Class: CBloomFilter

Inherits:
Object
  • Object
show all
Defined in:
ext/cbloomfilter/cbloomfilter.c

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.new(*args) ⇒ Object 



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# File 'ext/cbloomfilter/cbloomfilter.c', line 80

static VALUE bf_s_new(int argc, VALUE *argv, VALUE self) {
    struct BloomFilter *bf;
    VALUE arg1, arg2, arg3, arg4, arg5, obj;
    int m, k, s, b, r, bytes;

    obj = Data_Make_Struct(self, struct BloomFilter, NULL, bits_free, bf);

    /* default = Fugou approach :-) */
    arg1 = INT2FIX(100000000);
    arg2 = INT2FIX(4);
    arg3 = INT2FIX(0);
    arg4 = INT2FIX(1);
    arg5 = INT2FIX(0);

    switch (argc) {
        case 5:
      if (argv[4] == Qtrue) {
        arg5 = INT2FIX(1);
      }
        case 4:
      arg4 = argv[3];
        case 3:
      arg3 = argv[2];
        case 2:
      arg2 = argv[1];
        case 1:
      arg1 = argv[0];
      break;
    }

    m = FIX2INT(arg1);
    k = FIX2INT(arg2);
    s = FIX2INT(arg3);
    b = FIX2INT(arg4);
    r = FIX2INT(arg5);

    if (b < 1 || b > 8)
        rb_raise(rb_eArgError, "bucket size");
    if (m < 1)
        rb_raise(rb_eArgError, "array size");
    if (k < 1)
        rb_raise(rb_eArgError, "hash length");
    if (s < 0)
        rb_raise(rb_eArgError, "random seed");

    bf->b = b;
    bf->m = m;
    bf->k = k;
    bf->s = s;
    bf->r = r;
    bf->num_set = 0;

    bf->bytes = ((m * b) + 15) / 8;
    bf->ptr = ALLOC_N(unsigned char, bf->bytes);

    /* initialize the bits with zeros */
    memset(bf->ptr, 0, bf->bytes);
    rb_iv_set(obj, "@hash_value", rb_hash_new());

    return obj;
}

Instance Method Details

#b ⇒ Object 



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# File 'ext/cbloomfilter/cbloomfilter.c', line 161

static VALUE bf_b(VALUE self) {
    struct BloomFilter *bf;
    Data_Get_Struct(self, struct BloomFilter, bf);
    return INT2FIX(bf->b);
}

#bitmap ⇒ Object 



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# File 'ext/cbloomfilter/cbloomfilter.c', line 308

static VALUE bf_bitmap(VALUE self) {
    struct BloomFilter *bf;
    Data_Get_Struct(self, struct BloomFilter, bf);

    VALUE str = rb_str_new(0, bf->m);
    unsigned char* ptr = (unsigned char *) RSTRING_PTR(str);

    int i;
    for (i = 0; i < bf->m; i++)
        *ptr++ = bucket_get(bf, i);

    return str;
}

#clear ⇒ Object 



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# File 'ext/cbloomfilter/cbloomfilter.c', line 142

static VALUE bf_clear(VALUE self) {
    struct BloomFilter *bf;
    Data_Get_Struct(self, struct BloomFilter, bf);
    memset(bf->ptr, 0, bf->bytes);
    return Qtrue;
}

#delete(key) ⇒ Object 



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# File 'ext/cbloomfilter/cbloomfilter.c', line 221

static VALUE bf_delete(VALUE self, VALUE key) {
    int index, seed;
    int i, len, m, k, s;
    char *ckey;
    VALUE skey;
    struct BloomFilter *bf;
    Data_Get_Struct(self, struct BloomFilter, bf);

    skey = rb_obj_as_string(key);
    ckey = StringValuePtr(skey);
    len = (int) (RSTRING_LEN(skey)); /* length of the string in bytes */

    m = bf->m;
    k = bf->k;
    s = bf->s;

    for (i = 0; i <= k - 1; i++) {
        /* seeds for hash functions */
        seed = i + s;

        /* hash */
        index = (int) (crc32((unsigned int) (seed), ckey, len) % (unsigned int) (m));

        /*  set a bit at the index */
        bucket_unset(bf, index);
    }

    bf->num_set += 1;
    return Qnil;
}

#include?(*args) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'ext/cbloomfilter/cbloomfilter.c', line 253

static VALUE bf_include(int argc, VALUE* argv, VALUE self) {
    int index, seed;
    int i, len, m, k, s, tests_idx, vlen;
    char *ckey;
    VALUE tests, key, skey;
    struct BloomFilter *bf;

    rb_scan_args(argc, argv, "*", &tests);

