/src/json-c/json_tokener.c

Source
/*
 * $Id: json_tokener.c,v 1.20 2006/07/25 03:24:50 mclark Exp $
 *
 * Copyright (c) 2004, 2005 Metaparadigm Pte. Ltd.
 * Michael Clark <michael@metaparadigm.com>
 *
 * This library is free software; you can redistribute it and/or modify
 * it under the terms of the MIT license. See COPYING for details.
 *
 *
 * Copyright (c) 2008-2009 Yahoo! Inc.  All rights reserved.
 * The copyrights to the contents of this file are licensed under the MIT License
 * (https://www.opensource.org/licenses/mit-license.php)
 */

#include "config.h"

#include "math_compat.h"
#include <assert.h>
#include <errno.h>
#include <limits.h>
#include <math.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "debug.h"
#include "json_inttypes.h"
#include "json_object.h"
#include "json_object_private.h"
#include "json_tokener.h"
#include "json_util.h"
#include "printbuf.h"
#include "strdup_compat.h"

#ifdef HAVE_LOCALE_H
#include <locale.h>
#endif /* HAVE_LOCALE_H */
#ifdef HAVE_XLOCALE_H
#include <xlocale.h>
#endif
#ifdef HAVE_STRINGS_H
#include <strings.h>
#endif /* HAVE_STRINGS_H */

#define jt_hexdigit(x) (((x) <= '9') ? (x) - '0' : ((x)&7) + 9)

#if !HAVE_STRNCASECMP && defined(_WIN32)
/* MSC has the version as _strnicmp */
#define strncasecmp _strnicmp
#elif !HAVE_STRNCASECMP
#error You do not have strncasecmp on your system.
#endif /* HAVE_STRNCASECMP */

#if defined(_MSC_VER) && (_MSC_VER <= 1800)
/* VS2013 doesn't know about "inline" */
#define inline __inline
#elif defined(AIX_CC)
#define inline
#endif

/* The following helper functions are used to speed up parsing. They
 * are faster than their ctype counterparts because they assume that
 * the input is in ASCII and that the locale is set to "C". The
 * compiler will also inline these functions, providing an additional
 * speedup by saving on function calls.
 */
static inline int is_ws_char(char c)
{
  return c == ' '
      || c == '\t'
      || c == '\n'
      || c == '\r';
}

static inline int is_hex_char(char c)
{
  return (c >= '0' && c <= '9')
      || (c >= 'A' && c <= 'F')
      || (c >= 'a' && c <= 'f');
}

/* Use C99 NAN by default; if not available, nan("") should work too. */
#ifndef NAN
#define NAN nan("")
#endif /* !NAN */

static const char json_null_str[] = "null";
static const int json_null_str_len = sizeof(json_null_str) - 1;
static const char json_inf_str[] = "Infinity";
/* Swapped case "Infinity" to avoid need to call tolower() on input chars: */
static const char json_inf_str_invert[] = "iNFINITY";
static const unsigned int json_inf_str_len = sizeof(json_inf_str) - 1;
static const char json_nan_str[] = "NaN";
static const int json_nan_str_len = sizeof(json_nan_str) - 1;
static const char json_true_str[] = "true";
static const int json_true_str_len = sizeof(json_true_str) - 1;
static const char json_false_str[] = "false";
static const int json_false_str_len = sizeof(json_false_str) - 1;

/* clang-format off */
static const char *json_tokener_errors[] = {
  "success",
  "continue",
  "nesting too deep",
  "unexpected end of data",
  "unexpected character",
  "null expected",
  "boolean expected",
  "number expected",
  "array value separator ',' expected",
  "quoted object property name expected",
  "object property name separator ':' expected",
  "object value separator ',' expected",
  "invalid string sequence",
  "expected comment",
  "invalid utf-8 string",
  "buffer size overflow",
  "out of memory"
};
/* clang-format on */

/**
 * validete the utf-8 string in strict model.
 * if not utf-8 format, return err.
 */
static json_bool json_tokener_validate_utf8(const char c, unsigned int *nBytes);

static int json_tokener_parse_double(const char *buf, int len, double *retval);

const char *json_tokener_error_desc(enum json_tokener_error jerr)
{
  int jerr_int = (int)jerr;
  if (jerr_int < 0 ||
      jerr_int >= (int)(sizeof(json_tokener_errors) / sizeof(json_tokener_errors[0])))
    return "Unknown error, "
           "invalid json_tokener_error value passed to json_tokener_error_desc()";
  return json_tokener_errors[jerr];
}

enum json_tokener_error json_tokener_get_error(struct json_tokener *tok)
{
  return tok->err;
}

/* Stuff for decoding unicode sequences */
#define IS_HIGH_SURROGATE(uc) (((uc)&0xFFFFFC00) == 0xD800)
#define IS_LOW_SURROGATE(uc) (((uc)&0xFFFFFC00) == 0xDC00)
#define DECODE_SURROGATE_PAIR(hi, lo) ((((hi)&0x3FF) << 10) + ((lo)&0x3FF) + 0x10000)
static unsigned char utf8_replacement_char[3] = {0xEF, 0xBF, 0xBD};

struct json_tokener *json_tokener_new_ex(int depth)
{
  struct json_tokener *tok;

  if (depth < 1)
    return NULL;

