bit tag data More...

#include <BitPage.hpp>

Public Member Functions
	BitPage (int bits_per_ent, unsigned char init_val)
	Initialize memory.
void	get_bits (int offset, int count, int bits_per_ent, unsigned char *data) const
	Get tag values.
void	set_bits (int offset, int count, int bits_per_ent, const unsigned char *data)
	Set tag values.
void	set_bits (int offset, int count, int bits_per_ent, unsigned char value)
	Set several tag values to the same value.
unsigned char	get_bits (int offset, int bits_per_ent) const
	Get tag value.
void	set_bits (int offset, int bits_per_ent, unsigned char data)
	Set tag value.
void	search (unsigned char value, int offset, int count, int bits_per_ent, Range &results, EntityHandle start) const
	Search stored values for specified value.
Private Attributes
char	byteArray [BitTag::PageSize]
	The actual array of bytes.

Detailed Description

bit tag data

This class represents a fixed-size block of memory in which bit tag values are stored.

Definition at line 17 of file BitPage.hpp.

Constructor & Destructor Documentation

moab::BitPage::BitPage	(	int	bits_per_ent,
		unsigned char	init_val
	)

Initialize memory.

Parameters:

bits_per_ent	Number of bits in each tag value. MUST BE A POWER OF TWO.
init_val	The lower bits_per_ent bits of this byte are used to initialize each tag value.

Definition at line 22 of file BitPage.cpp.

References byteArray, and moab::BitTag::PageSize.

{
    unsigned char mask = (unsigned char)( 1 << per_ent ) - 1;  // 2^per_ent - 1
    init_val &= (unsigned char)mask;
    switch( per_ent )
    {
        default:
            assert( false );
            abort();
            break;  // must be power of two

            // Note: fall through such that all bits in init_val are set, but with odd structure to avoid
        // fall-through warnings
        case 1:
            init_val |= (unsigned char)( init_val << 1 );
            // fall through
        case 2:
            init_val |= (unsigned char)( init_val << 2 );
            // fall through
        case 4:
            init_val |= (unsigned char)( init_val << 4 );
            // fall through
        case 8:;
    }
    memset( byteArray, init_val, BitTag::PageSize );
}

Member Function Documentation

void moab::BitPage::get_bits	(	int	offset,
		int	count,
		int	bits_per_ent,
		unsigned char *	data
	)		const `[inline]`

Get tag values.

Get 'count' tag values, beginning with the one at 'offset'.

Parameters:

offset	Offset into list of values, where a value of zero indicates the first tag value, a value of one indicates the second tag value, etc. NOTE: This is the value offset, not the bit offset.
count	Number of consecutive tag values to get.
bits_per_ent	Number of bits composing each tag value. NOTE: Must be a power of two.
data	Memory into which to copy tag values. Each value is copied into a separate byte, such that the lower bits of the bit contain the tag value and any unused higher bits are zero.

Definition at line 149 of file BitPage.hpp.

Referenced by search().

{
    unsigned char* end = data + count;
    while( data != end )
        *( data++ ) = get_bits( offset++, per_ent );
}

unsigned char moab::BitPage::get_bits	(	int	offset,
		int	bits_per_ent
	)		const `[inline]`

Get tag value.

Get one tag value.

Parameters:

offset	Offset into list of values, where a value of zero indicates the first tag value, a value of one indicates the second tag value, etc. NOTE: This is the value offset, not the bit offset.
bits_per_ent	Number of bits composing each tag value. NOTE: Must be a power of two.

Returns:: A byte containing the tag value in the lower bits with any unused higher bits zeroed.

Definition at line 127 of file BitPage.hpp.

References byteArray, and moab::BitTag::PageSize.

{
    // Assume per_ent is a power of two, which should be guaranteed
    // by higher-level code.
    unsigned char mask = (unsigned char)( 1 << per_ent ) - 1;  // 2^per_ent - 1
    int byte           = ( offset * per_ent ) >> 3;            // shifting 3 is dividing by eight
    int bit            = ( offset * per_ent ) & 7;             // masking with 7 is modulo eight
    assert( byte < BitTag::PageSize );
    return (unsigned char)( byteArray[byte] >> bit ) & mask;
}

void moab::BitPage::search	(	unsigned char	value,
		int	offset,
		int	count,
		int	bits_per_ent,
		Range &	results,
		EntityHandle	start
	)		const

Search stored values for specified value.