    Data_Get_Struct(self, struct BloomFilter, bf);
    vlen = RARRAY_LEN(tests);
    for(tests_idx = 0; tests_idx < vlen; tests_idx++) {
      key = rb_ary_entry(tests, tests_idx);
      skey = rb_obj_as_string(key);
      ckey = StringValuePtr(skey);
      len = (int) (RSTRING_LEN(skey)); /* length of the string in bytes */

      m = bf->m;
      k = bf->k;
      s = bf->s;

      for (i = 0; i <= k - 1; i++) {
          /* seeds for hash functions */
          seed = i + s;

          /* hash */
          index = (int) (crc32((unsigned int) (seed), ckey, len) % (unsigned int) (m));

          /* check the bit at the index */
          if (!bucket_check(bf, index)) {
              return Qfalse; /* i.e., it is a new entry ; escape the loop */
          }
      }

      return Qtrue;
    }

}

#insert(key) ⇒ Object 



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# File 'ext/cbloomfilter/cbloomfilter.c', line 179

static VALUE bf_insert(VALUE self, VALUE key) {
    VALUE skey;
    int index, seed;
    int i, len, m, k, s;
    char *ckey;
    struct BloomFilter *bf;
    Data_Get_Struct(self, struct BloomFilter, bf);

    skey = rb_obj_as_string(key);
    ckey = StringValuePtr(skey);
    len = (int) (RSTRING_LEN(skey)); /* length of the string in bytes */

    m = bf->m;
    k = bf->k;
    s = bf->s;

    for (i = 0; i <= k - 1; i++) {
        /* seeds for hash functions */
        seed = i + s;

        /* hash */
        index = (int) (crc32((unsigned int) (seed), ckey, len) % (unsigned int) (m));

        /*  set a bit at the index */
        bucket_set(bf, index);
    }

    bf->num_set += 1;
    return Qnil;
}

#k ⇒ Object 



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# File 'ext/cbloomfilter/cbloomfilter.c', line 155

static VALUE bf_k(VALUE self) {
    struct BloomFilter *bf;
    Data_Get_Struct(self, struct BloomFilter, bf);
    return INT2FIX(bf->k);
}

#load(bitmap) ⇒ Object 



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# File 'ext/cbloomfilter/cbloomfilter.c', line 322

static VALUE bf_load(VALUE self, VALUE bitmap) {
    struct BloomFilter *bf;
    Data_Get_Struct(self, struct BloomFilter, bf);
    unsigned char* ptr = (unsigned char *) RSTRING_PTR(bitmap);

    int i;
    for (i = 0; i < bf->m; i++) {
      if (*ptr++)
        bucket_set(bf, i);
    }

    return Qnil;
}

#m ⇒ Object 



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# File 'ext/cbloomfilter/cbloomfilter.c', line 149

static VALUE bf_m(VALUE self) {
    struct BloomFilter *bf;
    Data_Get_Struct(self, struct BloomFilter, bf);
    return INT2FIX(bf->m);
}

#merge!(other) ⇒ Object 



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# File 'ext/cbloomfilter/cbloomfilter.c', line 210

static VALUE bf_merge(VALUE self, VALUE other) {
    struct BloomFilter *bf, *target;
    Data_Get_Struct(self, struct BloomFilter, bf);
    Data_Get_Struct(other, struct BloomFilter, target);
    int i;
    for (i = 0; i < bf->bytes; i++) {
        bf->ptr[i] |= target->ptr[i];
    }
    return Qnil;
}

#num_set ⇒ Object 



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# File 'ext/cbloomfilter/cbloomfilter.c', line 173

static VALUE bf_num_set(VALUE self) {
    struct BloomFilter *bf;
    Data_Get_Struct(self, struct BloomFilter, bf);
    return INT2FIX(bf->num_set);
}

#r ⇒ Object 



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# File 'ext/cbloomfilter/cbloomfilter.c', line 167

static VALUE bf_r(VALUE self) {
    struct BloomFilter *bf;
    Data_Get_Struct(self, struct BloomFilter, bf);
    return bf->r == 0 ? Qfalse : Qtrue;
}

#to_s ⇒ Object 



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# File 'ext/cbloomfilter/cbloomfilter.c', line 292

static VALUE bf_to_s(VALUE self) {
    struct BloomFilter *bf;
    unsigned char *ptr;
    int i;
    VALUE str;

    Data_Get_Struct(self, struct BloomFilter, bf);
    str = rb_str_new(0, bf->m);

    ptr = (unsigned char *) RSTRING_PTR(str);
    for (i = 0; i < bf->m; i++)
        *ptr++ = bucket_get(bf, i) ? '1' : '0';

    return str;
}