note description: "Eiffel implementations for Unicode encoding conversion." legal: "See notice at end of class." status: "See notice at end of class." date: "$Date: 2020-05-20 11:14:50 +0000 (Wed, 20 May 2020) $" revision: "$Revision: 104299 $" class UNICODE_CONVERSION inherit ENCODING_I create {ENCODING} default_create feature -- Query is_code_page_valid (a_code_page: READABLE_STRING_8): BOOLEAN -- Is a_code_page valid? do if a_code_page /= Void and then not a_code_page.is_empty then Result := Unicode_encodings.has (a_code_page) end end is_code_page_convertible (a_from_code_page, a_to_code_page: READABLE_STRING_8): BOOLEAN -- Is a_from_code_page convertible to a_to_code_page. do Result := a_from_code_page = {CODE_PAGE_CONSTANTS}.utf8 and then a_to_code_page = {CODE_PAGE_CONSTANTS}.utf32 if not Result then if a_from_code_page.is_case_insensitive_equal ({CODE_PAGE_CONSTANTS}.utf8) then Result := a_to_code_page.is_case_insensitive_equal ({CODE_PAGE_CONSTANTS}.utf8) or else a_to_code_page.is_case_insensitive_equal ({CODE_PAGE_CONSTANTS}.utf32) elseif a_from_code_page.is_case_insensitive_equal ({CODE_PAGE_CONSTANTS}.utf32) then Result := a_to_code_page.is_case_insensitive_equal ({CODE_PAGE_CONSTANTS}.utf32) or else a_to_code_page.is_case_insensitive_equal ({CODE_PAGE_CONSTANTS}.utf8) or else a_to_code_page.is_case_insensitive_equal ({CODE_PAGE_CONSTANTS}.utf16) elseif a_from_code_page.is_case_insensitive_equal ({CODE_PAGE_CONSTANTS}.utf16) then Result := a_to_code_page.is_case_insensitive_equal ({CODE_PAGE_CONSTANTS}.utf16) or else a_to_code_page.is_case_insensitive_equal ({CODE_PAGE_CONSTANTS}.utf32) elseif a_from_code_page.is_case_insensitive_equal ({CODE_PAGE_CONSTANTS}.utf7) then Result := a_to_code_page.is_case_insensitive_equal ({CODE_PAGE_CONSTANTS}.utf7) end end end Last_conversion_lost_data: BOOLEAN = False -- Has last conversion between two encodings lost data? is_valid_utf8 (a_string: READABLE_STRING_8): BOOLEAN -- Is a_string valid UTF-8 string? require a_string_not_void: a_string /= Void do Result := {UTF_CONVERTER}.is_valid_utf_8_string_8 (a_string) end is_valid_as_string_16 (a_string: READABLE_STRING_GENERAL): BOOLEAN -- Check high 16 bit of any char in a_string is zero. local i, nb: INTEGER_32 l_area: SPECIAL [CHARACTER_32] do if a_string /= Void then if a_string.is_string_32 then from nb := a_string.count Result := True l_area := a_string.as_string_32.area until i = nb or not Result loop Result := l_area [i].code <= 65535 i := i + 1 end else Result := True end end end feature -- Conversion convert_to (a_from_code_page: READABLE_STRING_8; a_from_string: READABLE_STRING_GENERAL; a_to_code_page: READABLE_STRING_8) -- Convert between Unicode encodings. do reset if a_from_code_page.is_case_insensitive_equal (a_to_code_page) then last_conversion_successful := True if a_from_string.is_string_8 then last_converted_string := a_from_string.to_string_8 else last_converted_string := a_from_string.as_string_32 end else if a_from_code_page.is_case_insensitive_equal ({CODE_PAGE_CONSTANTS}.utf8) then last_converted_string := utf8_to_utf32 (if a_from_string.is_valid_as_string_8 then a_from_string.to_string_8 