  tok = (struct json_tokener *)calloc(1, sizeof(struct json_tokener));
  if (!tok)
    return NULL;
  tok->stack = (struct json_tokener_srec *)calloc(depth, sizeof(struct json_tokener_srec));
  if (!tok->stack)
  {
    free(tok);
    return NULL;
  }
  tok->pb = printbuf_new();
  if (!tok->pb)
  {
    free(tok->stack);
    free(tok);
    return NULL;
  }
  tok->max_depth = depth;
  json_tokener_reset(tok);
  return tok;
}

struct json_tokener *json_tokener_new(void)
{
  return json_tokener_new_ex(JSON_TOKENER_DEFAULT_DEPTH);
}

void json_tokener_free(struct json_tokener *tok)
{
  if (!tok)
    return;
  json_tokener_reset(tok);
  if (tok->pb)
    printbuf_free(tok->pb);
  free(tok->stack);
  free(tok);
}

static void json_tokener_reset_level(struct json_tokener *tok, int depth)
{
  tok->stack[depth].state = json_tokener_state_eatws;
  tok->stack[depth].saved_state = json_tokener_state_start;
  json_object_put(tok->stack[depth].current);
  tok->stack[depth].current = NULL;
  free(tok->stack[depth].obj_field_name);
  tok->stack[depth].obj_field_name = NULL;
}

void json_tokener_reset(struct json_tokener *tok)
{
  int i;
  if (!tok)
    return;

  for (i = tok->depth; i >= 0; i--)
    json_tokener_reset_level(tok, i);
  tok->depth = 0;
  tok->err = json_tokener_success;
}

struct json_object *json_tokener_parse(const char *str)
{
  enum json_tokener_error jerr_ignored;
  struct json_object *obj;
  obj = json_tokener_parse_verbose(str, &jerr_ignored);
  return obj;
}

struct json_object *json_tokener_parse_verbose(const char *str, enum json_tokener_error *error)
{
  struct json_tokener *tok;
  struct json_object *obj;

  tok = json_tokener_new();
  if (!tok)
  {
    *error = json_tokener_error_memory;
    return NULL;
  }
  obj = json_tokener_parse_ex(tok, str, -1);
  *error = tok->err;
  if (tok->err != json_tokener_success
#if 0
    /* This would be a more sensible default, and cause parsing
     * things like "null123" to fail when the caller can't know
     * where the parsing left off, but starting to fail would
     * be a notable behaviour change.  Save for a 1.0 release.
     */
      || json_tokener_get_parse_end(tok) != strlen(str)
#endif
  )

  {
    if (obj != NULL)
      json_object_put(obj);
    obj = NULL;
  }

  json_tokener_free(tok);
  return obj;
}

#define state tok->stack[tok->depth].state
#define saved_state tok->stack[tok->depth].saved_state
#define current tok->stack[tok->depth].current
#define obj_field_name tok->stack[tok->depth].obj_field_name

/* Optimization:
 * json_tokener_parse_ex() consumed a lot of CPU in its main loop,
 * iterating character-by character.  A large performance boost is
 * achieved by using tighter loops to locally handle units such as
 * comments and strings.  Loops that handle an entire token within
 * their scope also gather entire strings and pass them to
 * printbuf_memappend() in a single call, rather than calling
 * printbuf_memappend() one char at a time.
 *
 * PEEK_CHAR() and ADVANCE_CHAR() macros are used for code that is
 * common to both the main loop and the tighter loops.
 */

/* PEEK_CHAR(dest, tok) macro:
 *   Peeks at the current char and stores it in dest.
 *   Returns 1 on success, sets tok->err and returns 0 if no more chars.
 *   Implicit inputs:  str, len, nBytesp vars
 */
#define PEEK_CHAR(dest, tok)                                                 \
  (((tok)->char_offset == len)                                         \
       ? (((tok)->depth == 0 && state == json_tokener_state_eatws &&   \
           saved_state == json_tokener_state_finish)                   \
              ? (((tok)->err = json_tokener_success), 0)               \
              : (((tok)->err = json_tokener_continue), 0))             \
       : (((tok->flags & JSON_TOKENER_VALIDATE_UTF8) &&                \
           (!json_tokener_validate_utf8(*str, nBytesp)))               \
              ? ((tok->err = json_tokener_error_parse_utf8_string), 0) \
              : (((dest) = *str), 1)))

/* ADVANCE_CHAR() macro:
 *   Increments str & tok->char_offset.
 *   For convenience of existing conditionals, returns the old value of c (0 on eof).
 *   Implicit inputs:  c var
 */
#define ADVANCE_CHAR(str, tok) (++(str), ((tok)->char_offset)++, c)

/* printbuf_memappend_checked(p, s, l) macro:
 *   Add string s of length l to printbuffer p.
 *   If operation fails abort parse operation with memory error.
 */
#define printbuf_memappend_checked(p, s, l)                   \
  do {                                                  \
    if (printbuf_memappend((p), (s), (l)) < 0)    \
    {                                             \
      tok->err = json_tokener_error_memory; \
      goto out;                             \
    }                                             \
  } while (0)

/* End optimization macro defs */

struct json_object *json_tokener_parse_ex(struct json_tokener *tok, const char *str, int len)
{
  struct json_object *obj = NULL;
  char c = '\1';
  unsigned int nBytes = 0;
  unsigned int *nBytesp = &nBytes;

#ifdef HAVE_USELOCALE
  locale_t oldlocale = uselocale(NULL);
  locale_t newloc;
#elif defined(HAVE_SETLOCALE)
  char *oldlocale = NULL;
#endif

  tok->char_offset = 0;
  tok->err = json_tokener_success;

