Class: Fiddle::Pointer

Inherits:
Object
  • Object
show all
Defined in:
pointer.c,
pointer.c

Overview

Fiddle::Pointer is a class to handle C pointers

Direct Known Subclasses

CStructEntity

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#Fiddle::Pointer.new(address) ⇒ Object #new(address, size) ⇒ Object #new(address, size, freefunc) ⇒ Object

Create a new pointer to address with an optional size and freefunc.

freefunc will be called when the instance is garbage collected.


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# File 'pointer.c', line 157

static VALUE
rb_fiddle_ptr_initialize(int argc, VALUE argv[], VALUE self)
{
    VALUE ptr, sym, size, wrap = 0, funcwrap = 0;
    struct ptr_data *data;
    void *p = NULL;
    freefunc_t f = NULL;
    long s = 0;

    if (rb_scan_args(argc, argv, "12", &ptr, &size, &sym) >= 1) {
	VALUE addrnum = rb_Integer(ptr);
	if (addrnum != ptr) wrap = ptr;
	p = NUM2PTR(addrnum);
    }
    if (argc >= 2) {
	s = NUM2LONG(size);
    }
    if (argc >= 3) {
	f = get_freefunc(sym, &funcwrap);
    }

    if (p) {
	TypedData_Get_Struct(self, struct ptr_data, &fiddle_ptr_data_type, data);
	if (data->ptr && data->free) {
	    /* Free previous memory. Use of inappropriate initialize may cause SEGV. */
	    (*(data->free))(data->ptr);
	}
	data->wrap[0] = wrap;
	data->wrap[1] = funcwrap;
	data->ptr  = p;
	data->size = s;
	data->free = f;
    }

    return Qnil;
}

Class Method Details

.Fiddle::PointerObject .to_ptr(val) ⇒ Object

Get the underlying pointer for ruby object val and return it as a Fiddle::Pointer object.


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# File 'pointer.c', line 641

static VALUE
rb_fiddle_ptr_s_to_ptr(VALUE self, VALUE val)
{
    VALUE ptr, wrap = val, vptr;

    if (RTEST(rb_obj_is_kind_of(val, rb_cIO))){
	rb_io_t *fptr;
	FILE *fp;
	GetOpenFile(val, fptr);
	fp = rb_io_stdio_file(fptr);
	ptr = rb_fiddle_ptr_new(fp, 0, NULL);
    }
    else if (RTEST(rb_obj_is_kind_of(val, rb_cString))){
	char *str = StringValuePtr(val);
	ptr = rb_fiddle_ptr_new(str, RSTRING_LEN(val), NULL);
    }
    else if ((vptr = rb_check_funcall(val, id_to_ptr, 0, 0)) != Qundef){
	if (rb_obj_is_kind_of(vptr, rb_cPointer)){
	    ptr = vptr;
	    wrap = 0;
	}
	else{
	    rb_raise(rb_eFiddleError, "to_ptr should return a Fiddle::Pointer object");
	}
    }
    else{
	VALUE num = rb_Integer(val);
	if (num == val) wrap = 0;
	ptr = rb_fiddle_ptr_new(NUM2PTR(num), 0, NULL);
    }
    if (wrap) RPTR_DATA(ptr)->wrap[0] = wrap;
    return ptr;
}

.Fiddle::Pointer.malloc(size, freefunc = nil) ⇒ Object

Allocate size bytes of memory and associate it with an optional freefunc that will be called when the pointer is garbage collected.

freefunc must be an address pointing to a function or an instance of Fiddle::Function


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# File 'pointer.c', line 205

static VALUE
rb_fiddle_ptr_s_malloc(int argc, VALUE argv[], VALUE klass)
{
    VALUE size, sym, obj, wrap = 0;
    long s;
    freefunc_t f;

    switch (rb_scan_args(argc, argv, "11", &size, &sym)) {
      case 1:
	s = NUM2LONG(size);
	f = NULL;
	break;
      case 2:
	s = NUM2LONG(size);
	f = get_freefunc(sym, &wrap);
	break;
      default:
	rb_bug("rb_fiddle_ptr_s_malloc");
    }

    obj = rb_fiddle_ptr_malloc(s,f);
    if (wrap) RPTR_DATA(obj)->wrap[1] = wrap;

    return obj;
}

.Fiddle::PointerObject .to_ptr(val) ⇒ Object

Get the underlying pointer for ruby object val and return it as a Fiddle::Pointer object.


