json_object.c

/*
 * Copyright (c) 2004, 2005 Metaparadigm Pte. Ltd.
 * Michael Clark <michael@metaparadigm.com>
 * Copyright (c) 2009 Hewlett-Packard Development Company, L.P.
 * Copyright (c) 2015-2017 Rainer Gerhards
 *
 * This library is free software; you can redistribute it and/or modify
 * it under the terms of the MIT license. See COPYING for details.
 *
 */

#include "config.h"

/* this is a work-around until we manage to fix configure.ac */
#ifndef _AIX
#pragma GCC diagnostic ignored "-Wdeclaration-after-statement"
#endif

#include <stdio.h>
#include <stdlib.h>
#include <stddef.h>
#include <string.h>
#include <math.h>
#include <errno.h>
#include <assert.h>
#include <stdint.h>

#include "debug.h"
#include "atomic.h"
#include "printbuf.h"
#include "arraylist.h"
#include "json.h"
#include "json_object.h"
#include "json_object_private.h"
#include "json_object_iterator.h"
#include "json_util.h"

#if !defined(HAVE_STRDUP)
# error You do not have strdup on your system.
#endif /* HAVE_STRDUP */

#if !defined(HAVE_SNPRINTF)
# error You do not have snprintf on your system.
#endif /* HAVE_SNPRINTF */

const char *fjson_number_chars = "0123456789.+-eE";
const char *fjson_hex_chars = "0123456789abcdefABCDEF";

static void fjson_object_generic_delete(struct fjson_object* jso);
static struct fjson_object* fjson_object_new(enum fjson_type o_type);

static fjson_object_to_json_string_fn fjson_object_object_to_json_string;
static fjson_object_to_json_string_fn fjson_object_boolean_to_json_string;
static fjson_object_to_json_string_fn fjson_object_int_to_json_string;
static fjson_object_to_json_string_fn fjson_object_double_to_json_string;
static fjson_object_to_json_string_fn fjson_object_string_to_json_string;
static fjson_object_to_json_string_fn fjson_object_array_to_json_string;

static int do_case_sensitive_comparison = 1;
void fjson_global_do_case_sensitive_comparison(const int newval)
{
    do_case_sensitive_comparison = newval;
}

/* helper for accessing the optimized string data component in fjson_object
 */
static const char *
get_string_component(struct fjson_object *jso)
{
    return (jso->o.c_string.len < LEN_DIRECT_STRING_DATA) ?
           jso->o.c_string.str.data : jso->o.c_string.str.ptr;
}

/* string escaping
 *
 * String escaping is a surprisingly performance intense operation.
 * I spent many hours in the profiler, and the root problem seems
 * to be that there is no easy way to detect the character classes
 * that need to be escaped, where the root cause is that these
 * characters are spread all over the ascii table. I tried
 * several approaches, including call tables, re-structuring
 * the case condition, different types of if conditions and
 * reordering the if conditions. What worked out best is this:
 * The regular case is that a character must not be escaped. So
 * we want to process that as fast as possible. In order to
 * detect this as quickly as possible, we have a lookup table
 * that tells us if a char needs escaping ("needsEscape", below).
 * This table has a spot for each ascii code. Note that it uses
 * chars, because anything larger causes worse cache operation
 * and anything smaller requires bit indexing and masking
 * operations, which are also comparatively costly. So plain
 * chars work best. What we then do is a single lookup into the
 * table to detect if we need to escape a character. If we need,
 * we go into the depth of actual escape detection. But if we
 * do NOT need to escape, we just quickly advance the index
 * and are done with that char. Note that it may look like the
 * extra table lookup costs performance, but right the contrary
 * is the case. We get amore than 30% performance increase due
 * to it (compared to the latest version of the code that did not
 * do the lookups).
 * rgerhards@adiscon.com, 2015-11-18
 * I have renamed needsEscape to char_needsEscape and made it
 * external. This makes it possible to share the implementation
 * with the newly contributed json_print.c module.
 * rgerhards, 2016-11-30
 */