  /* this interface is presently not 64-bit clean due to the int len argument
   * and the internal printbuf interface that takes 32-bit int len arguments
   * so the function limits the maximum string size to INT32_MAX (2GB).
   * If the function is called with len == -1 then strlen is called to check
   * the string length is less than INT32_MAX (2GB)
   */
  if ((len < -1) || (len == -1 && strlen(str) > INT32_MAX))
  {
    tok->err = json_tokener_error_size;
    return NULL;
  }

#ifdef HAVE_USELOCALE
  {
#ifdef HAVE_DUPLOCALE
    locale_t duploc = duplocale(oldlocale);
    if (duploc == NULL && errno == ENOMEM)
    {
      tok->err = json_tokener_error_memory;
      return NULL;
    }
    newloc = newlocale(LC_NUMERIC_MASK, "C", duploc);
#else
    newloc = newlocale(LC_NUMERIC_MASK, "C", oldlocale);
#endif
    if (newloc == NULL)
    {
      tok->err = json_tokener_error_memory;
#ifdef HAVE_DUPLOCALE
      freelocale(duploc);
#endif
      return NULL;
    }
#ifdef NEWLOCALE_NEEDS_FREELOCALE
#ifdef HAVE_DUPLOCALE
    // Older versions of FreeBSD (<12.4) don't free the locale
    // passed to newlocale(), so do it here
    freelocale(duploc);
#endif
#endif
    uselocale(newloc);
  }
#elif defined(HAVE_SETLOCALE)
  {
    char *tmplocale;
    tmplocale = setlocale(LC_NUMERIC, NULL);
    if (tmplocale)
    {
      oldlocale = strdup(tmplocale);
      if (oldlocale == NULL)
      {
        tok->err = json_tokener_error_memory;
        return NULL;
      }
    }
    setlocale(LC_NUMERIC, "C");
  }
#endif

  while (PEEK_CHAR(c, tok)) // Note: c might be '\0' !
  {

  redo_char:
    switch (state)
    {

    case json_tokener_state_eatws:
      /* Advance until we change state */
      while (is_ws_char(c))
      {
        if ((!ADVANCE_CHAR(str, tok)) || (!PEEK_CHAR(c, tok)))
          goto out;
      }
      if (c == '/' && !(tok->flags & JSON_TOKENER_STRICT))
      {
        printbuf_reset(tok->pb);
        printbuf_memappend_checked(tok->pb, &c, 1);
        state = json_tokener_state_comment_start;
      }
      else
      {
        state = saved_state;
        goto redo_char;
      }
      break;

    case json_tokener_state_start:
      switch (c)
      {
      case '{':
        state = json_tokener_state_eatws;
        saved_state = json_tokener_state_object_field_start;
        current = json_object_new_object();
        if (current == NULL)
        {
          tok->err = json_tokener_error_memory;
          goto out;
        }
        break;
      case '[':
        state = json_tokener_state_eatws;
        saved_state = json_tokener_state_array;
        current = json_object_new_array();
        if (current == NULL)
        {
          tok->err = json_tokener_error_memory;
          goto out;
        }
        break;
      case 'I':
      case 'i':
        state = json_tokener_state_inf;
        printbuf_reset(tok->pb);
        tok->st_pos = 0;
        goto redo_char;
      case 'N':
      case 'n':
        state = json_tokener_state_null; // or NaN
        printbuf_reset(tok->pb);
        tok->st_pos = 0;
        goto redo_char;
      case '\'':
        if (tok->flags & JSON_TOKENER_STRICT)
        {
          /* in STRICT mode only double-quote are allowed */
          tok->err = json_tokener_error_parse_unexpected;
          goto out;
        }
        /* FALLTHRU */
      case '"':
        state = json_tokener_state_string;
        printbuf_reset(tok->pb);
        tok->quote_char = c;
        break;
      case 'T':
      case 't':
      case 'F':
      case 'f':
        state = json_tokener_state_boolean;
        printbuf_reset(tok->pb);
        tok->st_pos = 0;
        goto redo_char;
      case '0':
      case '1':
      case '2':
      case '3':
      case '4':
      case '5':
      case '6':
      case '7':
      case '8':
      case '9':
      case '-':
        state = json_tokener_state_number;
        printbuf_reset(tok->pb);
        tok->is_double = 0;
        goto redo_char;
      default: tok->err = json_tokener_error_parse_unexpected; goto out;
      }
      break;

    case json_tokener_state_finish:
      if (tok->depth == 0)
        goto out;
      obj = json_object_get(current);
      json_tokener_reset_level(tok, tok->depth);
      tok->depth--;
      goto redo_char;

    case json_tokener_state_inf: /* aka starts with 'i' (or 'I', or "-i", or "-I") */
    {
      /* If we were guaranteed to have len set, then we could (usually) handle
       * the entire "Infinity" check in a single strncmp (strncasecmp), but
       * since len might be -1 (i.e. "read until \0"), we need to check it
       * a character at a time.
       * Trying to handle it both ways would make this code considerably more
       * complicated with likely little performance benefit.
       */
      int is_negative = 0;