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# File 'pointer.c', line 641

static VALUE
rb_fiddle_ptr_s_to_ptr(VALUE self, VALUE val)
{
    VALUE ptr, wrap = val, vptr;

    if (RTEST(rb_obj_is_kind_of(val, rb_cIO))){
	rb_io_t *fptr;
	FILE *fp;
	GetOpenFile(val, fptr);
	fp = rb_io_stdio_file(fptr);
	ptr = rb_fiddle_ptr_new(fp, 0, NULL);
    }
    else if (RTEST(rb_obj_is_kind_of(val, rb_cString))){
	char *str = StringValuePtr(val);
	ptr = rb_fiddle_ptr_new(str, RSTRING_LEN(val), NULL);
    }
    else if ((vptr = rb_check_funcall(val, id_to_ptr, 0, 0)) != Qundef){
	if (rb_obj_is_kind_of(vptr, rb_cPointer)){
	    ptr = vptr;
	    wrap = 0;
	}
	else{
	    rb_raise(rb_eFiddleError, "to_ptr should return a Fiddle::Pointer object");
	}
    }
    else{
	VALUE num = rb_Integer(val);
	if (num == val) wrap = 0;
	ptr = rb_fiddle_ptr_new(NUM2PTR(num), 0, NULL);
    }
    if (wrap) RPTR_DATA(ptr)->wrap[0] = wrap;
    return ptr;
}

Instance Method Details

#+(n) ⇒ Object

Returns a new pointer instance that has been advanced n bytes.


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# File 'pointer.c', line 495

static VALUE
rb_fiddle_ptr_plus(VALUE self, VALUE other)
{
    void *ptr;
    long num, size;

    ptr = rb_fiddle_ptr2cptr(self);
    size = RPTR_DATA(self)->size;
    num = NUM2LONG(other);
    return rb_fiddle_ptr_new((char *)ptr + num, size - num, 0);
}

#ptrObject

Returns a new Fiddle::Pointer instance that is a dereferenced pointer for this pointer.

Analogous to the star operator in C.


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# File 'pointer.c', line 266

static VALUE
rb_fiddle_ptr_ptr(VALUE self)
{
    struct ptr_data *data;

    TypedData_Get_Struct(self, struct ptr_data, &fiddle_ptr_data_type, data);
    return rb_fiddle_ptr_new(*((void**)(data->ptr)),0,0);
}

#-(n) ⇒ Object

Returns a new pointer instance that has been moved back n bytes.


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# File 'pointer.c', line 513

static VALUE
rb_fiddle_ptr_minus(VALUE self, VALUE other)
{
    void *ptr;
    long num, size;

    ptr = rb_fiddle_ptr2cptr(self);
    size = RPTR_DATA(self)->size;
    num = NUM2LONG(other);
    return rb_fiddle_ptr_new((char *)ptr - num, size + num, 0);
}

#refObject

Returns a new Fiddle::Pointer instance that is a reference pointer for this pointer.

Analogous to the ampersand operator in C.


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# File 'pointer.c', line 283

static VALUE
rb_fiddle_ptr_ref(VALUE self)
{
    struct ptr_data *data;

    TypedData_Get_Struct(self, struct ptr_data, &fiddle_ptr_data_type, data);
    return rb_fiddle_ptr_new(&(data->ptr),0,0);
}

#<=>(other) ⇒ -1, ...

Returns -1 if less than, 0 if equal to, 1 if greater than other.

Returns nil if ptr cannot be compared to other.

