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/*
* Copyright (C) 1998 NCSA
* All rights reserved.
*
* Programmer: Robb Matzke <matzke@llnl.gov>
* Wednesday, June 10, 1998
*
* Purpose: Operations on bit vectors. A bit vector is an array of bytes
* with the least-significant bits in the first byte. That is,
* the bytes are in little-endian order.
*/
#define H5T_PACKAGE
#include <H5private.h>
#include <H5Tpkg.h>
/*-------------------------------------------------------------------------
* Function: H5T_bit_copy
*
* Purpose: Copies bits from one vector to another.
*
* Return: void
*
* Programmer: Robb Matzke
* Wednesday, June 10, 1998
*
* Modifications:
*
*-------------------------------------------------------------------------
*/
void
H5T_bit_copy (uint8 *dst, size_t dst_offset, const uint8 *src,
size_t src_offset, size_t size)
{
uintn shift;
uintn mask_lo, mask_hi;
intn s_idx, d_idx;
/*
* Calculate shifts and masks. See diagrams below. MASK_LO in this
* example is 0x1f (the low five bits) and MASK_HI is 0xe0 (the high three
* bits). SHIFT is three since the source must be shifted right three bits
* to line up with the destination.
*/
shift = (dst_offset%8)-(src_offset%8);
mask_lo = (1<<(8-shift))-1;
mask_hi = ((1<<shift)-1) << (8-shift);
s_idx = src_offset / 8;
d_idx = dst_offset / 8;
/*
* Get things rolling. This means copying bits until we're aligned on a
* source byte. This the following example, four bits are copied to the
* destination.
*
* src[s_idx]
* +---------------+---------------+
* |7 6 5 4 3 2 1 0|7 6 5 4 3 2 1 0|
* +---------------+---------------+
* ... : : : : : | | | | |
* ... v v v v v V V V V V
* ...+---------------+---------------+
* ...|7 6 5 4 3 2 1 0|7 6 5 4 3 2 1 0|
* ...+---------------+---------------+
* dst[d_idx+1] dst[d_idx]
*/
if (src_offset%8 && size>0) {
}
/*
* The middle bits. We are aligned on a source byte which needs to be
* copied to two (or one in the degenerate case) destination bytes.
*
* src[s_idx]
* +---------------+
* |7 6 5 4 3 2 1 0|
* +---------------+
* | | | | | | | |
* V V V V V V V V
* +---------------+---------------+
* |7 6 5 4 3 2 1 0|7 6 5 4 3 2 1 0|
* +---------------+---------------+
* dst[d_idx+1] dst[d_idx]
*
*/
for (/*void*/; size>8; size-=8, d_idx++, s_idx++) {
if (shift) {
dst[d_idx+0] &= mask_lo;
dst[d_idx+0] |= (src[s_idx] << shift) & mask_hi;
dst[d_idx+1] &= mask_hi;
dst[d_idx+1] |= (src[s_idx] >> (8-shift)) & mask_lo;
} else {
dst[d_idx] = src[s_idx];
}
}
/* Finish up */
}
/*-------------------------------------------------------------------------
* Function: H5T_bit_set
*
* Purpose: Sets or clears bits in a contiguous region of a vector
* beginning at bit OFFSET and continuing for SIZE bits.
*
* Return: void
*
* Programmer: Robb Matzke
* Wednesday, June 10, 1998
*
* Modifications:
*
*-------------------------------------------------------------------------
*/
void
H5T_bit_set (uint8 *buf, size_t offset, size_t size, hbool_t value)
{
}
/*-------------------------------------------------------------------------
* Function: H5T_bit_find
*
* Purpose: Finds the first bit with the specified VALUE within a region
* of a bit vector. The region begins at OFFSET and continues
* for SIZE bits, but the region can be searched from the least
* significat end toward the most significant end with
*
* Return: Success: The position of the bit found, relative to
* the offset.
*
* Failure: -1
*
* Programmer: Robb Matzke
* Wednesday, June 10, 1998
*
* Modifications:
*
*-------------------------------------------------------------------------
*/
ssize_t
H5T_bit_find (uint8 *buf, size_t offset, size_t size, H5T_sdir_t direction,
hbool_t value)
{
return -1;
}
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