class Containers::Bitset

Copyright © 2011 Tyler McMullen

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Public Class Methods

from_s(p1) click to toggle source
static VALUE rb_bitset_from_s(VALUE self, VALUE s) {
    int length = RSTRING_LEN(s);
    char* data = StringValuePtr(s);
    Bitset * new_bs = bitset_new();
    int i;

    bitset_setup(new_bs, length);

    for (i = 0; i < length; i++) {
        if (data[i] == '1') {
            _set_bit(new_bs, i);
        }
    }

    return Data_Wrap_Struct(cBitset, 0, bitset_free, new_bs);
}
new(p1) click to toggle source
static VALUE rb_bitset_initialize(VALUE self, VALUE ary) {
    Bitset * bs = get_bitset(self);
    if (RB_TYPE_P(ary, T_ARRAY)) {
        int i;
        int len = (int) RARRAY_LEN(ary);
        bitset_setup(bs, len);
        for (i = 0; i < len; ++i) {
            // This could be more efficient, but if you're converting
            // from a Ruby array of bits, you're not looking
            // at blazing speed anyhow.
            if (RTEST(rb_ary_entry(ary, i))) {
                _set_bit(bs, i);
            }
        }
    } else {
        bitset_setup(bs, NUM2INT(ary));
    }
    return self;
}
unpack(str) click to toggle source

Convert a string created using the pack method back into a bitset.

# File lib/containers/bitset.rb, line 42
def self.unpack str
  bits = str.unpack("b*")[0]
  padding_bits = bits[0...3].to_i(2)
  from_s(bits[3 .. -1 - padding_bits])
end

Public Instance Methods

&(p1)
Alias for: intersect
-(p1)
Alias for: difference
==(p1) click to toggle source
static VALUE rb_bitset_equal(VALUE self, VALUE other) {
    int i;
    Bitset * bs = get_bitset(self);
    Bitset * other_bs = get_bitset(other);
    int max = INTS(bs);

    if (bs->len != other_bs->len)
       return Qfalse;
    for(i = 0; i < max; i++) {
       if (bs->data[i] != other_bs->data[i]) {
          return Qfalse;
       }
    }
    return Qtrue;
}
[](p1) click to toggle source
static VALUE rb_bitset_aref(VALUE self, VALUE index) {
    Bitset * bs = get_bitset(self);
    int idx = NUM2INT(index);
    validate_index(bs, idx);
    return _get_bit(bs, idx) > 0 ? Qtrue : Qfalse;
}
[]=(p1, p2) click to toggle source
static VALUE rb_bitset_aset(VALUE self, VALUE index, VALUE value) {
    Bitset * bs = get_bitset(self);
    int idx = NUM2INT(index);
    validate_index(bs, idx);
    assign_bit(bs, idx, value);
    return Qtrue;
}
^(p1)
Alias for: xor
and(p1)
Alias for: intersect
and!(p1)
Alias for: intersect!
cardinality() click to toggle source
static VALUE rb_bitset_cardinality(VALUE self) {
    Bitset * bs = get_bitset(self);
    return INT2NUM(cardinality(bs));
}
clear(*args) click to toggle source
static VALUE rb_bitset_clear(int argc, VALUE * argv, VALUE self) {
    int i;
    Bitset * bs = get_bitset(self);

