/*
 * $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(_MSC_VER)
/* 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, size_t 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)&0xFC00) == 0xD800)
#define IS_LOW_SURROGATE(uc) (((uc)&0xFC00) == 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;

    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)
{
    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, size_t 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 && strlen(str) > INT32_MAX))
    {
        tok->err = json_tokener_error_size;
        return NULL;
    }

#ifdef HAVE_USELOCALE
    {
        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);
        if (newloc == NULL)
        {
            tok->err = json_tokener_error_memory;
            freelocale(duploc);
            return NULL;
        }
#ifdef NEWLOCALE_NEEDS_FREELOCALE
        // Older versions of FreeBSD (<12.4) don't free the locale
        // passed to newlocale(), so do it here
        freelocale(duploc);
#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) && 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;
                }
                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, size_t len, double *retval)
{
    char *end;
    *retval = strtod(buf, &end);
    if (buf + len == end)
        return 0; // It worked
    return 1;
}
