/* ********************************************************************** * Copyright (C) 2002, International Business Machines * Corporation and others. All Rights Reserved. ********************************************************************** * file name: ucnv_u7.c * encoding: US-ASCII * tab size: 8 (not used) * indentation:4 * * created on: 2002jul01 * created by: Markus W. Scherer * * UTF-7 converter implementation. Used to be in ucnv_utf.c. */ #include "unicode/utypes.h" #include "unicode/ucnv.h" #include "unicode/ucnv_err.h" #include "ucnv_bld.h" #include "ucnv_cnv.h" /* UTF-7 -------------------------------------------------------------------- */ /* ### TODO: in convrtrs.txt and user guide, document version option (=1 for escaping set O characters) */ /* TODO: version=1 is not really for IMAP, fix documentation; consider version=2 for IMAP */ /* * UTF-7 is a stateful encoding of Unicode, somewhat like UTF7. * It is defined in RFC 2152 http://www.imc.org/rfc2152 . * It was intended for use in Internet email systems, using in its bytewise * encoding only a subset of 7-bit US-ASCII. * UTF-7 is deprecated in favor of UTF-8/16/32 and UTF7, but still * occasionally used. * * For converting Unicode to UTF-7, the RFC allows to encode some US-ASCII * characters directly or in base64. Especially, the characters in set O * as defined in the RFC (see below) may be encoded directly but are not * allowed in, e.g., email headers. * By default, the ICU UTF-7 converter encodes set O directly. * By choosing the option "version=1", set O will be escaped instead. * For example: * utf7Converter=ucnv_open("UTF-7,version=1"); */ /* * Tests for US-ASCII characters belonging to character classes * defined in UTF-7. * * Set D (directly encoded characters) consists of the following * characters: the upper and lower case letters A through Z * and a through z, the 10 digits 0-9, and the following nine special * characters (note that "+" and "=" are omitted): * '(),-./:? * * Set O (optional direct characters) consists of the following * characters (note that "\" and "~" are omitted): * !"#$%&*;<=>@[]^_`{|} * * According to the rules in RFC 2152, the byte values for the following * US-ASCII characters are not used in UTF-7 and are therefore illegal: * - all C0 control codes except for CR LF TAB * - BACKSLASH * - TILDE * - DEL * - all codes beyond US-ASCII, i.e. all >127 */ #define inSetD(c) \ ((uint8_t)((c)-97)<26 || (uint8_t)((c)-65)<26 || /* letters */ \ (uint8_t)((c)-48)<10 || /* digits */ \ (uint8_t)((c)-39)<3 || /* '() */ \ (uint8_t)((c)-44)<4 || /* ,-./ */ \ (c)==58 || (c)==63 /* :? */ \ ) #define inSetO(c) \ ((uint8_t)((c)-33)<6 || /* !"#$%& */ \ (uint8_t)((c)-59)<4 || /* ;<=> */ \ (uint8_t)((c)-93)<4 || /* ]^_` */ \ (uint8_t)((c)-123)<3 || /* {|} */ \ (c)==42 || (c)==64 || (c)==91 /* *@[ */ \ ) #define isCRLFTAB(c) ((c)==13 || (c)==10 || (c)==9) #define isCRLFSPTAB(c) ((c)==32 || (c)==13 || (c)==10 || (c)==9) #define PLUS 43 #define MINUS 45 #define BACKSLASH 92 #define TILDE 126 /* legal byte values: all US-ASCII graphic characters from space to before tilde, and CR LF TAB */ #define isLegalUTF7(c) (((uint8_t)((c)-32)<94 && (c)!