Find the offsets n in the data at which the specified value occurs, and for each one insert 'start + n' into the passed Range.

Parameters:

value	The value to look for
offset	The offset at which to begin searching
count	The number of values to search
bits_per_ent	Number of bits composing each tag value.
results	Result list.
start	The handle of the entity corresponding to the tag value stored at 'offset'

Definition at line 9 of file BitPage.cpp.

References moab::Range::begin(), get_bits(), and moab::Range::insert().

{
    const int end        = offset + count;
    Range::iterator hint = results.begin();
    while( offset != end )
    {
        if( get_bits( offset, per_ent ) == value ) hint = results.insert( hint, start );
        ++offset;
        ++start;
    }
}

void moab::BitPage::set_bits	(	int	offset,
		int	count,
		int	bits_per_ent,
		const unsigned char *	data
	)		`[inline]`

Set tag values.

Set 'count' tag values, beginning with the one at 'offset'.

Parameters:

offset	Offset into list of values, where a value of zero indicates the first tag value, a value of one indicates the second tag value, etc. NOTE: This is the value offset, not the bit offset.
count	Number of consecutive tag values to set.
bits_per_ent	Number of bits composing each tag value. NOTE: Must be a power of two.
data	Memory from which to copy tag values. Each value is copied from a separate byte. The lower 'bits_per_ent' of each byte are used as the tag value. Any additional higher bits are ignored.

Definition at line 156 of file BitPage.hpp.

Referenced by set_bits().

{
    const unsigned char* end = data + count;
    while( data != end )
        set_bits( offset++, per_ent, *( data++ ) );
}

void moab::BitPage::set_bits	(	int	offset,
		int	count,
		int	bits_per_ent,
		unsigned char	value
	)		`[inline]`

Set several tag values to the same value.

Set 'count' tag values to specified value.

Parameters:

offset	Offset into list of values, where a value of zero indicates the first tag value, a value of one indicates the second tag value, etc. NOTE: This is the value offset, not the bit offset.
count	Number of consecutive tag values to set.
bits_per_ent	Number of bits composing each tag value. NOTE: Must be a power of two.
value	The lower 'bits_per_ent' of this byte are used as the tag value. Any additional higher bits are ignored.

Definition at line 163 of file BitPage.hpp.

References set_bits().

{
    int end = offset + count;
    while( offset < end )
        set_bits( offset++, per_ent, value );
}

void moab::BitPage::set_bits	(	int	offset,
		int	bits_per_ent,
		unsigned char	data
	)		`[inline]`

Set tag value.

Parameters:

offset	Offset into list of values, where a value of zero indicates the first tag value, a value of one indicates the second tag value, etc. NOTE: This is the value offset, not the bit offset.
bits_per_ent	Number of bits composing each tag value. NOTE: Must be a power of two.
value	The lower 'bits_per_ent' of this byte are used as the tag value. Any additional higher bits are ignored.

Definition at line 138 of file BitPage.hpp.

References byteArray, and moab::BitTag::PageSize.

{
    int byte = ( offset * per_ent ) >> 3;  // shifting 3 is dividing by eight
    int bit  = ( offset * per_ent ) & 7;   // masking with 7 is modulo eight
    assert( byte < BitTag::PageSize );
    // Assume per_ent is a power of two, which should be guaranteed
    // by higher-level code.
    unsigned char mask = (unsigned char)( ( 1 << per_ent ) - 1 ) << bit;
    byteArray[byte]    = (char)( ( byteArray[byte] & ~mask ) | ( ( bits << bit ) & mask ) );
}

Member Data Documentation

char moab::BitPage::byteArray[BitTag::PageSize] [private]

The actual array of bytes.

Definition at line 124 of file BitPage.hpp.

Referenced by BitPage(), get_bits(), and set_bits().

List of all members.

The documentation for this class was generated from the following files:

Public Member Functions

Private Attributes

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation