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      1 //  2016 and later: Unicode, Inc. and others.
      2 // License & terms of use: http://www.unicode.org/copyright.html
      3 /*
      4 **********************************************************************
      5 *   Copyright (C) 2000-2016, International Business Machines
      6 *   Corporation and others.  All Rights Reserved.
      7 **********************************************************************
      8 *   file name:  ucnv_lmb.cpp
      9 *   encoding:   UTF-8
     10 *   tab size:   4 (not used)
     11 *   indentation:4
     12 *
     13 *   created on: 2000feb09
     14 *   created by: Brendan Murray
     15 *   extensively hacked up by: Jim Snyder-Grant
     16 *
     17 * Modification History:
     18 *
     19 *   Date        Name             Description
     20 *
     21 *   06/20/2000  helena           OS/400 port changes; mostly typecast.
     22 *   06/27/2000  Jim Snyder-Grant Deal with partial characters and small buffers.
     23 *                                Add comments to document LMBCS format and implementation
     24 *                                restructured order & breakdown of functions
     25 *   06/28/2000  helena           Major rewrite for the callback API changes.
     26 */
     27 
     28 #include "unicode/utypes.h"
     29 
     30 #if !UCONFIG_NO_CONVERSION && !UCONFIG_NO_LEGACY_CONVERSION && !UCONFIG_ONLY_HTML_CONVERSION
     31 
     32 #include "unicode/ucnv_err.h"
     33 #include "unicode/ucnv.h"
     34 #include "unicode/uset.h"
     35 #include "cmemory.h"
     36 #include "cstring.h"
     37 #include "uassert.h"
     38 #include "ucnv_imp.h"
     39 #include "ucnv_bld.h"
     40 #include "ucnv_cnv.h"
     41 
     42 #ifdef EBCDIC_RTL
     43     #include "ascii_a.h"
     44 #endif
     45 
     46 /*
     47   LMBCS
     48 
     49   (Lotus Multi-Byte Character Set)
     50 
     51   LMBCS was invented in the late 1980's and is primarily used in Lotus Notes
     52   databases and in Lotus 1-2-3 files. Programmers who work with the APIs
     53   into these products will sometimes need to deal with strings in this format.
     54 
     55   The code in this file provides an implementation for an ICU converter of
     56   LMBCS to and from Unicode.
     57 
     58   Since the LMBCS character set is only sparsely documented in existing
     59   printed or online material, we have added  extensive annotation to this
     60   file to serve as a guide to understanding LMBCS.
     61 
     62   LMBCS was originally designed with these four sometimes-competing design goals:
     63 
     64   -Provide encodings for the characters in 12 existing national standards
     65    (plus a few other characters)
     66   -Minimal memory footprint
     67   -Maximal speed of conversion into the existing national character sets
     68   -No need to track a changing state as you interpret a string.
     69 
     70 
     71   All of the national character sets LMBCS was trying to encode are 'ANSI'
     72   based, in that the bytes from 0x20 - 0x7F are almost exactly the
     73   same common Latin unaccented characters and symbols in all character sets.
     74 
     75   So, in order to help meet the speed & memory design goals, the common ANSI
     76   bytes from 0x20-0x7F are represented by the same single-byte values in LMBCS.
     77 
     78   The general LMBCS code unit is from 1-3 bytes. We can describe the 3 bytes as
     79   follows:
     80 
     81   [G] D1 [D2]
     82 
     83   That is, a sometimes-optional 'group' byte, followed by 1 and sometimes 2
     84   data bytes. The maximum size of a LMBCS chjaracter is 3 bytes:
     85 */
     86 #define ULMBCS_CHARSIZE_MAX      3
     87 /*
     88   The single-byte values from 0x20 to 0x7F are examples of single D1 bytes.
     89   We often have to figure out if byte values are below or above this, so we
     90   use the ANSI nomenclature 'C0' and 'C1' to refer to the range of control
     91   characters just above & below the common lower-ANSI  range */
     92 #define ULMBCS_C0END           0x1F
     93 #define ULMBCS_C1START         0x80
     94 /*
     95   Since LMBCS is always dealing in byte units. we create a local type here for
     96   dealing with these units of LMBCS code units:
     97 
     98 */
     99 typedef uint8_t ulmbcs_byte_t;
    100 
    101 /*
    102    Most of the values less than 0x20 are reserved in LMBCS to announce
    103    which national  character standard is being used for the 'D' bytes.
    104    In the comments we show the common name and the IBM character-set ID
    105    for these character-set announcers:
    106 */
    107 
    108 #define ULMBCS_GRP_L1         0x01   /* Latin-1    :ibm-850  */
    109 #define ULMBCS_GRP_GR         0x02   /* Greek      :ibm-851  */
    110 #define ULMBCS_GRP_HE         0x03   /* Hebrew     :ibm-1255 */
    111 #define ULMBCS_GRP_AR         0x04   /* Arabic     :ibm-1256 */
    112 #define ULMBCS_GRP_RU         0x05   /* Cyrillic   :ibm-1251 */
    113 #define ULMBCS_GRP_L2         0x06   /* Latin-2    :ibm-852  */
    114 #define ULMBCS_GRP_TR         0x08   /* Turkish    :ibm-1254 */
    115 #define ULMBCS_GRP_TH         0x0B   /* Thai       :ibm-874  */
    116 #define ULMBCS_GRP_JA         0x10   /* Japanese   :ibm-943  */
    117 #define ULMBCS_GRP_KO         0x11   /* Korean     :ibm-1261 */
    118 #define ULMBCS_GRP_TW         0x12   /* Chinese SC :ibm-950  */
    119 #define ULMBCS_GRP_CN         0x13   /* Chinese TC :ibm-1386 */
    120 
    121 /*
    122    So, the beginning of understanding LMBCS is that IF the first byte of a LMBCS
    123    character is one of those 12 values, you can interpret the remaining bytes of
    124    that character as coming from one of those character sets. Since the lower
    125    ANSI bytes already are represented in single bytes, using one of the character
    126    set announcers is used to announce a character that starts with a byte of
    127    0x80 or greater.
    128 
    129    The character sets are  arranged so that the single byte sets all appear
    130    before the multi-byte character sets. When we need to tell whether a
    131    group byte is for a single byte char set or not we use this define: */
    132 
    133 #define ULMBCS_DOUBLEOPTGROUP_START  0x10
    134 
    135 /*
    136 However, to fully understand LMBCS, you must also understand a series of
    137 exceptions & optimizations made in service of the design goals.
    138 
    139 First, those of you who are character set mavens may have noticed that
    140 the 'double-byte' character sets are actually multi-byte character sets
    141 that can have 1 or two bytes, even in the upper-ascii range. To force
    142 each group byte to introduce a fixed-width encoding (to make it faster to
    143 count characters), we use a convention of doubling up on the group byte
    144 to introduce any single-byte character > 0x80 in an otherwise double-byte
    145 character set. So, for example, the LMBCS sequence x10 x10 xAE is the
    146 same as '0xAE' in the Japanese code page 943.
    147 
    148 Next, you will notice that the list of group bytes has some gaps.
    149 These are used in various ways.
    150 
    151 We reserve a few special single byte values for common control
    152 characters. These are in the same place as their ANSI eqivalents for speed.
    153 */
    154 
    155 #define ULMBCS_HT    0x09   /* Fixed control char - Horizontal Tab */
    156 #define ULMBCS_LF    0x0A   /* Fixed control char - Line Feed */
    157 #define ULMBCS_CR    0x0D   /* Fixed control char - Carriage Return */
    158 
    159 /* Then, 1-2-3 reserved a special single-byte character to put at the
    160 beginning of internal 'system' range names: */
    161 
    162 #define ULMBCS_123SYSTEMRANGE  0x19
    163 
    164 /* Then we needed a place to put all the other ansi control characters
    165 that must be moved to different values because LMBCS reserves those
    166 values for other purposes. To represent the control characters, we start
    167 with a first byte of 0xF & add the control chaarcter value as the
    168 second byte */
    169 #define ULMBCS_GRP_CTRL       0x0F
    170 
    171 /* For the C0 controls (less than 0x20), we add 0x20 to preserve the
    172 useful doctrine that any byte less than 0x20 in a LMBCS char must be
    173 the first byte of a character:*/
    174 #define ULMBCS_CTRLOFFSET      0x20
    175 
    176 /*
    177 Where to put the characters that aren't part of any of the 12 national
    178 character sets? The first thing that was done, in the earlier years of
    179 LMBCS, was to use up the spaces of the form
    180 
    181   [G] D1,
    182 
    183  where  'G' was one of the single-byte character groups, and
    184  D1 was less than 0x80. These sequences are gathered together
    185  into a Lotus-invented doublebyte character set to represent a
    186  lot of stray values. Internally, in this implementation, we track this
    187  as group '0', as a place to tuck this exceptions list.*/
    188 
    189 #define ULMBCS_GRP_EXCEPT     0x00
    190 /*
    191  Finally, as the durability and usefulness of UNICODE became clear,
    192  LOTUS added a new group 0x14 to hold Unicode values not otherwise
    193  represented in LMBCS: */
    194 #define ULMBCS_GRP_UNICODE    0x14
    195 /* The two bytes appearing after a 0x14 are intrepreted as UFT-16 BE
    196 (Big-Endian) characters. The exception comes when the UTF16
    197 representation would have a zero as the second byte. In that case,
    198 'F6' is used in its place, and the bytes are swapped. (This prevents
    199 LMBCS from encoding any Unicode values of the form U+F6xx, but that's OK:
    200 0xF6xx is in the middle of the Private Use Area.)*/
    201 #define ULMBCS_UNICOMPATZERO   0xF6
    202 
    203 /* It is also useful in our code to have a constant for the size of
    204 a LMBCS char that holds a literal Unicode value */
    205 #define ULMBCS_UNICODE_SIZE      3
    206 
    207 /*
    208 To squish the LMBCS representations down even further, and to make
    209 translations even faster,sometimes the optimization group byte can be dropped
    210 from a LMBCS character. This is decided on a process-by-process basis. The
    211 group byte that is dropped is called the 'optimization group'.
