Class: FFI::Buffer
- Inherits:
-
AbstractMemory
- Object
- AbstractMemory
- FFI::Buffer
- Defined in:
- ext/ffi_c/Buffer.c,
ext/ffi_c/Buffer.c
Overview
A Buffer is a function argument type. It should be use with functions playing with C arrays.
Class Method Summary collapse
-
.alloc_in(*args) ⇒ Object
Create a new Buffer for in arguments (alias : new_in).
-
.alloc_inout(*args) ⇒ Object
Create a new Buffer for in and out arguments (alias : new_inout).
-
.alloc_out(*args) ⇒ Object
Create a new Buffer for out arguments (alias : new_out).
Instance Method Summary collapse
-
#+(offset) ⇒ Buffer
Add a Buffer with an offset.
-
#initialize(size, count = 1, clear = false) ⇒ self
constructor
A new instance of Buffer.
-
#initialize_copy(other) ⇒ self
DO NOT CALL THIS METHOD.
-
#inspect ⇒ String
Inspect a Buffer.
-
#order(*args) ⇒ Object
Set or get endianness of Buffer.
-
#slice(offset, length) ⇒ Buffer
Slice an existing Buffer.
Methods inherited from AbstractMemory
#[], #__copy_from__, #clear, #get, #get_array_of_float32, #get_array_of_float64, #get_array_of_pointer, #get_array_of_string, #get_bytes, #get_float32, #get_float64, #get_pointer, #get_string, #put, #put_array_of_float32, #put_array_of_float64, #put_array_of_pointer, #put_bytes, #put_float32, #put_float64, #put_pointer, #put_string, #read_array_of_double, #read_array_of_float, #read_array_of_pointer, #read_bytes, #read_double, #read_float, #read_pointer, #total, #type_size, #write_array_of_double, #write_array_of_float, #write_array_of_pointer, #write_bytes, #write_double, #write_float, #write_pointer
Constructor Details
#initialize(size, count = 1, clear = false) ⇒ self
A new instance of Buffer.
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# File 'ext/ffi_c/Buffer.c', line 96
static VALUE
buffer_initialize(int argc, VALUE* argv, VALUE self)
{
VALUE rbSize = Qnil, rbCount = Qnil, rbClear = Qnil;
Buffer* p;
int nargs;
Data_Get_Struct(self, Buffer, p);
nargs = rb_scan_args(argc, argv, "12", &rbSize, &rbCount, &rbClear);
p->memory.typeSize = rbffi_type_size(rbSize);
p->memory.size = p->memory.typeSize * (nargs > 1 ? NUM2LONG(rbCount) : 1);
if (p->memory.size > BUFFER_EMBED_MAXLEN) {
p->data.storage = xmalloc(p->memory.size + 7);
if (p->data.storage == NULL) {
rb_raise(rb_eNoMemError, "Failed to allocate memory size=%lu bytes", p->memory.size);
return Qnil;
}
/* ensure the memory is aligned on at least a 8 byte boundary */
p->memory.address = (void *) (((uintptr_t) p->data.storage + 0x7) & (uintptr_t) ~0x7UL);
if (p->memory.size > 0 && (nargs < 3 || RTEST(rbClear))) {
memset(p->memory.address, 0, p->memory.size);
}
} else {
p->memory.flags |= MEM_EMBED;
p->memory.address = (void *) &p->data.embed[0];
}
if (rb_block_given_p()) {
return rb_ensure(rb_yield, self, buffer_free, self);
}
return self;
}
|
Class Method Details
.alloc_in(*args) ⇒ Object
Create a new Buffer for in arguments (alias : new_in).
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# File 'ext/ffi_c/Buffer.c', line 167
static VALUE
buffer_alloc_inout(int argc, VALUE* argv, VALUE klass)
{
return buffer_initialize(argc, argv, buffer_allocate(klass));
}
|
.alloc_inout(*args) ⇒ Object
Create a new Buffer for in and out arguments (alias : new_inout).
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# File 'ext/ffi_c/Buffer.c', line 167
static VALUE
buffer_alloc_inout(int argc, VALUE* argv, VALUE klass)
{
return buffer_initialize(argc, argv, buffer_allocate(klass));
}
|
.alloc_out(*args) ⇒ Object
Create a new Buffer for out arguments (alias : new_out).