else {UTF_CONVERTER}.utf_32_string_to_utf_8_string_8 (a_from_string) end) last_conversion_successful := True elseif a_from_code_page.is_case_insensitive_equal ({CODE_PAGE_CONSTANTS}.utf32) then if a_to_code_page.is_case_insensitive_equal ({CODE_PAGE_CONSTANTS}.utf8) then last_converted_string := utf32_to_utf8 (a_from_string.as_string_32) last_conversion_successful := True elseif a_to_code_page.is_case_insensitive_equal ({CODE_PAGE_CONSTANTS}.utf16) then last_converted_string := utf32_to_utf16 (a_from_string.as_string_32) last_was_wide_string := True last_conversion_successful := True end elseif a_from_code_page.is_case_insensitive_equal ({CODE_PAGE_CONSTANTS}.utf16) then if a_to_code_page.is_case_insensitive_equal ({CODE_PAGE_CONSTANTS}.utf32) then last_converted_string := utf16_to_utf32 (a_from_string.as_string_32) last_conversion_successful := True end end end end feature -- Explicit Conversion utf8_to_utf32 (a_string: READABLE_STRING_8): STRING_32 -- UTF8 to UTF32 conversion, Eiffel implementation. require a_string_not_void: a_string /= Void do Result := {UTF_CONVERTER}.utf_8_string_8_to_string_32 (a_string) ensure result_not_void: Result /= Void end utf32_to_utf8 (a_string: READABLE_STRING_32): STRING_8 -- Convert UTF32 to UTF8. require a_string_not_void: a_string /= Void do Result := {UTF_CONVERTER}.utf_32_string_to_utf_8_string_8 (a_string) ensure result_not_void: Result /= Void end utf32_to_utf16 (a_str: READABLE_STRING_32): STRING_32 -- Convert utf32 to utf16 without data lose. require a_str_not_void: a_str /= Void local l_code: NATURAL_32 i, l_count: INTEGER_32 do create Result.make (a_str.count * 2) from i := 1 l_count := a_str.count until i > l_count loop l_code := a_str.code (i) & 1048575 if l_code > 65535 then l_code := l_code - 65536; Result.append_code (l_code |>> 10 | 55296); Result.append_code (l_code & 1023 | 56320) else Result.append_code (l_code) end i := i + 1 end ensure instance_free: class result_not_void: Result /= Void end utf16_to_utf32 (a_str: READABLE_STRING_32): STRING_32 -- Convert utf16 to utf32. require a_str_not_void: a_str /= Void local i, l_count: INTEGER_32 l_code: NATURAL_32 l_temp: NATURAL_32 l_lower: NATURAL_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) i := i + 1 l_temp := l_code & 65535 if i <= l_count then l_lower := a_str.code (i) & 65535 end if l_temp >= 55296 and then l_temp <= 56319 and then i <= l_count and then l_lower >= 56320 and then l_lower <= 57343 then Result.append_code ((l_temp & 1023) |<< 10 + l_lower & 1023 + 65536) i := i + 1 else Result.append_code (l_temp) end end ensure instance_free: class result_not_void: Result /= Void end append_code_point_to_utf8 (a_code: NATURAL_32; a_string: STRING_8) -- Append a Unicode code point a_code to a UTF-8 stream. require a_string_not_void: a_string /= Void a_code_is_valid: a_code >= 0 and then a_code <= 1114111 do {UTF_CONVERTER}.utf_32_code_into_utf_8_string_8 (a_code, a_string) ensure a_string_appended: (a_code <= 127 implies a_string.count = old a_string.count + 1) and ((a_code > 127 and a_code <= 2047) implies a_string.count = old a_string.count + 2) and ((a_code > 2047 and a_code <= 65535) implies