      /* Note: tok->st_pos must be 0 when state is set to json_tokener_state_inf */
      while (tok->st_pos < (int)json_inf_str_len)
      {
        char inf_char = *str;
        if (inf_char != json_inf_str[tok->st_pos] &&
            ((tok->flags & JSON_TOKENER_STRICT) ||
              inf_char != json_inf_str_invert[tok->st_pos])
           )
        {
          tok->err = json_tokener_error_parse_unexpected;
          goto out;
        }
        tok->st_pos++;
        (void)ADVANCE_CHAR(str, tok);
        if (!PEEK_CHAR(c, tok))
        {
          /* out of input chars, for now at least */
          goto out;
        }
      }
      /* We checked the full length of "Infinity", so create the object.
       * When handling -Infinity, the number parsing code will have dropped
       * the "-" into tok->pb for us, so check it now.
       */
      if (printbuf_length(tok->pb) > 0 && *(tok->pb->buf) == '-')
      {
        is_negative = 1;
      }
      current = json_object_new_double(is_negative ? -INFINITY : INFINITY);
      if (current == NULL)
      {
        tok->err = json_tokener_error_memory;
        goto out;
      }
      saved_state = json_tokener_state_finish;
      state = json_tokener_state_eatws;
      goto redo_char;
    }
    break;
    case json_tokener_state_null: /* aka starts with 'n' */
    {
      int size;
      int size_nan;
      printbuf_memappend_checked(tok->pb, &c, 1);
      size = json_min(tok->st_pos + 1, json_null_str_len);
      size_nan = json_min(tok->st_pos + 1, json_nan_str_len);
      if ((!(tok->flags & JSON_TOKENER_STRICT) &&
           strncasecmp(json_null_str, tok->pb->buf, size) == 0) ||
          (strncmp(json_null_str, tok->pb->buf, size) == 0))
      {
        if (tok->st_pos == json_null_str_len)
        {
          current = NULL;
          saved_state = json_tokener_state_finish;
          state = json_tokener_state_eatws;
          goto redo_char;
        }
      }
      else if ((!(tok->flags & JSON_TOKENER_STRICT) &&
                strncasecmp(json_nan_str, tok->pb->buf, size_nan) == 0) ||
               (strncmp(json_nan_str, tok->pb->buf, size_nan) == 0))
      {
        if (tok->st_pos == json_nan_str_len)
        {
          current = json_object_new_double(NAN);
          if (current == NULL)
          {
            tok->err = json_tokener_error_memory;
            goto out;
          }
          saved_state = json_tokener_state_finish;
          state = json_tokener_state_eatws;
          goto redo_char;
        }
      }
      else
      {
        tok->err = json_tokener_error_parse_null;
        goto out;
      }
      tok->st_pos++;
    }
    break;

    case json_tokener_state_comment_start:
      if (c == '*')
      {
        state = json_tokener_state_comment;
      }
      else if (c == '/')
      {
        state = json_tokener_state_comment_eol;
      }
      else
      {
        tok->err = json_tokener_error_parse_comment;
        goto out;
      }
      printbuf_memappend_checked(tok->pb, &c, 1);
      break;

    case json_tokener_state_comment:
    {
      /* Advance until we change state */
      const char *case_start = str;
      while (c != '*')
      {
        if (!ADVANCE_CHAR(str, tok) || !PEEK_CHAR(c, tok))
        {
          printbuf_memappend_checked(tok->pb, case_start,
                                     str - case_start);
          goto out;
        }
      }
      printbuf_memappend_checked(tok->pb, case_start, 1 + str - case_start);
      state = json_tokener_state_comment_end;
    }
    break;

    case json_tokener_state_comment_eol:
    {
      /* Advance until we change state */
      const char *case_start = str;
      while (c != '\n')
      {
        if (!ADVANCE_CHAR(str, tok) || !PEEK_CHAR(c, tok))
        {
          printbuf_memappend_checked(tok->pb, case_start,
                                     str - case_start);
          goto out;
        }
      }
      printbuf_memappend_checked(tok->pb, case_start, str - case_start);
      MC_DEBUG("json_tokener_comment: %s\n", tok->pb->buf);
      state = json_tokener_state_eatws;
    }
    break;

    case json_tokener_state_comment_end:
      printbuf_memappend_checked(tok->pb, &c, 1);
      if (c == '/')
      {
        MC_DEBUG("json_tokener_comment: %s\n", tok->pb->buf);
        state = json_tokener_state_eatws;
      }
      else
      {
        state = json_tokener_state_comment;
      }
      break;

    case json_tokener_state_string:
    {
      /* Advance until we change state */
      const char *case_start = str;
      while (1)
      {
        if (c == tok->quote_char)
        {
          printbuf_memappend_checked(tok->pb, case_start,
                                     str - case_start);
          current =
              json_object_new_string_len(tok->pb->buf, tok->pb->bpos);
          if (current == NULL)
          {
            tok->err = json_tokener_error_memory;
            goto out;
          }
          saved_state = json_tokener_state_finish;
          state = json_tokener_state_eatws;
          break;
        }
        else if (c == '\\')
        {
          printbuf_memappend_checked(tok->pb, case_start,
                                     str - case_start);
          saved_state = json_tokener_state_string;
          state = json_tokener_state_string_escape;
          break;
        }
        else if ((tok->flags & JSON_TOKENER_STRICT) && (unsigned char)c <= 0x1f)
        {
          // Disallow control characters in strict mode
          tok->err = json_tokener_error_parse_string;
          goto out;
        }
        if (!ADVANCE_CHAR(str, tok) || !PEEK_CHAR(c, tok))
        {
          printbuf_memappend_checked(tok->pb, case_start,
                                     str - case_start);
          goto out;
        }
      }
    }
    break;

