note description: "Helper routines for encoding conversion." legal: "See notice at end of class." status: "See notice at end of class." date: "$Date: 2020-05-19 14:18:09 +0000 (Tue, 19 May 2020) $" revision: "$Revision: 104255 $" class ENCODING_HELPER create default_create feature -- Conversion multi_byte_to_pointer (a_string: READABLE_STRING_8): MANAGED_POINTER -- Managed pointer of a_string. require a_string_not_void: a_string /= Void do Result := (create {C_STRING}.make (a_string)).managed_data ensure instance_free: class result_not_void: Result /= Void end wide_string_to_pointer (a_string: READABLE_STRING_32): MANAGED_POINTER -- Managed pointer of a_string which is taken as -- 16bits string. High 16bits of characters of a_string are discarded. require a_string_not_void: a_string /= Void local i, nb: INTEGER_32 do nb := a_string.count create Result.make ((nb + 1) * 2) from i := 0 until i = nb loop Result.put_natural_16 (a_string.code (i + 1).to_natural_16, i * 2) i := i + 1 end; Result.put_natural_16 (0, i * 2) ensure instance_free: class result_not_void: Result /= Void end pointer_to_multi_byte (a_multi_string: POINTER; a_count: INTEGER_32): STRING_8 -- STRING_8 read from a_multi_string. require a_multi_string_not_default: a_multi_string /= default_pointer a_count_non_negative: a_count >= 0 local i: INTEGER_32 l_managed_pointer: MANAGED_POINTER do create l_managed_pointer.share_from_pointer (a_multi_string, a_count) create Result.make (a_count) from i := 0 until i >= a_count loop Result.append_code (l_managed_pointer.read_natural_8 (i).to_natural_32) i := i + 1 end ensure instance_free: class result_not_void: Result /= Void end pointer_to_wide_string (a_w_string: POINTER; a_count: INTEGER_32): STRING_32 -- STRING_32 read from a_w_string of a_count bytes. require a_w_string_not_default: a_w_string /= default_pointer a_count_non_negative: a_count >= 0 local i: INTEGER_32 l_managed_pointer: MANAGED_POINTER l_size: INTEGER_32 do create l_managed_pointer.share_from_pointer (a_w_string, a_count) l_size := (a_count + 1) // 2 create Result.make (l_size) from i := 0 until i >= l_size loop if i * 2 <= a_count then Result.append_code (l_managed_pointer.read_natural_16 (i * 2).to_natural_32) end i := i + 1 end ensure instance_free: class result_not_void: Result /= Void end pointer_to_string_32 (a_w_string: POINTER; a_count: INTEGER_32): STRING_32 -- STRING_32 read from a_w_string of a_count bytes. require a_w_string_not_default: a_w_string /= default_pointer a_count_non_negative: a_count >= 0 local i: INTEGER_32 l_managed_pointer: MANAGED_POINTER l_size: INTEGER_32 do create l_managed_pointer.share_from_pointer (a_w_string, a_count) l_size := a_count // 4 create Result.make (l_size) from i := 0 until i >= l_size loop if i * 4 <= a_count then Result.append_code (l_managed_pointer.read_natural_32 (i * 4)) end i := i + 1 end ensure instance_free: class result_not_void: Result /= Void end string_32_to_multi_byte (a_string: STRING_32): STRING_8 -- Byte stream of a_string in endianness of the current platform. require a_string_not_void: a_string /= Void local i: INTEGER_32 l_code: NATURAL_32 l_count: INTEGER_32 l_is_little_endian: BOOLEAN do l_count := a_string.count if l_count > 0 then create Result.make (l_count * 4) from i := 1 l_is_little_endian := Is_little_endian until i > l_count loop l_code := a_string.code (i) if l_is_little_endian then Result.append_code (l_code & 255); Result.append_code (l_code & 65280 |>> 8); Result.append_code (l_code & 16711680 |>> 16); Result.append_code (l_code & 4278190080 |>> 24) else Result.append_code (l_code & 4278190080 |>> 24); Result.append_code (l_code & 16711680 |>> 16); Result.append_code (l_code & 65280 |>> 8); Result.append_code (l_code & 255) end i := i + 1 end else create Result.make_empty end ensure instance_free: class result_not_void: Result /= Void end string_8_to_wide_string (a_w_string: STRING_8): STRING_32 -- Interpret a_w_string as a sequence of 2-byte characters into a STRING_32 -- in endianness of the current platform. require a_w_string_not_void: a_w_string /= Void local i: INTEGER_32 l_size, l_count: INTEGER_32 l_is_little_endian: BOOLEAN l_code: NATURAL_32 do l_count := a_w_string.count l_size := (l_count + 1) // 2 l_is_little_endian := Is_little_endian create Result.make (l_size) from i := 1 until i > l_count loop if i + 1 <= l_count then if l_is_little_endian then l_code := a_w_string.code (i) | (a_w_string.code (i + 1) |<< 8) else l_code := (a_w_string.code (i) |<< 8) | a_w_string.code (i + 1) end; Result.append_code (l_code) end i := i + 1 end ensure instance_free: class result_not_void: Result /= Void end string_16_to_stream (a_string: STRING_32): STRING_8 -- We use a_string as 2 bytes encoding string, the first two bytes are not used. -- in the endianness of the current platform. require a_string_not_void: a_string /= Void local l_managed_pointer: MANAGED_POINTER i, l_count: INTEGER_32 do l_managed_pointer := wide_string_to_pointer (a_string) create Result.make (l_managed_pointer.count) from i := 0 l_count := l_managed_pointer.count - 2 until i = l_count loop Result.append_character (l_managed_pointer.read_natural_8 (i).to_character_8) i := i + 1 end ensure instance_free: class result_not_void: Result /= Void valid_count: Result.count = a_string.count * 2 end string_general_to_stream (a_string: READABLE_STRING_GENERAL): STRING_8 -- Streamize a_string. require a_string_not_void: a_string /= Void do if a_string.is_string_8 then Result := a_string.to_string_8 else Result := string_32_to_multi_byte (a_string.as_string_32) end ensure instance_free: class result_not_void: Result /= Void end feature -- Endian string_32_switch_endian (a_str: STRING_32): STRING_32 -- Switch endian of a_str for both high and low bits. require a_str_not_void: a_str /= Void local l_code: NATURAL_32 i, l_count: INTEGER_32 do l_count := a_str.count create Result.make (l_count) from i := 1 until i > l_count loop l_code := a_str.code (i); Result.append_code (l_code & 255 |<< 24 & 4278190080 + l_code & 65280 |<< 8 + l_code & 16711680 |>> 8 + l_code & 4278190080 |>> 24 & 255) i := i + 1 end ensure instance_free: class result_not_void: Result /= Void end string_16_switch_endian (a_str: STRING_32): STRING_32 -- Switch endian of a_str for low bits. -- High bits are cleaned. require a_str_not_void: a_str /= Void local l_code: NATURAL_32 i, l_count: INTEGER_32 do l_count := a_str.count create Result.make (l_count) from i := 1 until i > l_count loop l_code := a_str.code (i); Result.append_code (l_code & 255 |<< 8 & 65280 + l_code & 65280 |>> 8 & 255) i := i + 1 end ensure instance_free: class result_not_void: Result /= Void end Is_little_endian: BOOLEAN -- Is this system little endian? once Result := {PLATFORM}.is_little_endian ensure instance_free: class end note library: "Encoding: Library of reusable components for Eiffel." copyright: "Copyright (c) 1984-2020, Eiffel Software and others" license: "Eiffel Forum License v2 (see http://www.eiffel.com/licensing/forum.txt)" source: "[ Eiffel Software 5949 Hollister Ave., Goleta, CA 93117 USA Telephone 805-685-1006, Fax 805-685-6869 Website http://www.eiffel.com Customer support http://support.eiffel.com ]" end -- class ENCODING_HELPER
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