    if (argc == 1 && rb_obj_is_kind_of(argv[0], rb_const_get(rb_cObject, rb_intern("Array")))) {
        for(i = 0; i < RARRAY_LEN(argv[0]); i++) {
            VALUE index = RARRAY_PTR(argv[0])[i];
            int idx = NUM2INT(index);
            validate_index(bs, idx);
            _clear_bit(bs, idx);
        }
    } else {
        for(i = 0; i < argc; i++) {
            VALUE index = argv[i];
            int idx = NUM2INT(index);
            validate_index(bs, idx);
            _clear_bit(bs, idx);
        }
    }
    return Qtrue;
}
clear?(*args) click to toggle source
static VALUE rb_bitset_clear_p(int argc, VALUE * argv, VALUE self) {
    int i;
    Bitset * bs = get_bitset(self);
    for(i = 0; i < argc; i++) {
        VALUE index = argv[i];
        int idx = NUM2INT(index);
        validate_index(bs, idx);
        if(_get_bit(bs, idx) > 0)
            return Qfalse;
    }
    return Qtrue;
}
clone()
Alias for: dup
difference(p1) click to toggle source
static VALUE rb_bitset_difference(VALUE self, VALUE other) {
    Bitset * bs = get_bitset(self);
    Bitset * other_bs = get_bitset(other);
    Bitset * new_bs;
    int max = INTS(bs);
    int i;

    verify_equal_size(bs, other_bs);
    new_bs = bitset_new();
    bitset_setup(new_bs, bs->len);

    for(i = 0; i < max; i++) {
        uint64_t segment = bs->data[i];
        uint64_t other_segment = other_bs->data[i];
        new_bs->data[i] = segment & ~other_segment;
    }

    return Data_Wrap_Struct(cBitset, 0, bitset_free, new_bs);
}
Also aliased as: -
difference!(p1) click to toggle source
static VALUE rb_bitset_difference_mutable(VALUE self, VALUE other) {
    return mutable(self, other, &difference);
}
dup() click to toggle source
static VALUE rb_bitset_dup(VALUE self) {
    Bitset * bs = get_bitset(self);
    int max = INTS(bs);

    Bitset * new_bs = bitset_new();
    bitset_setup(new_bs, bs->len);

    memcpy(new_bs->data, bs->data, max * sizeof(bs->data[0]));
    return Data_Wrap_Struct(cBitset, 0, bitset_free, new_bs);
}
Also aliased as: clone
each() click to toggle source
static VALUE rb_bitset_each(VALUE self) {
    Bitset * bs = get_bitset(self);
    int i;

    for(i = 0; i < bs->len; i++) {
        rb_yield(_get_bit(bs, i) ? Qtrue : Qfalse);
    }

    return self;
}
each_set(*args) click to toggle source

Yield the bit numbers of each set bit in sequence to a block. If there is no block, return an array of those numbers.

static VALUE rb_bitset_each_set(int argc, VALUE * argv,  VALUE self) {
    Bitset * bs = get_bitset(self);
    int seg_no;
    int max = INTS(bs);
    uint64_t* seg_ptr = bs->data;
    int block_p = rb_block_given_p();
    VALUE ary = Qnil;
    int set_bit_no = -1;

    /* If there is one argument, it is an index into the notional
       output array, and return an int. If there are two arguments,
       return up to <n> arguments where is the second argument. */
    int min_set_bit_no = (argc > 0) ? NUM2INT(argv[0]) : 0;
    int max_set_bit_no;

    if (argc > 2) {
       VALUE error = rb_const_get(rb_cObject, rb_intern("ArgumentError"));
       rb_raise(error, "wrong number of arguments (given %d, expected 0..2)",
                argc);
    }

    if (min_set_bit_no < 0) {
        /* Convert negative numbers into offsets from the end of the array. */
        min_set_bit_no = cardinality(bs) + min_set_bit_no;
    }

    max_set_bit_no = (argc == 0)
        ? INT_MAX
        : (argc == 1)
        ? (min_set_bit_no + 1)
        : (min_set_bit_no + NUM2INT(argv[1]));

    if (min_set_bit_no < 0 || max_set_bit_no < min_set_bit_no)
        return Qnil;

    if (argc != 1 && !block_p) {
       ary = rb_ary_new();
    }
    if (min_set_bit_no < 0 || max_set_bit_no < min_set_bit_no)
        return Qnil;

    for (seg_no = 0; seg_no < max; ++seg_no, ++seg_ptr) {
       uint64_t segment = *seg_ptr;
       int bit_position = 0;
       bool finished = false;
       while (segment) {
          VALUE v;

