json-lexer.c

   1 /*
   2  * JSON lexer
   3  *
   4  * Copyright IBM, Corp. 2009
   5  *
   6  * Authors:
   7  *  Anthony Liguori   <aliguori@us.ibm.com>
   8  *
   9  * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
  10  * See the COPYING.LIB file in the top-level directory.
  11  *
  12  */
  13
  14 #include "qstring.h"
  15 #include "qlist.h"
  16 #include "qdict.h"
  17 #include "qint.h"
  18 #include "qemu-common.h"
  19 #include "json-lexer.h"
  20
  21 /*
  22  * \"([^\\\"]|(\\\"\\'\\\\\\/\\b\\f\\n\\r\\t\\u[0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F]))*\"
  23  * '([^\\']|(\\\"\\'\\\\\\/\\b\\f\\n\\r\\t\\u[0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F]))*'
  24  * 0|([1-9][0-9]*(.[0-9]+)?([eE]([-+])?[0-9]+))
  25  * [{}\[\],:]
  26  * [a-z]+
  27  *
  28  */
  29
  30 enum json_lexer_state {
  31     ERROR = 0,
  32     IN_DONE_STRING,
  33     IN_DQ_UCODE3,
  34     IN_DQ_UCODE2,
  35     IN_DQ_UCODE1,
  36     IN_DQ_UCODE0,
  37     IN_DQ_STRING_ESCAPE,
  38     IN_DQ_STRING,
  39     IN_SQ_UCODE3,
  40     IN_SQ_UCODE2,
  41     IN_SQ_UCODE1,
  42     IN_SQ_UCODE0,
  43     IN_SQ_STRING_ESCAPE,
  44     IN_SQ_STRING,
  45     IN_ZERO,
  46     IN_DIGITS,
  47     IN_DIGIT,
  48     IN_EXP_E,
  49     IN_MANTISSA,
  50     IN_MANTISSA_DIGITS,
  51     IN_NONZERO_NUMBER,
  52     IN_NEG_NONZERO_NUMBER,
  53     IN_KEYWORD,
  54     IN_ESCAPE,
  55     IN_ESCAPE_L,
  56     IN_ESCAPE_LL,
  57     IN_ESCAPE_I,
  58     IN_ESCAPE_I6,
  59     IN_ESCAPE_I64,
  60     IN_ESCAPE_DONE,
  61     IN_WHITESPACE,
  62     IN_OPERATOR_DONE,
  63     IN_START,
  64 };
  65
  66 #define TERMINAL(state) [0 ... 0x7F] = (state)
  67
  68 static const uint8_t json_lexer[][256] =  {
  69     [IN_DONE_STRING] = {
  70         TERMINAL(JSON_STRING),
  71     },
  72
  73     /* double quote string */
  74     [IN_DQ_UCODE3] = {
  75         ['0' ... '9'] = IN_DQ_STRING,
  76         ['a' ... 'f'] = IN_DQ_STRING,
  77         ['A' ... 'F'] = IN_DQ_STRING,
  78     },
  79     [IN_DQ_UCODE2] = {
  80         ['0' ... '9'] = IN_DQ_UCODE3,
  81         ['a' ... 'f'] = IN_DQ_UCODE3,
  82         ['A' ... 'F'] = IN_DQ_UCODE3,
  83     },
  84     [IN_DQ_UCODE1] = {
  85         ['0' ... '9'] = IN_DQ_UCODE2,
  86         ['a' ... 'f'] = IN_DQ_UCODE2,
  87         ['A' ... 'F'] = IN_DQ_UCODE2,
  88     },
  89     [IN_DQ_UCODE0] = {
  90         ['0' ... '9'] = IN_DQ_UCODE1,
  91         ['a' ... 'f'] = IN_DQ_UCODE1,
  92         ['A' ... 'F'] = IN_DQ_UCODE1,
  93     },
  94     [IN_DQ_STRING_ESCAPE] = {
  95         ['b'] = IN_DQ_STRING,
  96         ['f'] =  IN_DQ_STRING,
  97         ['n'] =  IN_DQ_STRING,
  98         ['r'] =  IN_DQ_STRING,
  99         ['t'] =  IN_DQ_STRING,
 100         ['/'] = IN_DQ_STRING,
 101         ['\\'] = IN_DQ_STRING,
 102         ['\''] = IN_DQ_STRING,
 103         ['\"'] = IN_DQ_STRING,
 104         ['u'] = IN_DQ_UCODE0,
 105     },
 106     [IN_DQ_STRING] = {
 107         [1 ... 0xFF] = IN_DQ_STRING,
 108         ['\\'] = IN_DQ_STRING_ESCAPE,
 109         ['"'] = IN_DONE_STRING,
 110     },
 111
 112     /* single quote string */