    212 
    213 For Notes, the optimzation group is always 0x1.*/
    214 #define ULMBCS_DEFAULTOPTGROUP 0x1
    215 /* For 1-2-3 files, the optimzation group is stored in the header of the 1-2-3
    216 file.
    217 
    218  In any case, when using ICU, you either pass in the
    219 optimization group as part of the name of the converter (LMBCS-1, LMBCS-2,
    220 etc.). Using plain 'LMBCS' as the name of the converter will give you
    221 LMBCS-1.
    222 
    223 
    224 *** Implementation strategy ***
    225 
    226 
    227 Because of the extensive use of other character sets, the LMBCS converter
    228 keeps a mapping between optimization groups and IBM character sets, so that
    229 ICU converters can be created and used as needed. */
    230 
    231 /* As you can see, even though any byte below 0x20 could be an optimization
    232 byte, only those at 0x13 or below can map to an actual converter. To limit
    233 some loops and searches, we define a value for that last group converter:*/
    234 
    235 #define ULMBCS_GRP_LAST       0x13   /* last LMBCS group that has a converter */
    236 
    237 static const char * const OptGroupByteToCPName[ULMBCS_GRP_LAST + 1] = {
    238    /* 0x0000 */ "lmb-excp", /* internal home for the LOTUS exceptions list */
    239    /* 0x0001 */ "ibm-850",
    240    /* 0x0002 */ "ibm-851",
    241    /* 0x0003 */ "windows-1255",
    242    /* 0x0004 */ "windows-1256",
    243    /* 0x0005 */ "windows-1251",
    244    /* 0x0006 */ "ibm-852",
    245    /* 0x0007 */ NULL,      /* Unused */
    246    /* 0x0008 */ "windows-1254",
    247    /* 0x0009 */ NULL,      /* Control char HT */
    248    /* 0x000A */ NULL,      /* Control char LF */
    249    /* 0x000B */ "windows-874",
    250    /* 0x000C */ NULL,      /* Unused */
    251    /* 0x000D */ NULL,      /* Control char CR */
    252    /* 0x000E */ NULL,      /* Unused */
    253    /* 0x000F */ NULL,      /* Control chars: 0x0F20 + C0/C1 character: algorithmic */
    254    /* 0x0010 */ "windows-932",
    255    /* 0x0011 */ "windows-949",
    256    /* 0x0012 */ "windows-950",
    257    /* 0x0013 */ "windows-936"
    258 
    259    /* The rest are null, including the 0x0014 Unicode compatibility region
    260    and 0x0019, the 1-2-3 system range control char */
    261 };
    262 
    263 
    264 /* That's approximately all the data that's needed for translating
    265   LMBCS to Unicode.
    266 
    267 
    268 However, to translate Unicode to LMBCS, we need some more support.
    269 
    270 That's because there are often more than one possible mappings from a Unicode
    271 code point back into LMBCS. The first thing we do is look up into a table
    272 to figure out if there are more than one possible mappings. This table,
    273 arranged by Unicode values (including ranges) either lists which group
    274 to use, or says that it could go into one or more of the SBCS sets, or
    275 into one or more of the DBCS sets.  (If the character exists in both DBCS &
    276 SBCS, the table will place it in the SBCS sets, to make the LMBCS code point
    277 length as small as possible. Here's the two special markers we use to indicate
    278 ambiguous mappings: */
    279 
    280 #define ULMBCS_AMBIGUOUS_SBCS   0x80   /* could fit in more than one
    281                                           LMBCS sbcs native encoding
    282                                           (example: most accented latin) */
    283 #define ULMBCS_AMBIGUOUS_MBCS   0x81   /* could fit in more than one
    284                                           LMBCS mbcs native encoding
    285                                           (example: Unihan) */
    286 #define ULMBCS_AMBIGUOUS_ALL   0x82
    287 /* And here's a simple way to see if a group falls in an appropriate range */
    288 #define ULMBCS_AMBIGUOUS_MATCH(agroup, xgroup) \
    289                   ((((agroup) == ULMBCS_AMBIGUOUS_SBCS) && \
    290                   (xgroup) < ULMBCS_DOUBLEOPTGROUP_START) || \
    291                   (((agroup) == ULMBCS_AMBIGUOUS_MBCS) && \
    292                   (xgroup) >= ULMBCS_DOUBLEOPTGROUP_START)) || \
    293                   ((agroup) == ULMBCS_AMBIGUOUS_ALL)
    294 
    295 
    296 /* The table & some code to use it: */
    297 
    298 
    299 static const struct _UniLMBCSGrpMap
    300 {
    301    const UChar uniStartRange;
    302    const UChar uniEndRange;
    303    const ulmbcs_byte_t  GrpType;
    304 } UniLMBCSGrpMap[]
    305 =
    306 {
    307 
    308     {0x0001, 0x001F,  ULMBCS_GRP_CTRL},
    309     {0x0080, 0x009F,  ULMBCS_GRP_CTRL},
    310     {0x00A0, 0x00A6,  ULMBCS_AMBIGUOUS_SBCS},
    311     {0x00A7, 0x00A8,  ULMBCS_AMBIGUOUS_ALL},
    312     {0x00A9, 0x00AF,  ULMBCS_AMBIGUOUS_SBCS},
    313     {0x00B0, 0x00B1,  ULMBCS_AMBIGUOUS_ALL},
    314     {0x00B2, 0x00B3,  ULMBCS_AMBIGUOUS_SBCS},
    315     {0x00B4, 0x00B4,  ULMBCS_AMBIGUOUS_ALL},
    316     {0x00B5, 0x00B5,  ULMBCS_AMBIGUOUS_SBCS},
    317     {0x00B6, 0x00B6,  ULMBCS_AMBIGUOUS_ALL},
    318     {0x00B7, 0x00D6,  ULMBCS_AMBIGUOUS_SBCS},
    319     {0x00D7, 0x00D7,  ULMBCS_AMBIGUOUS_ALL},
    320     {0x00D8, 0x00F6,  ULMBCS_AMBIGUOUS_SBCS},
    321     {0x00F7, 0x00F7,  ULMBCS_AMBIGUOUS_ALL},
    322     {0x00F8, 0x01CD,  ULMBCS_AMBIGUOUS_SBCS},
    323     {0x01CE, 0x01CE,  ULMBCS_GRP_TW },
    324     {0x01CF, 0x02B9,  ULMBCS_AMBIGUOUS_SBCS},
    325     {0x02BA, 0x02BA,  ULMBCS_GRP_CN},
    326     {0x02BC, 0x02C8,  ULMBCS_AMBIGUOUS_SBCS},
    327     {0x02C9, 0x02D0,  ULMBCS_AMBIGUOUS_MBCS},
    328     {0x02D8, 0x02DD,  ULMBCS_AMBIGUOUS_SBCS},
    329     {0x0384, 0x0390,  ULMBCS_AMBIGUOUS_SBCS},
    330     {0x0391, 0x03A9,  ULMBCS_AMBIGUOUS_ALL},
    331     {0x03AA, 0x03B0,  ULMBCS_AMBIGUOUS_SBCS},
    332     {0x03B1, 0x03C9,  ULMBCS_AMBIGUOUS_ALL},
    333     {0x03CA, 0x03CE,  ULMBCS_AMBIGUOUS_SBCS},
    334     {0x0400, 0x0400,  ULMBCS_GRP_RU},
    335     {0x0401, 0x0401,  ULMBCS_AMBIGUOUS_ALL},
    336     {0x0402, 0x040F,  ULMBCS_GRP_RU},
    337     {0x0410, 0x0431,  ULMBCS_AMBIGUOUS_ALL},
    338     {0x0432, 0x044E,  ULMBCS_GRP_RU},
    339     {0x044F, 0x044F,  ULMBCS_AMBIGUOUS_ALL},
    340     {0x0450, 0x0491,  ULMBCS_GRP_RU},
    341     {0x05B0, 0x05F2,  ULMBCS_GRP_HE},
    342     {0x060C, 0x06AF,  ULMBCS_GRP_AR},
    343     {0x0E01, 0x0E5B,  ULMBCS_GRP_TH},
    344     {0x200C, 0x200F,  ULMBCS_AMBIGUOUS_SBCS},
    345     {0x2010, 0x2010,  ULMBCS_AMBIGUOUS_MBCS},
    346     {0x2013, 0x2014,  ULMBCS_AMBIGUOUS_SBCS},
    347     {0x2015, 0x2015,  ULMBCS_AMBIGUOUS_MBCS},
    348     {0x2016, 0x2016,  ULMBCS_AMBIGUOUS_MBCS},
    349     {0x2017, 0x2017,  ULMBCS_AMBIGUOUS_SBCS},
    350     {0x2018, 0x2019,  ULMBCS_AMBIGUOUS_ALL},
    351     {0x201A, 0x201B,  ULMBCS_AMBIGUOUS_SBCS},
    352     {0x201C, 0x201D,  ULMBCS_AMBIGUOUS_ALL},
    353     {0x201E, 0x201F,  ULMBCS_AMBIGUOUS_SBCS},
    354     {0x2020, 0x2021,  ULMBCS_AMBIGUOUS_ALL},
    355     {0x2022, 0x2024,  ULMBCS_AMBIGUOUS_SBCS},
    356     {0x2025, 0x2025,  ULMBCS_AMBIGUOUS_MBCS},
    357     {0x2026, 0x2026,  ULMBCS_AMBIGUOUS_ALL},
    358     {0x2027, 0x2027,  ULMBCS_GRP_TW},
    359     {0x2030, 0x2030,  ULMBCS_AMBIGUOUS_ALL},
    360     {0x2031, 0x2031,  ULMBCS_AMBIGUOUS_SBCS},
    361     {0x2032, 0x2033,  ULMBCS_AMBIGUOUS_MBCS},
    362     {0x2035, 0x2035,  ULMBCS_AMBIGUOUS_MBCS},
    363     {0x2039, 0x203A,  ULMBCS_AMBIGUOUS_SBCS},
    364     {0x203B, 0x203B,  ULMBCS_AMBIGUOUS_MBCS},
    365     {0x203C, 0x203C,  ULMBCS_GRP_EXCEPT},
    366     {0x2074, 0x2074,  ULMBCS_GRP_KO},
    367     {0x207F, 0x207F,  ULMBCS_GRP_EXCEPT},
    368     {0x2081, 0x2084,  ULMBCS_GRP_KO},
    369     {0x20A4, 0x20AC,  ULMBCS_AMBIGUOUS_SBCS},
    370     {0x2103, 0x2109,  ULMBCS_AMBIGUOUS_MBCS},
    371     {0x2111, 0x2120,  ULMBCS_AMBIGUOUS_SBCS},
    372     /*zhujin: upgrade, for regressiont test, spr HKIA4YHTSU*/
    373     {0x2121, 0x2121,  ULMBCS_AMBIGUOUS_MBCS},
    374     {0x2122, 0x2126,  ULMBCS_AMBIGUOUS_SBCS},
    375     {0x212B, 0x212B,  ULMBCS_AMBIGUOUS_MBCS},
    376     {0x2135, 0x2135,  ULMBCS_AMBIGUOUS_SBCS},
    377     {0x2153, 0x2154,  ULMBCS_GRP_KO},
    378     {0x215B, 0x215E,  ULMBCS_GRP_EXCEPT},
    379     {0x2160, 0x2179,  ULMBCS_AMBIGUOUS_MBCS},
    380     {0x2190, 0x2193,  ULMBCS_AMBIGUOUS_ALL},
    381     {0x2194, 0x2195,  ULMBCS_GRP_EXCEPT},
    382     {0x2196, 0x2199,  ULMBCS_AMBIGUOUS_MBCS},
    383     {0x21A8, 0x21A8,  ULMBCS_GRP_EXCEPT},
    384     {0x21B8, 0x21B9,  ULMBCS_GRP_CN},
    385     {0x21D0, 0x21D1,  ULMBCS_GRP_EXCEPT},
    386     {0x21D2, 0x21D2,  ULMBCS_AMBIGUOUS_MBCS},
    387     {0x21D3, 0x21D3,  ULMBCS_GRP_EXCEPT},
    388     {0x21D4, 0x21D4,  ULMBCS_AMBIGUOUS_MBCS},
    389     {0x21D5, 0x21D5,  ULMBCS_GRP_EXCEPT},
    390     {0x21E7, 0x21E7,  ULMBCS_GRP_CN},
    391     {0x2200, 0x2200,  ULMBCS_AMBIGUOUS_MBCS},
    392     {0x2201, 0x2201,  ULMBCS_GRP_EXCEPT},
    393     {0x2202, 0x2202,  ULMBCS_AMBIGUOUS_MBCS},
    394     {0x2203, 0x2203,  ULMBCS_AMBIGUOUS_MBCS},
    395     {0x2204, 0x2206,  ULMBCS_GRP_EXCEPT},
    396     {0x2207, 0x2208,  ULMBCS_AMBIGUOUS_MBCS},
    397     {0x2209, 0x220A,  ULMBCS_GRP_EXCEPT},
    398     {0x220B, 0x220B,  ULMBCS_AMBIGUOUS_MBCS},
    399     {0x220F, 0x2215,  ULMBCS_AMBIGUOUS_MBCS},
    400     {0x2219, 0x2219,  ULMBCS_GRP_EXCEPT},
    401     {0x221A, 0x221A,  ULMBCS_AMBIGUOUS_MBCS},
    402     {0x221B, 0x221C,  ULMBCS_GRP_EXCEPT},
    403     {0x221D, 0x221E,  ULMBCS_AMBIGUOUS_MBCS},
    404     {0x221F, 0x221F,  ULMBCS_GRP_EXCEPT},
    405     {0x2220, 0x2220,  ULMBCS_AMBIGUOUS_MBCS},
    406     {0x2223, 0x222A,  ULMBCS_AMBIGUOUS_MBCS},
    407     {0x222B, 0x223D,  ULMBCS_AMBIGUOUS_MBCS},
    408     {0x2245, 0x2248,  ULMBCS_GRP_EXCEPT},
    409     {0x224C, 0x224C,  ULMBCS_GRP_TW},
    410     {0x2252, 0x2252,  ULMBCS_AMBIGUOUS_MBCS},
    411     {0x2260, 0x2261,  ULMBCS_AMBIGUOUS_MBCS},
    412     {0x2262, 0x2265,  ULMBCS_GRP_EXCEPT},
    413     {0x2266, 0x226F,  ULMBCS_AMBIGUOUS_MBCS},
    414     {0x2282, 0x2283,  ULMBCS_AMBIGUOUS_MBCS},
    415     {0x2284, 0x2285,  ULMBCS_GRP_EXCEPT},
    416     {0x2286, 0x2287,  ULMBCS_AMBIGUOUS_MBCS},
    417     {0x2288, 0x2297,  ULMBCS_GRP_EXCEPT},
    418     {0x2299, 0x22BF,  ULMBCS_AMBIGUOUS_MBCS},
    419     {0x22C0, 0x22C0,  ULMBCS_GRP_EXCEPT},
    420     {0x2310, 0x2310,  ULMBCS_GRP_EXCEPT},
    421     {0x2312, 0x2312,  ULMBCS_AMBIGUOUS_MBCS},
    422     {0x2318, 0x2321,  ULMBCS_GRP_EXCEPT},
    423     {0x2318, 0x2321,  ULMBCS_GRP_CN},
    424     {0x2460, 0x24E9,  ULMBCS_AMBIGUOUS_MBCS},
    425     {0x2500, 0x2500,  ULMBCS_AMBIGUOUS_SBCS},
    426     {0x2501, 0x2501,  ULMBCS_AMBIGUOUS_MBCS},
    427     {0x2502, 0x2502,  ULMBCS_AMBIGUOUS_ALL},
    428     {0x2503, 0x2503,  ULMBCS_AMBIGUOUS_MBCS},
    429     {0x2504, 0x2505,  ULMBCS_GRP_TW},
    430     {0x2506, 0x2665,  ULMBCS_AMBIGUOUS_ALL},
    431     {0x2666, 0x2666,  ULMBCS_GRP_EXCEPT},
    432     {0x2667, 0x2669,  ULMBCS_AMBIGUOUS_SBCS},
    433     {0x266A, 0x266A,  ULMBCS_AMBIGUOUS_ALL},
    434     {0x266B, 0x266C,  ULMBCS_AMBIGUOUS_SBCS},
    435     {0x266D, 0x266D,  ULMBCS_AMBIGUOUS_MBCS},
    436     {0x266E, 0x266E,  ULMBCS_AMBIGUOUS_SBCS},
    437     {0x266F, 0x266F,  ULMBCS_GRP_JA},
    438     {0x2670, 0x2E7F,  ULMBCS_AMBIGUOUS_SBCS},
    439     {0x2E80, 0xF861,  ULMBCS_AMBIGUOUS_MBCS},
    440     {0xF862, 0xF8FF,  ULMBCS_GRP_EXCEPT},
    441     {0xF900, 0xFA2D,  ULMBCS_AMBIGUOUS_MBCS},
    442     {0xFB00, 0xFEFF,  ULMBCS_AMBIGUOUS_SBCS},
    443     {0xFF01, 0xFFEE,  ULMBCS_AMBIGUOUS_MBCS},
    444     {0xFFFF, 0xFFFF,  ULMBCS_GRP_UNICODE}
    445 };
    446 
    447 static ulmbcs_byte_t
    448 FindLMBCSUniRange(UChar uniChar)
    449 {
    450    const struct _UniLMBCSGrpMap * pTable = UniLMBCSGrpMap;
    451 
    452    while (uniChar > pTable->uniEndRange)
    453    {
    454       pTable++;
    455    }
    456 
    457    if (uniChar >= pTable->uniStartRange)
    458    {
    459       return pTable->GrpType;
    460    }
    461    return ULMBCS_GRP_UNICODE;
