icuSources/common/uinvchar.cpp

   1 // © 2016 and later: Unicode, Inc. and others.
   2 // License & terms of use: http://www.unicode.org/copyright.html
   3 /*
   4 *******************************************************************************
   5 *
   6 *   Copyright (C) 1999-2010, International Business Machines
   7 *   Corporation and others.  All Rights Reserved.
   8 *
   9 *******************************************************************************
  10 *   file name:  uinvchar.c
  11 *   encoding:   UTF-8
  12 *   tab size:   8 (not used)
  13 *   indentation:2
  14 *
  15 *   created on: 2004sep14
  16 *   created by: Markus W. Scherer
  17 *
  18 *   Functions for handling invariant characters, moved here from putil.c
  19 *   for better modularization.
  20 */
  21
  22 #include "unicode/utypes.h"
  23 #include "unicode/ustring.h"
  24 #include "udataswp.h"
  25 #include "cstring.h"
  26 #include "cmemory.h"
  27 #include "uassert.h"
  28 #include "uinvchar.h"
  29
  30 /* invariant-character handling --------------------------------------------- */
  31
  32 /*
  33  * These maps for ASCII to/from EBCDIC map invariant characters (see utypes.h)
  34  * appropriately for most EBCDIC codepages.
  35  *
  36  * They currently also map most other ASCII graphic characters,
  37  * appropriately for codepages 37 and 1047.
  38  * Exceptions: The characters for []^ have different codes in 37 & 1047.
  39  * Both versions are mapped to ASCII.
  40  *
  41  *    ASCII 37 1047
  42  * [     5B BA   AD
  43  * ]     5D BB   BD
  44  * ^     5E B0   5F
  45  *
  46  * There are no mappings for variant characters from Unicode to EBCDIC.
  47  *
  48  * Currently, C0 control codes are also included in these maps.
  49  * Exceptions: S/390 Open Edition swaps LF and NEL codes compared with other
  50  * EBCDIC platforms; both codes (15 and 25) are mapped to ASCII LF (0A),
  51  * but there is no mapping for ASCII LF back to EBCDIC.
  52  *
  53  *    ASCII EBCDIC S/390-OE
  54  * LF    0A     25       15
  55  * NEL   85     15       25
  56  *
  57  * The maps below explicitly exclude the variant
  58  * control and graphical characters that are in ASCII-based
  59  * codepages at 0x80 and above.
  60  * "No mapping" is expressed by mapping to a 00 byte.
  61  *
  62  * These tables do not establish a converter or a codepage.
  63  */
  64
  65 static const uint8_t asciiFromEbcdic[256]={
  66     0x00, 0x01, 0x02, 0x03, 0x00, 0x09, 0x00, 0x7f, 0x00, 0x00, 0x00, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
  67     0x10, 0x11, 0x12, 0x13, 0x00, 0x0a, 0x08, 0x00, 0x18, 0x19, 0x00, 0x00, 0x1c, 0x1d, 0x1e, 0x1f,
  68     0x00, 0x00, 0x00, 0x00, 0x00, 0x0a, 0x17, 0x1b, 0x00, 0x00, 0x00, 0x00, 0x00, 0x05, 0x06, 0x07,
  69     0x00, 0x00, 0x16, 0x00, 0x00, 0x00, 0x00, 0x04, 0x00, 0x00, 0x00, 0x00, 0x14, 0x15, 0x00, 0x1a,
  70
  71     0x20, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x2e, 0x3c, 0x28, 0x2b, 0x7c,
  72     0x26, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x21, 0x24, 0x2a, 0x29, 0x3b, 0x5e,
  73     0x2d, 0x2f, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x2c, 0x25, 0x5f, 0x3e, 0x3f,
  74     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x60, 0x3a, 0x23, 0x40, 0x27, 0x3d, 0x22,
  75
  76     0x00, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  77     0x00, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, 0x70, 0x71, 0x72, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  78     0x00, 0x7e, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7a, 0x00, 0x00, 0x00, 0x5b, 0x00, 0x00,
  79     0x5e, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x5b, 0x5d, 0x00, 0x5d, 0x00, 0x00,
  80
