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Add basic binary operators (and, or, xor, not) to IO::Buffer.
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@ioquatix
ioquatix committed May 8, 2022
1 parent 679b6e4 commit 9646ba3
Showing 1 changed file with 241 additions and 0 deletions.
241 changes: 241 additions & 0 deletions io_buffer.c
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Original file line number Diff line number Diff line change
Expand Up @@ -20,6 +20,7 @@ VALUE rb_eIOBufferLockedError;
VALUE rb_eIOBufferAllocationError;
VALUE rb_eIOBufferAccessError;
VALUE rb_eIOBufferInvalidatedError;
VALUE rb_eIOBufferMaskError;

size_t RUBY_IO_BUFFER_PAGE_SIZE;
size_t RUBY_IO_BUFFER_DEFAULT_SIZE;
Expand Down Expand Up @@ -2061,6 +2062,234 @@ io_buffer_pwrite(VALUE self, VALUE io, VALUE length, VALUE offset)
return rb_io_buffer_pwrite(self, io, RB_NUM2SIZE(length), NUM2OFFT(offset));
}

static inline void
io_buffer_check_mask(const struct rb_io_buffer *buffer)
{
if (buffer->size == 0)
rb_raise(rb_eIOBufferMaskError, "Zero-length mask given!");
}

static void
memory_and(unsigned char * restrict output, unsigned char * restrict base, size_t size, unsigned char * restrict mask, size_t mask_size)
{
for (size_t offset = 0; offset < size; offset += 1) {
output[offset] = base[offset] & mask[offset % mask_size];
}
}

static VALUE
io_buffer_and(VALUE self, VALUE mask)
{
struct rb_io_buffer *data = NULL;
TypedData_Get_Struct(self, struct rb_io_buffer, &rb_io_buffer_type, data);

struct rb_io_buffer *mask_data = NULL;
TypedData_Get_Struct(mask, struct rb_io_buffer, &rb_io_buffer_type, mask_data);

io_buffer_check_mask(mask_data);

VALUE output = rb_io_buffer_new(NULL, data->size, io_flags_for_size(data->size));
struct rb_io_buffer *output_data = NULL;
TypedData_Get_Struct(output, struct rb_io_buffer, &rb_io_buffer_type, output_data);

memory_and(output_data->base, data->base, data->size, mask_data->base, mask_data->size);

return output;
}

static void
memory_or(unsigned char * restrict output, unsigned char * restrict base, size_t size, unsigned char * restrict mask, size_t mask_size)
{
for (size_t offset = 0; offset < size; offset += 1) {
output[offset] = base[offset] | mask[offset % mask_size];
}
}

static VALUE
io_buffer_or(VALUE self, VALUE mask)
{
struct rb_io_buffer *data = NULL;
TypedData_Get_Struct(self, struct rb_io_buffer, &rb_io_buffer_type, data);

struct rb_io_buffer *mask_data = NULL;
TypedData_Get_Struct(mask, struct rb_io_buffer, &rb_io_buffer_type, mask_data);

io_buffer_check_mask(mask_data);

VALUE output = rb_io_buffer_new(NULL, data->size, io_flags_for_size(data->size));
struct rb_io_buffer *output_data = NULL;
TypedData_Get_Struct(output, struct rb_io_buffer, &rb_io_buffer_type, output_data);

assert(output_data->size >= data->size);
memory_or(output_data->base, data->base, data->size, mask_data->base, mask_data->size);

return output;
}

void
memory_xor(unsigned char * restrict output, unsigned char * restrict base, size_t size, unsigned char * restrict mask, size_t mask_size)
{
for (size_t offset = 0; offset < size; offset += 1) {
output[offset] = base[offset] ^ mask[offset % mask_size];
}
}

static VALUE
io_buffer_xor(VALUE self, VALUE mask)
{
struct rb_io_buffer *data = NULL;
TypedData_Get_Struct(self, struct rb_io_buffer, &rb_io_buffer_type, data);

struct rb_io_buffer *mask_data = NULL;
TypedData_Get_Struct(mask, struct rb_io_buffer, &rb_io_buffer_type, mask_data);

io_buffer_check_mask(mask_data);

VALUE output = rb_io_buffer_new(NULL, data->size, io_flags_for_size(data->size));
struct rb_io_buffer *output_data = NULL;
TypedData_Get_Struct(output, struct rb_io_buffer, &rb_io_buffer_type, output_data);

assert(output_data->size >= data->size);
memory_xor(output_data->base, data->base, data->size, mask_data->base, mask_data->size);

return output;
}

void
memory_not(unsigned char * restrict output, unsigned char * restrict base, size_t size)
{
for (size_t offset = 0; offset < size; offset += 1) {
output[offset] = ~base[offset];
}
}

static VALUE
io_buffer_not(VALUE self)
{
struct rb_io_buffer *data = NULL;
TypedData_Get_Struct(self, struct rb_io_buffer, &rb_io_buffer_type, data);

