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Class: FFI::MemoryPointer

Relationships & Source Files
Super Chains via Extension / Inclusion / Inheritance
Class Chain:
self, Pointer, AbstractMemory
Instance Chain:
self, Pointer, AbstractMemory
Inherits: FFI::Pointer
Defined in: ext/ffi_c/MemoryPointer.c

Overview

A MemoryPointer is a specific Pointer. It points to a memory composed of cells. All cells have the same size.

Examples:

Create a new MemoryPointer

mp = FFI::MemoryPointer.new(:long, 16)   # Create a pointer on a memory of 16 long ints.

Create a new MemoryPointer from a String

mp1 = FFI::MemoryPointer.from_string("this is a string")
# same as:
mp2 = FFI::MemoryPointer.new(:char,16)
mp2.put_string("this is a string")

Constant Summary

AbstractMemory - Inherited

LONG_MAX

Pointer - Inherited

NULL, SIZE

Class Method Summary

Pointer - Inherited

.new

A new instance of Pointer.
.size

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

Instance Attribute Summary

Pointer - Inherited

#autorelease=, #autorelease?, #null?

AbstractMemory - Inherited

#size_limit?

Return true if self has a size limit.

Instance Method Summary

Pointer - Inherited

#+, #==,
#address

Alias for Pointer#to_i.
#free,
#initialize_copy

This method is internally used by #dup and #clone.
#inspect

Alias for Pointer#to_s.
#order

Get or set self‘s endianness.
#read

Read pointer’s contents as type
#read_array_of_type

Read an array of type of length length.
#read_string

Read pointer’s contents as a string, or the first len bytes of the equivalent string if len is not nil.
#read_string_length

Read the first len bytes of pointer’s contents as a string.
#read_string_to_null

Read pointer’s contents as a string.
#slice, #to_i, #to_ptr, #to_s, #type_size,
#write

Write value of type type to pointer’s content.
#write_array_of_type

Write ary in pointer’s contents as type.
#write_string

Write str in pointer’s contents, or first len bytes if len is not nil.
#write_string_length

Write len first bytes of str in pointer’s contents.

AbstractMemory - Inherited

#[], #__copy_from__, #clear,
#freeze

Freeze the AbstractMemory object and unset the writable flag.
#get, #get_array_of_double, #get_array_of_float,
#get_array_of_float32

Alias for AbstractMemory#get_array_of_float.
#get_array_of_float64

Alias for AbstractMemory#get_array_of_double.
#get_array_of_pointer, #get_array_of_string, #get_bytes, #get_double, #get_float,
#get_float32

Alias for AbstractMemory#get_float.
#get_float64

Alias for AbstractMemory#get_double.
#get_pointer, #get_string, #put, #put_array_of_double, #put_array_of_float,
#put_array_of_float32

Alias for AbstractMemory#put_array_of_float.
#put_array_of_float64

Alias for AbstractMemory#put_array_of_double.
#put_array_of_pointer, #put_bytes, #put_double, #put_float,
#put_float32

Alias for AbstractMemory#put_float.
#put_float64

Alias for AbstractMemory#put_double.
#put_pointer, #put_string, #read_array_of_double, #read_array_of_float, #read_array_of_pointer, #read_array_of_string, #read_bytes, #read_double, #read_float, #read_pointer, #size,
#total

Alias for AbstractMemory#size.
#type_size, #write_array_of_double, #write_array_of_float, #write_array_of_pointer, #write_bytes, #write_double, #write_float, #write_pointer

Constructor Details

.new(size, count = 1, clear = true) .new(instance)

[ GitHub ] 

  


# File 'ext/ffi_c/MemoryPointer.c', line 89



static VALUE
memptr_initialize(int argc, VALUE* argv, VALUE self)
{
    VALUE size = Qnil, count = Qnil, clear = Qnil;
    int nargs = rb_scan_args(argc, argv, "12", &size, &count, &clear);

    memptr_malloc(self, rbffi_type_size(size), nargs > 1 ? NUM2LONG(count) : 1,
        RTEST(clear) || clear == Qnil);

    if (rb_block_given_p()) {
        return rb_ensure(rb_yield, self, memptr_free, self);
    }

    return self;
}


  







Class Method Details



  

    

      .from_string(s)  
      Create(a {MemoryPointer} with {s} inside.)  
    

  



  

    
  





  


  [ GitHub ]


  

  


# File 'ext/ffi_c/MemoryPointer.c', line 181



static VALUE
memptr_s_from_string(VALUE klass, VALUE to_str)
{
    VALUE s = StringValue(to_str);
    VALUE args[] = { INT2FIX(1), LONG2NUM(RSTRING_LEN(s) + 1), Qfalse };
    VALUE obj = rb_class_new_instance(3, args, klass);
    rb_funcall(obj, rb_intern("put_string"), 2, INT2FIX(0), s);

    return obj;
}