  81     0x7b, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  82     0x7d, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f, 0x50, 0x51, 0x52, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  83     0x5c, 0x00, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5a, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  84     0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
  85 };
  86
  87 static const uint8_t ebcdicFromAscii[256]={
  88     0x00, 0x01, 0x02, 0x03, 0x37, 0x2d, 0x2e, 0x2f, 0x16, 0x05, 0x00, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
  89     0x10, 0x11, 0x12, 0x13, 0x3c, 0x3d, 0x32, 0x26, 0x18, 0x19, 0x3f, 0x27, 0x1c, 0x1d, 0x1e, 0x1f,
  90     0x40, 0x00, 0x7f, 0x00, 0x00, 0x6c, 0x50, 0x7d, 0x4d, 0x5d, 0x5c, 0x4e, 0x6b, 0x60, 0x4b, 0x61,
  91     0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8, 0xf9, 0x7a, 0x5e, 0x4c, 0x7e, 0x6e, 0x6f,
  92
  93     0x00, 0xc1, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7, 0xc8, 0xc9, 0xd1, 0xd2, 0xd3, 0xd4, 0xd5, 0xd6,
  94     0xd7, 0xd8, 0xd9, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9, 0x00, 0x00, 0x00, 0x00, 0x6d,
  95     0x00, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96,
  96     0x97, 0x98, 0x99, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7, 0xa8, 0xa9, 0x00, 0x00, 0x00, 0x00, 0x07,
  97
  98     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  99     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
 100     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
 101     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
 102
 103     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
 104     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
 105     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
 106     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
 107 };
 108
 109 /* Same as asciiFromEbcdic[] except maps all letters to lowercase. */
 110 static const uint8_t lowercaseAsciiFromEbcdic[256]={
 111     0x00, 0x01, 0x02, 0x03, 0x00, 0x09, 0x00, 0x7f, 0x00, 0x00, 0x00, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
 112     0x10, 0x11, 0x12, 0x13, 0x00, 0x0a, 0x08, 0x00, 0x18, 0x19, 0x00, 0x00, 0x1c, 0x1d, 0x1e, 0x1f,
 113     0x00, 0x00, 0x00, 0x00, 0x00, 0x0a, 0x17, 0x1b, 0x00, 0x00, 0x00, 0x00, 0x00, 0x05, 0x06, 0x07,
 114     0x00, 0x00, 0x16, 0x00, 0x00, 0x00, 0x00, 0x04, 0x00, 0x00, 0x00, 0x00, 0x14, 0x15, 0x00, 0x1a,
 115
 116     0x20, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x2e, 0x3c, 0x28, 0x2b, 0x7c,
 117     0x26, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x21, 0x24, 0x2a, 0x29, 0x3b, 0x5e,
 118     0x2d, 0x2f, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x2c, 0x25, 0x5f, 0x3e, 0x3f,
 119     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x60, 0x3a, 0x23, 0x40, 0x27, 0x3d, 0x22,
 120
 121     0x00, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 122     0x00, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, 0x70, 0x71, 0x72, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 123     0x00, 0x7e, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7a, 0x00, 0x00, 0x00, 0x5b, 0x00, 0x00,
 124     0x5e, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x5b, 0x5d, 0x00, 0x5d, 0x00, 0x00,
 125
 126     0x7b, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 127     0x7d, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, 0x70, 0x71, 0x72, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 128     0x7c, 0x00, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7a, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 129     0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
 130 };
 131
 132 /*
 133  * Bit sets indicating which characters of the ASCII repertoire
 134  * (by ASCII/Unicode code) are "invariant".
 135  * See utypes.h for more details.
