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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 07:42:04 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 07:42:04 +0000 |
commit | 0d47952611198ef6b1163f366dc03922d20b1475 (patch) | |
tree | 3d840a3b8c0daef0754707bfb9f5e873b6b1ac13 /nselib/unicode.lua | |
parent | Initial commit. (diff) | |
download | nmap-upstream.tar.xz nmap-upstream.zip |
Adding upstream version 7.94+git20230807.3be01efb1+dfsg.upstream/7.94+git20230807.3be01efb1+dfsgupstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | nselib/unicode.lua | 467 |
1 files changed, 467 insertions, 0 deletions
diff --git a/nselib/unicode.lua b/nselib/unicode.lua new file mode 100644 index 0000000..284b6e9 --- /dev/null +++ b/nselib/unicode.lua @@ -0,0 +1,467 @@ +--- +-- Library methods for handling unicode strings. +-- +-- @author Daniel Miller +-- @copyright Same as Nmap--See https://nmap.org/book/man-legal.html + + +local string = require "string" +local table = require "table" +local stdnse = require "stdnse" +local unittest = require "unittest" +local tableaux = require "tableaux" +local utf8 = require "utf8" +_ENV = stdnse.module("unicode", stdnse.seeall) + +-- Localize a few functions for a tiny speed boost, since these will be looped +-- over every char of a string +local byte = string.byte +local char = string.char +local pack = string.pack +local unpack = string.unpack +local concat = table.concat +local pcall = pcall + + +---Decode a buffer containing Unicode data. +--@param buf The string/buffer to be decoded +--@param decoder A Unicode decoder function (such as utf8_dec) +--@param bigendian For encodings that care about byte-order (such as UTF-16), +-- set this to true to force big-endian byte order. Default: +-- false (little-endian) +--@return A list-table containing the code points as numbers +function decode(buf, decoder, bigendian) + if decoder == utf8_dec then + return {utf8.codepoint(buf, 1, -1)} + end + local cp = {} + local pos = 1 + while pos <= #buf do + pos, cp[#cp+1] = decoder(buf, pos, bigendian) + end + return cp +end + +---Encode a list of Unicode code points +--@param list A list-table of code points as numbers +--@param encoder A Unicode encoder function (such as utf8_enc) +--@param bigendian For encodings that care about byte-order (such as UTF-16), +-- set this to true to force big-endian byte order. Default: +-- false (little-endian) +--@return An encoded string +function encode(list, encoder, bigendian) + if encoder == utf8_enc then + return utf8.char(table.unpack(list)) + end + local buf = {} + for i, cp in ipairs(list) do + buf[i] = encoder(cp, bigendian) + end + return table.concat(buf, "") +end + +---Transcode a string from one format to another +-- +--The string will be decoded and re-encoded in one pass. This saves some +--overhead vs simply passing the output of <code>unicode.encode</code> to +--<code>unicode.decode</code>. +--@param buf The string/buffer to be transcoded +--@param decoder A Unicode decoder function (such as utf16_dec) +--@param encoder A Unicode encoder function (such as utf8_enc) +--@param bigendian_dec Set this to true to force big-endian decoding. +--@param bigendian_enc Set this to true to force big-endian encoding. +--@return An encoded string +function transcode(buf, decoder, encoder, bigendian_dec, bigendian_enc) + local out = {} + local cp + local pos = 1 + -- Take advantage of Lua's built-in utf8 functions + if decoder == utf8_dec then + for _, cp in utf8.codes(buf) do + out[#out+1] = encoder(cp, bigendian_enc) + end + elseif encoder == utf8_enc then + while pos <= #buf do + pos, cp = decoder(buf, pos, bigendian_dec) + out[#out+1] = utf8.char(cp) + end + else + while pos <= #buf do + pos, cp = decoder(buf, pos, bigendian_dec) + out[#out+1] = encoder(cp, bigendian_enc) + end + end + return table.concat(out) +end + +--- Determine (poorly) the character encoding of a string +-- +-- First, the string is checked for a Byte-order Mark (BOM). This can be +-- examined to determine UTF-16 with endianness or UTF-8. If no BOM is found, +-- the string is examined. +-- +-- If null bytes are encountered, UTF-16 is assumed. Endianness is determined +-- by byte position, assuming the null is the high-order byte. Otherwise, if +-- byte values over 127 are found, UTF-8 decoding is attempted. If this fails, +-- the result is 'other', otherwise it is 'utf-8'. If no high bytes are found, +-- the result is 'ascii'. +-- +--@param buf The string/buffer to be identified +--@param len The number of bytes to inspect in order to identify the string. +-- Default: 100 +--@return A string describing the encoding: 'ascii', 'utf-8', 'utf-16be', +-- 'utf-16le', or 'other' meaning some unidentified 8-bit encoding +function chardet(buf, len) + local limit = len or 100 + if limit > #buf then + limit = #buf + end + -- Check BOM + if limit >= 2 then + local bom1, bom2 = byte(buf, 1, 2) + if bom1 == 0xff and bom2 == 0xfe then + return 'utf-16le' + elseif bom1 == 0xfe and bom2 == 0xff then + return 'utf-16be' + elseif limit >= 3 then + local bom3 = byte(buf, 3) + if bom1 == 0xef and bom2 == 0xbb and bom3 == 0xbf then + return 'utf-8' + end + end + end + -- Try bytes + local pos = 1 + local high = false + local is_utf8 = true + while pos < limit do + local c = byte(buf, pos) + if c == 0 then + if pos % 2 == 0 then + return 'utf-16le' + else + return 'utf-16be' + end + is_utf8 = false + pos = pos + 1 + elseif c > 127 then + if not high then + high = true + end + if is_utf8 then + local p, cp = utf8_dec(buf, pos) + if not p then + is_utf8 = false + else + pos = p + end + end + if not is_utf8 then + pos = pos + 1 + end + else + pos = pos + 1 + end + end + if high then + if is_utf8 then + return 'utf-8' + else + return 'other' + end + else + return 'ascii' + end +end + +---Encode a Unicode code point to UTF-16. See RFC 2781. +-- +-- Windows OS prior to Windows 2000 only supports UCS-2, so beware using this +-- function to encode code points above 0xFFFF. +--@param cp The Unicode code point as a number +--@param bigendian Set this to true to encode big-endian UTF-16. Default is +-- false (little-endian) +--@return A string containing the code point in UTF-16 encoding. +function utf16_enc(cp, bigendian) + local fmt = "<I2" + if bigendian then + fmt = ">I2" + end + + if cp % 1.0 ~= 0.0 or cp < 0 then + -- Only defined for nonnegative integers. + return nil + elseif cp <= 0xFFFF then + return pack(fmt, cp) + elseif cp <= 0x10FFFF then + cp = cp - 0x10000 + return pack(fmt .. fmt, 0xD800 + (cp >> 10), 0xDC00 + (cp & 0x3FF)) + else + return nil + end +end + +---Decodes a UTF-16 character. +-- +-- Does not check that the returned code point is a real character. +-- Specifically, it can be fooled by out-of-order lead- and trail-surrogate +-- characters. +--@param buf A string containing the character +--@param pos The index in the string where the character begins +--@param bigendian Set this to true to encode big-endian UTF-16. Default is +-- false (little-endian) +--@return pos The index in the string where the character ended +--@return cp The code point of the character as a number +function utf16_dec(buf, pos, bigendian) + local fmt = "<I2" + if bigendian then + fmt = ">I2" + end + + local cp + cp, pos = unpack(fmt, buf, pos) + if cp >= 0xD800 and cp <= 0xDFFF then + local high = (cp - 0xD800) << 10 + cp, pos = unpack(fmt, buf, pos) + cp = 0x10000 + high + cp - 0xDC00 + end + return pos, cp +end + +---Encode a Unicode code point to UTF-8. See RFC 3629. +-- +-- Does not check that cp is a real character; that is, doesn't exclude the +-- surrogate range U+D800 - U+DFFF and a handful of others. +-- @class function +--@param cp The Unicode code point as a number +--@return A string containing the code point in UTF-8 encoding. +utf8_enc = utf8.char + +---Decodes a UTF-8 character. +-- +-- Does not check that the returned code point is a real character. +--@param buf A string containing the character +--@param pos The index in the string where the character begins +--@return pos The index in the string where the character ended or nil on error +--@return cp The code point of the character as a number, or an error string +function utf8_dec(buf, pos) + pos = pos or 1 + local status, cp = pcall(utf8.codepoint, buf, pos) + if status then + return utf8.offset(buf, 2, pos), cp + else + return nil, cp + end +end + +-- Code Page 437, native US-English Windows OEM code page +local cp437_decode = { + [0x80] = 0x00c7, + [0x81] = 0x00fc, + [0x82] = 0x00e9, + [0x83] = 0x00e2, + [0x84] = 0x00e4, + [0x85] = 0x00e0, + [0x86] = 0x00e5, + [0x87] = 0x00e7, + [0x88] = 0x00ea, + [0x89] = 0x00eb, + [0x8a] = 0x00e8, + [0x8b] = 0x00ef, + [0x8c] = 0x00ee, + [0x8d] = 0x00ec, + [0x8e] = 0x00c4, + [0x8f] = 0x00c5, + [0x90] = 0x00c9, + [0x91] = 0x00e6, + [0x92] = 0x00c6, + [0x93] = 0x00f4, + [0x94] = 0x00f6, + [0x95] = 0x00f2, + [0x96] = 0x00fb, + [0x97] = 0x00f9, + [0x98] = 0x00ff, + [0x99] = 0x00d6, + [0x9a] = 0x00dc, + [0x9b] = 0x00a2, + [0x9c] = 0x00a3, + [0x9d] = 0x00a5, + [0x9e] = 0x20a7, + [0x9f] = 0x0192, + [0xa0] = 0x00e1, + [0xa1] = 0x00ed, + [0xa2] = 0x00f3, + [0xa3] = 0x00fa, + [0xa4] = 0x00f1, + [0xa5] = 0x00d1, + [0xa6] = 0x00aa, + [0xa7] = 0x00ba, + [0xa8] = 0x00bf, + [0xa9] = 0x2310, + [0xaa] = 0x00ac, + [0xab] = 0x00bd, + [0xac] = 0x00bc, + [0xad] = 0x00a1, + [0xae] = 0x00ab, + [0xaf] = 0x00bb, + [0xb0] = 0x2591, + [0xb1] = 0x2592, + [0xb2] = 0x2593, + [0xb3] = 0x2502, + [0xb4] = 0x2524, + [0xb5] = 0x2561, + [0xb6] = 0x2562, + [0xb7] = 0x2556, + [0xb8] = 0x2555, + [0xb9] = 0x2563, + [0xba] = 0x2551, + [0xbb] = 0x2557, + [0xbc] = 0x255d, + [0xbd] = 0x255c, + [0xbe] = 0x255b, + [0xbf] = 0x2510, + [0xc0] = 0x2514, + [0xc1] = 0x2534, + [0xc2] = 0x252c, + [0xc3] = 0x251c, + [0xc4] = 0x2500, + [0xc5] = 0x253c, + [0xc6] = 0x255e, + [0xc7] = 0x255f, + [0xc8] = 0x255a, + [0xc9] = 0x2554, + [0xca] = 0x2569, + [0xcb] = 0x2566, + [0xcc] = 0x2560, + [0xcd] = 0x2550, + [0xce] = 0x256c, + [0xcf] = 0x2567, + [0xd0] = 0x2568, + [0xd1] = 0x2564, + [0xd2] = 0x2565, + [0xd3] = 0x2559, + [0xd4] = 0x2558, + [0xd5] = 0x2552, + [0xd6] = 0x2553, + [0xd7] = 0x256b, + [0xd8] = 0x256a, + [0xd9] = 0x2518, + [0xda] = 0x250c, + [0xdb] = 0x2588, + [0xdc] = 0x2584, + [0xdd] = 0x258c, + [0xde] = 0x2590, + [0xdf] = 0x2580, + [0xe0] = 0x03b1, + [0xe1] = 0x00df, + [0xe2] = 0x0393, + [0xe3] = 0x03c0, + [0xe4] = 0x03a3, + [0xe5] = 0x03c3, + [0xe6] = 0x00b5, + [0xe7] = 0x03c4, + [0xe8] = 0x03a6, + [0xe9] = 0x0398, + [0xea] = 0x03a9, + [0xeb] = 0x03b4, + [0xec] = 0x221e, + [0xed] = 0x03c6, + [0xee] = 0x03b5, + [0xef] = 0x2229, + [0xf0] = 0x2261, + [0xf1] = 0x00b1, + [0xf2] = 0x2265, + [0xf3] = 0x2264, + [0xf4] = 0x2320, + [0xf5] = 0x2321, + [0xf6] = 0x00f7, + [0xf7] = 0x2248, + [0xf8] = 0x00b0, + [0xf9] = 0x2219, + [0xfa] = 0x00b7, + [0xfb] = 0x221a, + [0xfc] = 0x207f, + [0xfd] = 0x00b2, + [0xfe] = 0x25a0, + [0xff] = 0x00a0, +} +local