    462 }
    463 
    464 /*
    465 We also ask the creator of a converter to send in a preferred locale
    466 that we can use in resolving ambiguous mappings. They send the locale
    467 in as a string, and we map it, if possible, to one of the
    468 LMBCS groups. We use this table, and the associated code, to
    469 do the lookup: */
    470 
    471 /**************************************************
    472   This table maps locale ID's to LMBCS opt groups.
    473   The default return is group 0x01. Note that for
    474   performance reasons, the table is sorted in
    475   increasing alphabetic order, with the notable
    476   exception of zhTW. This is to force the check
    477   for Traditonal Chinese before dropping back to
    478   Simplified.
    479 
    480   Note too that the Latin-1 groups have been
    481   commented out because it's the default, and
    482   this shortens the table, allowing a serial
    483   search to go quickly.
    484  *************************************************/
    485 
    486 static const struct _LocaleLMBCSGrpMap
    487 {
    488    const char    *LocaleID;
    489    const ulmbcs_byte_t OptGroup;
    490 } LocaleLMBCSGrpMap[] =
    491 {
    492     {"ar", ULMBCS_GRP_AR},
    493     {"be", ULMBCS_GRP_RU},
    494     {"bg", ULMBCS_GRP_L2},
    495    /* {"ca", ULMBCS_GRP_L1}, */
    496     {"cs", ULMBCS_GRP_L2},
    497    /* {"da", ULMBCS_GRP_L1}, */
    498    /* {"de", ULMBCS_GRP_L1}, */
    499     {"el", ULMBCS_GRP_GR},
    500    /* {"en", ULMBCS_GRP_L1}, */
    501    /* {"es", ULMBCS_GRP_L1}, */
    502    /* {"et", ULMBCS_GRP_L1}, */
    503    /* {"fi", ULMBCS_GRP_L1}, */
    504    /* {"fr", ULMBCS_GRP_L1}, */
    505     {"he", ULMBCS_GRP_HE},
    506     {"hu", ULMBCS_GRP_L2},
    507    /* {"is", ULMBCS_GRP_L1}, */
    508    /* {"it", ULMBCS_GRP_L1}, */
    509     {"iw", ULMBCS_GRP_HE},
    510     {"ja", ULMBCS_GRP_JA},
    511     {"ko", ULMBCS_GRP_KO},
    512    /* {"lt", ULMBCS_GRP_L1}, */
    513    /* {"lv", ULMBCS_GRP_L1}, */
    514     {"mk", ULMBCS_GRP_RU},
    515    /* {"nl", ULMBCS_GRP_L1}, */
    516    /* {"no", ULMBCS_GRP_L1}, */
    517     {"pl", ULMBCS_GRP_L2},
    518    /* {"pt", ULMBCS_GRP_L1}, */
    519     {"ro", ULMBCS_GRP_L2},
    520     {"ru", ULMBCS_GRP_RU},
    521     {"sh", ULMBCS_GRP_L2},
    522     {"sk", ULMBCS_GRP_L2},
    523     {"sl", ULMBCS_GRP_L2},
    524     {"sq", ULMBCS_GRP_L2},
    525     {"sr", ULMBCS_GRP_RU},
    526    /* {"sv", ULMBCS_GRP_L1}, */
    527     {"th", ULMBCS_GRP_TH},
    528     {"tr", ULMBCS_GRP_TR},
    529     {"uk", ULMBCS_GRP_RU},
    530    /* {"vi", ULMBCS_GRP_L1}, */
    531     {"zhTW", ULMBCS_GRP_TW},
    532     {"zh", ULMBCS_GRP_CN},
    533     {NULL, ULMBCS_GRP_L1}
    534 };
    535 
    536 
    537 static ulmbcs_byte_t
    538 FindLMBCSLocale(const char *LocaleID)
    539 {
    540    const struct _LocaleLMBCSGrpMap *pTable = LocaleLMBCSGrpMap;
    541 
    542    if ((!LocaleID) || (!*LocaleID))
    543    {
    544       return 0;
    545    }
    546 
    547    while (pTable->LocaleID)
    548    {
    549       if (*pTable->LocaleID == *LocaleID) /* Check only first char for speed */
    550       {
    551          /* First char matches - check whole name, for entry-length */
    552          if (uprv_strncmp(pTable->LocaleID, LocaleID, strlen(pTable->LocaleID)) == 0)
    553             return pTable->OptGroup;
    554       }
    555       else
    556       if (*pTable->LocaleID > *LocaleID) /* Sorted alphabetically - exit */
    557          break;
    558       pTable++;
    559    }
    560    return ULMBCS_GRP_L1;
    561 }
    562 
    563 
    564 /*
    565   Before we get to the main body of code, here's how we hook up to the rest
    566   of ICU. ICU converters are required to define a structure that includes
    567   some function pointers, and some common data, in the style of a C++
    568   vtable. There is also room in there for converter-specific data. LMBCS
    569   uses that converter-specific data to keep track of the 12 subconverters
    570   we use, the optimization group, and the group (if any) that matches the
    571   locale. We have one structure instantiated for each of the 12 possible
    572   optimization groups. To avoid typos & to avoid boring the reader, we
    573   put the declarations of these structures and functions into macros. To see
    574   the definitions of these structures, see unicode\ucnv_bld.h
    575 */
    576 
    577 typedef struct
    578   {
    579     UConverterSharedData *OptGrpConverter[ULMBCS_GRP_LAST+1];    /* Converter per Opt. grp. */
    580     uint8_t    OptGroup;                  /* default Opt. grp. for this LMBCS session */
    581     uint8_t    localeConverterIndex;      /* reasonable locale match for index */
    582   }
    583 UConverterDataLMBCS;
    584 
    585 U_CDECL_BEGIN
    586 static void  U_CALLCONV _LMBCSClose(UConverter * _this);
    587 U_CDECL_END
    588 
    589 #define DECLARE_LMBCS_DATA(n) \
    590 static const UConverterImpl _LMBCSImpl##n={\
    591     UCNV_LMBCS_##n,\
    592     NULL,NULL,\
    593     _LMBCSOpen##n,\
    594     _LMBCSClose,\
    595     NULL,\
    596     _LMBCSToUnicodeWithOffsets,\
    597     _LMBCSToUnicodeWithOffsets,\
    598     _LMBCSFromUnicode,\
    599     _LMBCSFromUnicode,\
    600     NULL,\
    601     NULL,\
    602     NULL,\
    603     NULL,\
    604     _LMBCSSafeClone,\
    605     ucnv_getCompleteUnicodeSet,\
    606     NULL,\
    607     NULL\
    608 };\
    609 static const UConverterStaticData _LMBCSStaticData##n={\
    610   sizeof(UConverterStaticData),\
    611  "LMBCS-"  #n,\
    612     0, UCNV_IBM, UCNV_LMBCS_##n, 1, 3,\
    613     { 0x3f, 0, 0, 0 },1,FALSE,FALSE,0,0,{0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0} \
    614 };\
    615 const UConverterSharedData _LMBCSData##n= \
    616         UCNV_IMMUTABLE_SHARED_DATA_INITIALIZER(&_LMBCSStaticData##n, &_LMBCSImpl##n);
    617 
    618  /* The only function we needed to duplicate 12 times was the 'open'
    619 function, which will do basically the same thing except set a  different
    620 optimization group. So, we put the common stuff into a worker function,
    621 and set up another macro to stamp out the 12 open functions:*/
    622 #define DEFINE_LMBCS_OPEN(n) \
    623 static void U_CALLCONV \
    624    _LMBCSOpen##n(UConverter* _this, UConverterLoadArgs* pArgs, UErrorCode* err) \
    625 { _LMBCSOpenWorker(_this, pArgs, err, n); }
    626 
    627 
    628 
    629 /* Here's the open worker & the common close function */
    630 static void
    631 _LMBCSOpenWorker(UConverter*  _this,
    632                  UConverterLoadArgs *pArgs,
    633                  UErrorCode*  err,
    634                  ulmbcs_byte_t OptGroup)
    635 {
    636     UConverterDataLMBCS * extraInfo = (UConverterDataLMBCS*)uprv_malloc (sizeof (UConverterDataLMBCS));
    637     _this->extraInfo = extraInfo;
    638     if(extraInfo != NULL)
    639     {
    640         UConverterNamePieces stackPieces;
    641         UConverterLoadArgs stackArgs= UCNV_LOAD_ARGS_INITIALIZER;
    642         ulmbcs_byte_t i;
    643 
    644         uprv_memset(extraInfo, 0, sizeof(UConverterDataLMBCS));
    645 
    646         stackArgs.onlyTestIsLoadable = pArgs->onlyTestIsLoadable;
    647 
    648         for (i=0; i <= ULMBCS_GRP_LAST && U_SUCCESS(*err); i++)
    649         {
    650             if(OptGroupByteToCPName[i] != NULL) {
    651                 extraInfo->OptGrpConverter[i] = ucnv_loadSharedData(OptGroupByteToCPName[i], &stackPieces, &stackArgs, err);
    652             }
    653         }
    654 