    case json_tokener_state_string_escape:
      switch (c)
      {
      case '"':
      case '\\':
      case '/':
        printbuf_memappend_checked(tok->pb, &c, 1);
        state = saved_state;
        break;
      case 'b':
      case 'n':
      case 'r':
      case 't':
      case 'f':
        if (c == 'b')
          printbuf_memappend_checked(tok->pb, "\b", 1);
        else if (c == 'n')
          printbuf_memappend_checked(tok->pb, "\n", 1);
        else if (c == 'r')
          printbuf_memappend_checked(tok->pb, "\r", 1);
        else if (c == 't')
          printbuf_memappend_checked(tok->pb, "\t", 1);
        else if (c == 'f')
          printbuf_memappend_checked(tok->pb, "\f", 1);
        state = saved_state;
        break;
      case 'u':
        tok->ucs_char = 0;
        tok->st_pos = 0;
        state = json_tokener_state_escape_unicode;
        break;
      default: tok->err = json_tokener_error_parse_string; goto out;
      }
      break;

      // ===================================================

    case json_tokener_state_escape_unicode:
    {
      /* Handle a 4-byte \uNNNN sequence, or two sequences if a surrogate pair */
      while (1)
      {
        if (!c || !is_hex_char(c))
        {
          tok->err = json_tokener_error_parse_string;
          goto out;
        }
        tok->ucs_char |=
            ((unsigned int)jt_hexdigit(c) << ((3 - tok->st_pos) * 4));
        tok->st_pos++;
        if (tok->st_pos >= 4)
          break;

        (void)ADVANCE_CHAR(str, tok);
        if (!PEEK_CHAR(c, tok))
        {
          /*
           * We're out of characters in the current call to
           * json_tokener_parse(), but a subsequent call might
           * provide us with more, so leave our current state
           * as-is (including tok->high_surrogate) and return.
           */
          goto out;
        }
      }
      tok->st_pos = 0;

      /* Now, we have a full \uNNNN sequence in tok->ucs_char */

      /* If the *previous* sequence was a high surrogate ... */
      if (tok->high_surrogate)
      {
        if (IS_LOW_SURROGATE(tok->ucs_char))
        {
          /* Recalculate the ucs_char, then fall thru to process normally */
          tok->ucs_char = DECODE_SURROGATE_PAIR(tok->high_surrogate,
                                                tok->ucs_char);
        }
        else
        {
          /* High surrogate was not followed by a low surrogate
           * Replace the high and process the rest normally
           */
          printbuf_memappend_checked(tok->pb,
                                     (char *)utf8_replacement_char, 3);
        }
        tok->high_surrogate = 0;
      }

      if (tok->ucs_char < 0x80)
      {
        unsigned char unescaped_utf[1];
        unescaped_utf[0] = tok->ucs_char;
        printbuf_memappend_checked(tok->pb, (char *)unescaped_utf, 1);
      }
      else if (tok->ucs_char < 0x800)
      {
        unsigned char unescaped_utf[2];
        unescaped_utf[0] = 0xc0 | (tok->ucs_char >> 6);
        unescaped_utf[1] = 0x80 | (tok->ucs_char & 0x3f);
        printbuf_memappend_checked(tok->pb, (char *)unescaped_utf, 2);
      }
      else if (IS_HIGH_SURROGATE(tok->ucs_char))
      {
        /*
         * The next two characters should be \u, HOWEVER,
         * we can't simply peek ahead here, because the
         * characters we need might not be passed to us
         * until a subsequent call to json_tokener_parse.
         * Instead, transition through a couple of states.
         * (now):
         *   _escape_unicode => _unicode_need_escape
         * (see a '\\' char):
         *   _unicode_need_escape => _unicode_need_u
         * (see a 'u' char):
         *   _unicode_need_u => _escape_unicode
         *      ...and we'll end up back around here.
         */
        tok->high_surrogate = tok->ucs_char;
        tok->ucs_char = 0;
        state = json_tokener_state_escape_unicode_need_escape;
        break;
      }
      else if (IS_LOW_SURROGATE(tok->ucs_char))
      {
        /* Got a low surrogate not preceded by a high */
        printbuf_memappend_checked(tok->pb, (char *)utf8_replacement_char, 3);
      }
      else if (tok->ucs_char < 0x10000)
      {
        unsigned char unescaped_utf[3];
        unescaped_utf[0] = 0xe0 | (tok->ucs_char >> 12);
        unescaped_utf[1] = 0x80 | ((tok->ucs_char >> 6) & 0x3f);
        unescaped_utf[2] = 0x80 | (tok->ucs_char & 0x3f);
        printbuf_memappend_checked(tok->pb, (char *)unescaped_utf, 3);
      }
      else if (tok->ucs_char < 0x110000)
      {
        unsigned char unescaped_utf[4];
        unescaped_utf[0] = 0xf0 | ((tok->ucs_char >> 18) & 0x07);
        unescaped_utf[1] = 0x80 | ((tok->ucs_char >> 12) & 0x3f);
        unescaped_utf[2] = 0x80 | ((tok->ucs_char >> 6) & 0x3f);
        unescaped_utf[3] = 0x80 | (tok->ucs_char & 0x3f);
        printbuf_memappend_checked(tok->pb, (char *)unescaped_utf, 4);
      }
      else
      {
        /* Don't know what we got--insert the replacement char */
        printbuf_memappend_checked(tok->pb, (char *)utf8_replacement_char, 3);
      }
      state = saved_state; // i.e. _state_string or _state_object_field
    }
    break;