 136  *
 137  * As invariant are considered the characters of the ASCII repertoire except
 138  * for the following:
 139  * 21  '!' <exclamation mark>
 140  * 23  '#' <number sign>
 141  * 24  '$' <dollar sign>
 142  *
 143  * 40  '@' <commercial at>
 144  *
 145  * 5b  '[' <left bracket>
 146  * 5c  '\' <backslash>
 147  * 5d  ']' <right bracket>
 148  * 5e  '^' <circumflex>
 149  *
 150  * 60  '`' <grave accent>
 151  *
 152  * 7b  '{' <left brace>
 153  * 7c  '|' <vertical line>
 154  * 7d  '}' <right brace>
 155  * 7e  '~' <tilde>
 156  */
 157 static const uint32_t invariantChars[4]={
 158     0xfffffbff, /* 00..1f but not 0a */
 159     0xffffffe5, /* 20..3f but not 21 23 24 */
 160     0x87fffffe, /* 40..5f but not 40 5b..5e */
 161     0x87fffffe  /* 60..7f but not 60 7b..7e */
 162 };
 163
 164 /*
 165  * test unsigned types (or values known to be non-negative) for invariant characters,
 166  * tests ASCII-family character values
 167  */
 168 #define UCHAR_IS_INVARIANT(c) (((c)<=0x7f) && (invariantChars[(c)>>5]&((uint32_t)1<<((c)&0x1f)))!=0)
 169
 170 /* test signed types for invariant characters, adds test for positive values */
 171 #define SCHAR_IS_INVARIANT(c) ((0<=(c)) && UCHAR_IS_INVARIANT(c))
 172
 173 #if U_CHARSET_FAMILY==U_ASCII_FAMILY
 174 #define CHAR_TO_UCHAR(c) c
 175 #define UCHAR_TO_CHAR(c) c
 176 #elif U_CHARSET_FAMILY==U_EBCDIC_FAMILY
 177 #define CHAR_TO_UCHAR(u) asciiFromEbcdic[u]
 178 #define UCHAR_TO_CHAR(u) ebcdicFromAscii[u]
 179 #else
 180 #   error U_CHARSET_FAMILY is not valid
 181 #endif
 182
 183
 184 U_CAPI void U_EXPORT2
 185 u_charsToUChars(const char *cs, UChar *us, int32_t length) {
 186     UChar u;
 187     uint8_t c;
 188
 189     /*
 190      * Allow the entire ASCII repertoire to be mapped _to_ Unicode.
 191      * For EBCDIC systems, this works for characters with codes from
 192      * codepages 37 and 1047 or compatible.
 193      */
 194     while(length>0) {
 195         c=(uint8_t)(*cs++);
 196         u=(UChar)CHAR_TO_UCHAR(c);
 197         U_ASSERT((u!=0 || c==0)); /* only invariant chars converted? */
 198         *us++=u;
 199         --length;
 200     }
 201 }
 202
 203 U_CAPI void U_EXPORT2
 204 u_UCharsToChars(const UChar *us, char *cs, int32_t length) {
 205     UChar u;
 206
 207     while(length>0) {
 208         u=*us++;
 209         if(!UCHAR_IS_INVARIANT(u)) {
 210             U_ASSERT(FALSE); /* Variant characters were used. These are not portable in ICU. */
 211             u=0;
 212         }
 213         *cs++=(char)UCHAR_TO_CHAR(u);
 214         --length;
 215     }
 216 }
 217
 218 U_CAPI UBool U_EXPORT2
 219 uprv_isInvariantString(const char *s, int32_t length) {
 220     uint8_t c;
 221
 222     for(;;) {
 223         if(length<0) {
 224             /* NUL-terminated */
 225             c=(uint8_t)*s++;
 226             if(c==0) {
 227                 break;
 228             }
 229         } else {
 230             /* count length */
 231             if(length==0) {
 232                 break;
 233             }
 234             --length;
 235             c=(uint8_t)*s++;
 236             if(c==0) {
 237                 continue; /* NUL is invariant */
 238             }
 239         }
 240         /* c!=0 now, one branch below checks c==0 for variant characters */
 241
 242         /*
 243          * no assertions here because these functions are legitimately called
 244          * for strings with variant characters
 245          */
 246 #if U_CHARSET_FAMILY==U_ASCII_FAMILY
 247         if(!UCHAR_IS_INVARIANT(c)) {
 248             return FALSE; /* found a variant char */
 249         }