 113     [IN_SQ_UCODE3] = {
 114         ['0' ... '9'] = IN_SQ_STRING,
 115         ['a' ... 'f'] = IN_SQ_STRING,
 116         ['A' ... 'F'] = IN_SQ_STRING,
 117     },
 118     [IN_SQ_UCODE2] = {
 119         ['0' ... '9'] = IN_SQ_UCODE3,
 120         ['a' ... 'f'] = IN_SQ_UCODE3,
 121         ['A' ... 'F'] = IN_SQ_UCODE3,
 122     },
 123     [IN_SQ_UCODE1] = {
 124         ['0' ... '9'] = IN_SQ_UCODE2,
 125         ['a' ... 'f'] = IN_SQ_UCODE2,
 126         ['A' ... 'F'] = IN_SQ_UCODE2,
 127     },
 128     [IN_SQ_UCODE0] = {
 129         ['0' ... '9'] = IN_SQ_UCODE1,
 130         ['a' ... 'f'] = IN_SQ_UCODE1,
 131         ['A' ... 'F'] = IN_SQ_UCODE1,
 132     },
 133     [IN_SQ_STRING_ESCAPE] = {
 134         ['b'] = IN_SQ_STRING,
 135         ['f'] =  IN_SQ_STRING,
 136         ['n'] =  IN_SQ_STRING,
 137         ['r'] =  IN_SQ_STRING,
 138         ['t'] =  IN_SQ_STRING,
 139         ['/'] = IN_DQ_STRING,
 140         ['\\'] = IN_DQ_STRING,
 141         ['\''] = IN_SQ_STRING,
 142         ['\"'] = IN_SQ_STRING,
 143         ['u'] = IN_SQ_UCODE0,
 144     },
 145     [IN_SQ_STRING] = {
 146         [1 ... 0xFF] = IN_SQ_STRING,
 147         ['\\'] = IN_SQ_STRING_ESCAPE,
 148         ['\''] = IN_DONE_STRING,
 149     },
 150
 151     /* Zero */
 152     [IN_ZERO] = {
 153         TERMINAL(JSON_INTEGER),
 154         ['0' ... '9'] = ERROR,
 155         ['.'] = IN_MANTISSA,
 156     },
 157
 158     /* Float */
 159     [IN_DIGITS] = {
 160         TERMINAL(JSON_FLOAT),
 161         ['0' ... '9'] = IN_DIGITS,
 162     },
 163
 164     [IN_DIGIT] = {
 165         ['0' ... '9'] = IN_DIGITS,
 166     },
 167
 168     [IN_EXP_E] = {
 169         ['-'] = IN_DIGIT,
 170         ['+'] = IN_DIGIT,
 171         ['0' ... '9'] = IN_DIGITS,
 172     },
 173
 174     [IN_MANTISSA_DIGITS] = {
 175         TERMINAL(JSON_FLOAT),
 176         ['0' ... '9'] = IN_MANTISSA_DIGITS,
 177         ['e'] = IN_EXP_E,
 178         ['E'] = IN_EXP_E,
 179     },
 180
 181     [IN_MANTISSA] = {
 182         ['0' ... '9'] = IN_MANTISSA_DIGITS,
 183     },
 184
 185     /* Number */
 186     [IN_NONZERO_NUMBER] = {
 187         TERMINAL(JSON_INTEGER),
 188         ['0' ... '9'] = IN_NONZERO_NUMBER,
 189         ['e'] = IN_EXP_E,
 190         ['E'] = IN_EXP_E,
 191         ['.'] = IN_MANTISSA,
 192     },
 193
 194     [IN_NEG_NONZERO_NUMBER] = {
 195         ['0'] = IN_ZERO,
 196         ['1' ... '9'] = IN_NONZERO_NUMBER,
 197     },
 198
 199     /* keywords */
 200     [IN_KEYWORD] = {
 201         TERMINAL(JSON_KEYWORD),
 202         ['a' ... 'z'] = IN_KEYWORD,
 203     },
 204
 205     /* whitespace */
 206     [IN_WHITESPACE] = {
 207         TERMINAL(JSON_SKIP),
 208         [' '] = IN_WHITESPACE,
 209         ['\t'] = IN_WHITESPACE,
 210         ['\r'] = IN_WHITESPACE,
 211         ['\n'] = IN_WHITESPACE,
 212     },
 213
 214     /* operator */
 215     [IN_OPERATOR_DONE] = {
 216         TERMINAL(JSON_OPERATOR),
 217     },
 218
 219     /* escape */
 220     [IN_ESCAPE_DONE] = {
 221         TERMINAL(JSON_ESCAPE),
 222     },
 223
 224     [IN_ESCAPE_LL] = {
 225         ['d'] = IN_ESCAPE_DONE,
 226     },