    case json_tokener_state_escape_unicode_need_escape:
      // We get here after processing a high_surrogate
      // require a '\\' char
      if (!c || c != '\\')
      {
        /* Got a high surrogate without another sequence following
         * it.  Put a replacement char in for the high surrogate
         * and pop back up to _state_string or _state_object_field.
         */
        printbuf_memappend_checked(tok->pb, (char *)utf8_replacement_char, 3);
        tok->high_surrogate = 0;
        tok->ucs_char = 0;
        tok->st_pos = 0;
        state = saved_state;
        goto redo_char;
      }
      state = json_tokener_state_escape_unicode_need_u;
      break;

    case json_tokener_state_escape_unicode_need_u:
      /* We already had a \ char, check that it's \u */
      if (!c || c != 'u')
      {
        /* Got a high surrogate with some non-unicode escape
         * sequence following it.
         * Put a replacement char in for the high surrogate
         * and handle the escape sequence normally.
         */
        printbuf_memappend_checked(tok->pb, (char *)utf8_replacement_char, 3);
        tok->high_surrogate = 0;
        tok->ucs_char = 0;
        tok->st_pos = 0;
        state = json_tokener_state_string_escape;
        goto redo_char;
      }
      state = json_tokener_state_escape_unicode;
      break;

      // ===================================================

    case json_tokener_state_boolean:
    {
      int size1, size2;
      printbuf_memappend_checked(tok->pb, &c, 1);
      size1 = json_min(tok->st_pos + 1, json_true_str_len);
      size2 = json_min(tok->st_pos + 1, json_false_str_len);
      if ((!(tok->flags & JSON_TOKENER_STRICT) &&
           strncasecmp(json_true_str, tok->pb->buf, size1) == 0) ||
          (strncmp(json_true_str, tok->pb->buf, size1) == 0))
      {
        if (tok->st_pos == json_true_str_len)
        {
          current = json_object_new_boolean(1);
          if (current == NULL)
          {
            tok->err = json_tokener_error_memory;
            goto out;
          }
          saved_state = json_tokener_state_finish;
          state = json_tokener_state_eatws;
          goto redo_char;
        }
      }
      else if ((!(tok->flags & JSON_TOKENER_STRICT) &&
                strncasecmp(json_false_str, tok->pb->buf, size2) == 0) ||
               (strncmp(json_false_str, tok->pb->buf, size2) == 0))
      {
        if (tok->st_pos == json_false_str_len)
        {
          current = json_object_new_boolean(0);
          if (current == NULL)
          {
            tok->err = json_tokener_error_memory;
            goto out;
          }
          saved_state = json_tokener_state_finish;
          state = json_tokener_state_eatws;
          goto redo_char;
        }
      }
      else
      {
        tok->err = json_tokener_error_parse_boolean;
        goto out;
      }
      tok->st_pos++;
    }
    break;

    case json_tokener_state_number:
    {
      /* Advance until we change state */
      const char *case_start = str;
      int case_len = 0;
      int is_exponent = 0;
      int neg_sign_ok = 1;
      int pos_sign_ok = 0;
      if (printbuf_length(tok->pb) > 0)
      {
        /* We don't save all state from the previous incremental parse
           so we need to re-generate it based on the saved string so far.
         */
        char *e_loc = strchr(tok->pb->buf, 'e');
        if (!e_loc)
          e_loc = strchr(tok->pb->buf, 'E');
        if (e_loc)
        {
          char *last_saved_char =
              &tok->pb->buf[printbuf_length(tok->pb) - 1];
          is_exponent = 1;
          pos_sign_ok = neg_sign_ok = 1;
          /* If the "e" isn't at the end, we can't start with a '-' */
          if (e_loc != last_saved_char)
          {
            neg_sign_ok = 0;
            pos_sign_ok = 0;
          }
          // else leave it set to 1, i.e. start of the new input
        }
      }

      while (c && ((c >= '0' && c <= '9') ||
                   (!is_exponent && (c == 'e' || c == 'E')) ||
                   (neg_sign_ok && c == '-') || (pos_sign_ok && c == '+') ||
                   (!tok->is_double && c == '.')))
      {
        pos_sign_ok = neg_sign_ok = 0;
        ++case_len;

        /* non-digit characters checks */
        /* note: since the main loop condition to get here was
         * an input starting with 0-9 or '-', we are
         * protected from input starting with '.' or
         * e/E.
         */
        switch (c)
        {
        case '.':
          tok->is_double = 1;
          pos_sign_ok = 1;
          neg_sign_ok = 1;
          break;
        case 'e': /* FALLTHRU */
        case 'E':
          is_exponent = 1;
          tok->is_double = 1;
          /* the exponent part can begin with a negative sign */
          pos_sign_ok = neg_sign_ok = 1;
          break;
        default: break;
        }

        if (!ADVANCE_CHAR(str, tok) || !PEEK_CHAR(c, tok))
        {
          printbuf_memappend_checked(tok->pb, case_start, case_len);
          goto out;
        }
      }
      /*
        Now we know c isn't a valid number char, but check whether
        it might have been intended to be, and return a potentially
        more understandable error right away.
        However, if we're at the top-level, use the number as-is
        because c can be part of a new object to parse on the
        next call to json_tokener_parse().
       */
      if (tok->depth > 0 && c != ',' && c != ']' && c != '}' && c != '/' &&
          c != 'I' && c != 'i' && !is_ws_char(c))
      {
        tok->err = json_tokener_error_parse_number;
        goto out;
      }
      if (case_len > 0)
        printbuf_memappend_checked(tok->pb, case_start, case_len);