 250 #elif U_CHARSET_FAMILY==U_EBCDIC_FAMILY
 251         c=CHAR_TO_UCHAR(c);
 252         if(c==0 || !UCHAR_IS_INVARIANT(c)) {
 253             return FALSE; /* found a variant char */
 254         }
 255 #else
 256 #   error U_CHARSET_FAMILY is not valid
 257 #endif
 258     }
 259     return TRUE;
 260 }
 261
 262 U_CAPI UBool U_EXPORT2
 263 uprv_isInvariantUString(const UChar *s, int32_t length) {
 264     UChar c;
 265
 266     for(;;) {
 267         if(length<0) {
 268             /* NUL-terminated */
 269             c=*s++;
 270             if(c==0) {
 271                 break;
 272             }
 273         } else {
 274             /* count length */
 275             if(length==0) {
 276                 break;
 277             }
 278             --length;
 279             c=*s++;
 280         }
 281
 282         /*
 283          * no assertions here because these functions are legitimately called
 284          * for strings with variant characters
 285          */
 286         if(!UCHAR_IS_INVARIANT(c)) {
 287             return FALSE; /* found a variant char */
 288         }
 289     }
 290     return TRUE;
 291 }
 292
 293 /* UDataSwapFn implementations used in udataswp.c ------- */
 294
 295 /* convert ASCII to EBCDIC and verify that all characters are invariant */
 296 U_CAPI int32_t U_EXPORT2
 297 uprv_ebcdicFromAscii(const UDataSwapper *ds,
 298                      const void *inData, int32_t length, void *outData,
 299                      UErrorCode *pErrorCode) {
 300     const uint8_t *s;
 301     uint8_t *t;
 302     uint8_t c;
 303
 304     int32_t count;
 305
 306     if(pErrorCode==NULL || U_FAILURE(*pErrorCode)) {
 307         return 0;
 308     }
 309     if(ds==NULL || inData==NULL || length<0 || (length>0 && outData==NULL)) {
 310         *pErrorCode=U_ILLEGAL_ARGUMENT_ERROR;
 311         return 0;
 312     }
 313
 314     /* setup and swapping */
 315     s=(const uint8_t *)inData;
 316     t=(uint8_t *)outData;
 317     count=length;
 318     while(count>0) {
 319         c=*s++;
 320         if(!UCHAR_IS_INVARIANT(c)) {
 321             udata_printError(ds, "uprv_ebcdicFromAscii() string[%d] contains a variant character in position %d\n",
 322                              length, length-count);
 323             *pErrorCode=U_INVALID_CHAR_FOUND;
 324             return 0;
 325         }
 326         *t++=ebcdicFromAscii[c];
 327         --count;
 328     }
 329
 330     return length;
 331 }
 332
 333 /* this function only checks and copies ASCII strings without conversion */
 334 U_CFUNC int32_t
 335 uprv_copyAscii(const UDataSwapper *ds,
 336                const void *inData, int32_t length, void *outData,
 337                UErrorCode *pErrorCode) {
 338     const uint8_t *s;
 339     uint8_t c;
 340
 341     int32_t count;
 342
 343     if(pErrorCode==NULL || U_FAILURE(*pErrorCode)) {
 344         return 0;
 345     }
 346     if(ds==NULL || inData==NULL || length<0 || (length>0 && outData==NULL)) {
 347         *pErrorCode=U_ILLEGAL_ARGUMENT_ERROR;
 348         return 0;
 349     }
 350
 351     /* setup and checking */
 352     s=(const uint8_t *)inData;
 353     count=length;
 354     while(count>0) {
 355         c=*s++;
 356         if(!UCHAR_IS_INVARIANT(c)) {
 357             udata_printError(ds, "uprv_copyFromAscii() string[%d] contains a variant character in position %d\n",
 358                              length, length-count);
 359             *pErrorCode=U_INVALID_CHAR_FOUND;
 360             return 0;
 361         }
 362         --count;
 363     }
 364
 365     if(length>0 && inData!=outData) {