          if (!(segment & 1)) {
             int shift = psnip_builtin_ctz64(segment);
             bit_position += shift;
             segment >>= shift;
          }
          v = INT2NUM(_seg_no_to_bit_no(seg_no) + bit_position);
          ++bit_position;
          segment >>= 1;
          ++set_bit_no;
          if (set_bit_no < min_set_bit_no) {
             continue;
          }
          if (set_bit_no >= max_set_bit_no) {
              finished = true;
             break;
          }
          if (block_p) {
             rb_yield(v);
          } else if (argc == 1) {
              return v;
          } else {
             rb_ary_push(ary, v);
          }
       }
       if (finished) {
           break;
       }
    }

    return block_p ? self : ary;
}
Also aliased as: to_a
empty?() click to toggle source
static VALUE rb_bitset_empty_p(VALUE self) {
    Bitset * bs = get_bitset(self);
    int seg_no;
    int max = INTS(bs);
    uint64_t* seg_ptr = bs->data;

    for (seg_no = 0; seg_no < max; ++seg_no, ++seg_ptr) {
       if (*seg_ptr) {
          return Qfalse;
       }
    }
    return Qtrue;
}
flip(*args) click to toggle source
static VALUE rb_bitset_flip(int argc, VALUE * argv, VALUE self) {
    int i;
    Bitset * bs = get_bitset(self);

    if (argc == 1 && rb_obj_is_kind_of(argv[0], rb_const_get(rb_cObject, rb_intern("Array")))) {
        for(i = 0; i < RARRAY_LEN(argv[0]); i++) {
            VALUE index = RARRAY_PTR(argv[0])[i];
            int idx = NUM2INT(index);
            validate_index(bs, idx);
            if (_get_bit(bs, idx) == 0) {
                _set_bit(bs, idx);
            } else {
                _clear_bit(bs, idx);
            }
        }
    } else {
        for(i = 0; i < argc; i++) {
            VALUE index = argv[i];
            int idx = NUM2INT(index);
            validate_index(bs, idx);
            if (_get_bit(bs, idx) == 0) {
                _set_bit(bs, idx);
            } else {
                _clear_bit(bs, idx);
            }
        }
    }
    return Qtrue;
}
hamming(p1) click to toggle source
static VALUE rb_bitset_hamming(VALUE self, VALUE other) {
    Bitset * bs = get_bitset(self);
    Bitset * other_bs = get_bitset(other);

    int max = INTS(bs);
    int count = 0;
    int i;
    for(i = 0; i < max; i++) {
        uint64_t segment = bs->data[i];
        uint64_t other_segment = other_bs->data[i];
        count += psnip_builtin_popcount64(segment ^ other_segment);
    }

    return INT2NUM(count);
}
inspect()
Alias for: to_s
intersect(p1) click to toggle source
static VALUE rb_bitset_intersect(VALUE self, VALUE other) {
    Bitset * bs = get_bitset(self);
    Bitset * other_bs = get_bitset(other);
    Bitset * new_bs;
    int max = INTS(bs);
    int i;

    verify_equal_size(bs, other_bs);
    new_bs = bitset_new();
    bitset_setup(new_bs, bs->len);

    for(i = 0; i < max; i++) {
        uint64_t segment = bs->data[i];
        uint64_t other_segment = other_bs->data[i];
        new_bs->data[i] = segment & other_segment;
    }

    return Data_Wrap_Struct(cBitset, 0, bitset_free, new_bs);
}
Also aliased as: &, and
intersect!(p1) click to toggle source
static VALUE rb_bitset_intersect_mutable(VALUE self, VALUE other) {
    return mutable(self, other, &and);
}
Also aliased as: and!
length()
Alias for: size
marshal_dump() click to toggle source
static VALUE rb_bitset_marshall_dump(VALUE self) {
    Bitset * bs = get_bitset(self);
    VALUE hash = rb_hash_new();
    VALUE data = rb_str_new((const char *) bs->data, BYTES(bs));

    rb_hash_aset(hash, ID2SYM(rb_intern("len")), UINT2NUM(bs->len));
    rb_hash_aset(hash, ID2SYM(rb_intern("data")), data);

    return hash;
}
marshal_load(p1) click to toggle source
static VALUE rb_bitset_marshall_load(VALUE self, VALUE hash) {
    Bitset * bs = get_bitset(self);
    int len = NUM2INT(rb_hash_aref(hash, ID2SYM(rb_intern("len"))));

