class Fiddle::Pointer
Fiddle::Pointer is a class to handle C pointers
Public Class Methods
Get the underlying pointer for ruby object val and return it as a Fiddle::Pointer object.
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);
wrap = 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_eFiddleDLError, "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) RB_OBJ_WRITE(ptr, &RPTR_DATA(ptr)->wrap[0], wrap);
return ptr;
}
Examples¶ ↑
# Automatically freeing the pointer when the block is exited - recommended Fiddle::Pointer.malloc(size, Fiddle::RUBY_FREE) do |pointer| ... end # Manually freeing but relying on the garbage collector otherwise pointer = Fiddle::Pointer.malloc(size, Fiddle::RUBY_FREE) ... pointer.call_free # Relying on the garbage collector - may lead to unlimited memory allocated before freeing any, but safe pointer = Fiddle::Pointer.malloc(size, Fiddle::RUBY_FREE) ... # Only manually freeing pointer = Fiddle::Pointer.malloc(size) begin ... ensure Fiddle.free pointer end # No free function and no call to free - the native memory will leak if the pointer is garbage collected pointer = Fiddle::Pointer.malloc(size) ...
Allocate size bytes of memory and associate it with an optional freefunc.
If a block is supplied, the pointer will be yielded to the block instead of being returned, and the return value of the block will be returned. A freefunc must be supplied if a block is.
If a freefunc is supplied it will be called once, when the pointer is garbage collected or when the block is left if a block is supplied or when the user calls call_free, whichever happens first. freefunc must be an address pointing to a function or an instance of Fiddle::Function.
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(klass, s,f);
if (wrap) RB_OBJ_WRITE(obj, &RPTR_DATA(obj)->wrap[1], wrap);
if (rb_block_given_p()) {
if (!f) {
rb_raise(rb_eArgError, "a free function must be supplied to Fiddle::Pointer.malloc when it is called with a block");
}
return rb_ensure(rb_yield, obj, rb_fiddle_ptr_call_free, obj);
} else {
return obj;
}
}
Create a new pointer to address with an optional size and freefunc.
freefunc will be called when the instance is garbage collected.
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);
}
RB_OBJ_WRITE(self, &data->wrap[0], wrap);
RB_OBJ_WRITE(self, &data->wrap[1], funcwrap);
data->ptr = p;
data->size = s;
data->free = f;
}
return Qnil;
}
Or read the memory at address address with length len and return a string with that memory
static VALUE
rb_fiddle_ptr_read_mem(VALUE klass, VALUE address, VALUE len)
{
return rb_str_new((char *)NUM2PTR(address), NUM2ULONG(len));
}
Get the underlying pointer for ruby object val and return it as a Fiddle::Pointer object.
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);
wrap = 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_eFiddleDLError, "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) RB_OBJ_WRITE(ptr, &RPTR_DATA(ptr)->wrap[0], wrap);
return ptr;
}
Write bytes in str to the location pointed to by address.
static VALUE
rb_fiddle_ptr_write_mem(VALUE klass, VALUE addr, VALUE str)
{
memcpy(NUM2PTR(addr), StringValuePtr(str), RSTRING_LEN(str));
return str;
}
Public Instance Methods
Returns a new pointer instance that has been advanced n bytes.
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);
}
Returns a new Fiddle::Pointer instance that is a dereferenced pointer for this pointer.
Analogous to the star operator in C.
Returns a new pointer instance that has been moved back n bytes.
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);
}
Returns a new Fiddle::Pointer instance that is a reference pointer for this pointer.
Analogous to the ampersand operator in C.
Returns -1 if less than, 0 if equal to, 1 if greater than other.
Returns nil if ptr cannot be compared to other.
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);
}
Returns true if other wraps the same pointer, otherwise returns false.
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;
}
Returns integer stored at index.
If start and length are given, a string containing the bytes from start of length will be returned.
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_eFiddleDLError, "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;
}
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.
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_eFiddleDLError, "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;
}
Call the free function for this pointer. Calling more than once will do nothing. Does nothing if there is no free function attached.
static VALUE
rb_fiddle_ptr_call_free(VALUE self)
{
struct ptr_data *pdata;
TypedData_Get_Struct(self, struct ptr_data, &fiddle_ptr_data_type, pdata);
fiddle_ptr_free_ptr(pdata);
return Qnil;
}
Returns true if other wraps the same pointer, otherwise returns false.
Get the free function for this pointer.
Returns a new instance of Fiddle::Function.
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);
}
Set the free function for this pointer to function in the given Fiddle::Function.
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;
}
Returns if the free function for this pointer has been called.
static VALUE
rb_fiddle_ptr_freed_p(VALUE self)
{
struct ptr_data *pdata;
TypedData_Get_Struct(self, struct ptr_data, &fiddle_ptr_data_type, pdata);
return pdata->freed ? Qtrue : Qfalse;
}
Returns a string formatted with an easily readable representation of the internal state of the pointer.
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);
}
Returns true if this is a null pointer.
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;
}
Returns a new Fiddle::Pointer instance that is a dereferenced pointer for this pointer.
Analogous to the star operator in C.
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);
}
Returns a new Fiddle::Pointer instance that is a reference pointer for this pointer.
Analogous to the ampersand operator in C.
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);
}
Get the size of this pointer.
static VALUE
rb_fiddle_ptr_size_get(VALUE self)
{
return LONG2NUM(RPTR_DATA(self)->size);
}
Set the size of this pointer to size
static VALUE
rb_fiddle_ptr_size_set(VALUE self, VALUE size)
{
RPTR_DATA(self)->size = NUM2LONG(size);
return size;
}
Returns the integer memory location of this pointer.
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);
}
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
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;
}
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
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;
}
Cast this pointer to a ruby object.
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);
}