char char_needsEscape[256] = {
    1, 1, 1, 1, 1, 1, 1, 1, /* ascii codes 0 .. 7 */
    1, 1, 1, 1, 1, 1, 1, 1,
    1, 1, 1, 1, 1, 1, 1, 1,
    1, 1, 1, 1, 1, 1, 1, 1,
    0, 0, 1, 0, 0, 0, 0, 0, /* ascii codes 32 .. 39 */
    0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 1, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0
};

static void fjson_escape_str(struct printbuf *pb, const char *str)
{
    const char *start_offset = str;
    while(1) { /* broken below on 0-byte */
        if(char_needsEscape[*((unsigned char*)str)]) {
            if(*str == '\0')
                break;
            if(str != start_offset)
                printbuf_memappend_no_nul(pb, start_offset, str - start_offset);
            switch(*str) {
            case '\b': printbuf_memappend_no_nul(pb, "\\b", 2);
                break;
            case '\n': printbuf_memappend_no_nul(pb, "\\n", 2);
                break;
            case '\r': printbuf_memappend_no_nul(pb, "\\r", 2);
                break;
            case '\t': printbuf_memappend_no_nul(pb, "\\t", 2);
                break;
            case '\f': printbuf_memappend_no_nul(pb, "\\f", 2);
                break;
            case '"': printbuf_memappend_no_nul(pb, "\\\"", 2);
                break;
            case '\\': printbuf_memappend_no_nul(pb, "\\\\", 2);
                break;
            default: sprintbuf(pb, "\\u00%c%c",
                fjson_hex_chars[*str >> 4],
                fjson_hex_chars[*str & 0xf]);
                break;
            }
            start_offset = ++str;
        } else
            ++str;
    }
    if(str != start_offset)
        printbuf_memappend_no_nul(pb, start_offset, str - start_offset);
}


/* reference counting */

extern struct fjson_object* fjson_object_get(struct fjson_object *jso)
{
    if (!jso) return jso;
    const int cnt = ATOMIC_INC_AND_FETCH_int(&jso->_ref_count, &jso->_mut_ref_count);
    if (cnt == 1) return NULL; /* this means it was previously zero, so this object will be destroyed */
    
    return jso;
}

int fjson_object_put(struct fjson_object *jso)
{
    if(!jso) return 0;

    const int cnt = ATOMIC_DEC_AND_FETCH(&jso->_ref_count, &jso->_mut_ref_count);
    if(cnt > 0) return 0;

    jso->_delete(jso);
    return 1;
}


/* generic object construction and destruction parts */

static void fjson_object_generic_delete(struct fjson_object* jso)
{
    if (jso) {
        printbuf_free(jso->_pb);
        DESTROY_ATOMIC_HELPER_MUT(jso->_mut_ref_count);
        free(jso);
    }
}

static struct fjson_object* fjson_object_new(const enum fjson_type o_type)
{
    struct fjson_object *const jso = (struct fjson_object*)calloc(sizeof(struct fjson_object), 1);
    if (!jso)
        return NULL;
    jso->o_type = o_type;
    jso->_ref_count = 1;
    jso->_delete = &fjson_object_generic_delete;
    INIT_ATOMIC_HELPER_MUT(jso->_mut_ref_count);
    return jso;
}


/* type checking functions */

int fjson_object_is_type(struct fjson_object *jso, enum fjson_type type)
{
    if (!jso)
        return (type == fjson_type_null);
    return (jso->o_type == type);
}

enum fjson_type fjson_object_get_type(struct fjson_object *jso)
{
    if (!jso)
        return fjson_type_null;
    return jso->o_type;
}