 366         uprv_memcpy(outData, inData, length);
 367     }
 368
 369     return length;
 370 }
 371
 372 /* convert EBCDIC to ASCII and verify that all characters are invariant */
 373 U_CFUNC int32_t
 374 uprv_asciiFromEbcdic(const UDataSwapper *ds,
 375                      const void *inData, int32_t length, void *outData,
 376                      UErrorCode *pErrorCode) {
 377     const uint8_t *s;
 378     uint8_t *t;
 379     uint8_t c;
 380
 381     int32_t count;
 382
 383     if(pErrorCode==NULL || U_FAILURE(*pErrorCode)) {
 384         return 0;
 385     }
 386     if(ds==NULL || inData==NULL || length<0 ||  (length>0 && outData==NULL)) {
 387         *pErrorCode=U_ILLEGAL_ARGUMENT_ERROR;
 388         return 0;
 389     }
 390
 391     /* setup and swapping */
 392     s=(const uint8_t *)inData;
 393     t=(uint8_t *)outData;
 394     count=length;
 395     while(count>0) {
 396         c=*s++;
 397         if(c!=0 && ((c=asciiFromEbcdic[c])==0 || !UCHAR_IS_INVARIANT(c))) {
 398             udata_printError(ds, "uprv_asciiFromEbcdic() string[%d] contains a variant character in position %d\n",
 399                              length, length-count);
 400             *pErrorCode=U_INVALID_CHAR_FOUND;
 401             return 0;
 402         }
 403         *t++=c;
 404         --count;
 405     }
 406
 407     return length;
 408 }
 409
 410 /* this function only checks and copies EBCDIC strings without conversion */
 411 U_CFUNC int32_t
 412 uprv_copyEbcdic(const UDataSwapper *ds,
 413                 const void *inData, int32_t length, void *outData,
 414                 UErrorCode *pErrorCode) {
 415     const uint8_t *s;
 416     uint8_t c;
 417
 418     int32_t count;
 419
 420     if(pErrorCode==NULL || U_FAILURE(*pErrorCode)) {
 421         return 0;
 422     }
 423     if(ds==NULL || inData==NULL || length<0 || (length>0 && outData==NULL)) {
 424         *pErrorCode=U_ILLEGAL_ARGUMENT_ERROR;
 425         return 0;
 426     }
 427
 428     /* setup and checking */
 429     s=(const uint8_t *)inData;
 430     count=length;
 431     while(count>0) {
 432         c=*s++;
 433         if(c!=0 && ((c=asciiFromEbcdic[c])==0 || !UCHAR_IS_INVARIANT(c))) {
 434             udata_printError(ds, "uprv_copyEbcdic() string[%] contains a variant character in position %d\n",
 435                              length, length-count);
 436             *pErrorCode=U_INVALID_CHAR_FOUND;
 437             return 0;
 438         }
 439         --count;
 440     }
 441
 442     if(length>0 && inData!=outData) {
 443         uprv_memcpy(outData, inData, length);
 444     }
 445
 446     return length;
 447 }
 448
 449 /* compare invariant strings; variant characters compare less than others and unlike each other */
 450 U_CFUNC int32_t
 451 uprv_compareInvAscii(const UDataSwapper *ds,
 452                      const char *outString, int32_t outLength,
 453                      const UChar *localString, int32_t localLength) {
 454     (void)ds;
 455     int32_t minLength;
 456     UChar32 c1, c2;
 457     uint8_t c;
 458
 459     if(outString==NULL || outLength<-1 || localString==NULL || localLength<-1) {
 460         return 0;
 461     }
 462
 463     if(outLength<0) {
 464         outLength=(int32_t)uprv_strlen(outString);
 465     }
 466     if(localLength<0) {
 467         localLength=u_strlen(localString);
 468     }
 469
 470     minLength= outLength<localLength ? outLength : localLength;
 471
 472     while(minLength>0) {
 473         c=(uint8_t)*outString++;
 474         if(UCHAR_IS_INVARIANT(c)) {
 475             c1=c;
 476         } else {
 477             c1=-1;