cp437_encode = tableaux.invert(cp437_decode) + +---Encode a Unicode code point to CP437 +-- +-- Returns nil if the code point cannot be found in CP437 +--@param cp The Unicode code point as a number +--@return A string containing the related CP437 character +function cp437_enc(cp) + if cp < 0x80 then + return char(cp) + else + local bv = cp437_encode[cp] + if bv == nil then + return nil + else + return char(bv) + end + end +end + +---Decodes a CP437 character +--@param buf A string containing the character +--@param pos The index in the string where the character begins +--@return pos The index in the string where the character ended +--@return cp The code point of the character as a number +function cp437_dec(buf, pos) + pos = pos or 1 + local bv = byte(buf, pos) + if bv < 0x80 then + return pos + 1, bv + else + return pos + 1, cp437_decode[bv] + end +end + +---Helper function for the common case of UTF-16 to UTF-8 transcoding, such as +--from a Windows/SMB unicode string to a printable ASCII (subset of UTF-8) +--string. +--@param from A string in UTF-16, little-endian +--@return The string in UTF-8 +function utf16to8(from) + return transcode(from, utf16_dec, utf8_enc, false, nil) +end + +---Helper function for the common case of UTF-8 to UTF-16 transcoding, such as +--from a printable ASCII (subset of UTF-8) string to a Windows/SMB unicode +--string. +--@param from A string in UTF-8 +--@return The string in UTF-16, little-endian +function utf8to16(from) + return transcode(from, utf8_dec, utf16_enc, nil, false) +end + +if not unittest.testing() then + return _ENV +end + +test_suite = unittest.TestSuite:new() +test_suite:add_test(function() + local pos, cp = utf8_dec("\xE6\x97\xA5\xE6\x9C\xAC\xE8\xAA\x9E") + return pos == 4 and cp == 0x65E5, string.format("Expected 4, 0x65E5; got %d, 0x%x", pos, cp) + end, "utf8_dec") + +test_suite:add_test(unittest.equal(encode({0x65E5,0x672C,0x8A9E}, utf8_enc), "\xE6\x97\xA5\xE6\x9C\xAC\xE8\xAA\x9E"),"encode utf-8") +test_suite:add_test(unittest.equal(encode({0x12345,61,82,97}, utf16_enc), "\x08\xD8\x45\xDF=\0R\0a\0"),"encode utf-16") +test_suite:add_test(unittest.equal(encode({0x12345,61,82,97}, utf16_enc, true), "\xD8\x08\xDF\x45\0=\0R\0a"),"encode utf-16, big-endian") +test_suite:add_test(unittest.table_equal(decode("\xE6\x97\xA5\xE6\x9C\xAC\xE8\xAA\x9E", utf8_dec), {0x65E5,0x672C,0x8A9E}),"decode utf-8") +test_suite:add_test(unittest.table_equal(decode("\x08\xD8\x45\xDF=\0R\0a\0", utf16_dec), {0x12345,61,82,97}),"decode utf-16") +test_suite:add_test(unittest.table_equal(decode("\xD8\x08\xDF\x45\0=\0R\0a", utf16_dec, true), {0x12345,61,82,97}),"decode utf-16, big-endian") +test_suite:add_test(unittest.equal(utf16to8("\x08\xD8\x45\xDF=\0R\0a\0"), "\xF0\x92\x8D\x85=Ra"),"utf16to8") +test_suite:add_test(unittest.equal(utf8to16("\xF0\x92\x8D\x85=Ra"), "\x08\xD8\x45\xDF=\0R\0a\0"),"utf8to16") +test_suite:add_test(unittest.equal(encode({0x221e, 0x2248, 0x30}, cp437_enc), "\xec\xf70"), "encode cp437") +test_suite:add_test(unittest.table_equal(decode("\x81ber", cp437_dec), {0xfc, 0x62, 0x65, 0x72}), "decode cp437") +test_suite:add_test(unittest.equal(chardet("\x08\xD8\x45\xDF=\0R\0a\0"), 'utf-16le'), "detect utf-16le") +test_suite:add_test(unittest.equal(chardet("\xD8\x08\xDF\x45\0=\0R\0a"), 'utf-16be'), "detect utf-16be") +test_suite:add_test(unittest.equal(chardet("...\xF0\x92\x8D\x85=Ra"), 'utf-8'), "detect utf-8") +test_suite:add_test(unittest.equal(chardet("This sentence is completely normal."), 'ascii'), "detect ascii") +test_suite:add_test(unittest.equal(chardet('Comme ci, comme \xe7a'), 'other'), "detect other") + +return _ENV |