a_string.count = old a_string.count + 3) and ((a_code > 65535 and a_code <= 1114111) implies a_string.count = old a_string.count + 4) end read_character_from_utf8 (a_position: INTEGER_32; a_read_bytes: detachable INTEGER_32_REF; a_string: READABLE_STRING_8): CHARACTER_32 -- Read a Unicode character from UTF-8 string. -- a_string is in UTF-8. -- a_position is the starting byte point of a character. -- a_read_bytes is the number of bytes read. require a_string_not_void: a_string /= Void a_position_in_range: a_position > 0 and a_position <= a_string.count a_position_valid: a_string.code (a_position).to_natural_8 <= 127 or (a_string.code (a_position).to_natural_8 & 224) = 192 or (a_string.code (a_position).to_natural_8 & 240) = 224 or (a_string.code (a_position).to_natural_8 & 248) = 240 or (a_string.code (a_position).to_natural_8 & 252) = 248 or (a_string.code (a_position).to_natural_8 & 254) = 252 local l_pos: INTEGER_32 l_nat8: NATURAL_8 l_code: NATURAL_32 do l_pos := a_position l_nat8 := a_string.code (l_pos).to_natural_8 if l_nat8 <= 127 then Result := l_nat8.to_character_32 elseif (l_nat8 & 224) = 192 then l_code := (l_nat8 & 31).to_natural_32 |<< 6 l_pos := l_pos + 1 l_nat8 := a_string.code (l_pos).to_natural_8 l_code := l_code | (l_nat8 & 63).to_natural_32 Result := l_code.to_character_32 elseif (l_nat8 & 240) = 224 then l_code := (l_nat8 & 15).to_natural_32 |<< 12 l_nat8 := a_string.code (l_pos + 1).to_natural_8 l_code := l_code | ((l_nat8 & 63).to_natural_32 |<< 6) l_nat8 := a_string.code (l_pos + 2).to_natural_8 l_code := l_code | (l_nat8 & 63).to_natural_32 Result := l_code.to_character_32 l_pos := l_pos + 2 elseif (l_nat8 & 248) = 240 then l_code := (l_nat8 & 7).to_natural_32 |<< 18 l_nat8 := a_string.code (l_pos + 1).to_natural_8 l_code := l_code | ((l_nat8 & 63).to_natural_32 |<< 12) l_nat8 := a_string.code (l_pos + 2).to_natural_8 l_code := l_code | ((l_nat8 & 63).to_natural_32 |<< 6) l_nat8 := a_string.code (l_pos + 3).to_natural_8 l_code := l_code | (l_nat8 & 63).to_natural_32 Result := l_code.to_character_32 l_pos := l_pos + 3 elseif (l_nat8 & 252) = 248 then Result := ' '.to_character_32 l_pos := l_pos + 4 else Result := ' '.to_character_32 l_pos := l_pos + 5 end if a_read_bytes /= Void then a_read_bytes.set_item (l_pos - a_position + 1) end end feature {NONE} -- Implementation Unicode_encodings: STRING_TABLE [READABLE_STRING_8] -- Supported Unicode encodings. once create Result.make (8); Result.put ({CODE_PAGE_CONSTANTS}.utf7, {CODE_PAGE_CONSTANTS}.utf7); Result.put ({CODE_PAGE_CONSTANTS}.utf8, {CODE_PAGE_CONSTANTS}.utf8); Result.put ({CODE_PAGE_CONSTANTS}.utf16, {CODE_PAGE_CONSTANTS}.utf16); Result.put ({CODE_PAGE_CONSTANTS}.utf16_le, {CODE_PAGE_CONSTANTS}.utf16_le); Result.put ({CODE_PAGE_CONSTANTS}.utf32, {CODE_PAGE_CONSTANTS}.utf32); Result.put ({CODE_PAGE_CONSTANTS}.utf32_le, {CODE_PAGE_CONSTANTS}.utf32_le); Result.put ({CODE_PAGE_CONSTANTS}.utf16_be, {CODE_PAGE_CONSTANTS}.utf16_be); Result.put ({CODE_PAGE_CONSTANTS}.utf32_be, {CODE_PAGE_CONSTANTS}.utf32_be) 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 UNICODE_CONVERSION
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