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# File 'ext/ffi_c/Buffer.c', line 167
static VALUE
buffer_alloc_inout(int argc, VALUE* argv, VALUE klass)
{
return buffer_initialize(argc, argv, buffer_allocate(klass));
}
|
Instance Method Details
#+(offset) ⇒ Buffer
Add a Buffer with an offset
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# File 'ext/ffi_c/Buffer.c', line 199
static VALUE
buffer_plus(VALUE self, VALUE rbOffset)
{
Buffer* ptr;
long offset = NUM2LONG(rbOffset);
Data_Get_Struct(self, Buffer, ptr);
return slice(self, offset, ptr->memory.size - offset);
}
|
#initialize_copy(other) ⇒ self
DO NOT CALL THIS METHOD.
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# File 'ext/ffi_c/Buffer.c', line 140
static VALUE
buffer_initialize_copy(VALUE self, VALUE other)
{
AbstractMemory* src;
Buffer* dst;
Data_Get_Struct(self, Buffer, dst);
src = rbffi_AbstractMemory_Cast(other, BufferClass);
if ((dst->memory.flags & MEM_EMBED) == 0 && dst->data.storage != NULL) {
xfree(dst->data.storage);
}
dst->data.storage = xmalloc(src->size + 7);
if (dst->data.storage == NULL) {
rb_raise(rb_eNoMemError, "failed to allocate memory size=%lu bytes", src->size);
return Qnil;
}
dst->memory.address = (void *) (((uintptr_t) dst->data.storage + 0x7) & (uintptr_t) ~0x7UL);
dst->memory.size = src->size;
dst->memory.typeSize = src->typeSize;
/* finally, copy the actual buffer contents */
memcpy(dst->memory.address, src->address, src->size);
return self;
}
|
#inspect ⇒ String
Inspect a Buffer.
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# File 'ext/ffi_c/Buffer.c', line 228
static VALUE
buffer_inspect(VALUE self)
{
char tmp[100];
Buffer* ptr;
Data_Get_Struct(self, Buffer, ptr);
snprintf(tmp, sizeof(tmp), "#<FFI:Buffer:%p address=%p size=%ld>", ptr, ptr->memory.address, ptr->memory.size);
return rb_str_new2(tmp);
}
|
#order ⇒ :big, :little #order(order) ⇒ self
Set or get endianness of Buffer.
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# File 'ext/ffi_c/Buffer.c', line 258
static VALUE
buffer_order(int argc, VALUE* argv, VALUE self)
{
Buffer* ptr;
Data_Get_Struct(self, Buffer, ptr);
if (argc == 0) {
int order = (ptr->memory.flags & MEM_SWAP) == 0 ? BYTE_ORDER : SWAPPED_ORDER;
return order == BIG_ENDIAN ? ID2SYM(rb_intern("big")) : ID2SYM(rb_intern("little"));
} else {
VALUE rbOrder = Qnil;
int order = BYTE_ORDER;
if (rb_scan_args(argc, argv, "1", &rbOrder) < 1) {
rb_raise(rb_eArgError, "need byte order");
}
if (SYMBOL_P(rbOrder)) {
ID id = SYM2ID(rbOrder);
if (id == rb_intern("little")) {
order = LITTLE_ENDIAN;
} else if (id == rb_intern("big") || id == rb_intern("network")) {
order = BIG_ENDIAN;
}
}
if (order != BYTE_ORDER) {
Buffer* p2;
VALUE retval = slice(self, 0, ptr->memory.size);
Data_Get_Struct(retval, Buffer, p2);
p2->memory.flags |= MEM_SWAP;
return retval;
}
return self;
}
}
|
#slice(offset, length) ⇒ Buffer
Slice an existing Buffer.
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# File 'ext/ffi_c/Buffer.c', line 217
static VALUE
buffer_slice(VALUE self, VALUE rbOffset, VALUE rbLength)
{
return slice(self, NUM2LONG(rbOffset), NUM2LONG(rbLength));
}
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