=BACKSLASH) || isCRLFTAB(c)) /* encode directly sets D and O and CR LF SP TAB */ static const UBool encodeDirectlyMaximum[128]={ /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0 }; /* encode directly set D and CR LF SP TAB but not set O */ static const UBool encodeDirectlyRestricted[128]={ /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0 }; static const uint8_t toBase64[64]={ /* A-Z */ 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, /* a-z */ 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, /* 0-9 */ 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, /* +/ */ 43, 47 }; static const int8_t fromBase64[128]={ /* C0 controls, -1 for legal ones (CR LF TAB), -3 for illegal ones */ -3, -3, -3, -3, -3, -3, -3, -3, -3, -1, -1, -3, -3, -1, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, /* general punctuation with + and / and a special value (-2) for - */ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -2, -1, 63, /* digits */ 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1, /* A-Z */ -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -3, -1, -1, -1, /* a-z */ -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -3, -3 }; /* * converter status values: * * toUnicodeStatus: * 24 inDirectMode (boolean) * 23..16 base64Counter (-1..7) * 15..0 bits (up to 14 bits incoming base64) * * fromUnicodeStatus: * 31..28 version (0: set O direct 1: set O escaped) * 24 inDirectMode (boolean) * 23..16 base64Counter (0..2) * 7..0 bits (6 bits outgoing base64) * */ static void _UTF7Reset(UConverter *cnv, UConverterResetChoice choice) { if(choice<=UCNV_RESET_TO_UNICODE) { /* reset toUnicode */ cnv->toUnicodeStatus=0x1000000; /* inDirectMode=TRUE */ cnv->toULength=0; } if(choice!=UCNV_RESET_TO_UNICODE) { /* reset fromUnicode */ cnv->fromUnicodeStatus=(cnv->fromUnicodeStatus&0xf0000000)|0x1000000; /* keep version, inDirectMode=TRUE */ } } static void _UTF7Open(UConverter *cnv, const char *name, const char *locale, uint32_t options, UErrorCode *pErrorCode) { if((options&0xf)<=1) { cnv->fromUnicodeStatus=(options&0xf)<<28; _UTF7Reset(cnv, UCNV_RESET_BOTH); } else { *pErrorCode=U_ILLEGAL_ARGUMENT_ERROR; } } static void _UTF7ToUnicodeWithOffsets(UConverterToUnicodeArgs *pArgs, UErrorCode *pErrorCode) { UConverter *cnv; const uint8_t *source, *sourceLimit; UChar *target; const UChar *targetLimit; int32_t *offsets; uint8_t *bytes; uint8_t byteIndex; int32_t length, targetCapacity; /* UTF-7 state */ uint16_t bits; int8_t base64Counter; UBool inDirectMode; int8_t base64Value; int32_t sourceIndex, nextSourceIndex; uint8_t b; /* set up the local pointers */ cnv=pArgs->converter; source=(const uint8_t *)pArgs->source; sourceLimit=(const uint8_t *)pArgs->sourceLimit; target=pArgs->target; targetLimit=pArgs->targetLimit; offsets=pArgs->offsets; /* get the state machine state */ { uint32_t status=cnv->toUnicodeStatus; inDirectMode=(UBool)((status>>24)&1); base64Counter=(int8_t)(status>>16); bits=(uint16_t)status; } bytes=cnv->toUBytes; byteIndex=cnv->toULength; /* sourceIndex=-1 if the current character began in the previous buffer */ sourceIndex=byteIndex==0 ? 0 : -1; nextSourceIndex=0; loop: if(inDirectMode) { directMode: /* * In Direct Mode, most US-ASCII characters are encoded directly, i.e., * with their US-ASCII byte values. * Backslash and Tilde and most control characters are not allowed in UTF-7. * A plus sign starts Unicode (or "escape") Mode. * * In Direct Mode, only the sourceIndex is used. */ byteIndex=0; length=sourceLimit-source; targetCapacity=targetLimit-target; if(length>targetCapacity) { length=targetCapacity; } while(length>0) { b=*source++; if(!isLegalUTF7(b)) { /* illegal */ bytes[0]=b; byteIndex=1; nextSourceIndex=sourceIndex+1; goto callback; } else if(b!=PLUS) { /* write directly encoded character */ *target++=b; if(offsets!