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         ['u'] = IN_DQ_UCODE0,
 103     },
 104     [IN_DQ_STRING] = {
 105         [1 ... 0xFF] = IN_DQ_STRING,
 106         ['\\'] = IN_DQ_STRING_ESCAPE,
 107         ['"'] = IN_DONE_STRING,
 108     },
 109
 110     /* single quote string */
 111     [IN_SQ_UCODE3] = {
 112         ['0' ... '9'] = IN_SQ_STRING,
 113         ['a' ... 'f'] = IN_SQ_STRING,
 114         ['A' ... 'F'] = IN_SQ_STRING,
 115     },
 116     [IN_SQ_UCODE2] = {
 117         ['0' ... '9'] = IN_SQ_UCODE3,
 118         ['a' ... 'f'] = IN_SQ_UCODE3,
 119         ['A' ... 'F'] = IN_SQ_UCODE3,
 120     },
 121     [IN_SQ_UCODE1] = {
 122         ['0' ... '9'] = IN_SQ_UCODE2,
 123         ['a' ... 'f'] = IN_SQ_UCODE2,
 124         ['A' ... 'F'] = IN_SQ_UCODE2,
 125     },
 126     [IN_SQ_UCODE0] = {
 127         ['0' ... '9'] = IN_SQ_UCODE1,
 128         ['a' ... 'f'] = IN_SQ_UCODE1,
 129         ['A' ... 'F'] = IN_SQ_UCODE1,
 130     },
 131     [IN_SQ_STRING_ESCAPE] = {
 132         ['b'] = IN_SQ_STRING,
 133         ['f'] =  IN_SQ_STRING,
 134         ['n'] =  IN_SQ_STRING,
 135         ['r'] =  IN_SQ_STRING,
 136         ['t'] =  IN_SQ_STRING,
 137         ['\''] = IN_SQ_STRING,
 138         ['\"'] = IN_SQ_STRING,
 139         ['u'] = IN_SQ_UCODE0,
 140     },
 141     [IN_SQ_STRING] = {
 142         [1 ... 0xFF] = IN_SQ_STRING,
 143         ['\\'] = IN_SQ_STRING_ESCAPE,
 144         ['\''] = IN_DONE_STRING,
 145     },
 146
 147     /* Zero */
 148     [IN_ZERO] = {
 149         TERMINAL(JSON_INTEGER),
 150         ['0' ... '9'] = ERROR,
 151         ['.'] = IN_MANTISSA,
 152     },
 153
 154     /* Float */
 155     [IN_DIGITS] = {
 156         TERMINAL(JSON_FLOAT),
 157         ['0' ... '9'] = IN_DIGITS,
 158     },
 159
 160     [IN_DIGIT] = {
 161         ['0' ... '9'] = IN_DIGITS,
 162     },
 163
 164     [IN_EXP_E] = {
 165         ['-'] = IN_DIGIT,
 166         ['+'] = IN_DIGIT,
 167         ['0' ... '9'] = IN_DIGITS,
 168     },
 169
 170     [IN_MANTISSA_DIGITS] = {
 171         TERMINAL(JSON_FLOAT),
 172         ['0' ... '9'] = IN_MANTISSA_DIGITS,
 173         ['e'] = IN_EXP_E,
 174         ['E'] = IN_EXP_E,
 175     },
 176
 177     [IN_MANTISSA] = {
 178         ['0' ... '9'] = IN_MANTISSA_DIGITS,
 179     },
 180
 181     /* Number */
 182     [IN_NONZERO_NUMBER] = {
 183         TERMINAL(JSON_INTEGER),
 184         ['0' ... '9'] = IN_NONZERO_NUMBER,
 185         ['e'] = IN_EXP_E,
 186         ['E'] = IN_EXP_E,
 187         ['.'] = IN_MANTISSA,
 188     },
 189
 190     [IN_NEG_NONZERO_NUMBER] = {
 191         ['0'] = IN_ZERO,
 192         ['1' ... '9'] = IN_NONZERO_NUMBER,
 193     },
 194
 195     /* keywords */
 196     [IN_KEYWORD] = {
 197         TERMINAL(JSON_KEYWORD),
 198         ['a' ... 'z'] = IN_KEYWORD,
 199     },
 200
 201     /* whitespace */
 202     [IN_WHITESPACE] = {
 203         TERMINAL(JSON_SKIP),
 204         [' '] = IN_WHITESPACE,
 205         ['\t'] = IN_WHITESPACE,
 206         ['\r'] = IN_WHITESPACE,
 207         ['\n'] = IN_WHITESPACE,
 208     },
 209
 210     /* operator */
 211     [IN_OPERATOR_DONE] = {
 212         TERMINAL(JSON_OPERATOR),
 213     },
 214
 215     /* escape */
 216     [IN_ESCAPE_DONE] = {