    655         if(U_FAILURE(*err) || pArgs->onlyTestIsLoadable) {
    656             _LMBCSClose(_this);
    657             return;
    658         }
    659         extraInfo->OptGroup = OptGroup;
    660         extraInfo->localeConverterIndex = FindLMBCSLocale(pArgs->locale);
    661     }
    662     else
    663     {
    664         *err = U_MEMORY_ALLOCATION_ERROR;
    665     }
    666 }
    667 
    668 U_CDECL_BEGIN
    669 static void  U_CALLCONV
    670 _LMBCSClose(UConverter *   _this)
    671 {
    672     if (_this->extraInfo != NULL)
    673     {
    674         ulmbcs_byte_t Ix;
    675         UConverterDataLMBCS * extraInfo = (UConverterDataLMBCS *) _this->extraInfo;
    676 
    677         for (Ix=0; Ix <= ULMBCS_GRP_LAST; Ix++)
    678         {
    679            if (extraInfo->OptGrpConverter[Ix] != NULL)
    680               ucnv_unloadSharedDataIfReady(extraInfo->OptGrpConverter[Ix]);
    681         }
    682         if (!_this->isExtraLocal) {
    683             uprv_free (_this->extraInfo);
    684             _this->extraInfo = NULL;
    685         }
    686     }
    687 }
    688 
    689 typedef struct LMBCSClone {
    690     UConverter cnv;
    691     UConverterDataLMBCS lmbcs;
    692 } LMBCSClone;
    693 
    694 static UConverter *  U_CALLCONV
    695 _LMBCSSafeClone(const UConverter *cnv,
    696                 void *stackBuffer,
    697                 int32_t *pBufferSize,
    698                 UErrorCode *status) {
    699     (void)status;
    700     LMBCSClone *newLMBCS;
    701     UConverterDataLMBCS *extraInfo;
    702     int32_t i;
    703 
    704     if(*pBufferSize<=0) {
    705         *pBufferSize=(int32_t)sizeof(LMBCSClone);
    706         return NULL;
    707     }
    708 
    709     extraInfo=(UConverterDataLMBCS *)cnv->extraInfo;
    710     newLMBCS=(LMBCSClone *)stackBuffer;
    711 
    712     /* ucnv.c/ucnv_safeClone() copied the main UConverter already */
    713 
    714     uprv_memcpy(&newLMBCS->lmbcs, extraInfo, sizeof(UConverterDataLMBCS));
    715 
    716     /* share the subconverters */
    717     for(i = 0; i <= ULMBCS_GRP_LAST; ++i) {
    718         if(extraInfo->OptGrpConverter[i] != NULL) {
    719             ucnv_incrementRefCount(extraInfo->OptGrpConverter[i]);
    720         }
    721     }
    722 
    723     newLMBCS->cnv.extraInfo = &newLMBCS->lmbcs;
    724     newLMBCS->cnv.isExtraLocal = TRUE;
    725     return &newLMBCS->cnv;
    726 }
    727 
    728 /*
    729  * There used to be a _LMBCSGetUnicodeSet() function here (up to svn revision 20117)
    730  * which added all code points except for U+F6xx
    731  * because those cannot be represented in the Unicode group.
    732  * However, it turns out that windows-950 has roundtrips for all of U+F6xx
    733  * which means that LMBCS can convert all Unicode code points after all.
    734  * We now simply use ucnv_getCompleteUnicodeSet().
    735  *
    736  * This may need to be looked at again as Lotus uses _LMBCSGetUnicodeSet(). (091216)
    737  */
    738 
    739 /*
    740    Here's the basic helper function that we use when converting from
    741    Unicode to LMBCS, and we suspect that a Unicode character will fit into
    742    one of the 12 groups. The return value is the number of bytes written
    743    starting at pStartLMBCS (if any).
    744 */
    745 
    746 static size_t
    747 LMBCSConversionWorker (
    748    UConverterDataLMBCS * extraInfo,    /* subconverters, opt & locale groups */
    749    ulmbcs_byte_t group,                /* The group to try */
    750    ulmbcs_byte_t  * pStartLMBCS,              /* where to put the results */
    751    UChar * pUniChar,                   /* The input unicode character */
    752    ulmbcs_byte_t * lastConverterIndex, /* output: track last successful group used */
    753    UBool * groups_tried                /* output: track any unsuccessful groups */
    754 )
    755 {
    756    ulmbcs_byte_t  * pLMBCS = pStartLMBCS;
    757    UConverterSharedData * xcnv = extraInfo->OptGrpConverter[group];
    758 
    759    int bytesConverted;
    760    uint32_t value;
    761    ulmbcs_byte_t firstByte;
    762 
    763    U_ASSERT(xcnv);
    764    U_ASSERT(group<ULMBCS_GRP_UNICODE);
    765 
    766    bytesConverted = ucnv_MBCSFromUChar32(xcnv, *pUniChar, &value, FALSE);
    767 
    768    /* get the first result byte */
    769    if(bytesConverted > 0) {
    770       firstByte = (ulmbcs_byte_t)(value >> ((bytesConverted - 1) * 8));
    771    } else {
    772       /* most common failure mode is an unassigned character */
    773       groups_tried[group] = TRUE;
    774       return 0;
    775    }
    776 
    777    *lastConverterIndex = group;
    778 
    779    /* All initial byte values in lower ascii range should have been caught by now,
    780       except with the exception group.
    781     */
    782    U_ASSERT((firstByte <= ULMBCS_C0END) || (firstByte >= ULMBCS_C1START) || (group == ULMBCS_GRP_EXCEPT));
    783 
    784    /* use converted data: first write 0, 1 or two group bytes */
    785    if (group != ULMBCS_GRP_EXCEPT && extraInfo->OptGroup != group)
    786    {
    787       *pLMBCS++ = group;
    788       if (bytesConverted == 1 && group >= ULMBCS_DOUBLEOPTGROUP_START)
    789       {
    790          *pLMBCS++ = group;
    791       }
    792    }
    793 
    794   /* don't emit control chars */
    795    if ( bytesConverted == 1 && firstByte < 0x20 )
    796       return 0;
    797 
    798 
    799    /* then move over the converted data */
    800    switch(bytesConverted)
    801    {
    802    case 4:
    803       *pLMBCS++ = (ulmbcs_byte_t)(value >> 24);
    804       U_FALLTHROUGH;
    805    case 3:
    806       *pLMBCS++ = (ulmbcs_byte_t)(value >> 16);
    807       U_FALLTHROUGH;
    808    case 2:
    809       *pLMBCS++ = (ulmbcs_byte_t)(value >> 8);
    810       U_FALLTHROUGH;
    811    case 1:
    812       *pLMBCS++ = (ulmbcs_byte_t)value;
    813       U_FALLTHROUGH;
    814    default:
    815       /* will never occur */
    816       break;
    817    }
    818 
    819    return (pLMBCS - pStartLMBCS);
    820 }
    821 
    822 
    823 /* This is a much simpler version of above, when we
    824 know we are writing LMBCS using the Unicode group
    825 */
    826 static size_t
    827 LMBCSConvertUni(ulmbcs_byte_t * pLMBCS, UChar uniChar)
    828 {
    829      /* encode into LMBCS Unicode range */
    830    uint8_t LowCh =   (uint8_t)(uniChar & 0x00FF);
    831    uint8_t HighCh  = (uint8_t)(uniChar >> 8);
    832 
    833    *pLMBCS++ = ULMBCS_GRP_UNICODE;
    834 
    835    if (LowCh == 0)
    836    {
    837       *pLMBCS++ = ULMBCS_UNICOMPATZERO;
    838       *pLMBCS++ = HighCh;
    839    }
    840    else
    841    {
    842       *pLMBCS++ = HighCh;
    843       *pLMBCS++ = LowCh;
    844    }
    845    return ULMBCS_UNICODE_SIZE;
    846 }
    847 
    848 
    849 
    850 /* The main Unicode to LMBCS conversion function */
    851 static void  U_CALLCONV
    852 _LMBCSFromUnicode(UConverterFromUnicodeArgs*     args,
    853                   UErrorCode*     err)
    854 {
    855    ulmbcs_byte_t lastConverterIndex = 0;
    856    UChar uniChar;
    857    ulmbcs_byte_t  LMBCS[ULMBCS_CHARSIZE_MAX];
    858    ulmbcs_byte_t  * pLMBCS;
    859    int32_t bytes_written;
    860    UBool groups_tried[ULMBCS_GRP_LAST+1];
    861    UConverterDataLMBCS * extraInfo = (UConverterDataLMBCS *) args->converter->extraInfo;
    862    int sourceIndex = 0;
    863 
    864    /* Basic strategy: attempt to fill in local LMBCS 1-char buffer.(LMBCS)
    865       If that succeeds, see if it will all fit into the target & copy it over
    866       if it does.