      // Check for -Infinity
      if (tok->pb->buf[0] == '-' && case_len <= 1 && (c == 'i' || c == 'I'))
      {
        state = json_tokener_state_inf;
        tok->st_pos = 0;
        goto redo_char;
      }
      if (tok->is_double && !(tok->flags & JSON_TOKENER_STRICT))
      {
        /* Trim some chars off the end, to allow things
           like "123e+" to parse ok. */
        while (printbuf_length(tok->pb) > 1)
        {
          char last_char = tok->pb->buf[printbuf_length(tok->pb) - 1];
          if (last_char != 'e' && last_char != 'E' &&
              last_char != '-' && last_char != '+')
          {
            break;
          }
          tok->pb->buf[printbuf_length(tok->pb) - 1] = '\0';
          printbuf_length(tok->pb)--;
        }
      }
    }
      {
        int64_t num64;
        uint64_t numuint64;
        double numd;
        if (!tok->is_double && tok->pb->buf[0] == '-' &&
            json_parse_int64(tok->pb->buf, &num64) == 0)
        {
          if (errno == ERANGE && (tok->flags & JSON_TOKENER_STRICT))
          {
            tok->err = json_tokener_error_parse_number;
            goto out;
          }
          current = json_object_new_int64(num64);
          if (current == NULL)
          {
            tok->err = json_tokener_error_memory;
            goto out;
          }
        }
        else if (!tok->is_double && tok->pb->buf[0] != '-' &&
                 json_parse_uint64(tok->pb->buf, &numuint64) == 0)
        {
          if (errno == ERANGE && (tok->flags & JSON_TOKENER_STRICT))
          {
            tok->err = json_tokener_error_parse_number;
            goto out;
          }
          if (numuint64 && tok->pb->buf[0] == '0' &&
              (tok->flags & JSON_TOKENER_STRICT))
          {
            tok->err = json_tokener_error_parse_number;
            goto out;
          }
          if (numuint64 <= INT64_MAX)
          {
            num64 = (uint64_t)numuint64;
            current = json_object_new_int64(num64);
            if (current == NULL)
            {
              tok->err = json_tokener_error_memory;
              goto out;
            }
          }
          else
          {
            current = json_object_new_uint64(numuint64);
            if (current == NULL)
            {
              tok->err = json_tokener_error_memory;
              goto out;
            }
          }
        }
        else if (tok->is_double &&
                 json_tokener_parse_double(
                     tok->pb->buf, printbuf_length(tok->pb), &numd) == 0)
        {
          current = json_object_new_double_s(numd, tok->pb->buf);
          if (current == NULL)
          {
            tok->err = json_tokener_error_memory;
            goto out;
          }
        }
        else
        {
          tok->err = json_tokener_error_parse_number;
          goto out;
        }
        saved_state = json_tokener_state_finish;
        state = json_tokener_state_eatws;
        goto redo_char;
      }
      break;

    case json_tokener_state_array_after_sep:
    case json_tokener_state_array:
      if (c == ']')
      {
        // Minimize memory usage; assume parsed objs are unlikely to be changed
        json_object_array_shrink(current, 0);

        if (state == json_tokener_state_array_after_sep &&
            (tok->flags & JSON_TOKENER_STRICT))
        {
          tok->err = json_tokener_error_parse_unexpected;
          goto out;
        }
        saved_state = json_tokener_state_finish;
        state = json_tokener_state_eatws;
      }
      else
      {
        if (tok->depth >= tok->max_depth - 1)
        {
          tok->err = json_tokener_error_depth;
          goto out;
        }
        state = json_tokener_state_array_add;
        tok->depth++;
        json_tokener_reset_level(tok, tok->depth);
        goto redo_char;
      }
      break;

    case json_tokener_state_array_add:
      if (json_object_array_add(current, obj) != 0)
      {
        tok->err = json_tokener_error_memory;
        goto out;
      }
      saved_state = json_tokener_state_array_sep;
      state = json_tokener_state_eatws;
      goto redo_char;

    case json_tokener_state_array_sep:
      if (c == ']')
      {
        // Minimize memory usage; assume parsed objs are unlikely to be changed
        json_object_array_shrink(current, 0);

        saved_state = json_tokener_state_finish;
        state = json_tokener_state_eatws;
      }
      else if (c == ',')
      {
        saved_state = json_tokener_state_array_after_sep;
        state = json_tokener_state_eatws;
      }
      else
      {
        tok->err = json_tokener_error_parse_array;
        goto out;
      }
      break;

    case json_tokener_state_object_field_start:
    case json_tokener_state_object_field_start_after_sep:
      if (c == '}')
      {
        if (state == json_tokener_state_object_field_start_after_sep &&
            (tok->flags & JSON_TOKENER_STRICT))
        {
          tok->err = json_tokener_error_parse_unexpected;
          goto out;
        }
        saved_state = json_tokener_state_finish;
        state = json_tokener_state_eatws;
      }
      else if (c == '"' || c == '\'')
      {
        tok->quote_char = c;
        printbuf_reset(tok->pb);
        state = json_tokener_state_object_field;
      }
      else
      {
        tok->err = json_tokener_error_parse_object_key_name;
        goto out;
      }
      break;