Returns:

  • (-1, 0, 1, nil)

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# File 'pointer.c', line 474

static VALUE
rb_fiddle_ptr_cmp(VALUE self, VALUE other)
{
    void *ptr1, *ptr2;
    SIGNED_VALUE diff;

    if(!rb_obj_is_kind_of(other, rb_cPointer)) return Qnil;

    ptr1 = rb_fiddle_ptr2cptr(self);
    ptr2 = rb_fiddle_ptr2cptr(other);
    diff = (SIGNED_VALUE)ptr1 - (SIGNED_VALUE)ptr2;
    if (!diff) return INT2FIX(0);
    return diff > 0 ? INT2NUM(1) : INT2NUM(-1);
}

#==(other) ⇒ Boolean #eql?(other) ⇒ Boolean

Returns true if other wraps the same pointer, otherwise returns false.

Overloads:

  • #==(other) ⇒ Boolean

    Returns:

    • (Boolean)
  • #eql?(other) ⇒ Boolean

    Returns:

    • (Boolean)

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# File 'pointer.c', line 453

static VALUE
rb_fiddle_ptr_eql(VALUE self, VALUE other)
{
    void *ptr1, *ptr2;

    if(!rb_obj_is_kind_of(other, rb_cPointer)) return Qfalse;

    ptr1 = rb_fiddle_ptr2cptr(self);
    ptr2 = rb_fiddle_ptr2cptr(other);

    return ptr1 == ptr2 ? Qtrue : Qfalse;
}

#[](index) ⇒ Integer #[](start, length) ⇒ String

Returns integer stored at index.

If start and length are given, a string containing the bytes from start of length will be returned.

Overloads:

  • #[](index) ⇒ Integer

    Returns:

    • (Integer)
  • #[](start, length) ⇒ String

    Returns:

    • (String)

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# File 'pointer.c', line 535

static VALUE
rb_fiddle_ptr_aref(int argc, VALUE argv[], VALUE self)
{
    VALUE arg0, arg1;
    VALUE retval = Qnil;
    size_t offset, len;
    struct ptr_data *data;

    TypedData_Get_Struct(self, struct ptr_data, &fiddle_ptr_data_type, data);
    if (!data->ptr) rb_raise(rb_eFiddleError, "NULL pointer dereference");
    switch( rb_scan_args(argc, argv, "11", &arg0, &arg1) ){
      case 1:
	offset = NUM2ULONG(arg0);
	retval = INT2NUM(*((char *)data->ptr + offset));
	break;
      case 2:
	offset = NUM2ULONG(arg0);
	len    = NUM2ULONG(arg1);
	retval = rb_str_new((char *)data->ptr + offset, len);
	break;
      default:
	rb_bug("rb_fiddle_ptr_aref()");
    }
    return retval;
}

#[]=(index) ⇒ Integer #[]=(start, length) ⇒ String

Set the value at index to int.

Or, set the memory at start until length with the contents of string, the memory from dl_cptr, or the memory pointed at by the memory address addr.

Overloads:

  • #[]=(index) ⇒ Integer

    Returns:

    • (Integer)
  • #[]=(start, length) ⇒ String

    Returns:

    • (String)

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# File 'pointer.c', line 572

static VALUE
rb_fiddle_ptr_aset(int argc, VALUE argv[], VALUE self)
{
    VALUE arg0, arg1, arg2;
    VALUE retval = Qnil;
    size_t offset, len;
    void *mem;
    struct ptr_data *data;

    TypedData_Get_Struct(self, struct ptr_data, &fiddle_ptr_data_type, data);
    if (!data->ptr) rb_raise(rb_eFiddleError, "NULL pointer dereference");
    switch( rb_scan_args(argc, argv, "21", &arg0, &arg1, &arg2) ){
      case 2:
	offset = NUM2ULONG(arg0);
	((char*)data->ptr)[offset] = NUM2UINT(arg1);
	retval = arg1;
	break;
      case 3:
	offset = NUM2ULONG(arg0);
	len    = NUM2ULONG(arg1);
	if (RB_TYPE_P(arg2, T_STRING)) {
	    mem = StringValuePtr(arg2);
	}
	else if( rb_obj_is_kind_of(arg2, rb_cPointer) ){
	    mem = rb_fiddle_ptr2cptr(arg2);
	}
	else{
	    mem    = NUM2PTR(arg2);
	}
	memcpy((char *)data->ptr + offset, mem, len);
	retval = arg2;
	break;
      default:
	rb_bug("rb_fiddle_ptr_aset()");
    }
    return retval;
}

#==(other) ⇒ Boolean #eql?(other) ⇒ Boolean

Returns true if other wraps the same pointer, otherwise returns false.