    867 
    868       We try conversions in the following order:
    869 
    870       1. Single-byte ascii & special fixed control chars (&null)
    871       2. Look up group in table & try that (could be
    872             A) Unicode group
    873             B) control group,
    874             C) national encoding,
    875                or ambiguous SBCS or MBCS group (on to step 4...)
    876 
    877       3. If its ambiguous, try this order:
    878          A) The optimization group
    879          B) The locale group
    880          C) The last group that succeeded with this string.
    881          D) every other group that's relevent (single or double)
    882          E) If its single-byte ambiguous, try the exceptions group
    883 
    884       4. And as a grand fallback: Unicode
    885    */
    886 
    887     /*Fix for SPR#DJOE66JFN3 (Lotus)*/
    888     ulmbcs_byte_t OldConverterIndex = 0;
    889 
    890    while (args->source < args->sourceLimit && !U_FAILURE(*err))
    891    {
    892       /*Fix for SPR#DJOE66JFN3 (Lotus)*/
    893       OldConverterIndex = extraInfo->localeConverterIndex;
    894 
    895       if (args->target >= args->targetLimit)
    896       {
    897          *err = U_BUFFER_OVERFLOW_ERROR;
    898          break;
    899       }
    900       uniChar = *(args->source);
    901       bytes_written = 0;
    902       pLMBCS = LMBCS;
    903 
    904       /* check cases in rough order of how common they are, for speed */
    905 
    906       /* single byte matches: strategy 1 */
    907       /*Fix for SPR#DJOE66JFN3 (Lotus)*/
    908       if((uniChar>=0x80) && (uniChar<=0xff)
    909       /*Fix for SPR#JUYA6XAERU and TSAO7GL5NK (Lotus)*/ &&(uniChar!=0xB1) &&(uniChar!=0xD7) &&(uniChar!=0xF7)
    910         &&(uniChar!=0xB0) &&(uniChar!=0xB4) &&(uniChar!=0xB6) &&(uniChar!=0xA7) &&(uniChar!=0xA8))
    911       {
    912             extraInfo->localeConverterIndex = ULMBCS_GRP_L1;
    913       }
    914       if (((uniChar > ULMBCS_C0END) && (uniChar < ULMBCS_C1START)) ||
    915           uniChar == 0 || uniChar == ULMBCS_HT || uniChar == ULMBCS_CR ||
    916           uniChar == ULMBCS_LF || uniChar == ULMBCS_123SYSTEMRANGE
    917           )
    918       {
    919          *pLMBCS++ = (ulmbcs_byte_t ) uniChar;
    920          bytes_written = 1;
    921       }
    922 
    923 
    924       if (!bytes_written)
    925       {
    926          /* Check by UNICODE range (Strategy 2) */
    927          ulmbcs_byte_t group = FindLMBCSUniRange(uniChar);
    928 
    929          if (group == ULMBCS_GRP_UNICODE)  /* (Strategy 2A) */
    930          {
    931             pLMBCS += LMBCSConvertUni(pLMBCS,uniChar);
    932 
    933             bytes_written = (int32_t)(pLMBCS - LMBCS);
    934          }
    935          else if (group == ULMBCS_GRP_CTRL)  /* (Strategy 2B) */
    936          {
    937             /* Handle control characters here */
    938             if (uniChar <= ULMBCS_C0END)
    939             {
    940                *pLMBCS++ = ULMBCS_GRP_CTRL;
    941                *pLMBCS++ = (ulmbcs_byte_t)(ULMBCS_CTRLOFFSET + uniChar);
    942             }
    943             else if (uniChar >= ULMBCS_C1START && uniChar <= ULMBCS_C1START + ULMBCS_CTRLOFFSET)
    944             {
    945                *pLMBCS++ = ULMBCS_GRP_CTRL;
    946                *pLMBCS++ = (ulmbcs_byte_t ) (uniChar & 0x00FF);
    947             }
    948             bytes_written = (int32_t)(pLMBCS - LMBCS);
    949          }
    950          else if (group < ULMBCS_GRP_UNICODE)  /* (Strategy 2C) */
    951          {
    952             /* a specific converter has been identified - use it */
    953             bytes_written = (int32_t)LMBCSConversionWorker (
    954                               extraInfo, group, pLMBCS, &uniChar,
    955                               &lastConverterIndex, groups_tried);
    956          }
    957          if (!bytes_written)    /* the ambiguous group cases  (Strategy 3) */
    958          {
    959             uprv_memset(groups_tried, 0, sizeof(groups_tried));
    960 
    961             /* check for non-default optimization group (Strategy 3A )*/
    962             if ((extraInfo->OptGroup != 1) && (ULMBCS_AMBIGUOUS_MATCH(group, extraInfo->OptGroup)))
    963             {
    964                 /*zhujin: upgrade, merge #39299 here (Lotus) */
    965                 /*To make R5 compatible translation, look for exceptional group first for non-DBCS*/
    966 
    967                 if(extraInfo->localeConverterIndex < ULMBCS_DOUBLEOPTGROUP_START)
    968                 {
    969                   bytes_written = (int32_t)LMBCSConversionWorker (extraInfo,
    970                      ULMBCS_GRP_L1, pLMBCS, &uniChar,
    971                      &lastConverterIndex, groups_tried);
    972 
    973                   if(!bytes_written)
    974                   {
    975                      bytes_written = (int32_t)LMBCSConversionWorker (extraInfo,
    976                          ULMBCS_GRP_EXCEPT, pLMBCS, &uniChar,
    977                          &lastConverterIndex, groups_tried);
    978                   }
    979                   if(!bytes_written)
    980                   {
    981                       bytes_written = (int32_t)LMBCSConversionWorker (extraInfo,
    982                           extraInfo->localeConverterIndex, pLMBCS, &uniChar,
    983                           &lastConverterIndex, groups_tried);
    984                   }
    985                 }
    986                 else
    987                 {
    988                      bytes_written = (int32_t)LMBCSConversionWorker (extraInfo,
    989                          extraInfo->localeConverterIndex, pLMBCS, &uniChar,
    990                          &lastConverterIndex, groups_tried);
    991                 }
    992             }
    993             /* check for locale optimization group (Strategy 3B) */
    994             if (!bytes_written && (extraInfo->localeConverterIndex) && (ULMBCS_AMBIGUOUS_MATCH(group, extraInfo->localeConverterIndex)))
    995             {
    996                 bytes_written = (int32_t)LMBCSConversionWorker (extraInfo,
    997                         extraInfo->localeConverterIndex, pLMBCS, &uniChar, &lastConverterIndex, groups_tried);
    998             }
    999             /* check for last optimization group used for this string (Strategy 3C) */
   1000             if (!bytes_written && (lastConverterIndex) && (ULMBCS_AMBIGUOUS_MATCH(group, lastConverterIndex)))
   1001             {
   1002                 bytes_written = (int32_t)LMBCSConversionWorker (extraInfo,
   1003                         lastConverterIndex, pLMBCS, &uniChar, &lastConverterIndex, groups_tried);
   1004             }
   1005             if (!bytes_written)
   1006             {
   1007                /* just check every possible matching converter (Strategy 3D) */
   1008                ulmbcs_byte_t grp_start;
   1009                ulmbcs_byte_t grp_end;
   1010                ulmbcs_byte_t grp_ix;
   1011                grp_start = (ulmbcs_byte_t)((group == ULMBCS_AMBIGUOUS_MBCS)
   1012                         ? ULMBCS_DOUBLEOPTGROUP_START
   1013                         :  ULMBCS_GRP_L1);
   1014                grp_end = (ulmbcs_byte_t)((group == ULMBCS_AMBIGUOUS_MBCS)
   1015                         ? ULMBCS_GRP_LAST
   1016                         :  ULMBCS_GRP_TH);
   1017                if(group == ULMBCS_AMBIGUOUS_ALL)
   1018                {
   1019                    grp_start = ULMBCS_GRP_L1;
   1020                    grp_end = ULMBCS_GRP_LAST;
   1021                }
   1022                for (grp_ix = grp_start;
   1023                    grp_ix <= grp_end && !bytes_written;