/* extended conversion to string */

const char* fjson_object_to_json_string_ext(struct fjson_object *jso, int flags)
{
    if (!jso)
        return "null";

    if ((!jso->_pb) && !(jso->_pb = printbuf_new()))
        return NULL;

    printbuf_reset(jso->_pb);

    jso->_to_json_string(jso, jso->_pb, 0, flags);

    printbuf_terminate_string(jso->_pb);
    return jso->_pb->buf;
}

/* backwards-compatible conversion to string */

const char* fjson_object_to_json_string(struct fjson_object *jso)
{
    return fjson_object_to_json_string_ext(jso, FJSON_TO_STRING_SPACED);
}

static void indent(struct printbuf *pb, int level, int flags)
{
    if (flags & FJSON_TO_STRING_PRETTY)
    {
        if (flags & FJSON_TO_STRING_PRETTY_TAB)
        {
            printbuf_memset(pb, -1, '\t', level);
        }
        else
        {
            printbuf_memset(pb, -1, ' ', level * 2);
        }
    }
}

/* fjson_object_object */

static int fjson_object_object_to_json_string(struct fjson_object* jso,
                         struct printbuf *pb,
                         int level,
                         int flags)
{
    struct fjson_object *val;
    int had_children = 0;

    printbuf_memappend_char(pb, '{' /*}*/);
    if (flags & FJSON_TO_STRING_PRETTY)
        printbuf_memappend_char(pb, '\n');
    struct fjson_object_iterator it = fjson_object_iter_begin(jso);
    struct fjson_object_iterator itEnd = fjson_object_iter_end(jso);
    while (!fjson_object_iter_equal(&it, &itEnd)) {
        if (had_children)
        {
            printbuf_memappend_char(pb, ',');
            if (flags & FJSON_TO_STRING_PRETTY)
                printbuf_memappend_char(pb, '\n');
        }
        had_children = 1;
        if (flags & FJSON_TO_STRING_SPACED)
            printbuf_memappend_char(pb, ' ');
        indent(pb, level+1, flags);
        printbuf_memappend_char(pb, '\"');
        fjson_escape_str(pb, fjson_object_iter_peek_name(&it));
        if (flags & FJSON_TO_STRING_SPACED)
            printbuf_memappend_no_nul(pb, "\": ", 3);
        else
            printbuf_memappend_no_nul(pb, "\":", 2);
        val = fjson_object_iter_peek_value(&it);
        if(val == NULL)
            printbuf_memappend_no_nul(pb, "null", 4);
        else
            val->_to_json_string(val, pb, level+1,flags);
        fjson_object_iter_next(&it);
    }
    if (flags & FJSON_TO_STRING_PRETTY)
    {
        if (had_children)
            printbuf_memappend_no_nul(pb, "\n",1);
        indent(pb,level,flags);
    }
    if (flags & FJSON_TO_STRING_SPACED)
        printbuf_memappend_no_nul(pb, /*{*/ " }", 2);
    else
        printbuf_memappend_char(pb, /*{*/ '}');
    return 0; /* we need to keep compatible with the API */
}


static void fjson_object_object_delete(struct fjson_object *const __restrict__ jso)
{
    struct _fjson_child_pg *pg = &jso->o.c_obj.pg;
    struct _fjson_child_pg *del = NULL; /* do NOT delete first elt! */
    while (pg != NULL) {
        for (int i = 0 ; i < FJSON_OBJECT_CHLD_PG_SIZE ; ++i) {
            if (pg->children[i].k == NULL)
                continue; /* indicates empty slot */
            if(!pg->children[i].flags.k_is_constant)
                free ((void*)pg->children[i].k);
            fjson_object_put (pg->children[i].v);
        }
        pg = pg->next;
        free(del);
        del = pg;
    }
    fjson_object_generic_delete(jso);
}

struct fjson_object* fjson_object_new_object(void)
{
    struct fjson_object *jso = fjson_object_new(fjson_type_object);
    if (!jso)
        return NULL;
    jso->_delete = &fjson_object_object_delete;
    jso->_to_json_string = &fjson_object_object_to_json_string;
    jso->o.c_obj.nelem = 0;
    jso->o.c_obj.lastpg = &jso->o.c_obj.pg;
    return jso;
}


