instance method
IO::Buffer#set_string
(*untyped) -> untyped
set_string(string, [offset, [length, [source_offset]]]) → size
io_buffer.c
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static VALUE
io_buffer_set_string(int argc, VALUE *argv, VALUE self)
{
rb_check_arity(argc, 1, 4);
struct rb_io_buffer *buffer = NULL;
TypedData_Get_Struct(self, struct rb_io_buffer, &rb_io_buffer_type, buffer);
VALUE string = rb_str_to_str(argv[0]);
const void *source_base = RSTRING_PTR(string);
size_t source_size = RSTRING_LEN(string);
VALUE result = io_buffer_copy_from(buffer, source_base, source_size, argc-1, argv+1);
RB_GC_GUARD(string);
return result;
}
Efficiently copy from a source String into the buffer, at offset using memmove.
Example
buf = IO::Buffer.new(8) # => # #<IO::Buffer 0x0000557412714a20+8 INTERNAL> # 0x00000000 00 00 00 00 00 00 00 00 ........ # set buffer starting from offset 1, take 2 bytes starting from string's # second buf.set_string('test', 1, 2, 1) # => 2 buf # => # #<IO::Buffer 0x0000557412714a20+8 INTERNAL> # 0x00000000 00 65 73 00 00 00 00 00 .es.....
See also copy for examples of how buffer writing might be used for changing associated strings and files.