    case json_tokener_state_object_field:
    {
      /* Advance until we change state */
      const char *case_start = str;
      while (1)
      {
        if (c == tok->quote_char)
        {
          printbuf_memappend_checked(tok->pb, case_start,
                                     str - case_start);
          obj_field_name = strdup(tok->pb->buf);
          if (obj_field_name == NULL)
          {
            tok->err = json_tokener_error_memory;
            goto out;
          }
          saved_state = json_tokener_state_object_field_end;
          state = json_tokener_state_eatws;
          break;
        }
        else if (c == '\\')
        {
          printbuf_memappend_checked(tok->pb, case_start,
                                     str - case_start);
          saved_state = json_tokener_state_object_field;
          state = json_tokener_state_string_escape;
          break;
        }
        else if ((tok->flags & JSON_TOKENER_STRICT) && (unsigned char)c <= 0x1f)
        {
          // Disallow control characters in strict mode
          tok->err = json_tokener_error_parse_string;
          goto out;
        }
        if (!ADVANCE_CHAR(str, tok) || !PEEK_CHAR(c, tok))
        {
          printbuf_memappend_checked(tok->pb, case_start,
                                     str - case_start);
          goto out;
        }
      }
    }
    break;

    case json_tokener_state_object_field_end:
      if (c == ':')
      {
        saved_state = json_tokener_state_object_value;
        state = json_tokener_state_eatws;
      }
      else
      {
        tok->err = json_tokener_error_parse_object_key_sep;
        goto out;
      }
      break;

    case json_tokener_state_object_value:
      if (tok->depth >= tok->max_depth - 1)
      {
        tok->err = json_tokener_error_depth;
        goto out;
      }
      state = json_tokener_state_object_value_add;
      tok->depth++;
      json_tokener_reset_level(tok, tok->depth);
      goto redo_char;

    case json_tokener_state_object_value_add:
      if (json_object_object_add(current, obj_field_name, obj) != 0)
      {
        tok->err = json_tokener_error_memory;
        goto out;
      }
      free(obj_field_name);
      obj_field_name = NULL;
      saved_state = json_tokener_state_object_sep;
      state = json_tokener_state_eatws;
      goto redo_char;

    case json_tokener_state_object_sep:
      /* { */
      if (c == '}')
      {
        saved_state = json_tokener_state_finish;
        state = json_tokener_state_eatws;
      }
      else if (c == ',')
      {
        saved_state = json_tokener_state_object_field_start_after_sep;
        state = json_tokener_state_eatws;
      }
      else
      {
        tok->err = json_tokener_error_parse_object_value_sep;
        goto out;
      }
      break;
    }
    (void)ADVANCE_CHAR(str, tok);
    if (!c) // This is the char *before* advancing
      break;
  } /* while(PEEK_CHAR) */

out:
  if ((tok->flags & JSON_TOKENER_VALIDATE_UTF8) && (nBytes != 0))
  {
    tok->err = json_tokener_error_parse_utf8_string;
  }
  if (c && (state == json_tokener_state_finish) && (tok->depth == 0) &&
      (tok->flags & (JSON_TOKENER_STRICT | JSON_TOKENER_ALLOW_TRAILING_CHARS)) ==
          JSON_TOKENER_STRICT)
  {
    /* unexpected char after JSON data */
    tok->err = json_tokener_error_parse_unexpected;
  }
  if (!c)
  {
    /* We hit an eof char (0) */
    if (state != json_tokener_state_finish && saved_state != json_tokener_state_finish)
      tok->err = json_tokener_error_parse_eof;
  }

#ifdef HAVE_USELOCALE
  uselocale(oldlocale);
  freelocale(newloc);
#elif defined(HAVE_SETLOCALE)
  setlocale(LC_NUMERIC, oldlocale);
  free(oldlocale);
#endif

  if (tok->err == json_tokener_success)
  {
    json_object *ret = json_object_get(current);
    int ii;

    /* Partially reset, so we parse additional objects on subsequent calls. */
    for (ii = tok->depth; ii >= 0; ii--)
      json_tokener_reset_level(tok, ii);
    return ret;
  }

  MC_DEBUG("json_tokener_parse_ex: error %s at offset %d\n", json_tokener_errors[tok->err],
           tok->char_offset);
  return NULL;
}

static json_bool json_tokener_validate_utf8(const char c, unsigned int *nBytes)
{
  unsigned char chr = c;
  if (*nBytes == 0)
  {
    if (chr >= 0x80)
    {
      if ((chr & 0xe0) == 0xc0)
        *nBytes = 1;
      else if ((chr & 0xf0) == 0xe0)
        *nBytes = 2;
      else if ((chr & 0xf8) == 0xf0)
        *nBytes = 3;
      else
        return 0;
    }
  }
  else
  {
    if ((chr & 0xC0) != 0x80)
      return 0;
    (*nBytes)--;
  }
  return 1;
}

void json_tokener_set_flags(struct json_tokener *tok, int flags)
{
  tok->flags = flags;
}

size_t json_tokener_get_parse_end(struct json_tokener *tok)
{
  assert(tok->char_offset >= 0); /* Drop this line when char_offset becomes a size_t */
  return (size_t)tok->char_offset;
}

static int json_tokener_parse_double(const char *buf, int len, double *retval)
{
  char *end;
  *retval = strtod(buf, &end);
  if (buf + len == end)
    return 0; // It worked
  return 1;
}

Coverage Report

Created: 2026-02-11 06:19