=NULL) { *offsets++=sourceIndex++; } } else /* PLUS */ { /* switch to Unicode mode */ nextSourceIndex=++sourceIndex; inDirectMode=FALSE; byteIndex=0; bits=0; base64Counter=-1; goto unicodeMode; } --length; } if(source=targetLimit) { /* target is full */ *pErrorCode=U_BUFFER_OVERFLOW_ERROR; } } else { unicodeMode: /* * In Unicode (or "escape") Mode, UTF-16BE is base64-encoded. * The base64 sequence ends with any character that is not in the base64 alphabet. * A terminating minus sign is consumed. * * In Unicode Mode, the sourceIndex has the index to the start of the current * base64 bytes, while nextSourceIndex is precisely parallel to source, * keeping the index to the following byte. * Note that in 2 out of 3 cases, UChars overlap within a base64 byte. */ while(source=126) { /* illegal - test other illegal US-ASCII values by base64Value==-3 */ inDirectMode=TRUE; goto callback; } else if((base64Value=fromBase64[b])>=0) { /* collect base64 bytes into UChars */ switch(base64Counter) { case -1: /* -1 is immediately after the + */ case 0: bits=base64Value; base64Counter=1; break; case 1: case 3: case 4: case 6: bits=(uint16_t)((bits<<6)|base64Value); ++base64Counter; break; case 2: *target++=(UChar)((bits<<4)|(base64Value>>2)); if(offsets!=NULL) { *offsets++=sourceIndex; sourceIndex=nextSourceIndex-1; } bytes[0]=b; /* keep this byte in case an error occurs */ byteIndex=1; bits=(uint16_t)(base64Value&3); base64Counter=3; break; case 5: *target++=(UChar)((bits<<2)|(base64Value>>4)); if(offsets!=NULL) { *offsets++=sourceIndex; sourceIndex=nextSourceIndex-1; } bytes[0]=b; /* keep this byte in case an error occurs */ byteIndex=1; bits=(uint16_t)(base64Value&15); base64Counter=6; break; case 7: *target++=(UChar)((bits<<6)|base64Value); if(offsets!=NULL) { *offsets++=sourceIndex; sourceIndex=nextSourceIndex; } byteIndex=0; bits=0; base64Counter=0; break; default: /* will never occur */ break; } } else if(base64Value==-2) { /* minus sign terminates the base64 sequence */ inDirectMode=TRUE; if(base64Counter==-1) { /* +- i.e. a minus immediately following a plus */ *target++=PLUS; if(offsets!=NULL) { *offsets++=sourceIndex-1; } } else { /* absorb the minus and leave the Unicode Mode */ if(bits!=0) { /* bits are illegally left over, a UChar is incomplete */ goto callback; } } sourceIndex=nextSourceIndex; goto directMode; } else if(base64Value==-1) /* for any legal character except base64 and minus sign */ { /* leave the Unicode Mode */ inDirectMode=TRUE; if(base64Counter==-1) { /* illegal: + immediately followed by something other than base64 or minus sign */ /* include the plus sign in the reported sequence */ --sourceIndex; bytes[0]=PLUS; bytes[1]=b; byteIndex=2; goto callback; } else if(bits==0) { /* un-read the character in case it is a plus sign */ --source; sourceIndex=nextSourceIndex-1; goto directMode; } else { /* bits are illegally left over, a UChar is incomplete */ goto callback; } } else /* base64Value==-3 for illegal characters */ { /* illegal */ inDirectMode=TRUE; goto callback; } } else { /* target is full */ *pErrorCode=U_BUFFER_OVERFLOW_ERROR; break; } } } endloop: if(pArgs->flush && source>=sourceLimit) { /* reset the state for the next conversion */ if(!inDirectMode && bits!=0 && U_SUCCESS(*pErrorCode)) { /* a character byte sequence remains incomplete */ *pErrorCode=U_TRUNCATED_CHAR_FOUND; } cnv->toUnicodeStatus=0x1000000; /* inDirectMode=TRUE */ cnv->toULength=0; } else { /* set the converter state back into UConverter */ cnv->toUnicodeStatus=((uint32_t)inDirectMode<<24)|((uint32_t)((uint8_t)base64Counter)<<16)|(uint32_t)bits; cnv->toULength=byteIndex; } finish: /* write back the updated pointers */ pArgs->source=(const char *)source; pArgs->target=target; pArgs->offsets=offsets; return; callback: /* call the callback function with all the preparations and post-processing */ /* update the arguments structure */ pArgs->source=(const char *)source; pArgs->target=target; pArgs->offsets=offsets; /* copy the current bytes to invalidCharBuffer */ for(b=0; b<(uint8_t)byteIndex; ++b) { cnv->invalidCharBuffer[b]=(char)bytes[b]; } cnv->invalidCharLength=byteIndex; /* set the converter state in UConverter to deal with the next character */ cnv->toUnicodeStatus=(uint32_t)inDirectMode<<24; cnv->toULength=0; /* call the callback function */ *pErrorCode=U_ILLEGAL_CHAR_FOUND; cnv->fromCharErrorBehaviour(cnv->toUContext, pArgs, cnv->invalidCharBuffer, cnv->invalidCharLength, UCNV_ILLEGAL, pErrorCode); /* get the converter state from UConverter */ { uint32_t status=cnv->toUnicodeStatus; inDirectMode=(UBool)((status>>24)&1); base64Counter=(int8_t)(status>>16); bits=(uint16_t)status; } byteIndex=cnv->toULength; /* update target and deal with offsets if necessary */ offsets=ucnv_updateCallbackOffsets(offsets, pArgs->target-target, sourceIndex); target=pArgs->target; /* update the source pointer and index */ sourceIndex=nextSourceIndex+((const uint8_t *)pArgs->source-source); source=(const uint8_t *)pArgs->source; /* * If the callback overflowed the target, then we need to * stop here with an overflow indication. */ if(*pErrorCode==U_BUFFER_OVERFLOW_ERROR) { goto endloop; } else if(cnv->UCharErrorBufferLength>0) { /* target is full */ *pErrorCode=U_BUFFER_OVERFLOW_ERROR; goto endloop; } else if(U_FAILURE(*pErrorCode)) { /* break on error */ cnv->toUnicodeStatus=0x1000000; /* inDirectMode=TRUE */ cnv->toULength=0; goto finish; } else { goto loop; } } static UChar32 _UTF7GetNextUChar(UConverterToUnicodeArgs *pArgs, UErrorCode *pErrorCode) { return ucnv_getNextUCharFromToUImpl(pArgs, _UTF7ToUnicodeWithOffsets, TRUE, pErrorCode); } static void _UTF7FromUnicodeWithOffsets(UConverterFromUnicodeArgs *pArgs, UErrorCode *pErrorCode) { UConverter *cnv; const UChar *source, *sourceLimit; uint8_t *target, *targetLimit; int32_t *offsets; int32_t length, targetCapacity, sourceIndex; UChar c; /* UTF-7 state */ const UBool *encodeDirectly; uint8_t bits; int8_t base64Counter; UBool inDirectMode; /* set up the local pointers */ cnv=pArgs->converter; /* set up the local pointers */ source=pArgs->source; sourceLimit=pArgs->sourceLimit; target=(uint8_t *)pArgs->target; targetLimit=(uint8_t *)pArgs->targetLimit; offsets=pArgs->offsets; /* get the state machine state */ { uint32_t status=cnv->fromUnicodeStatus; encodeDirectly= status<0x10000000 ? encodeDirectlyMaximum : encodeDirectlyRestricted; inDirectMode=(UBool)((status>>24)&1); base64Counter=(int8_t)(status>>16); bits=(uint8_t)status; } /* UTF-7 always encodes UTF-16 code units, therefore we need only a simple sourceIndex */ sourceIndex=0; if(inDirectMode) { directMode: length=sourceLimit-source; targetCapacity=targetLimit-target; if(length>targetCapacity) { length=targetCapacity; } while(length>0) { c=*source++; /* currently always encode CR LF SP TAB directly */ if(c<=127 && encodeDirectly[c]) { /* encode directly */ *target++=(uint8_t)c; if(offsets!=NULL) { *offsets++=sourceIndex++; } } else if(c==PLUS) { /* output +- for + */ *target++=PLUS; if(targetcharErrorBuffer[0]=MINUS; cnv->charErrorBufferLength=1; *pErrorCode=U_BUFFER_OVERFLOW_ERROR; break; } } else { /* un-read this character and switch to Unicode Mode */ --source; *target++=PLUS; if(offsets!