   1024                     grp_ix++)
   1025                {
   1026                   if (extraInfo->OptGrpConverter [grp_ix] && !groups_tried [grp_ix])
   1027                   {
   1028                      bytes_written = (int32_t)LMBCSConversionWorker (extraInfo,
   1029                        grp_ix, pLMBCS, &uniChar,
   1030                        &lastConverterIndex, groups_tried);
   1031                   }
   1032                }
   1033                 /* a final conversion fallback to the exceptions group if its likely
   1034                      to be single byte  (Strategy 3E) */
   1035                if (!bytes_written && grp_start == ULMBCS_GRP_L1)
   1036                {
   1037                   bytes_written = (int32_t)LMBCSConversionWorker (extraInfo,
   1038                      ULMBCS_GRP_EXCEPT, pLMBCS, &uniChar,
   1039                      &lastConverterIndex, groups_tried);
   1040                }
   1041             }
   1042             /* all of our other strategies failed. Fallback to Unicode. (Strategy 4)*/
   1043             if (!bytes_written)
   1044             {
   1045 
   1046                pLMBCS += LMBCSConvertUni(pLMBCS, uniChar);
   1047                bytes_written = (int32_t)(pLMBCS - LMBCS);
   1048             }
   1049          }
   1050       }
   1051 
   1052       /* we have a translation. increment source and write as much as posible to target */
   1053       args->source++;
   1054       pLMBCS = LMBCS;
   1055       while (args->target < args->targetLimit && bytes_written--)
   1056       {
   1057          *(args->target)++ = *pLMBCS++;
   1058          if (args->offsets)
   1059          {
   1060             *(args->offsets)++ = sourceIndex;
   1061          }
   1062       }
   1063       sourceIndex++;
   1064       if (bytes_written > 0)
   1065       {
   1066          /* write any bytes that didn't fit in target to the error buffer,
   1067             common code will move this to target if we get called back with
   1068             enough target room
   1069          */
   1070          uint8_t * pErrorBuffer = args->converter->charErrorBuffer;
   1071          *err = U_BUFFER_OVERFLOW_ERROR;
   1072          args->converter->charErrorBufferLength = (int8_t)bytes_written;
   1073          while (bytes_written--)
   1074          {
   1075             *pErrorBuffer++ = *pLMBCS++;
   1076          }
   1077       }
   1078       /*Fix for SPR#DJOE66JFN3 (Lotus)*/
   1079       extraInfo->localeConverterIndex = OldConverterIndex;
   1080    }
   1081 }
   1082 
   1083 
   1084 /* Now, the Unicode from LMBCS section */
   1085 
   1086 
   1087 /* A function to call when we are looking at the Unicode group byte in LMBCS */
   1088 static UChar
   1089 GetUniFromLMBCSUni(char const ** ppLMBCSin)  /* Called with LMBCS-style Unicode byte stream */
   1090 {
   1091    uint8_t  HighCh = *(*ppLMBCSin)++;  /* Big-endian Unicode in LMBCS compatibility group*/
   1092    uint8_t  LowCh  = *(*ppLMBCSin)++;
   1093 
   1094    if (HighCh == ULMBCS_UNICOMPATZERO )
   1095    {
   1096       HighCh = LowCh;
   1097       LowCh = 0; /* zero-byte in LSB special character */
   1098    }
   1099    return (UChar)((HighCh << 8) | LowCh);
   1100 }
   1101 
   1102 
   1103 
   1104 /* CHECK_SOURCE_LIMIT: Helper macro to verify that there are at least'index'
   1105    bytes left in source up to  sourceLimit.Errors appropriately if not.
   1106    If we reach the limit, then update the source pointer to there to consume
   1107    all input as required by ICU converter semantics.
   1108 */
   1109 
   1110 #define CHECK_SOURCE_LIMIT(index) \
   1111      if (args->source+index > args->sourceLimit){\
   1112          *err = U_TRUNCATED_CHAR_FOUND;\
   1113          args->source = args->sourceLimit;\
   1114          return 0xffff;}
   1115 
   1116 /* Return the Unicode representation for the current LMBCS character */
   1117 
   1118 static UChar32  U_CALLCONV
   1119 _LMBCSGetNextUCharWorker(UConverterToUnicodeArgs*   args,
   1120                          UErrorCode*   err)
   1121 {
   1122     UChar32 uniChar = 0;    /* an output UNICODE char */
   1123     ulmbcs_byte_t   CurByte; /* A byte from the input stream */
   1124 
   1125     /* error check */
   1126     if (args->source >= args->sourceLimit)
   1127     {
   1128         *err = U_ILLEGAL_ARGUMENT_ERROR;
   1129         return 0xffff;
   1130     }
   1131     /* Grab first byte & save address for error recovery */
   1132     CurByte = *((ulmbcs_byte_t  *) (args->source++));
   1133 
   1134     /*
   1135     * at entry of each if clause:
   1136     * 1. 'CurByte' points at the first byte of a LMBCS character
   1137     * 2. '*source'points to the next byte of the source stream after 'CurByte'
   1138     *
   1139     * the job of each if clause is:
   1140     * 1. set '*source' to point at the beginning of next char (nop if LMBCS char is only 1 byte)
   1141     * 2. set 'uniChar' up with the right Unicode value, or set 'err' appropriately
   1142     */
   1143 
   1144     /* First lets check the simple fixed values. */
   1145 
   1146     if(((CurByte > ULMBCS_C0END) && (CurByte < ULMBCS_C1START)) /* ascii range */
   1147     ||  (CurByte == 0)
   1148     ||  CurByte == ULMBCS_HT || CurByte == ULMBCS_CR
   1149     ||  CurByte == ULMBCS_LF || CurByte == ULMBCS_123SYSTEMRANGE)
   1150     {
   1151         uniChar = CurByte;
   1152     }
   1153     else
   1154     {
   1155         UConverterDataLMBCS * extraInfo;
   1156         ulmbcs_byte_t group;
   1157         UConverterSharedData *cnv;
   1158 
   1159         if (CurByte == ULMBCS_GRP_CTRL)  /* Control character group - no opt group update */
   1160         {
   1161             ulmbcs_byte_t  C0C1byte;
   1162             CHECK_SOURCE_LIMIT(1);
   1163             C0C1byte = *(args->source)++;
   1164             uniChar = (C0C1byte < ULMBCS_C1START) ? C0C1byte - ULMBCS_CTRLOFFSET : C0C1byte;
   1165         }
   1166         else
   1167         if (CurByte == ULMBCS_GRP_UNICODE) /* Unicode compatibility group: BigEndian UTF16 */
   1168         {
   1169             CHECK_SOURCE_LIMIT(2);
   1170 
   1171             /* don't check for error indicators fffe/ffff below */
   1172             return GetUniFromLMBCSUni(&(args->source));
   1173         }
   1174         else if (CurByte <= ULMBCS_CTRLOFFSET)
   1175         {
   1176             group = CurByte;                   /* group byte is in the source */
   1177             extraInfo = (UConverterDataLMBCS *) args->converter->extraInfo;
   1178             if (group > ULMBCS_GRP_LAST || (cnv = extraInfo->OptGrpConverter[group]) == NULL)
   1179             {
   1180                 /* this is not a valid group byte - no converter*/
   1181                 *err = U_INVALID_CHAR_FOUND;
   1182             }
   1183             else if (group >= ULMBCS_DOUBLEOPTGROUP_START)    /* double byte conversion */
   1184             {
   1185 
   1186                 CHECK_SOURCE_LIMIT(2);
   1187 
   1188                 /* check for LMBCS doubled-group-byte case */
   1189                 if (*args->source == group) {
   1190                     /* single byte */
   1191                     ++args->source;
   1192                     uniChar = ucnv_MBCSSimpleGetNextUChar(cnv, args->source, 1, FALSE);
   1193                     ++args->source;
   1194                 } else {
   1195                     /* double byte */
   1196                     uniChar = ucnv_MBCSSimpleGetNextUChar(cnv, args->source, 2, FALSE);
   1197                     args->source += 2;
   1198                 }
   1199             }
   1200             else {                                  /* single byte conversion */
