libs/smux/xer_support.c

   1 /*
   2  * Copyright (c) 2003, 2004 X/IO Labs, xiolabs.com.
   3  * Copyright (c) 2003, 2004, 2005 Lev Walkin <vlm@lionet.info>.
   4  *      All rights reserved.
   5  * Redistribution and modifications are permitted subject to BSD license.
   6  */
   7 #include <asn_system.h>
   8 #include <xer_support.h>
   9
  10 /* Parser states */
  11 typedef enum {
  12         ST_TEXT,
  13         ST_TAG_START,
  14         ST_TAG_BODY,
  15         ST_TAG_QUOTE_WAIT,
  16         ST_TAG_QUOTED_STRING,
  17         ST_TAG_UNQUOTED_STRING,
  18         ST_COMMENT_WAIT_DASH1,  /* "<!--"[1] */
  19         ST_COMMENT_WAIT_DASH2,  /* "<!--"[2] */
  20         ST_COMMENT,
  21         ST_COMMENT_CLO_DASH2,   /* "-->"[0] */
  22         ST_COMMENT_CLO_RT       /* "-->"[1] */
  23 } pstate_e;
  24
  25 static pxml_chunk_type_e final_chunk_type[] = {
  26         PXML_TEXT,
  27         PXML_TAG_END,
  28         PXML_COMMENT_END,
  29         PXML_TAG_END,
  30         PXML_COMMENT_END,
  31 };
  32
  33
  34 static int
  35 _charclass[256] = {
  36         0,0,0,0,0,0,0,0, 0,1,1,0,1,1,0,0,
  37         0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,
  38         1,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,
  39         2,2,2,2,2,2,2,2, 2,2,0,0,0,0,0,0,       /* 01234567 89       */
  40         0,3,3,3,3,3,3,3, 3,3,3,3,3,3,3,3,       /*  ABCDEFG HIJKLMNO */
  41         3,3,3,3,3,3,3,3, 3,3,3,0,0,0,0,0,       /* PQRSTUVW XYZ      */
  42         0,3,3,3,3,3,3,3, 3,3,3,3,3,3,3,3,       /*  abcdefg hijklmno */
  43         3,3,3,3,3,3,3,3, 3,3,3,0,0,0,0,0        /* pqrstuvw xyz      */
  44 };
  45 #define WHITESPACE(c)   (_charclass[(unsigned char)(c)] == 1)
  46 #define ALNUM(c)        (_charclass[(unsigned char)(c)] >= 2)
  47 #define ALPHA(c)        (_charclass[(unsigned char)(c)] == 3)
  48
  49 /* Aliases for characters, ASCII/UTF-8 */
  50 #define EXCLAM  0x21    /* '!' */
  51 #define CQUOTE  0x22    /* '"' */
  52 #define CDASH   0x2d    /* '-' */
  53 #define CSLASH  0x2f    /* '/' */
  54 #define LANGLE  0x3c    /* '<' */
  55 #define CEQUAL  0x3d    /* '=' */
  56 #define RANGLE  0x3e    /* '>' */
  57 #define CQUEST  0x3f    /* '?' */
  58
  59 /* Invoke token callback */
  60 #define TOKEN_CB_CALL(type, _ns, _current_too, _final) do {     \
  61                 int _ret;                                       \
  62                 pstate_e ns  = _ns;                             \
  63                 ssize_t _sz = (p - chunk_start) + _current_too; \
  64                 if (!_sz) {                                     \
  65                         /* Shortcut */                          \
  66                         state = _ns;                            \
  67                         break;                                  \
  68                 }                                               \
  69                 _ret = cb(type, chunk_start, _sz, key);         \
  70                 if(_ret < _sz) {                                \
  71                         if(_current_too && _ret == -1)          \
  72                                 state = ns;                     \
  73                         goto finish;                            \
  74                 }                                               \
  75                 chunk_start = p + _current_too;                 \
  76                 state = ns;                                     \
  77         } while(0)
  78
  79 #define TOKEN_CB(_type, _ns, _current_too)                      \
  80         TOKEN_CB_CALL(_type, _ns, _current_too, 0)
  81
  82 #define TOKEN_CB_FINAL(_type, _ns, _current_too)                \
  83         TOKEN_CB_CALL(final_chunk_type[_type], _ns, _current_too, 1)
  84
  85 /*
  86  * Parser itself
  87  */
  88 ssize_t pxml_parse(int *stateContext, const void *xmlbuf, size_t size, pxml_callback_f *cb, void *key) {
  89         pstate_e state = (pstate_e)*stateContext;
  90         const char *chunk_start = (const char *)xmlbuf;
  91         const char *p = chunk_start;
  92         const char *end = p + size;
  93
  94         for(; p < end; p++) {
  95           int C = *(const unsigned char *)p;
  96           switch(state) {
  97           case ST_TEXT:
  98                 /*
  99                  * Initial state: we're in the middle of some text,
 100                  * or just have started.
