Class: FFI::Pointer

Inherits:
AbstractMemoryClass
  • Object
show all
Defined in:
lib/ffi/pointer.rb,
ext/ffi_c/Pointer.c

Constant Summary collapse

SIZE = 
Platform::ADDRESS_SIZE / 8
NULL = 
rbffi_NullPointerSingleton

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(*args) ⇒ Object 



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# File 'ext/ffi_c/Pointer.c', line 84

static VALUE
ptr_initialize(int argc, VALUE* argv, VALUE self)
{
    Pointer* p;
    VALUE rbType = Qnil, rbAddress = Qnil;
    int typeSize = 1;

    Data_Get_Struct(self, Pointer, p);

    switch (rb_scan_args(argc, argv, "11", &rbType, &rbAddress)) {
        case 1:
            rbAddress = rbType;
            typeSize = 1;
            break;
        case 2:
            typeSize = rbffi_type_size(rbType);
            break;
        default:
            rb_raise(rb_eArgError, "Invalid arguments");
    }

    if (rb_obj_is_kind_of(rbAddress, rbffi_PointerClass)) {
        Pointer* orig;

        p->parent = rbAddress;
        Data_Get_Struct(rbAddress, Pointer, orig);
        p->memory = orig->memory;

    } else {

        p->memory.address = (void*)(uintptr_t) NUM2LL(rbAddress);
        p->memory.size = LONG_MAX;
        if (p->memory.address == NULL) {
            p->memory.access = 0;
        }
    }

    p->memory.typeSize = typeSize;

    return self;
}

Class Method Details

.size ⇒ Object

Return the size of a pointer on the current platform, in bytes



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# File 'lib/ffi/pointer.rb', line 7

def self.size
  SIZE
end

Instance Method Details

#+(offset) ⇒ Object 



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# File 'ext/ffi_c/Pointer.c', line 127

static VALUE
ptr_plus(VALUE self, VALUE offset)
{
    AbstractMemory* ptr;
    Pointer* p;
    VALUE retval;
    long off = NUM2LONG(offset);

    Data_Get_Struct(self, AbstractMemory, ptr);
    checkBounds(ptr, off, 1);

    retval = Data_Make_Struct(rbffi_PointerClass, Pointer, ptr_mark, -1, p);

    p->memory.address = ptr->address + off;
    p->memory.size = ptr->size == LONG_MAX ? LONG_MAX : ptr->size - off;
    p->memory.ops = &rbffi_AbstractMemoryOps;
    p->memory.access = ptr->access;
    p->memory.typeSize = ptr->typeSize;
    p->parent = self;

    return retval;
}

#==(other) ⇒ Object 



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# File 'ext/ffi_c/Pointer.c', line 172

static VALUE
ptr_equals(VALUE self, VALUE other)
{
    Pointer* ptr;
    
    Data_Get_Struct(self, Pointer, ptr);

    return ptr->memory.address == POINTER(other)->address ? Qtrue : Qfalse;
}

#address ⇒ Object Also known as: to_i 



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# File 'ext/ffi_c/Pointer.c', line 182

static VALUE
ptr_address(VALUE self)
{
    Pointer* ptr;
    
    Data_Get_Struct(self, Pointer, ptr);

    return ULL2NUM((uintptr_t) ptr->memory.address);
}

#inspect ⇒ Object 



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# File 'ext/ffi_c/Pointer.c', line 150

static VALUE
ptr_inspect(VALUE self)
{
    Pointer* ptr;
    char tmp[100];

    Data_Get_Struct(self, Pointer, ptr);
    snprintf(tmp, sizeof(tmp), "#<FFI::Pointer address=%p>", ptr->memory.address);

    return rb_str_new2(tmp);
}

#null? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'ext/ffi_c/Pointer.c', line 162

static VALUE
ptr_null_p(VALUE self)
{
    Pointer* ptr;

    Data_Get_Struct(self, Pointer, ptr);

    return ptr->memory.address == NULL ? Qtrue : Qfalse;
}

#read_array_of_int(length) ⇒ Object 



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# File 'lib/ffi/pointer.rb', line 94

def read_array_of_int(length)
  get_array_of_int32(0, length)
end

#read_array_of_long(length) ⇒ Object 



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# File 'lib/ffi/pointer.rb', line 102

def read_array_of_long(length)
  get_array_of_long(0, length)
end

#read_array_of_pointer(length) ⇒ Object 



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# File 'lib/ffi/pointer.rb', line 110

def read_array_of_pointer(length)
  read_array_of_type(:pointer, :read_pointer, length)
end

