160 lines
3.9 KiB
Ruby
160 lines
3.9 KiB
Ruby
class Sane
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include Singleton
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attr_reader :version
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def self.open
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instance.send(:init)
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yield instance
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ensure
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instance.send(:exit)
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end
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def devices
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get_devices.map { |device| Device.new(device) }
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end
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private
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def not_initialized?
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version.nil?
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end
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def initialized?
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!not_initialized?
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end
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def init
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ensure_not_initialized!
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version_code = FFI::MemoryPointer.new(:int)
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check_status!(API.sane_init(version_code, FFI::Pointer::NULL))
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@version = version_code.read_int
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end
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def exit
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ensure_initialized!
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API.sane_exit
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@version = nil
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end
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def get_devices
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ensure_initialized!
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devices_pointer_pointer = FFI::MemoryPointer.new(:pointer)
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check_status!(API.sane_get_devices(devices_pointer_pointer, 0))
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devices_pointer = devices_pointer_pointer.read_pointer
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[].tap do |result|
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until devices_pointer.read_pointer.null?
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result << API::Device.new(devices_pointer.read_pointer).to_hash
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devices_pointer += FFI.type_size(:pointer)
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end
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end
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end
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def open(device_name)
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ensure_initialized!
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device_handle_pointer = FFI::MemoryPointer.new(:pointer)
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check_status!(API.sane_open(device_name, device_handle_pointer))
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device_handle_pointer.read_pointer
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end
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def close(device_handle)
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ensure_initialized!
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API.sane_close(device_handle)
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end
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def get_option_descriptor(device_handle, option)
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ensure_initialized!
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result = API.sane_get_option_descriptor(device_handle, option)
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API::OptionDescriptor.new(result).to_hash
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end
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def get_option(device_handle, option)
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ensure_initialized!
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descriptor = get_option_descriptor(device_handle, option)
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case descriptor[:type]
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when :string
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value_pointer = FFI::MemoryPointer.new(:pointer)
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when :bool, :int, :fixed
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value_pointer = FFI::MemoryPointer.new(:int)
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else
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return nil
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end
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check_status!(API.sane_control_option(device_handle, option, :get_value, value_pointer, FFI::Pointer::NULL))
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case descriptor[:type]
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when :string
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value_pointer.read_string
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when :bool
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!value_pointer.read_int.zero?
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when :int, :fixed
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value_pointer.read_int
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end
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end
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def set_option(device_handle, option, value)
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ensure_initialized!
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descriptor = get_option_descriptor(device_handle, option)
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case descriptor[:type]
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when :string
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value_pointer = FFI::MemoryPointer.from_string(value)
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when :int, :fixed
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value_pointer = FFI::MemoryPointer.new(:int).write_int(value)
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when :bool
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value_pointer = FFI::MemoryPointer.new(:int).write_int(value ? 1 : 0)
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else
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return nil
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end
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check_status!(API.sane_control_option(device_handle, option, :set_value, value_pointer, FFI::Pointer::NULL))
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case descriptor[:type]
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when :string
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value_pointer.read_string
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when :bool
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!value_pointer.read_int.zero?
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when :int, :fixed
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value_pointer.read_int
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end
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end
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def start(handle)
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ensure_initialized!
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API.sane_start(handle)
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end
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def read(handle, size = 64 * 1024)
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ensure_initialized!
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data_pointer = FFI::MemoryPointer.new(:char, size)
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length_pointer = FFI::MemoryPointer.new(:int)
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check_status!(API.sane_read(handle, data_pointer, size, length_pointer))
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data_pointer.read_string(length_pointer.read_int)
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end
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def strstatus(status)
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ensure_initialized!
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API.sane_strstatus(status)
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end
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def get_parameters(handle)
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ensure_initialized!
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parameters_pointer = FFI::MemoryPointer.new(API::Parameters.size)
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check_status!(API.sane_get_parameters(handle, parameters_pointer))
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API::Parameters.new(parameters_pointer).to_hash
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end
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def ensure_not_initialized!
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raise "SANE library is already initialized" if initialized?
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end
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def ensure_initialized!
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raise "SANE library is not initialized" if not_initialized?
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end
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def check_status!(status)
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raise Error.new(strstatus(status), status) unless status == :good
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end
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end
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