 217         TERMINAL(JSON_ESCAPE),
 218     },
 219
 220     [IN_ESCAPE_LL] = {
 221         ['d'] = IN_ESCAPE_DONE,
 222     },
 223
 224     [IN_ESCAPE_L] = {
 225         ['d'] = IN_ESCAPE_DONE,
 226         ['l'] = IN_ESCAPE_LL,
 227     },
 228
 229     [IN_ESCAPE_I64] = {
 230         ['d'] = IN_ESCAPE_DONE,
 231     },
 232
 233     [IN_ESCAPE_I6] = {
 234         ['4'] = IN_ESCAPE_I64,
 235     },
 236
 237     [IN_ESCAPE_I] = {
 238         ['6'] = IN_ESCAPE_I6,
 239     },
 240
 241     [IN_ESCAPE] = {
 242         ['d'] = IN_ESCAPE_DONE,
 243         ['i'] = IN_ESCAPE_DONE,
 244         ['p'] = IN_ESCAPE_DONE,
 245         ['s'] = IN_ESCAPE_DONE,
 246         ['f'] = IN_ESCAPE_DONE,
 247         ['l'] = IN_ESCAPE_L,
 248         ['I'] = IN_ESCAPE_I,
 249     },
 250
 251     /* top level rule */
 252     [IN_START] = {
 253         ['"'] = IN_DQ_STRING,
 254         ['\''] = IN_SQ_STRING,
 255         ['0'] = IN_ZERO,
 256         ['1' ... '9'] = IN_NONZERO_NUMBER,
 257         ['-'] = IN_NEG_NONZERO_NUMBER,
 258         ['{'] = IN_OPERATOR_DONE,
 259         ['}'] = IN_OPERATOR_DONE,
 260         ['['] = IN_OPERATOR_DONE,
 261         [']'] = IN_OPERATOR_DONE,
 262         [','] = IN_OPERATOR_DONE,
 263         [':'] = IN_OPERATOR_DONE,
 264         ['a' ... 'z'] = IN_KEYWORD,
 265         ['%'] = IN_ESCAPE,
 266         [' '] = IN_WHITESPACE,
 267         ['\t'] = IN_WHITESPACE,
 268         ['\r'] = IN_WHITESPACE,
 269         ['\n'] = IN_WHITESPACE,
 270     },
 271 };
 272
 273 void json_lexer_init(JSONLexer *lexer, JSONLexerEmitter func)
 274 {
 275     lexer->emit = func;
 276     lexer->state = IN_START;
 277     lexer->token = qstring_new();
 278 }
 279
 280 static int json_lexer_feed_char(JSONLexer *lexer, char ch)
 281 {
 282     char buf[2];
 283
 284     lexer->x++;
 285     if (ch == '\n') {
 286         lexer->x = 0;
 287         lexer->y++;
 288     }
 289
 290     lexer->state = json_lexer[lexer->state][(uint8_t)ch];
 291
 292     switch (lexer->state) {
 293     case JSON_OPERATOR:
 294     case JSON_ESCAPE:
 295     case JSON_INTEGER:
 296     case JSON_FLOAT:
 297     case JSON_KEYWORD:
 298     case JSON_STRING:
 299         lexer->emit(lexer, lexer->token, lexer->state, lexer->x, lexer->y);
 300     case JSON_SKIP:
 301         lexer->state = json_lexer[IN_START][(uint8_t)ch];
 302         QDECREF(lexer->token);
 303         lexer->token = qstring_new();
 304         break;
 305     case ERROR:
 306         return -EINVAL;
 307     default:
 308         break;
 309     }
 310
 311     buf[0] = ch;
 312     buf[1] = 0;
 313
 314     qstring_append(lexer->token, buf);
 315
 316     return 0;
 317 }
 318
 319 int json_lexer_feed(JSONLexer *lexer, const char *buffer, size_t size)
 320 {
 321     size_t i;
 322
 323     for (i = 0; i < size; i++) {
 324         int err;
 325
 326         err = json_lexer_feed_char(lexer, buffer[i]);
 327         if (err < 0) {
 328             return err;
 329         }
 330     }
 331
 332     return 0;
 333 }
 334
 335 int json_lexer_flush(JSONLexer *lexer)
 336 {
 337     return json_lexer_feed_char(lexer, 0);
 338 }
 339
 340 void json_lexer_destroy(JSONLexer *lexer)
 341 {
 342     QDECREF(lexer->token);
 343 }