 101                  */
 102                 if (C == LANGLE)
 103                         /* We're now in the tag, probably */
 104                         TOKEN_CB(PXML_TEXT, ST_TAG_START, 0);
 105                 break;
 106           case ST_TAG_START:
 107                 if (ALPHA(C) || (C == CSLASH))
 108                         state = ST_TAG_BODY;
 109                 else if (C == EXCLAM)
 110                         state = ST_COMMENT_WAIT_DASH1;
 111                 else
 112                         /*
 113                          * Not characters and not whitespace.
 114                          * Must be something like "3 < 4".
 115                          */
 116                         TOKEN_CB(PXML_TEXT, ST_TEXT, 1);/* Flush as data */
 117                 break;
 118           case ST_TAG_BODY:
 119                 switch(C) {
 120                 case RANGLE:
 121                         /* End of the tag */
 122                         TOKEN_CB_FINAL(PXML_TAG, ST_TEXT, 1);
 123                         break;
 124                 case LANGLE:
 125                         /*
 126                          * The previous tag wasn't completed, but still
 127                          * recognized as valid. (Mozilla-compatible)
 128                          */
 129                         TOKEN_CB_FINAL(PXML_TAG, ST_TAG_START, 0);
 130                         break;
 131                 case CEQUAL:
 132                         state = ST_TAG_QUOTE_WAIT;
 133                         break;
 134                 }
 135                 break;
 136           case ST_TAG_QUOTE_WAIT:
 137                 /*
 138                  * State after the equal sign ("=") in the tag.
 139                  */
 140                 switch(C) {
 141                 case CQUOTE:
 142                         state = ST_TAG_QUOTED_STRING;
 143                         break;
 144                 case RANGLE:
 145                         /* End of the tag */
 146                         TOKEN_CB_FINAL(PXML_TAG, ST_TEXT, 1);
 147                         break;
 148                 default:
 149                         if(!WHITESPACE(C))
 150                                 /* Unquoted string value */
 151                                 state = ST_TAG_UNQUOTED_STRING;
 152                 }
 153                 break;
 154           case ST_TAG_QUOTED_STRING:
 155                 /*
 156                  * Tag attribute's string value in quotes.
 157                  */
 158                 if(C == CQUOTE) {
 159                         /* Return back to the tag state */
 160                         state = ST_TAG_BODY;
 161                 }
 162                 break;
 163           case ST_TAG_UNQUOTED_STRING:
 164                 if(C == RANGLE) {
 165                         /* End of the tag */
 166                         TOKEN_CB_FINAL(PXML_TAG, ST_TEXT, 1);
 167                 } else if(WHITESPACE(C)) {
 168                         /* Return back to the tag state */
 169                         state = ST_TAG_BODY;
 170                 }
 171                 break;
 172           case ST_COMMENT_WAIT_DASH1:
 173                 if(C == CDASH) {
 174                         state = ST_COMMENT_WAIT_DASH2;
 175                 } else {
 176                         /* Some ordinary tag. */
 177                         state = ST_TAG_BODY;
 178                 }
 179                 break;
 180           case ST_COMMENT_WAIT_DASH2:
 181                 if(C == CDASH) {
 182                         /* Seen "<--" */
 183                         state = ST_COMMENT;
 184                 } else {
 185                         /* Some ordinary tag */
 186                         state = ST_TAG_BODY;
 187                 }
 188                 break;
 189           case ST_COMMENT:
 190                 if(C == CDASH) {
 191                         state = ST_COMMENT_CLO_DASH2;
 192                 }
 193                 break;
 194           case ST_COMMENT_CLO_DASH2:
 195                 if(C == CDASH) {
 196                         state = ST_COMMENT_CLO_RT;
 197                 } else {
 198                         /* This is not an end of a comment */
 199                         state = ST_COMMENT;
 200                 }
 201                 break;
 202           case ST_COMMENT_CLO_RT:
 203                 if(C == RANGLE) {
 204                         TOKEN_CB_FINAL(PXML_COMMENT, ST_TEXT, 1);
 205                 } else if(C == CDASH) {
 206                         /* Maintain current state, still waiting for '>' */
 207                 } else {
 208                         state = ST_COMMENT;
 209                 }
 210                 break;
 211           } /* switch(*ptr) */
 212         } /* for() */
 213
 214         /*
 215          * Flush the partially processed chunk, state permitting.
 216          */
 217         if(p - chunk_start) {
 218                 switch (state) {
 219                 case ST_COMMENT:
 220                         TOKEN_CB(PXML_COMMENT, state, 0);
 221                         break;
 222                 case ST_TEXT:
 223                         TOKEN_CB(PXML_TEXT, state, 0);
 224                         break;
 225                 default: break; /* a no-op */
 226                 }
 227         }
 228
 229 finish:
 230         *stateContext = (int)state;
 231         return chunk_start - (const char *)xmlbuf;
 232 }
 233