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