/* finds the child with given key if it exists in a json object
 * and returns a pointer to it. Returns NULL if not found.
 */
static struct _fjson_child*
_fjson_find_child(struct fjson_object *const __restrict__ jso,
    const char *const key)
{
    struct fjson_object_iterator it = fjson_object_iter_begin(jso);
    struct fjson_object_iterator itEnd = fjson_object_iter_end(jso);
    while (!fjson_object_iter_equal(&it, &itEnd)) {
        if (do_case_sensitive_comparison) {
            if (!strcmp (key, fjson_object_iter_peek_name(&it)))
                return _fjson_object_iter_peek_child(&it);
        } else {
            if (!strcasecmp (key, fjson_object_iter_peek_name(&it)))
                return _fjson_object_iter_peek_child(&it);
        }
        fjson_object_iter_next(&it);
    }
    return NULL;
}

/* get an empty entry/slot for adding a new child. If the current data
 * structure is full, alloc a new page. Returns NULL on (malloc) error.
 */
static struct _fjson_child *
fjson_child_get_empty_etry(struct fjson_object *const __restrict__ jso)
{
    struct _fjson_child *chld = NULL;
    struct _fjson_child_pg *pg;
    int pg_idx;

    if (jso->o.c_obj.ndeleted > 0) {
        /* we first fill deleted spots */
        pg = &jso->o.c_obj.pg;
        while (chld == NULL) {
            for (int i = 0 ; i < FJSON_OBJECT_CHLD_PG_SIZE ; ++i) {
                if(pg->children[i].k == NULL) {
                    chld = &(pg->children[i]);
                    --jso->o.c_obj.ndeleted;
                    goto done;
                }
            }
            pg = pg->next;
        }
        /* if we reach this point, we have a program error */
        assert(0);
        goto done;
    }

    pg_idx = jso->o.c_obj.nelem % FJSON_OBJECT_CHLD_PG_SIZE;
    if (jso->o.c_obj.nelem > 0 && pg_idx == 0) {
        if((pg = calloc(1, sizeof(struct _fjson_child_pg))) == NULL) {
            errno = ENOMEM;
            goto done;
        }
        jso->o.c_obj.lastpg->next = pg;
        jso->o.c_obj.lastpg = pg;
    }
    pg = jso->o.c_obj.lastpg;
    if (pg->children[pg_idx].k == NULL) {
        /* we can use this spot and save us search time */
        chld = &(pg->children[pg_idx]);
        goto done;
    }

done:   return chld;
}

void fjson_object_object_add_ex(struct fjson_object *const __restrict__ jso,
    const char *const key,
    struct fjson_object *const val,
    const unsigned opts)
{
    // We lookup the entry and replace the value, rather than just deleting
    // and re-adding it, so the existing key remains valid.
    struct _fjson_child *chld;
    chld = (opts & FJSON_OBJECT_ADD_KEY_IS_NEW) ? NULL : _fjson_find_child(jso, key);
    if (chld != NULL) {
        if (chld->v != NULL)
            fjson_object_put(chld->v);
        chld->v = val;
        goto done;
    }

    /* insert new entry */
    if ((chld = fjson_child_get_empty_etry(jso)) == NULL)
        goto done;
    chld->k = (opts & FJSON_OBJECT_KEY_IS_CONSTANT) ? key : strdup(key);
    chld->flags.k_is_constant = (opts & FJSON_OBJECT_KEY_IS_CONSTANT) != 0;
    chld->v = val;
    ++jso->o.c_obj.nelem;

done:
    return;
}

void fjson_object_object_add(struct fjson_object *const __restrict__ jso,
    const char *const key,
    struct fjson_object *const val)
{
    fjson_object_object_add_ex(jso, key, val, 0);
}


int fjson_object_object_length(struct fjson_object *jso)
{
    return jso->o.c_obj.nelem;
}

struct fjson_object* fjson_object_object_get(struct fjson_object* jso, const char *key)
{
    struct fjson_object *result = NULL;
    fjson_object_object_get_ex(jso, key, &result);
    return result;
}

fjson_bool fjson_object_object_get_ex(struct fjson_object* jso, const char *key, struct fjson_object **value)
{
    if (value != NULL)
        *value = NULL;

    if (NULL == jso)
        return FALSE;

