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CFBitVector Reference

Overview

CFBitVector and its derived mutable type, CFMutableBitVector, manage ordered collections of bit values, which are either 0 or 1. CFBitVector creates static bit vectors and CFMutableBitVector creates dynamic bit vectors.

Functions by Task

Creating a Bit Vector

• CFBitVectorCreate
• CFBitVectorCreateCopy

Getting Information About a Bit Vector

• CFBitVectorContainsBit
• CFBitVectorGetBitAtIndex
• CFBitVectorGetBits
• CFBitVectorGetCount
• CFBitVectorGetCountOfBit
• CFBitVectorGetFirstIndexOfBit
• CFBitVectorGetLastIndexOfBit

Getting the CFBitVector Type ID

• CFBitVectorGetTypeID

Functions

CFBitVectorContainsBit

Returns whether a bit vector contains a particular bit value.

Boolean CFBitVectorContainsBit (
   CFBitVectorRef bv,
   CFRange range,
   CFBit value
);

Parameters

bv

The bit vector to search.

range

The range of bits in bv to search.

value

The bit value for which to search.

Return Value

true if the specified range of bits in bv contains value, otherwise false.

Availability

• Available in Mac OS X v10.0 and later.

Declared In

CFBitVector.h

CFBitVectorCreate

Creates an immutable bit vector from a block of memory.

CFBitVectorRef CFBitVectorCreate (
   CFAllocatorRef allocator,
   const UInt8 *bytes,
   CFIndex numBits
);

Parameters

allocator

The allocator to use to allocate memory for the new bit vector. Pass NULL or kCFAllocatorDefault to use the current default allocator.

bytes

A pointer to the bit values to store in the new bit vector. The values are copied into the bit vector’s own memory. The bit indices are numbered left-to-right with 0 being the left-most, or most-significant, bit in the byte stream.

numBits

The number of bits in the bit vector.

Return Value

A new bit vector. Ownership follows the Create Rule.

Availability

• Available in Mac OS X v10.0 and later.

Declared In

CFBitVector.h

CFBitVectorCreateCopy

Creates an immutable bit vector that is a copy of another bit vector.

CFBitVectorRef CFBitVectorCreateCopy (
   CFAllocatorRef allocator,
   CFBitVectorRef bv
);

Parameters

allocator

The allocator to use to allocate memory for the new bit vector. Pass NULL or kCFAllocatorDefault to use the current default allocator.

bv

The bit vector to copy.

Return Value

A new bit vector holding the same bit values as bv. Ownership follows the Create Rule.

Availability

• Available in Mac OS X v10.0 and later.

Declared In

CFBitVector.h

CFBitVectorGetBitAtIndex

Returns the bit value at a given index in a bit vector.

CFBit CFBitVectorGetBitAtIndex (
   CFBitVectorRef bv,
   CFIndex idx
);

Parameters

bv

The bit vector to examine.

idx

The index of the bit value in bv to return.

Return Value

The bit value at index idx in bv.

Availability

• Available in Mac OS X v10.0 and later.

Declared In

CFBitVector.h

CFBitVectorGetBits

Returns the bit values in a range of indices in a bit vector.

void CFBitVectorGetBits (
   CFBitVectorRef bv,
   CFRange range,
   UInt8 *bytes
);

Parameters

bv

The bit vector to examine.

range

The range of bit values to return.

bytes

On return, contains the requested bit values from bv. This argument must point to enough memory to hold the number of bits requested. The requested bits are left-aligned with the first requested bit stored in the left-most, or most-significant, bit of the byte stream.

Availability

• Available in Mac OS X v10.0 and later.

Declared In

CFBitVector.h

CFBitVectorGetCount

Returns the number of bit values in a bit vector.

CFIndex CFBitVectorGetCount (
   CFBitVectorRef bv
);

Parameters

bv

The bit vector to examine.

Return Value

The current size of bv.

Availability

• Available in Mac OS X v10.0 and later.

Declared In

CFBitVector.h

CFBitVectorGetCountOfBit

Counts the number of times a certain bit value occurs within a range of bits in a bit vector.

CFIndex CFBitVectorGetCountOfBit (
   CFBitVectorRef bv,
   CFRange range,
   CFBit value
);

Parameters

bv

The bit vector to examine.

range

The range of bits in bv to search.

value

The bit value to count.

Return Value

The number of occurrences of value in the specified range of bv.

Availability

• Available in Mac OS X v10.0 and later.

Declared In

CFBitVector.h

CFBitVectorGetFirstIndexOfBit

Locates the first occurrence of a certain bit value within a range of bits in a bit vector.

CFIndex CFBitVectorGetFirstIndexOfBit (
   CFBitVectorRef bv,
   CFRange range,
   CFBit value
);

Parameters

bv

The bit vector to examine.

range

The range of bits in bv to search.

value

The bit value for which to search.

Return Value

The index of the first occurrence of value in the specified range of bv, or kCFNotFound if value is not present.

Availability

• Available in Mac OS X v10.0 and later.

Declared In

CFBitVector.h

CFBitVectorGetLastIndexOfBit

Locates the last occurrence of a certain bit value within a range of bits in a bit vector.

CFIndex CFBitVectorGetLastIndexOfBit (
   CFBitVectorRef bv,
   CFRange range,
   CFBit value
);

Parameters

bv

The bit vector to examine.

range

The range of bits in bv to search.

value

The bit value for which to search.

Return Value

The index of the last occurrence of value in the specified range of bv, or kCFNotFound if value is not present.

Availability

• Available in Mac OS X v10.0 and later.

Declared In

CFBitVector.h

CFBitVectorGetTypeID

Returns the type identifier for the CFBitVector opaque type.

CFTypeID CFBitVectorGetTypeID (
   void
);

Return Value

The type identifier for the CFBitVector opaque type.

Discussion

CFMutableBitVector objects have the same type identifier as CFBitVector objects.

Availability

• Available in Mac OS X v10.0 and later.

Declared In

CFBitVector.h

Data Types

CFBit

A binary value of either 0 or 1.

typedef UInt32 CFBit;

Availability

• Available in Mac OS X v10.0 and later.

Declared In

CFBitVector.h

CFBitVectorRef

A reference to an immutable bit vector object.

typedef const struct __CFBitVector *CFBitVectorRef;

Availability

• Available in Mac OS X v10.0 and later.

Declared In

CFBitVector.h

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