bits

In particular, i want to preset desired size, fetch a bitmap from external source, and then work with data in classy objecty-oriented manner. I presume what TBits isnt just a straightforward collection of Booleans and internal storage is contiguous. Am i correct with such assumptions? Correct, TBits is internally bit-structured, so it's not a straightforward collection of booleans. Yes, storage is handled by allocating contiguous memory big enough to carry the size( in increments of SizeOf(integer)). To get access to the internal data pointer, class helpers can be used. Type TBitsHelper =

Searched the postgresql docs http://www.postgresql.org/docs/8.4/interactive/functions-bitstring.html for information on converting bit varying to integer But couldnt' find any info. select '011111'::bit(4)::varbit(4)::integer as varbit Appreciate your response. Erwin Brandstetter One way: SELECT b, lpad(b::text, 32, '0')::bit(32)::int FROM ( VALUES ('01'::varbit) ,('011111') ,('111') ) t (b); Result: b | lpad -------+------ 01 | 1 011111 | 31 111 | 7 Related answer: Convert hex in text representation to decimal number Let's say our table has 3 columns and 3 rows. We can simulate it with:

I need to store a dynamic array of bits. The C++ reference page on vector< bool > has the following information: The storage is not necessarily an array of bool values, but the library implementation may optimize storage so that each value is stored in a single bit. How do I make sure that my program that uses vector<bool> does in fact store bits in a vector instead of boolean values (bytes)? Don't try to do that. Instead, use boost::dynamic_bitset which clearly indicates what you actually want. The vector<bool> optimization actually creates a number of possibilities for bugs, for example when

I want to find if a bit in a sequense is 1 or 0 (true or false) if i have some bitsequense of 11010011, how can i check if the 4th position is True or False? example: 10010101 (4th bit) -> False 10010101 (3rd bit) -> True Without the slow byte shifting: if bits & 0b1000: ... EDIT: Actually, (1 << 3) is optimized out by the compiler. >>> dis.dis(lambda x: x & (1 << 3)) 1 0 LOAD_FAST 0 (x) 3 LOAD_CONST 3 (8) 6 BINARY_AND 7 RETURN_VALUE >>> dis.dis(lambda x: x & 0b1000) 1 0 LOAD_FAST 0 (x) 3 LOAD_CONST 1 (8) 6 BINARY_AND 7 RETURN_VALUE The two solutions are equivalent, choose the one that looks

I am looking for an efficient way how to easily convert a BitSet to a binary string. Let us say that its usual length would be thousands of bits. For example, lets have this: BitSet bits = new BitSet(8); bits.set(1); bits.set(3); And this is the desired result: String result = toBinaryString(bits); // expected: result = "01010000" I have some ideas in general (streams, etc.), but there might be some obvious standard method I am just missing. So this is the most efficient way I have tried so far: private static class FixedSizeBitSet extends BitSet { private final int nbits; public