    VALUE data = rb_hash_aref(hash, ID2SYM(rb_intern("data")));

    bitset_setup(bs, len);

    bs->data = (uint64_t *) calloc(INTS(bs), sizeof(uint64_t));
    memcpy(bs->data, RSTRING_PTR(data), BYTES(bs));

    return Qnil;
}
not() click to toggle source
static VALUE rb_bitset_not(VALUE self) {
    Bitset * bs = get_bitset(self);
    Bitset * new_bs = bitset_new();
    int max = INTS(bs);
    int i;

    bitset_setup(new_bs, bs->len);
    for(i = 0; i < max; i++) {
        uint64_t segment = bs->data[i];
        new_bs->data[i] = ~segment;
    }
    if(_bit_no(bs->len) != 0)
        new_bs->data[max-1] &= _bit_mask(bs->len) - 1;

    return Data_Wrap_Struct(cBitset, 0, bitset_free, new_bs);
}
Also aliased as: ~
or(p1)
Alias for: union
or!(p1)
Alias for: union!
pack() click to toggle source

You could make a good case that this is redundant with Marshal.dump and Marshal.load, but it does save a few bytes.

# File lib/containers/bitset.rb, line 34
def pack
  # Number of bits of zero padding in this representation.
  padding_bits = (size+3) & 7
  padding_bits = (padding_bits == 0) ? 0 : (8 - padding_bits)
  [("%03b" % padding_bits) + self.to_s].pack("b*")
end
reset!() click to toggle source
static VALUE rb_bitset_reset(VALUE self) {
    Bitset * bs = get_bitset(self);
    memset(bs->data, 0, (INTS(bs) * sizeof(uint64_t)) );
    return self;
}
reverse() click to toggle source

This could run a bit faster if you worked at it.

static VALUE rb_bitset_reverse(VALUE self, VALUE index_array) {
    int i;
    Bitset * bs = get_bitset(self);
    int len = bs->len;
    Bitset * new_bs = bitset_new();
    bitset_setup(new_bs, len);
    for (i = 0; i < len; ++i) {
       if (_get_bit(bs, i)) {
          _set_bit(new_bs, len - i - 1);
       }
    }

    return Data_Wrap_Struct(cBitset, 0, bitset_free, new_bs);
}
select_bits(p1)
Alias for: values_at
set(*args) click to toggle source
static VALUE rb_bitset_set(int argc, VALUE * argv, VALUE self) {
    int i;
    Bitset * bs = get_bitset(self);

    if (argc == 1 && rb_obj_is_kind_of(argv[0], rb_const_get(rb_cObject, rb_intern("Array")))) {
        for(i = 0; i < RARRAY_LEN(argv[0]); i++) {
            VALUE index = RARRAY_PTR(argv[0])[i];
            int idx = NUM2INT(index);
            validate_index(bs, idx);
            _set_bit(bs, idx);
        }
    } else {
        for(i = 0; i < argc; i++) {
            VALUE index = argv[i];
            int idx = NUM2INT(index);
            validate_index(bs, idx);
            _set_bit(bs, idx);
        }
    }
    return Qtrue;
}
set?(*args) click to toggle source
static VALUE rb_bitset_set_p(int argc, VALUE * argv, VALUE self) {
    int i;
    Bitset * bs = get_bitset(self);
    for(i = 0; i < argc; i++) {
        VALUE index = argv[i];
        int idx = NUM2INT(index);
        validate_index(bs, idx);
        if(_get_bit(bs, idx) == 0)
            return Qfalse;
    }
    return Qtrue;
}
size() click to toggle source
static VALUE rb_bitset_size(VALUE self) {
    Bitset * bs = get_bitset(self);
    return INT2NUM(bs->len);
}
Also aliased as: length
symmetric_difference(p1)
Alias for: xor
symmetric_difference!(p1)
Alias for: xor!
to_a(*args)

Yield the bit numbers of each set bit in sequence to a block. If there is no block, return an array of those numbers.