   1201                 CHECK_SOURCE_LIMIT(1);
   1202                 CurByte = *(args->source)++;
   1203 
   1204                 if (CurByte >= ULMBCS_C1START)
   1205                 {
   1206                     uniChar = _MBCS_SINGLE_SIMPLE_GET_NEXT_BMP(cnv, CurByte);
   1207                 }
   1208                 else
   1209                 {
   1210                     /* The non-optimizable oddballs where there is an explicit byte
   1211                     * AND the second byte is not in the upper ascii range
   1212                     */
   1213                     char bytes[2];
   1214 
   1215                     extraInfo = (UConverterDataLMBCS *) args->converter->extraInfo;
   1216                     cnv = extraInfo->OptGrpConverter [ULMBCS_GRP_EXCEPT];
   1217 
   1218                     /* Lookup value must include opt group */
   1219                     bytes[0] = group;
   1220                     bytes[1] = CurByte;
   1221                     uniChar = ucnv_MBCSSimpleGetNextUChar(cnv, bytes, 2, FALSE);
   1222                 }
   1223             }
   1224         }
   1225         else if (CurByte >= ULMBCS_C1START) /* group byte is implicit */
   1226         {
   1227             extraInfo = (UConverterDataLMBCS *) args->converter->extraInfo;
   1228             group = extraInfo->OptGroup;
   1229             cnv = extraInfo->OptGrpConverter[group];
   1230             if (group >= ULMBCS_DOUBLEOPTGROUP_START)    /* double byte conversion */
   1231             {
   1232                 if (!ucnv_MBCSIsLeadByte(cnv, CurByte))
   1233                 {
   1234                     CHECK_SOURCE_LIMIT(0);
   1235 
   1236                     /* let the MBCS conversion consume CurByte again */
   1237                     uniChar = ucnv_MBCSSimpleGetNextUChar(cnv, args->source - 1, 1, FALSE);
   1238                 }
   1239                 else
   1240                 {
   1241                     CHECK_SOURCE_LIMIT(1);
   1242                     /* let the MBCS conversion consume CurByte again */
   1243                     uniChar = ucnv_MBCSSimpleGetNextUChar(cnv, args->source - 1, 2, FALSE);
   1244                     ++args->source;
   1245                 }
   1246             }
   1247             else                                   /* single byte conversion */
   1248             {
   1249                 uniChar = _MBCS_SINGLE_SIMPLE_GET_NEXT_BMP(cnv, CurByte);
   1250             }
   1251         }
   1252     }
   1253     return uniChar;
   1254 }
   1255 
   1256 
   1257 /* The exported function that converts lmbcs to one or more
   1258    UChars - currently UTF-16
   1259 */
   1260 static void  U_CALLCONV
   1261 _LMBCSToUnicodeWithOffsets(UConverterToUnicodeArgs*    args,
   1262                      UErrorCode*    err)
   1263 {
   1264    char LMBCS [ULMBCS_CHARSIZE_MAX];
   1265    UChar uniChar;    /* one output UNICODE char */
   1266    const char * saveSource; /* beginning of current code point */
   1267    const char * pStartLMBCS = args->source;  /* beginning of whole string */
   1268    const char * errSource = NULL; /* pointer to actual input in case an error occurs */
   1269    int8_t savebytes = 0;
   1270 
   1271    /* Process from source to limit, or until error */
   1272    while (U_SUCCESS(*err) && args->sourceLimit > args->source && args->targetLimit > args->target)
   1273    {
   1274       saveSource = args->source; /* beginning of current code point */
   1275 
   1276       if (args->converter->toULength) /* reassemble char from previous call */
   1277       {
   1278         const char *saveSourceLimit;
   1279         size_t size_old = args->converter->toULength;
   1280 
   1281          /* limit from source is either remainder of temp buffer, or user limit on source */
   1282         size_t size_new_maybe_1 = sizeof(LMBCS) - size_old;
   1283         size_t size_new_maybe_2 = args->sourceLimit - args->source;
   1284         size_t size_new = (size_new_maybe_1 < size_new_maybe_2) ? size_new_maybe_1 : size_new_maybe_2;
   1285 
   1286 
   1287         uprv_memcpy(LMBCS, args->converter->toUBytes, size_old);
   1288         uprv_memcpy(LMBCS + size_old, args->source, size_new);
   1289         saveSourceLimit = args->sourceLimit;
   1290         args->source = errSource = LMBCS;
   1291         args->sourceLimit = LMBCS+size_old+size_new;
   1292         savebytes = (int8_t)(size_old+size_new);
   1293         uniChar = (UChar) _LMBCSGetNextUCharWorker(args, err);
   1294         args->source = saveSource + ((args->source - LMBCS) - size_old);
   1295         args->sourceLimit = saveSourceLimit;
   1296 
   1297         if (*err == U_TRUNCATED_CHAR_FOUND)
   1298         {
   1299             /* evil special case: source buffers so small a char spans more than 2 buffers */
   1300             args->converter->toULength = savebytes;
   1301             uprv_memcpy(args->converter->toUBytes, LMBCS, savebytes);
   1302             args->source = args->sourceLimit;
   1303             *err = U_ZERO_ERROR;
   1304             return;
   1305          }
   1306          else
   1307          {
   1308             /* clear the partial-char marker */
   1309             args->converter->toULength = 0;
   1310          }
   1311       }
   1312       else
   1313       {
   1314          errSource = saveSource;
   1315          uniChar = (UChar) _LMBCSGetNextUCharWorker(args, err);
   1316          savebytes = (int8_t)(args->source - saveSource);
   1317       }
   1318       if (U_SUCCESS(*err))
   1319       {
   1320          if (uniChar < 0xfffe)
   1321          {
   1322             *(args->target)++ = uniChar;
   1323             if(args->offsets)
   1324             {
   1325                *(args->offsets)++ = (int32_t)(saveSource - pStartLMBCS);
   1326             }
   1327          }
   1328          else if (uniChar == 0xfffe)
   1329          {
   1330             *err = U_INVALID_CHAR_FOUND;
   1331          }
   1332          else /* if (uniChar == 0xffff) */
   1333          {
   1334             *err = U_ILLEGAL_CHAR_FOUND;
   1335          }
   1336       }
   1337    }
   1338    /* if target ran out before source, return U_BUFFER_OVERFLOW_ERROR */
   1339    if (U_SUCCESS(*err) && args->sourceLimit > args->source && args->targetLimit <= args->target)
   1340    {
   1341       *err = U_BUFFER_OVERFLOW_ERROR;
   1342    }
   1343    else if (U_FAILURE(*err))
   1344    {
   1345       /* If character incomplete or unmappable/illegal, store it in toUBytes[] */
   1346       args->converter->toULength = savebytes;
   1347       if (savebytes > 0) {
   1348          uprv_memcpy(args->converter->toUBytes, errSource, savebytes);
   1349       }
   1350       if (*err == U_TRUNCATED_CHAR_FOUND) {
   1351          *err = U_ZERO_ERROR;
   1352       }
   1353    }
   1354 }
   1355 
   1356 /* And now, the macroized declarations of data & functions: */
   1357 DEFINE_LMBCS_OPEN(1)
   1358 DEFINE_LMBCS_OPEN(2)
   1359 DEFINE_LMBCS_OPEN(3)
   1360 DEFINE_LMBCS_OPEN(4)
   1361 DEFINE_LMBCS_OPEN(5)
   1362 DEFINE_LMBCS_OPEN(6)
   1363 DEFINE_LMBCS_OPEN(8)
   1364 DEFINE_LMBCS_OPEN(11)
   1365 DEFINE_LMBCS_OPEN(16)
   1366 DEFINE_LMBCS_OPEN(17)
   1367 DEFINE_LMBCS_OPEN(18)
   1368 DEFINE_LMBCS_OPEN(19)
   1369 
   1370 
   1371 DECLARE_LMBCS_DATA(1)
   1372 DECLARE_LMBCS_DATA(2)
   1373 DECLARE_LMBCS_DATA(3)
   1374 DECLARE_LMBCS_DATA(4)
   1375 DECLARE_LMBCS_DATA(5)
   1376 DECLARE_LMBCS_DATA(6)
   1377 DECLARE_LMBCS_DATA(8)
   1378 DECLARE_LMBCS_DATA(11)
   1379 DECLARE_LMBCS_DATA(16)
   1380 DECLARE_LMBCS_DATA(17)
   1381 DECLARE_LMBCS_DATA(18)
   1382 DECLARE_LMBCS_DATA(19)
   1383 
   1384 U_CDECL_END
   1385 
   1386 #endif /* #if !UCONFIG_NO_LEGACY_CONVERSION */
   1387