    if(jso->o_type == fjson_type_object) {
        struct _fjson_child *const chld = _fjson_find_child(jso, key);
        if (chld == 0) {
            return FALSE;
        } else {
            if (value != NULL)
                *value = chld->v;
            return TRUE;
        }
    } else {
        if (value != NULL)
            *value = NULL;
        return FALSE;
    }
}

void fjson_object_object_del(struct fjson_object* jso, const char *key)
{
    struct _fjson_child *const chld = _fjson_find_child(jso, key);
    if (chld != NULL) {
        if(!chld->flags.k_is_constant) {
            free((void*)chld->k);
        }
        fjson_object_put(chld->v);
        chld->flags.k_is_constant = 0;
        chld->k = NULL;
        chld->v = NULL;
        --jso->o.c_obj.nelem;
        ++jso->o.c_obj.ndeleted;
    }
}


/* fjson_object_boolean */

static int fjson_object_boolean_to_json_string(struct fjson_object* jso,
                          struct printbuf *pb,
                          int __attribute__((unused)) level,
                          int __attribute__((unused)) flags)
{
    if (jso->o.c_boolean)
        printbuf_memappend_no_nul(pb, "true", 4);
    else
        printbuf_memappend_no_nul(pb, "false", 5);
    return 0; /* we need to keep compatible with the API */
}

struct fjson_object* fjson_object_new_boolean(fjson_bool b)
{
    struct fjson_object *jso = fjson_object_new(fjson_type_boolean);
    if (!jso)
        return NULL;
    jso->_to_json_string = &fjson_object_boolean_to_json_string;
    jso->o.c_boolean = b;
    return jso;
}

fjson_bool fjson_object_get_boolean(struct fjson_object *jso)
{
    if (!jso)
        return FALSE;
    switch(jso->o_type)
    {
    case fjson_type_boolean:
        return jso->o.c_boolean;
    case fjson_type_int:
        return (jso->o.c_int64 != 0);
    case fjson_type_double:
        return (jso->o.c_double.value != 0);
    case fjson_type_string:
        return (jso->o.c_string.len != 0);
    case fjson_type_null:
    case fjson_type_object:
    case fjson_type_array:
    default:
        return FALSE;
    }
}


/* fjson_object_int */

static int fjson_object_int_to_json_string(struct fjson_object* jso,
                      struct printbuf *pb,
                      int __attribute__((unused)) level,
                      int __attribute__((unused)) flags)
{
    sprintbuf(pb, "%" PRId64, jso->o.c_int64);
    return 0; /* we need to keep compatible with the API */
}

struct fjson_object* fjson_object_new_int(int32_t i)
{
    struct fjson_object *jso = fjson_object_new(fjson_type_int);
    if (!jso)
        return NULL;
    jso->_to_json_string = &fjson_object_int_to_json_string;
    jso->o.c_int64 = i;
    return jso;
}

int32_t fjson_object_get_int(struct fjson_object *jso)
{
    int64_t cint64;
    enum fjson_type o_type;

    if(!jso) return 0;

    o_type = jso->o_type;
    cint64 = jso->o.c_int64;

    if (o_type == fjson_type_string) {
        /*
         * Parse strings into 64-bit numbers, then use the
         * 64-to-32-bit number handling below.
         */
        if (fjson_parse_int64(get_string_component(jso), &cint64) != 0)
            return 0; /* whoops, it didn't work. */
        o_type = fjson_type_int;
    }

    switch(o_type) {
    case fjson_type_int:
        /* Make sure we return the correct values for out of range numbers. */
        if (cint64 <= INT32_MIN)
            return INT32_MIN;
        else if (cint64 >= INT32_MAX)
            return INT32_MAX;
        else
            return (int32_t)cint64;
    case fjson_type_double:
        return (int32_t)jso->o.c_double.value;
    case fjson_type_boolean:
        return jso->o.c_boolean;
    case fjson_type_null:
    case fjson_type_object:
    case fjson_type_array:
    case fjson_type_string:
    default:
        return 0;
    }
}

struct fjson_object* fjson_object_new_int64(int64_t i)
{
    struct fjson_object *jso = fjson_object_new(fjson_type_int);
    if (!jso)
        return NULL;
    jso->_to_json_string = &fjson_object_int_to_json_string;
    jso->o.c_int64 = i;
    return jso;
}