Alias for: each_set
to_binary_array() click to toggle source
static VALUE rb_bitset_to_binary_array(VALUE self) {
    Bitset * bs = get_bitset(self);
    int i;

    VALUE array = rb_ary_new2(bs->len / 2);
    for(i = 0; i < bs->len; i++) {
        rb_ary_push(array, INT2NUM(_get_bit(bs, i) > 0 ? 1 : 0));
    }

    return array;
}
to_s() click to toggle source
static VALUE rb_bitset_to_s(VALUE self) {
    Bitset * bs = get_bitset(self);

    int i;
    char * data = malloc(bs->len + 1);
    for(i = 0; i < bs->len; i++) {
        data[i] = _get_bit(bs, i)  ? '1' : '0';
    }
    data[bs->len] = 0;

    return rb_str_new2(data);
}
Also aliased as: inspect
union(p1) click to toggle source
static VALUE rb_bitset_union(VALUE self, VALUE other) {
    Bitset * bs = get_bitset(self);
    Bitset * other_bs = get_bitset(other);
    Bitset * new_bs;
    int max = INTS(bs);
    int i;

    verify_equal_size(bs, other_bs);
    new_bs = bitset_new();
    bitset_setup(new_bs, bs->len);

    for(i = 0; i < max; i++) {
        uint64_t segment = bs->data[i];
        uint64_t other_segment = other_bs->data[i];
        new_bs->data[i] = segment | other_segment;
    }

    return Data_Wrap_Struct(cBitset, 0, bitset_free, new_bs);
}
Also aliased as: |, or
union!(p1) click to toggle source
static VALUE rb_bitset_union_mutable(VALUE self, VALUE other) {
    return mutable(self, other, &or);
}
Also aliased as: or!
values_at(p1) click to toggle source
static VALUE rb_bitset_values_at(VALUE self, VALUE index_array) {
    int i;
    Bitset * bs = get_bitset(self);
    int blen = bs->len;
    int alen = RARRAY_LEN(index_array);
    VALUE *ptr = RARRAY_PTR(index_array);
    Bitset * new_bs = bitset_new();
    bitset_setup(new_bs, alen);
    for (i = 0; i < alen; ++i) {
       int idx = NUM2INT(ptr[i]);
       if (idx >= 0 && idx < blen && _get_bit(bs, idx)) {
          _set_bit(new_bs, i);
       }
    }

    return Data_Wrap_Struct(cBitset, 0, bitset_free, new_bs);
}
Also aliased as: select_bits
xor(p1) click to toggle source
static VALUE rb_bitset_xor(VALUE self, VALUE other) {
    Bitset * bs = get_bitset(self);
    Bitset * other_bs = get_bitset(other);
    Bitset * new_bs;
    int max = INTS(bs);
    int i;

    verify_equal_size(bs, other_bs);
    new_bs = bitset_new();
    bitset_setup(new_bs, bs->len);

    for(i = 0; i < max; i++) {
        uint64_t segment = bs->data[i];
        uint64_t other_segment = other_bs->data[i];
        new_bs->data[i] = segment ^ other_segment;
    }

    return Data_Wrap_Struct(cBitset, 0, bitset_free, new_bs);
}
Also aliased as: ^, symmetric_difference
xor!(p1) click to toggle source
static VALUE rb_bitset_xor_mutable(VALUE self, VALUE other) {
    return mutable(self, other, &xor);
}
Also aliased as: symmetric_difference!
|(p1)
Alias for: union
~()
Alias for: not