Class: Kmp::String

Inherits:
Object
  • Object
show all
Defined in:
lib/kmp/string.rb,
ext/kmp/kmp_string.c

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(rb_string) ⇒ Object 



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# File 'ext/kmp/kmp_string.c', line 23

static VALUE initialize(VALUE self, VALUE rb_string)
{
    struct Str * str;

    Check_Type(rb_string, T_STRING);
    Data_Get_Struct(self, struct Str, str);

    str->ptr = calloc(RSTRING_LEN(rb_string) + 1 , sizeof(char));
    memcpy(str->ptr, StringValuePtr(rb_string), RSTRING_LEN(rb_string));

    rb_iv_set(self, "@str", rb_string);
    rb_iv_set(self, "@length", INT2NUM(RSTRING_LEN(rb_string)));

    return self;
}

Instance Attribute Details

#length ⇒ Object (readonly)

#str ⇒ Object (readonly)

Instance Method Details

#inspect ⇒ Object 



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# File 'lib/kmp/string.rb', line 3

def inspect
  str
end

#match(rb_str) ⇒ Object 



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# File 'ext/kmp/kmp_string.c', line 57

static VALUE match(VALUE self, VALUE rb_str)
{
    VALUE positions = rb_ary_new();
    struct Str * obj;
    char * str;
    char * ptrn;
    int * prefix;
    int n,m,q;

    Data_Get_Struct(self, struct Str, obj);
    str = calloc(strlen(obj->ptr) + 1, sizeof(char));
    strcpy(str, obj->ptr);

    ptrn = (char *) calloc(RSTRING_LEN(rb_str) + 1, sizeof(char));
    memcpy(ptrn, StringValuePtr(rb_str), RSTRING_LEN(rb_str));

    prefix = compute_prefix(ptrn);

    n = strlen(str);
    m = strlen(ptrn);

    q = -1;
    for(int i=0; i<n; i++)
    {
        while( q>-1 && ptrn[q+1]!=str[i] ) q = prefix[q];
        if( ptrn[q+1]==str[i] ) q = q+1;
        if( q==m-1 )
        {
            rb_ary_push(positions, INT2NUM(i-m+1));
            q = prefix[q];
        }
    }
    free(prefix);
    free(ptrn);
    free(str);

    return positions;
}