 478         }
 479
 480         c2=*localString++;
 481         if(!UCHAR_IS_INVARIANT(c2)) {
 482             c2=-2;
 483         }
 484
 485         if((c1-=c2)!=0) {
 486             return c1;
 487         }
 488
 489         --minLength;
 490     }
 491
 492     /* strings start with same prefix, compare lengths */
 493     return outLength-localLength;
 494 }
 495
 496 U_CFUNC int32_t
 497 uprv_compareInvEbcdic(const UDataSwapper *ds,
 498                       const char *outString, int32_t outLength,
 499                       const UChar *localString, int32_t localLength) {
 500     (void)ds;
 501     int32_t minLength;
 502     UChar32 c1, c2;
 503     uint8_t c;
 504
 505     if(outString==NULL || outLength<-1 || localString==NULL || localLength<-1) {
 506         return 0;
 507     }
 508
 509     if(outLength<0) {
 510         outLength=(int32_t)uprv_strlen(outString);
 511     }
 512     if(localLength<0) {
 513         localLength=u_strlen(localString);
 514     }
 515
 516     minLength= outLength<localLength ? outLength : localLength;
 517
 518     while(minLength>0) {
 519         c=(uint8_t)*outString++;
 520         if(c==0) {
 521             c1=0;
 522         } else if((c1=asciiFromEbcdic[c])!=0 && UCHAR_IS_INVARIANT(c1)) {
 523             /* c1 is set */
 524         } else {
 525             c1=-1;
 526         }
 527
 528         c2=*localString++;
 529         if(!UCHAR_IS_INVARIANT(c2)) {
 530             c2=-2;
 531         }
 532
 533         if((c1-=c2)!=0) {
 534             return c1;
 535         }
 536
 537         --minLength;
 538     }
 539
 540     /* strings start with same prefix, compare lengths */
 541     return outLength-localLength;
 542 }
 543
 544 U_CAPI int32_t U_EXPORT2
 545 uprv_compareInvEbcdicAsAscii(const char *s1, const char *s2) {
 546     int32_t c1, c2;
 547
 548     for(;; ++s1, ++s2) {
 549         c1=(uint8_t)*s1;
 550         c2=(uint8_t)*s2;
 551         if(c1!=c2) {
 552             if(c1!=0 && ((c1=asciiFromEbcdic[c1])==0 || !UCHAR_IS_INVARIANT(c1))) {
 553                 c1=-(int32_t)(uint8_t)*s1;
 554             }
 555             if(c2!=0 && ((c2=asciiFromEbcdic[c2])==0 || !UCHAR_IS_INVARIANT(c2))) {
 556                 c2=-(int32_t)(uint8_t)*s2;
 557             }
 558             return c1-c2;
 559         } else if(c1==0) {
 560             return 0;
 561         }
 562     }
 563 }
 564
 565 U_CAPI char U_EXPORT2
 566 uprv_ebcdicToLowercaseAscii(char c) {
 567     return (char)lowercaseAsciiFromEbcdic[(uint8_t)c];
 568 }
 569
 570 U_INTERNAL uint8_t* U_EXPORT2
 571 uprv_aestrncpy(uint8_t *dst, const uint8_t *src, int32_t n)
 572 {
 573   uint8_t *orig_dst = dst;
 574
 575   if(n==-1) {
 576     n = uprv_strlen((const char*)src)+1; /* copy NUL */
 577   }
 578   /* copy non-null */
 579   while(*src && n>0) {
 580     *(dst++) = asciiFromEbcdic[*(src++)];
 581     n--;
 582   }
 583   /* pad */
 584   while(n>0) {
 585     *(dst++) = 0;
 586     n--;
 587   }
 588   return orig_dst;
 589 }
 590
 591 U_INTERNAL uint8_t* U_EXPORT2
 592 uprv_eastrncpy(uint8_t *dst, const uint8_t *src, int32_t n)
 593 {
 594   uint8_t *orig_dst = dst;
 595
 596   if(n==-1) {
 597     n = uprv_strlen((const char*)src)+1; /* copy NUL */
 598   }
 599   /* copy non-null */
 600   while(*src && n>0) {
 601     char ch = ebcdicFromAscii[*(src++)];
 602     if(ch == 0) {
 603       ch = ebcdicFromAscii[0x3f]; /* questionmark (subchar) */
 604     }
 605     *(dst++) = ch;
 606     n--;
 607   }
 608   /* pad */
 609   while(n>0) {
 610     *(dst++) = 0;
 611     n--;
 612   }
 613   return orig_dst;
 614 }
 615