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.



158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
# File 'pointer.c', line 158

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.



642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
# File 'pointer.c', line 642

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);
    }
    OBJ_INFECT(ptr, val);
    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



206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
# File 'pointer.c', line 206

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.



642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
# File 'pointer.c', line 642

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);
    }
    OBJ_INFECT(ptr, val);
    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.



496
497
498
499
500
501
502
503
504
505
506
# File 'pointer.c', line 496

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.



267
268
269
270
271
272
273
274
# File 'pointer.c', line 267

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.



514
515
516
517
518
519
520
521
522
523
524
# File 'pointer.c', line 514

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.



284
285
286
287
288
289
290
291
# File 'pointer.c', line 284

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.



475
476
477
478
479
480
481
482
483
484
485
486
487
488
# File 'pointer.c', line 475

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.



454
455
456
457
458
459
460
461
462
463
464
465
# File 'pointer.c', line 454

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.



536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
# File 'pointer.c', line 536

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_tainted_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.



573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
# File 'pointer.c', line 573

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.



454
455
456
457
458
459
460
461
462
463
464
465
# File 'pointer.c', line 454

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



333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
# File 'pointer.c', line 333

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.



313
314
315
316
317
318
319
320
321
322
# File 'pointer.c', line 313

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.



436
437
438
439
440
441
442
443
444
# File 'pointer.c', line 436

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), data, data->ptr, data->size, data->free);
}

#null?Boolean

Returns true if this is a null pointer.



298
299
300
301
302
303
304
305
# File 'pointer.c', line 298

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.



267
268
269
270
271
272
273
274
# File 'pointer.c', line 267

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.



284
285
286
287
288
289
290
291
# File 'pointer.c', line 284

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.



628
629
630
631
632
# File 'pointer.c', line 628

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



616
617
618
619
620
621
# File 'pointer.c', line 616

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.



237
238
239
240
241
242
243
244
# File 'pointer.c', line 237

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.



237
238
239
240
241
242
243
244
# File 'pointer.c', line 237

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



369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
# File 'pointer.c', line 369

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_tainted_str_new2((char*)(data->ptr));
	break;
      case 1:
	len = NUM2INT(arg1);
	val = rb_tainted_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



407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
# File 'pointer.c', line 407

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_tainted_str_new((char*)(data->ptr),data->size);
	break;
      case 1:
	len = NUM2INT(arg1);
	val = rb_tainted_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.



251
252
253
254
255
256
257
# File 'pointer.c', line 251

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);
}