizeof(v2));
        size     = MIN(size, 8 * sizeof(v2) - d_offset);
        memset(v2, 0xff, sizeof v2);

        /* Clear some bits in v2 */
        H5T__bit_set(v2, d_offset, size, false);
        for (j = 0; j < (int)sizeof(v2); j++)
            if (0xff != v2[j])
                break;
        if (size > 0 && j >= (int)sizeof(v2)) {
            H5_FAILED();
            puts("    Unable to find cleared region in buffer");
            goto failed;
        }
        if (0 == size && j < (int)sizeof(v2)) {
            H5_FAILED();
            puts("    Found cleared bits when we shouldn't have");
            goto failed;
        }

        /* Look for the zeros and ones */
        n = H5T__bit_find(v2, (size_t)0, 8 * sizeof(v2), H5T_BIT_LSB, 0);
        if (size > 0 && n != (ssize_t)d_offset) {
            H5_FAILED();
            printf("    Unable to find first cleared bit in destination "
                   "(n=%d)\n",
                   (int)n);
            goto failed;
        }
        if (0 == size && n >= 0) {
            H5_FAILED();
            puts("    Found cleared bits and shouldn't have!");
            goto failed;
        }
        n = H5T__bit_find(v2, d_offset, 8 * sizeof(v2) - d_offset, H5T_BIT_LSB, 1);
        if (d_offset + size < 8 * sizeof(v2) && n != (ssize_t)size) {
            H5_FAILED();
            printf("    Unable to find last cleared bit in destination "
                   "(n=%d)\n",
                   (int)n);
            goto failed;
        }
        if (d_offset + size == 8 * sizeof(v2) && n >= 0) {
            H5_FAILED();
            puts("    High-order ones are present and shouldn't be!");
            goto failed;
        }

        /*
         * Look for zeros and ones in reverse order.  This is only to test
         * that reverse searches work as expected.
         */
        n = H5T__bit_find(v2, (size_t)0, 8 * sizeof(v2), H5T_BIT_MSB, 0);
        if (size > 0 && (size_t)(n + 1) != d_offset + size) {
            H5_FAILED();
            printf("    Unable to find last cleared bit in destination "
                   "(reverse, n=%d)\n",
                   (int)n);
            goto failed;
        }
        if (0 == size && n >= 0) {
            H5_FAILED();
            puts("    Found cleared bits but shouldn't have (reverse)!");
            goto failed;
        }
        n = H5T__bit_find(v2, (size_t)0, d_offset + size, H5T_BIT_MSB, 1);
        if (d_offset > 0 && n + 1 != (ssize_t)d_offset) {
            H5_FAILED();
            printf("    Unable to find beginning of cleared bit region "
                   "(reverse, n=%d)\n",
                   (int)n);
            goto failed;
        }
        if (0 == d_offset && n >= 0) {
            H5_FAILED();
            puts("    Found leading ones but shouldn't have!");
            goto failed;
        }
    }

    PASSED();
    return 0;

failed:
    printf("    i=%d, d_offset=%lu, size=%lu\n", i, (unsigned long)d_offset, (unsigned long)size);
    printf("    d = 0x");
    for (j = sizeof(v2) - 1; j >= 0; --j)
        printf("%02x", v2[j]);
    printf("\n");
    return -1;
}

/*-------------------------------------------------------------------------
 * Function:    main
 *
 * Purpose:
 *
 * Return:      EXIT_SUCCESS/EXIT_FAILURE
 *
 *-------------------------------------------------------------------------
 */
int
main(void)
{
    int nerrors = 0;

    /*
     * Open the library explicitly.
     */
    H5open();

    nerrors += test_find() < 0 ? 1 : 0;
    nerrors += test_set() < 0 ? 1 : 0;
    nerrors += test_clear() < 0 ? 1 : 0;
    nerrors += test_copy() < 0 ? 1 : 0;
    nerrors += test_shift() < 0 ? 1 : 0;
    nerrors += test_increment() < 0 ? 1 : 0;
    nerrors += test_decrement() < 0 ? 1 : 0;
    nerrors += test_negate() < 0 ? 1 : 0;

    if (nerrors) {
        printf("***** %u FAILURE%s! *****\n", nerrors, 1 == nerrors ? "" : "S");
        exit(EXIT_FAILURE);
    }
    printf("All bit tests passed.\n");

    H5close();

    exit(EXIT_SUCCESS);
} /* end main() */