VALUE output = rb_io_buffer_new(NULL, data->size, io_flags_for_size(data->size));
struct rb_io_buffer *output_data = NULL;
TypedData_Get_Struct(output, struct rb_io_buffer, &rb_io_buffer_type, output_data);

assert(output_data->size >= data->size);
memory_not(output_data->base, data->base, data->size);

return output;
}

static inline int
io_buffer_overlaps(const struct rb_io_buffer *a, const struct rb_io_buffer *b)
{
if (a->base > b->base) {
return io_buffer_overlaps(b, a);
}

return (b->base >= a->base) && (b->base <= (void*)((unsigned char *)a->base + a->size));
}

static inline void
io_buffer_check_overlaps(struct rb_io_buffer *a, struct rb_io_buffer *b)
{
if (io_buffer_overlaps(a, b))
rb_raise(rb_eIOBufferMaskError, "Mask overlaps source data!");
}

static void
memory_and_inplace(unsigned char * restrict base, size_t size, unsigned char * restrict mask, size_t mask_size)
{
for (size_t offset = 0; offset < size; offset += 1) {
base[offset] &= mask[offset % mask_size];
}
}

static VALUE
io_buffer_and_inplace(VALUE self, VALUE mask)
{
struct rb_io_buffer *data = NULL;
TypedData_Get_Struct(self, struct rb_io_buffer, &rb_io_buffer_type, data);

struct rb_io_buffer *mask_data = NULL;
TypedData_Get_Struct(mask, struct rb_io_buffer, &rb_io_buffer_type, mask_data);

io_buffer_check_mask(mask_data);
io_buffer_check_overlaps(data, mask_data);

memory_and_inplace(data->base, data->size, mask_data->base, mask_data->size);

return self;
}

static void
memory_or_inplace(unsigned char * restrict base, size_t size, unsigned char * restrict mask, size_t mask_size)
{
for (size_t offset = 0; offset < size; offset += 1) {
base[offset] |= mask[offset % mask_size];
}
}

static VALUE
io_buffer_or_inplace(VALUE self, VALUE mask)
{
struct rb_io_buffer *data = NULL;
TypedData_Get_Struct(self, struct rb_io_buffer, &rb_io_buffer_type, data);

struct rb_io_buffer *mask_data = NULL;
TypedData_Get_Struct(mask, struct rb_io_buffer, &rb_io_buffer_type, mask_data);

io_buffer_check_mask(mask_data);
io_buffer_check_overlaps(data, mask_data);

memory_or_inplace(data->base, data->size, mask_data->base, mask_data->size);

return self;
}

void
memory_xor_inplace(unsigned char * restrict base, size_t size, unsigned char * restrict mask, size_t mask_size)
{
for (size_t offset = 0; offset < size; offset += 1) {
base[offset] ^= mask[offset % mask_size];
}
}

static VALUE
io_buffer_xor_inplace(VALUE self, VALUE mask)
{
struct rb_io_buffer *data = NULL;
TypedData_Get_Struct(self, struct rb_io_buffer, &rb_io_buffer_type, data);

struct rb_io_buffer *mask_data = NULL;
TypedData_Get_Struct(mask, struct rb_io_buffer, &rb_io_buffer_type, mask_data);

io_buffer_check_mask(mask_data);
io_buffer_check_overlaps(data, mask_data);

memory_xor_inplace(data->base, data->size, mask_data->base, mask_data->size);

return self;
}

void
memory_not_inplace(unsigned char * restrict base, size_t size)
{
for (size_t offset = 0; offset < size; offset += 1) {
base[offset] = ~base[offset];
}
}

static VALUE
io_buffer_not_inplace(VALUE self)
{
struct rb_io_buffer *data = NULL;
TypedData_Get_Struct(self, struct rb_io_buffer, &rb_io_buffer_type, data);

memory_not_inplace(data->base, data->size);

return self;
}

/*
* Document-class: IO::Buffer
*
Expand Down Expand Up @@ -2152,6 +2381,7 @@ Init_IO_Buffer(void)
rb_eIOBufferAllocationError = rb_define_class_under(rb_cIOBuffer, "AllocationError", rb_eRuntimeError);
rb_eIOBufferAccessError = rb_define_class_under(rb_cIOBuffer, "AccessError", rb_eRuntimeError);
rb_eIOBufferInvalidatedError = rb_define_class_under(rb_cIOBuffer, "InvalidatedError", rb_eRuntimeError);
rb_eIOBufferMaskError = rb_define_class_under(rb_cIOBuffer, "MaskError", rb_eArgError);

rb_define_alloc_func(rb_cIOBuffer, rb_io_buffer_type_allocate);
rb_define_singleton_method(rb_cIOBuffer, "for", rb_io_buffer_type_for, 1);
Expand Down Expand Up @@ -2236,6 +2466,17 @@ Init_IO_Buffer(void)
rb_define_method(rb_cIOBuffer, "get_string", io_buffer_get_string, -1);
rb_define_method(rb_cIOBuffer, "set_string", io_buffer_set_string, -1);

// Binary data manipulations:
rb_define_method(rb_cIOBuffer, "&", io_buffer_and, 1);
rb_define_method(rb_cIOBuffer, "|", io_buffer_or, 1);
rb_define_method(rb_cIOBuffer, "^", io_buffer_xor, 1);
rb_define_method(rb_cIOBuffer, "~", io_buffer_not, 0);

rb_define_method(rb_cIOBuffer, "and!", io_buffer_and_inplace, 1);
rb_define_method(rb_cIOBuffer, "or!", io_buffer_or_inplace, 1);
rb_define_method(rb_cIOBuffer, "xor!", io_buffer_xor_inplace, 1);
rb_define_method(rb_cIOBuffer, "not!", io_buffer_not_inplace, 0);

// IO operations:
rb_define_method(rb_cIOBuffer, "read", io_buffer_read, 2);
rb_define_method(rb_cIOBuffer, "pread", io_buffer_pread, 3);
Expand Down

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