uint32_t fjson_object_get_uint(struct fjson_object *jso)
{
    int64_t cint = fjson_object_get_int64(jso);
    if (errno) return 0;

    if (cint > UINT32_MAX) return UINT32_MAX;

    if (cint < 0) return 0;

    return (uint32_t) cint;
}

int64_t fjson_object_get_int64(struct fjson_object *jso)
{
    int64_t cint;

    if (!jso)
        return 0;
    switch(jso->o_type)
    {
    case fjson_type_int:
        return jso->o.c_int64;
    case fjson_type_double:
        return (int64_t)jso->o.c_double.value;
    case fjson_type_boolean:
        return jso->o.c_boolean;
    case fjson_type_string:
        if (fjson_parse_int64(get_string_component(jso), &cint) == 0)
            return cint;
        ATTR_FALLTHROUGH
    case fjson_type_null:
    case fjson_type_object:
    case fjson_type_array:
    default:
        return 0;
    }
}


/* fjson_object_double */

static int fjson_object_double_to_json_string(struct fjson_object* jso,
                         struct printbuf *pb,
                         int __attribute__((unused)) level,
                         int __attribute__((unused)) flags)
{
    char buf[128], *p, *q;
    int size;
    double dummy;  /* needed for modf() */
    
    if (jso->o.c_double.source) {
        printbuf_memappend_no_nul(pb, jso->o.c_double.source, strlen(jso->o.c_double.source));
        return 0; /* we need to keep compatible with the API */
    }
    
    /* Although JSON RFC does not support
     * NaN or Infinity as numeric values
     * ECMA 262 section 9.8.1 defines
     * how to handle these cases as strings
     */
    if(isnan(jso->o.c_double.value))
        size = snprintf(buf, sizeof(buf), "NaN");
    else if(isinf(jso->o.c_double.value))
        if(jso->o.c_double.value > 0)
            size = snprintf(buf, sizeof(buf), "Infinity");
        else
            size = snprintf(buf, sizeof(buf), "-Infinity");
    else
        size = snprintf(buf, sizeof(buf),
            (modf(jso->o.c_double.value, &dummy)==0)?"%.17g.0":"%.17g",
            jso->o.c_double.value);

    p = strchr(buf, ',');
    if (p) {
        *p = '.';
    } else {
        p = strchr(buf, '.');
    }
    if (p && (flags & FJSON_TO_STRING_NOZERO)) {
        /* last useful digit, always keep 1 zero */
        p++;
        for (q=p ; *q ; q++) {
            if (*q!='0') p=q;
        }
        /* drop trailing zeroes */
        *(++p) = 0;
        size = p-buf;
    }
    printbuf_memappend_no_nul(pb, buf, size);
    return 0; /* we need to keep compatible with the API */
}

static void fjson_object_double_delete(struct fjson_object *jso)
{
    free(jso->o.c_double.source);
    fjson_object_generic_delete(jso);
}

struct fjson_object* fjson_object_new_double(double d)
{
    struct fjson_object *jso = fjson_object_new(fjson_type_double);
    if (!jso)
        return NULL;
    jso->_to_json_string = &fjson_object_double_to_json_string;
    jso->o.c_double.value = d;
    jso->o.c_double.source = NULL;
    return jso;
}

struct fjson_object* fjson_object_new_double_s(double d, const char *ds)
{
    struct fjson_object *jso = fjson_object_new_double(d);
    if (!jso)
        return NULL;

    jso->o.c_double.source = strdup(ds);
    if (!jso->o.c_double.source)
    {
        fjson_object_generic_delete(jso);
        errno = ENOMEM;
        return NULL;
    }
    jso->_delete = &fjson_object_double_delete;
    return jso;
}

double fjson_object_get_double(struct fjson_object *jso)
{
    double cdouble;
    char *errPtr = NULL;

    if(!jso) return 0.0;
    switch(jso->o_type) {
    case fjson_type_double:
        return jso->o.c_double.value;
    case fjson_type_int:
        return jso->o.c_int64;
    case fjson_type_boolean:
        return jso->o.c_boolean;
    case fjson_type_string:
        errno = 0;
        cdouble = strtod(get_string_component(jso), &errPtr);

