This class defines a bit field that is part of some larger array or that uses an allocated piece of memory. More...
#include <chomp/struct/bitfield.h>
Public Member Functions | |
| BitField () | |
| The constructor of an undefined bit field. | |
| ~BitField () | |
| The destructor which actually does nothing. | |
| bool | defined () const |
| Returns true if the bit field has already been defined, that is, it is bound with some memory piece, or its memory has been allocated. | |
| void | define (unsigned char *buf, int_t length) |
| Define the bit field as a piece of a larger memory buffer. | |
| void | allocate (int_t length) |
| Allocates memory for a bit field. | |
| void | free () |
| Releases the memory allocated for the bit field. | |
| void | set (int_t n) |
| Sets the given bit to 1. | |
| void | clear (int_t n) |
| Clears the given bit (sets it to 0). | |
| int | test (int_t n) const |
| Tests the given bit. Returns 0 or 1. | |
| void | takebits (const BitField &from, int_t length) |
| Copies all the bits from the given bitfield. | |
| void | clearall (int_t length) |
| Clears all the bits in the entire bit field of specified length. | |
| int | find (int_t after, int_t length) const |
| Finds the first bit that is set to 1, beginning at the given one. | |
| int_t | hashkey (int_t length) const |
| Returns the first key for hashing. | |
| int_t | hashadd (int_t length) const |
| Returns the second key for hashing. | |
Private Attributes | |
| unsigned char * | table |
| The table of 8-bit cells which store the subsequent bits. | |
Friends | |
| bool | thesame (const BitField &b1, const BitField &b2, int_t length) |
| Compares two bit fields of the giben length. | |
| void | int2bits (int bits, int_t length, BitField &field) |
| Converts an integer into the bits of a bit field of the given length. | |
| int | bits2int (const BitField &field, int_t length) |
| Converts the bits of a bit field of the given length into an integer. | |
This class defines a bit field that is part of some larger array or that uses an allocated piece of memory.
This class may be useful for efficient management of multiple bit fields, or just one bit field. Note the very specific behavior of memory management!
Definition at line 73 of file bitfield.h.
| chomp::homology::BitField::BitField | ( | ) | [inline] |
The constructor of an undefined bit field.
Definition at line 160 of file bitfield.h.
References table.
| chomp::homology::BitField::~BitField | ( | ) | [inline] |
The destructor which actually does nothing.
Definition at line 178 of file bitfield.h.
| void chomp::homology::BitField::allocate | ( | int_t | length ) |
Allocates memory for a bit field.
The memory enough to store the given number of bits (the length of the bit field) is allocated with the 'new' operator.
| void chomp::homology::BitField::clear | ( | int_t | n ) | [inline] |
| void chomp::homology::BitField::clearall | ( | int_t | length ) |
Clears all the bits in the entire bit field of specified length.
Note that the bit field itself does not store its length.
| void chomp::homology::BitField::define | ( | unsigned char * | buf, |
| int_t | length | ||
| ) |
Define the bit field as a piece of a larger memory buffer.
The memory enough to store the given number of bits (the length of the bit field) will be used.
| bool chomp::homology::BitField::defined | ( | ) | const [inline] |
Returns true if the bit field has already been defined, that is, it is bound with some memory piece, or its memory has been allocated.
Definition at line 166 of file bitfield.h.
References table.
| int chomp::homology::BitField::find | ( | int_t | after, |
| int_t | length | ||
| ) | const |
Finds the first bit that is set to 1, beginning at the given one.
Return the number of the bit, or -1 if not found. Note that the bit field itself does not store its length, so this length must be provided as an argument of this function.
| void chomp::homology::BitField::free | ( | ) | [inline] |
Releases the memory allocated for the bit field.
This must be used if the memory was allocated, because the destructor does not deallocte the memory.
Definition at line 171 of file bitfield.h.
References table.
| int_t chomp::homology::BitField::hashadd | ( | int_t | length ) | const |
Returns the second key for hashing.
Note that the bit field itself does not store its length, so this length must be provided as an argument of this function.
| int_t chomp::homology::BitField::hashkey | ( | int_t | length ) | const |
Returns the first key for hashing.
Note that the bit field itself does not store its length, so this length must be provided as an argument of this function.
| void chomp::homology::BitField::set | ( | int_t | n ) | [inline] |
| void chomp::homology::BitField::takebits | ( | const BitField & | from, |
| int_t | length | ||
| ) |
Copies all the bits from the given bitfield.
Assumes that both bit fields have the specified length. Note that the bit field itself does not store its length.
| int chomp::homology::BitField::test | ( | int_t | n ) | const [inline] |
| int bits2int | ( | const BitField & | field, |
| int_t | length | ||
| ) | [friend] |
Converts the bits of a bit field of the given length into an integer.
The length must not exceed the size of the integer.
Definition at line 214 of file bitfield.h.
| void int2bits | ( | int | bits, |
| int_t | length, | ||
| BitField & | field | ||
| ) | [friend] |
Converts an integer into the bits of a bit field of the given length.
The length must not exceed the size of the integer.
Definition at line 200 of file bitfield.h.
Compares two bit fields of the giben length.
Returns true if they are the same, false otherwise.
unsigned char* chomp::homology::BitField::table [private] |
The table of 8-bit cells which store the subsequent bits.
It is either an address of some allocated memory, or an address of portion of some other memory, for example, allocated collectively for a large number of bit fields.
Definition at line 154 of file bitfield.h.
Referenced by BitField(), clear(), defined(), free(), set(), and test().
1.7.2