#read_array_of_type(type, reader, length) ⇒ Object 



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# File 'lib/ffi/pointer.rb', line 74

def read_array_of_type(type, reader, length)
  ary = []
  size = FFI.type_size(type)
  tmp = self
  length.times { |j|
    ary << tmp.send(reader)
    tmp += size unless j == length-1 # avoid OOB
  }
  ary
end

#read_float ⇒ Object 



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# File 'lib/ffi/pointer.rb', line 46

def read_float
  get_float32(0)
end

#read_int ⇒ Object

Read a C int from the memory pointed to.



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# File 'lib/ffi/pointer.rb', line 16

def read_int
  get_int32(0)
end

#read_long ⇒ Object

Read a C long from the memory pointed to.



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# File 'lib/ffi/pointer.rb', line 26

def read_long
  get_long(0)
end

#read_long_long ⇒ Object

Read a C long long from the memory pointed to.



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# File 'lib/ffi/pointer.rb', line 35

def read_long_long
  get_int64(0)
end

#read_pointer ⇒ Object 



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# File 'lib/ffi/pointer.rb', line 39

def read_pointer
  get_pointer(0)
end

#read_string(len = nil) ⇒ Object 



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# File 'lib/ffi/pointer.rb', line 53

def read_string(len=nil)
  if len
    get_bytes(0, len)
  else
    get_string(0)
  end
end

#read_string_length(len) ⇒ Object 



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# File 'lib/ffi/pointer.rb', line 60

def read_string_length(len)
  get_bytes(0, len)
end

#read_string_to_null ⇒ Object 



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# File 'lib/ffi/pointer.rb', line 63

def read_string_to_null
  get_string(0)
end

#write_array_of_int(ary) ⇒ Object 



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# File 'lib/ffi/pointer.rb', line 98

def write_array_of_int(ary)
  put_array_of_int32(0, ary)
end

#write_array_of_long(ary) ⇒ Object 



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# File 'lib/ffi/pointer.rb', line 106

def write_array_of_long(ary)
  put_array_of_long(0, ary)
end

#write_array_of_pointer(ary) ⇒ Object 



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# File 'lib/ffi/pointer.rb', line 114

def write_array_of_pointer(ary)
  write_array_of_type(:pointer, :write_pointer, ary)
end

#write_array_of_type(type, writer, ary) ⇒ Object 



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# File 'lib/ffi/pointer.rb', line 85

def write_array_of_type(type, writer, ary)
  size = FFI.type_size(type)
  tmp = self
  ary.each_with_index {|i, j|
    tmp.send(writer, i)
    tmp += size unless j == ary.length-1 # avoid OOB
  }
  self
end

#write_float(obj) ⇒ Object 



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# File 'lib/ffi/pointer.rb', line 49

def write_float(obj)
  put_float32(0, obj)
end

#write_int(obj) ⇒ Object

Write obj as a C int at the memory pointed to.



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# File 'lib/ffi/pointer.rb', line 11

def write_int(obj)
  put_int32(0, obj)
end

#write_long(obj) ⇒ Object

Write obj as a C long at the memory pointed to.



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# File 'lib/ffi/pointer.rb', line 21

def write_long(obj)
  put_long(0, obj)
end

#write_long_long(obj) ⇒ Object

Write obj as a C long long at the memory pointed to.



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# File 'lib/ffi/pointer.rb', line 30

def write_long_long(obj)
  put_int64(0, obj)
end

#write_pointer(ptr) ⇒ Object 



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# File 'lib/ffi/pointer.rb', line 42

def write_pointer(ptr)
  put_pointer(0, ptr)
end

#write_string(str, len = nil) ⇒ Object 



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# File 'lib/ffi/pointer.rb', line 69

def write_string(str, len=nil)
  len = str.size unless len
  # Write the string data without NUL termination
  put_bytes(0, str, 0, len)
end

#write_string_length(str, len) ⇒ Object 



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# File 'lib/ffi/pointer.rb', line 66

def write_string_length(str, len)
  put_bytes(0, str, 0, len)
end