161 lines
4.9 KiB
Ruby
161 lines
4.9 KiB
Ruby
#
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# Copyright (C) 2008, 2009 Wayne Meissner
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# Copyright (c) 2007, 2008 Evan Phoenix
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#
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# This file is part of ruby-ffi.
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#
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# All rights reserved.
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#
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# Redistribution and use in source and binary forms, with or without
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# modification, are permitted provided that the following conditions are met:
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#
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# * Redistributions of source code must retain the above copyright notice, this
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# list of conditions and the following disclaimer.
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# * Redistributions in binary form must reproduce the above copyright notice
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# this list of conditions and the following disclaimer in the documentation
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# and/or other materials provided with the distribution.
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# * Neither the name of the Ruby FFI project nor the names of its contributors
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# may be used to endorse or promote products derived from this software
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# without specific prior written permission.
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#
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# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
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# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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# SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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# OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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#
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require 'ffi/platform'
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module FFI
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class Pointer
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# Pointer size
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SIZE = Platform::ADDRESS_SIZE / 8
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# Return the size of a pointer on the current platform, in bytes
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# @return [Numeric]
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def self.size
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SIZE
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end
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# @param [nil,Numeric] len length of string to return
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# @return [String]
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# Read pointer's contents as a string, or the first +len+ bytes of the
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# equivalent string if +len+ is not +nil+.
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def read_string(len=nil)
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if len
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return ''.b if len == 0
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get_bytes(0, len)
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else
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get_string(0)
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end
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end
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# @param [Numeric] len length of string to return
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# @return [String]
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# Read the first +len+ bytes of pointer's contents as a string.
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#
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# Same as:
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# ptr.read_string(len) # with len not nil
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def read_string_length(len)
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get_bytes(0, len)
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end
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# @return [String]
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# Read pointer's contents as a string.
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#
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# Same as:
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# ptr.read_string # with no len
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def read_string_to_null
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get_string(0)
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end
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# @param [String] str string to write
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# @param [Numeric] len length of string to return
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# @return [self]
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# Write +len+ first bytes of +str+ in pointer's contents.
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#
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# Same as:
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# ptr.write_string(str, len) # with len not nil
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def write_string_length(str, len)
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put_bytes(0, str, 0, len)
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end
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# @param [String] str string to write
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# @param [Numeric] len length of string to return
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# @return [self]
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# Write +str+ in pointer's contents, or first +len+ bytes if
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# +len+ is not +nil+.
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def write_string(str, len=nil)
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len = str.bytesize unless len
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# Write the string data without NUL termination
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put_bytes(0, str, 0, len)
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end
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# @param [Type] type type of data to read from pointer's contents
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# @param [Symbol] reader method to send to +self+ to read +type+
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# @param [Numeric] length
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# @return [Array]
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# Read an array of +type+ of length +length+.
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# @example
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# ptr.read_array_of_type(TYPE_UINT8, :read_uint8, 4) # -> [1, 2, 3, 4]
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def read_array_of_type(type, reader, length)
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ary = []
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size = FFI.type_size(type)
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tmp = self
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length.times { |j|
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ary << tmp.send(reader)
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tmp += size unless j == length-1 # avoid OOB
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}
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ary
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end
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# @param [Type] type type of data to write to pointer's contents
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# @param [Symbol] writer method to send to +self+ to write +type+
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# @param [Array] ary
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# @return [self]
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# Write +ary+ in pointer's contents as +type+.
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# @example
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# ptr.write_array_of_type(TYPE_UINT8, :put_uint8, [1, 2, 3 ,4])
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def write_array_of_type(type, writer, ary)
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size = FFI.type_size(type)
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ary.each_with_index { |val, i|
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break unless i < self.size
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self.send(writer, i * size, val)
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}
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self
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end
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# @return [self]
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def to_ptr
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self
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end
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# @param [Symbol,Type] type of data to read
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# @return [Object]
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# Read pointer's contents as +type+
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#
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# Same as:
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# ptr.get(type, 0)
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def read(type)
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get(type, 0)
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end
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# @param [Symbol,Type] type of data to read
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# @param [Object] value to write
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# @return [nil]
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# Write +value+ of type +type+ to pointer's content
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#
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# Same as:
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# ptr.put(type, 0)
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def write(type, value)
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put(type, 0, value)
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end
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end
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end
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