Overloads:

  • #==(other) ⇒ Boolean

    Returns:

    • (Boolean)
  • #eql?(other) ⇒ Boolean

    Returns:

    • (Boolean)

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# File 'pointer.c', line 453

static VALUE
rb_fiddle_ptr_eql(VALUE self, VALUE other)
{
    void *ptr1, *ptr2;

    if(!rb_obj_is_kind_of(other, rb_cPointer)) return Qfalse;

    ptr1 = rb_fiddle_ptr2cptr(self);
    ptr2 = rb_fiddle_ptr2cptr(other);

    return ptr1 == ptr2 ? Qtrue : Qfalse;
}

#freeFiddle::Function

Get the free function for this pointer.

Returns a new instance of Fiddle::Function.

See Fiddle::Function.new

Returns:


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# File 'pointer.c', line 332

static VALUE
rb_fiddle_ptr_free_get(VALUE self)
{
    struct ptr_data *pdata;
    VALUE address;
    VALUE arg_types;
    VALUE ret_type;

    TypedData_Get_Struct(self, struct ptr_data, &fiddle_ptr_data_type, pdata);

    if (!pdata->free)
	return Qnil;

    address = PTR2NUM(pdata->free);
    ret_type = INT2NUM(TYPE_VOID);
    arg_types = rb_ary_new();
    rb_ary_push(arg_types, INT2NUM(TYPE_VOIDP));

    return rb_fiddle_new_function(address, arg_types, ret_type);
}

#free=(function) ⇒ Object

Set the free function for this pointer to function in the given Fiddle::Function.


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# File 'pointer.c', line 312

static VALUE
rb_fiddle_ptr_free_set(VALUE self, VALUE val)
{
    struct ptr_data *data;

    TypedData_Get_Struct(self, struct ptr_data, &fiddle_ptr_data_type, data);
    data->free = get_freefunc(val, &data->wrap[1]);

    return Qnil;
}

#inspectObject

Returns a string formatted with an easily readable representation of the internal state of the pointer.


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# File 'pointer.c', line 435

static VALUE
rb_fiddle_ptr_inspect(VALUE self)
{
    struct ptr_data *data;

    TypedData_Get_Struct(self, struct ptr_data, &fiddle_ptr_data_type, data);
    return rb_sprintf("#<%"PRIsVALUE":%p ptr=%p size=%ld free=%p>",
		      RB_OBJ_CLASSNAME(self), (void *)data, data->ptr, data->size, (void *)data->free);
}

#null?Boolean

Returns true if this is a null pointer.

Returns:

  • (Boolean)

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# File 'pointer.c', line 297

static VALUE
rb_fiddle_ptr_null_p(VALUE self)
{
    struct ptr_data *data;

    TypedData_Get_Struct(self, struct ptr_data, &fiddle_ptr_data_type, data);
    return data->ptr ? Qfalse : Qtrue;
}

#ptrObject

Returns a new Fiddle::Pointer instance that is a dereferenced pointer for this pointer.

Analogous to the star operator in C.


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# File 'pointer.c', line 266

static VALUE
rb_fiddle_ptr_ptr(VALUE self)
{
    struct ptr_data *data;

    TypedData_Get_Struct(self, struct ptr_data, &fiddle_ptr_data_type, data);
    return rb_fiddle_ptr_new(*((void**)(data->ptr)),0,0);
}

#refObject

Returns a new Fiddle::Pointer instance that is a reference pointer for this pointer.