        /* if conversion stopped at the first character, return 0.0 */
        if (errPtr == get_string_component(jso))
            return 0.0;

        /*
        * Check that the conversion terminated on something sensible
        *
        * For example, { "pay" : 123AB } would parse as 123.
        */
        if (*errPtr != '\0')
            return 0.0;

        /*
        * If strtod encounters a string which would exceed the
        * capacity of a double, it returns +/- HUGE_VAL and sets
        * errno to ERANGE. But +/- HUGE_VAL is also a valid result
        * from a conversion, so we need to check errno.
        *
        * Underflow also sets errno to ERANGE, but it returns 0 in
        * that case, which is what we will return anyway.
        *
        * See CERT guideline ERR30-C
        */
        if ((HUGE_VAL == cdouble || -HUGE_VAL == cdouble) &&
            (ERANGE == errno))
            cdouble = 0.0;
        return cdouble;
    case fjson_type_null:
    case fjson_type_object:
    case fjson_type_array:
    default:
        return 0.0;
    }
}


/* fjson_object_string */

static int fjson_object_string_to_json_string(struct fjson_object* jso,
                         struct printbuf *pb,
                         int __attribute__((unused)) level,
                         int __attribute__((unused)) flags)
{
    printbuf_memappend_char(pb, '\"');
    fjson_escape_str(pb, get_string_component(jso));
    printbuf_memappend_char(pb, '\"');
    return 0; /* we need to keep compatible with the API */
}

static void fjson_object_string_delete(struct fjson_object* jso)
{
    if(jso->o.c_string.len >= LEN_DIRECT_STRING_DATA)
        free(jso->o.c_string.str.ptr);
    fjson_object_generic_delete(jso);
}

struct fjson_object* fjson_object_new_string(const char *s)
{
    struct fjson_object *jso = fjson_object_new(fjson_type_string);
    if (!jso)
        return NULL;
    jso->_delete = &fjson_object_string_delete;
    jso->_to_json_string = &fjson_object_string_to_json_string;
    jso->o.c_string.len = strlen(s);
    if(jso->o.c_string.len < LEN_DIRECT_STRING_DATA) {
        memcpy(jso->o.c_string.str.data, s, jso->o.c_string.len);
    } else {
        jso->o.c_string.str.ptr = strdup(s);
        if (!jso->o.c_string.str.ptr)
        {
            fjson_object_generic_delete(jso);
            errno = ENOMEM;
            return NULL;
        }
    }
    return jso;
}

struct fjson_object* fjson_object_new_string_len(const char *s, int len)
{
    char *dstbuf;
    struct fjson_object *jso = fjson_object_new(fjson_type_string);
    if (!jso)
        return NULL;
    jso->_delete = &fjson_object_string_delete;
    jso->_to_json_string = &fjson_object_string_to_json_string;
    if(len < LEN_DIRECT_STRING_DATA) {
        dstbuf = jso->o.c_string.str.data;
    } else {
        jso->o.c_string.str.ptr = (char*)malloc(len + 1);
        if (!jso->o.c_string.str.ptr)
        {
            fjson_object_generic_delete(jso);
            errno = ENOMEM;
            return NULL;
        }
        dstbuf = jso->o.c_string.str.ptr;
    }
    memcpy(dstbuf, (void *)s, len);
    dstbuf[len] = '\0';
    jso->o.c_string.len = len;
    return jso;
}

const char* fjson_object_get_string(struct fjson_object *jso)
{
    if (!jso)
        return NULL;
    if(jso->o_type == fjson_type_string)
        return get_string_component(jso);
    else
        return fjson_object_to_json_string(jso);
}

int fjson_object_get_string_len(struct fjson_object *jso)
{
    if (!jso)
        return 0;
    if(jso->o_type == fjson_type_string)
        return jso->o.c_string.len;
    else
        return 0;
}