=NULL) { *offsets++=sourceIndex; } inDirectMode=FALSE; base64Counter=0; goto unicodeMode; } --length; } if(source=targetLimit) { /* target is full */ *pErrorCode=U_BUFFER_OVERFLOW_ERROR; } } else { unicodeMode: while(sourcecharErrorBuffer[0]=MINUS; cnv->charErrorBufferLength=1; *pErrorCode=U_BUFFER_OVERFLOW_ERROR; break; } } goto directMode; } else { /* * base64 this character: * Output 2 or 3 base64 bytes for the remaining bits of the previous character * and the bits of this character, each implicitly in UTF-16BE. * * Here, bits is an 8-bit variable because only 6 bits need to be kept from one * character to the next. The actual 2 or 4 bits are shifted to the left edge * of the 6-bits field 5..0 to make the termination of the base64 sequence easier. */ switch(base64Counter) { case 0: *target++=toBase64[c>>10]; if(target>4)&0x3f]; if(offsets!=NULL) { *offsets++=sourceIndex; *offsets++=sourceIndex++; } } else { if(offsets!=NULL) { *offsets++=sourceIndex++; } cnv->charErrorBuffer[0]=toBase64[(c>>4)&0x3f]; cnv->charErrorBufferLength=1; *pErrorCode=U_BUFFER_OVERFLOW_ERROR; } bits=(uint8_t)((c&15)<<2); base64Counter=1; break; case 1: *target++=toBase64[bits|(c>>14)]; if(target>8)&0x3f]; if(target>2)&0x3f]; if(offsets!=NULL) { *offsets++=sourceIndex; *offsets++=sourceIndex; *offsets++=sourceIndex++; } } else { if(offsets!=NULL) { *offsets++=sourceIndex; *offsets++=sourceIndex++; } cnv->charErrorBuffer[0]=toBase64[(c>>2)&0x3f]; cnv->charErrorBufferLength=1; *pErrorCode=U_BUFFER_OVERFLOW_ERROR; } } else { if(offsets!=NULL) { *offsets++=sourceIndex++; } cnv->charErrorBuffer[0]=toBase64[(c>>8)&0x3f]; cnv->charErrorBuffer[1]=toBase64[(c>>2)&0x3f]; cnv->charErrorBufferLength=2; *pErrorCode=U_BUFFER_OVERFLOW_ERROR; } bits=(uint8_t)((c&3)<<4); base64Counter=2; break; case 2: *target++=toBase64[bits|(c>>12)]; if(target>6)&0x3f]; if(targetcharErrorBuffer[0]=toBase64[c&0x3f]; cnv->charErrorBufferLength=1; *pErrorCode=U_BUFFER_OVERFLOW_ERROR; } } else { if(offsets!=NULL) { *offsets++=sourceIndex++; } cnv->charErrorBuffer[0]=toBase64[(c>>6)&0x3f]; cnv->charErrorBuffer[1]=toBase64[c&0x3f]; cnv->charErrorBufferLength=2; *pErrorCode=U_BUFFER_OVERFLOW_ERROR; } bits=0; base64Counter=0; break; default: /* will never occur */ break; } } } else { /* target is full */ *pErrorCode=U_BUFFER_OVERFLOW_ERROR; break; } } } if(pArgs->flush && source>=sourceLimit) { /* flush remaining bits to the target */ if(!inDirectMode && base64Counter!=0) { if(targetcharErrorBuffer[0]=toBase64[bits]; cnv->charErrorBufferLength=1; *pErrorCode=U_BUFFER_OVERFLOW_ERROR; } } /* reset the state for the next conversion */ cnv->fromUnicodeStatus=(cnv->fromUnicodeStatus&0xf0000000)|0x1000000; /* keep version, inDirectMode=TRUE */ } else { /* set the converter state back into UConverter */ cnv->fromUnicodeStatus= (cnv->fromUnicodeStatus&0xf0000000)| /* keep version*/ ((uint32_t)inDirectMode<<24)|((uint32_t)base64Counter<<16)|(uint32_t)bits; } /* write back the updated pointers */ pArgs->source=source; pArgs->target=(char *)target; pArgs->offsets=offsets; return; } static const char * _UTF7GetName(const UConverter *cnv) { switch(cnv->fromUnicodeStatus>>28) { case 1: return "UTF-7,version=1"; default: return "UTF-7"; } } static const UConverterImpl _UTF7Impl={ UCNV_UTF7, NULL, NULL, _UTF7Open, NULL, _UTF7Reset, _UTF7ToUnicodeWithOffsets, _UTF7ToUnicodeWithOffsets, _UTF7FromUnicodeWithOffsets, _UTF7FromUnicodeWithOffsets, _UTF7GetNextUChar, NULL, _UTF7GetName, NULL /* we don't need writeSub() because we never call a callback at fromUnicode() */ }; static const UConverterStaticData _UTF7StaticData={ sizeof(UConverterStaticData), "UTF-7", 0, /* TODO CCSID for UTF-7 */ UCNV_IBM, UCNV_UTF7, 1, 4, { 0x3f, 0, 0, 0 }, 1, /* the subchar is not used */ FALSE, FALSE, 0, 0, { 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 } /* reserved */ }; const UConverterSharedData _UTF7Data={ sizeof(UConverterSharedData), ~((uint32_t)0), NULL, NULL, &_UTF7StaticData, FALSE, &_UTF7Impl, 0 };