Analogous to the ampersand operator in C.


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# File 'pointer.c', line 283

static VALUE
rb_fiddle_ptr_ref(VALUE self)
{
    struct ptr_data *data;

    TypedData_Get_Struct(self, struct ptr_data, &fiddle_ptr_data_type, data);
    return rb_fiddle_ptr_new(&(data->ptr),0,0);
}

#sizeObject

Get the size of this pointer.


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# File 'pointer.c', line 627

static VALUE
rb_fiddle_ptr_size_get(VALUE self)
{
    return LONG2NUM(RPTR_DATA(self)->size);
}

#size=(size) ⇒ Object

Set the size of this pointer to size


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# File 'pointer.c', line 615

static VALUE
rb_fiddle_ptr_size_set(VALUE self, VALUE size)
{
    RPTR_DATA(self)->size = NUM2LONG(size);
    return size;
}

#to_iObject

Returns the integer memory location of this pointer.


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# File 'pointer.c', line 236

static VALUE
rb_fiddle_ptr_to_i(VALUE self)
{
    struct ptr_data *data;

    TypedData_Get_Struct(self, struct ptr_data, &fiddle_ptr_data_type, data);
    return PTR2NUM(data->ptr);
}

#to_iObject

Returns the integer memory location of this pointer.


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# File 'pointer.c', line 236

static VALUE
rb_fiddle_ptr_to_i(VALUE self)
{
    struct ptr_data *data;

    TypedData_Get_Struct(self, struct ptr_data, &fiddle_ptr_data_type, data);
    return PTR2NUM(data->ptr);
}

#to_sString #to_s(len) ⇒ String

Returns the pointer contents as a string.

When called with no arguments, this method will return the contents until the first NULL byte.

When called with len, a string of len bytes will be returned.

See to_str

Overloads:

  • #to_sString

    Returns:

    • (String)
  • #to_s(len) ⇒ String

    Returns:

    • (String)

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# File 'pointer.c', line 368

static VALUE
rb_fiddle_ptr_to_s(int argc, VALUE argv[], VALUE self)
{
    struct ptr_data *data;
    VALUE arg1, val;
    int len;

    TypedData_Get_Struct(self, struct ptr_data, &fiddle_ptr_data_type, data);
    switch (rb_scan_args(argc, argv, "01", &arg1)) {
      case 0:
	val = rb_str_new2((char*)(data->ptr));
	break;
      case 1:
	len = NUM2INT(arg1);
	val = rb_str_new((char*)(data->ptr), len);
	break;
      default:
	rb_bug("rb_fiddle_ptr_to_s");
    }

    return val;
}

#to_strString #to_str(len) ⇒ String

Returns the pointer contents as a string.

When called with no arguments, this method will return the contents with the length of this pointer's size.

When called with len, a string of len bytes will be returned.

See to_s

Overloads:

  • #to_strString

    Returns:

    • (String)
  • #to_str(len) ⇒ String

    Returns:

    • (String)

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# File 'pointer.c', line 406

static VALUE
rb_fiddle_ptr_to_str(int argc, VALUE argv[], VALUE self)
{
    struct ptr_data *data;
    VALUE arg1, val;
    int len;

    TypedData_Get_Struct(self, struct ptr_data, &fiddle_ptr_data_type, data);
    switch (rb_scan_args(argc, argv, "01", &arg1)) {
      case 0:
	val = rb_str_new((char*)(data->ptr),data->size);
	break;
      case 1:
	len = NUM2INT(arg1);
	val = rb_str_new((char*)(data->ptr), len);
	break;
      default:
	rb_bug("rb_fiddle_ptr_to_str");
    }

    return val;
}

#to_valueObject

Cast this pointer to a ruby object.


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# File 'pointer.c', line 250

static VALUE
rb_fiddle_ptr_to_value(VALUE self)
{
    struct ptr_data *data;
    TypedData_Get_Struct(self, struct ptr_data, &fiddle_ptr_data_type, data);
    return (VALUE)(data->ptr);
}