/* fjson_object_array */

static int fjson_object_array_to_json_string(struct fjson_object* jso,
    struct printbuf *pb,
    int level,
    int flags)
{
    int had_children = 0;
    int ii;
    printbuf_memappend_char(pb, '[');
    if (flags & FJSON_TO_STRING_PRETTY)
        printbuf_memappend_char(pb, '\n');
    for(ii=0; ii < fjson_object_array_length(jso); ii++)
    {
        struct fjson_object *val;
        if (had_children)
        {
            printbuf_memappend_char(pb, ',');
            if (flags & FJSON_TO_STRING_PRETTY)
                printbuf_memappend_char(pb, '\n');
        }
        had_children = 1;
        if (flags & FJSON_TO_STRING_SPACED)
            printbuf_memappend_char(pb, ' ');
        indent(pb, level + 1, flags);
        val = fjson_object_array_get_idx(jso, ii);
        if(val == NULL)
            printbuf_memappend_no_nul(pb, "null", 4);
        else
            val->_to_json_string(val, pb, level+1, flags);
    }
    if (flags & FJSON_TO_STRING_PRETTY)
    {
        if (had_children)
            printbuf_memappend_char(pb, '\n');
        indent(pb,level,flags);
    }

    if (flags & FJSON_TO_STRING_SPACED)
        printbuf_memappend_no_nul(pb, " ]", 2);
    else
        printbuf_memappend_char(pb, ']');
    return 0; /* we need to keep compatible with the API */
}

static void fjson_object_array_entry_free(void *data)
{
    fjson_object_put((struct fjson_object*)data);
}

static void fjson_object_array_delete(struct fjson_object* jso)
{
    array_list_free(jso->o.c_array);
    fjson_object_generic_delete(jso);
}

struct fjson_object* fjson_object_new_array(void)
{
    struct fjson_object *jso = fjson_object_new(fjson_type_array);
    if (!jso)
        return NULL;
    jso->_delete = &fjson_object_array_delete;
    jso->_to_json_string = &fjson_object_array_to_json_string;
    jso->o.c_array = array_list_new(&fjson_object_array_entry_free);
    return jso;
}

struct array_list* fjson_object_get_array(struct fjson_object *jso)
{
    if (!jso)
        return NULL;
    if(jso->o_type == fjson_type_array)
        return jso->o.c_array;
    else
        return NULL;
}

void fjson_object_array_sort(struct fjson_object *jso, int(*sort_fn)(const void *, const void *))
{
    array_list_sort(jso->o.c_array, sort_fn);
}

struct fjson_object* fjson_object_array_bsearch(
        const struct fjson_object *key,
        const struct fjson_object *jso,
        int (*sort_fn)(const void *, const void *))
{
    struct fjson_object **result;

    result = (struct fjson_object **)array_list_bsearch(
            (const void **)&key, jso->o.c_array, sort_fn);

    if (!result)
        return NULL;
    return *result;
}

int fjson_object_array_length(struct fjson_object *jso)
{
    return array_list_length(jso->o.c_array);
}

int fjson_object_array_add(struct fjson_object *jso,struct fjson_object *val)
{
    return array_list_add(jso->o.c_array, val);
}

int fjson_object_array_add_idx(struct fjson_object *jso, int idx, struct fjson_object *val)
{
    return array_list_add_idx(jso->o.c_array, idx, val);
}

int fjson_object_array_put_idx(struct fjson_object *jso, int idx,
                  struct fjson_object *val)
{
    return array_list_put_idx(jso->o.c_array, idx, val);
}

struct fjson_object* fjson_object_array_get_idx(struct fjson_object *jso,
                          int idx)
{
    return (struct fjson_object*)array_list_get_idx(jso->o.c_array, idx);
}

/*
 * Deleting the idx-th element in the array type object.
 */
void fjson_object_array_del_idx(struct fjson_object *jso, int idx)
{
    array_list_del_idx(jso->o.c_array, idx);
}

int fjson_object_get_member_count(struct fjson_object *jso)
{
    return jso->o.c_obj.nelem;
}