 227
 228     [IN_ESCAPE_L] = {
 229         ['d'] = IN_ESCAPE_DONE,
 230         ['l'] = IN_ESCAPE_LL,
 231     },
 232
 233     [IN_ESCAPE_I64] = {
 234         ['d'] = IN_ESCAPE_DONE,
 235     },
 236
 237     [IN_ESCAPE_I6] = {
 238         ['4'] = IN_ESCAPE_I64,
 239     },
 240
 241     [IN_ESCAPE_I] = {
 242         ['6'] = IN_ESCAPE_I6,
 243     },
 244
 245     [IN_ESCAPE] = {
 246         ['d'] = IN_ESCAPE_DONE,
 247         ['i'] = IN_ESCAPE_DONE,
 248         ['p'] = IN_ESCAPE_DONE,
 249         ['s'] = IN_ESCAPE_DONE,
 250         ['f'] = IN_ESCAPE_DONE,
 251         ['l'] = IN_ESCAPE_L,
 252         ['I'] = IN_ESCAPE_I,
 253     },
 254
 255     /* top level rule */
 256     [IN_START] = {
 257         ['"'] = IN_DQ_STRING,
 258         ['\''] = IN_SQ_STRING,
 259         ['0'] = IN_ZERO,
 260         ['1' ... '9'] = IN_NONZERO_NUMBER,
 261         ['-'] = IN_NEG_NONZERO_NUMBER,
 262         ['{'] = IN_OPERATOR_DONE,
 263         ['}'] = IN_OPERATOR_DONE,
 264         ['['] = IN_OPERATOR_DONE,
 265         [']'] = IN_OPERATOR_DONE,
 266         [','] = IN_OPERATOR_DONE,
 267         [':'] = IN_OPERATOR_DONE,
 268         ['a' ... 'z'] = IN_KEYWORD,
 269         ['%'] = IN_ESCAPE,
 270         [' '] = IN_WHITESPACE,
 271         ['\t'] = IN_WHITESPACE,
 272         ['\r'] = IN_WHITESPACE,
 273         ['\n'] = IN_WHITESPACE,
 274     },
 275 };
 276
 277 void json_lexer_init(JSONLexer *lexer, JSONLexerEmitter func)
 278 {
 279     lexer->emit = func;
 280     lexer->state = IN_START;
 281     lexer->token = qstring_new();
 282     lexer->x = lexer->y = 0;
 283 }
 284
 285 static int json_lexer_feed_char(JSONLexer *lexer, char ch)
 286 {
 287     char buf[2];
 288
 289     lexer->x++;
 290     if (ch == '\n') {
 291         lexer->x = 0;
 292         lexer->y++;
 293     }
 294
 295     lexer->state = json_lexer[lexer->state][(uint8_t)ch];
 296
 297     switch (lexer->state) {
 298     case JSON_OPERATOR:
 299     case JSON_ESCAPE:
 300     case JSON_INTEGER:
 301     case JSON_FLOAT:
 302     case JSON_KEYWORD:
 303     case JSON_STRING:
 304         lexer->emit(lexer, lexer->token, lexer->state, lexer->x, lexer->y);
 305     case JSON_SKIP:
 306         lexer->state = json_lexer[IN_START][(uint8_t)ch];
 307         QDECREF(lexer->token);
 308         lexer->token = qstring_new();
 309         break;
 310     case ERROR:
 311         return -EINVAL;
 312     default:
 313         break;
 314     }
 315
 316     buf[0] = ch;
 317     buf[1] = 0;
 318
 319     qstring_append(lexer->token, buf);
 320
 321     return 0;
 322 }
 323
 324 int json_lexer_feed(JSONLexer *lexer, const char *buffer, size_t size)
 325 {
 326     size_t i;
 327
 328     for (i = 0; i < size; i++) {
 329         int err;
 330
 331         err = json_lexer_feed_char(lexer, buffer[i]);
 332         if (err < 0) {
 333             return err;
 334         }
 335     }
 336
 337     return 0;
 338 }
 339
 340 int json_lexer_flush(JSONLexer *lexer)
 341 {
 342     return json_lexer_feed_char(lexer, 0);
 343 }
 344
 345 void json_lexer_destroy(JSONLexer *lexer)
 346 {
 347     QDECREF(lexer->token);
 348 }