#include "Python.h"
#include "structmember.h"
#if PY_VERSION_HEX < 0x02060000 && !defined(Py_TYPE)
#define Py_TYPE(ob)     (((PyObject*)(ob))->ob_type)
#endif
#if PY_VERSION_HEX < 0x02050000 && !defined(PY_SSIZE_T_MIN)
typedef int Py_ssize_t;
#define PY_SSIZE_T_MAX INT_MAX
#define PY_SSIZE_T_MIN INT_MIN
#define PyInt_FromSsize_t PyInt_FromLong
#define PyInt_AsSsize_t PyInt_AsLong
#endif
#ifndef Py_IS_FINITE
#define Py_IS_FINITE(X) (!Py_IS_INFINITY(X) && !Py_IS_NAN(X))
#endif

#ifdef __GNUC__
#define UNUSED __attribute__((__unused__))
#else
#define UNUSED
#endif

#define DEFAULT_ENCODING "utf-8"

#define PyScanner_Check(op) PyObject_TypeCheck(op, &PyScannerType)
#define PyScanner_CheckExact(op) (Py_TYPE(op) == &PyScannerType)
#define PyEncoder_Check(op) PyObject_TypeCheck(op, &PyEncoderType)
#define PyEncoder_CheckExact(op) (Py_TYPE(op) == &PyEncoderType)

static PyTypeObject PyScannerType;
static PyTypeObject PyEncoderType;

typedef struct _PyScannerObject {
    PyObject_HEAD
    PyObject *encoding;
    PyObject *strict;
    PyObject *object_hook;
    PyObject *pairs_hook;
    PyObject *parse_float;
    PyObject *parse_int;
    PyObject *parse_constant;
} PyScannerObject;

static PyMemberDef scanner_members[] = {
    {"encoding", T_OBJECT, offsetof(PyScannerObject, encoding), READONLY, "encoding"},
    {"strict", T_OBJECT, offsetof(PyScannerObject, strict), READONLY, "strict"},
    {"object_hook", T_OBJECT, offsetof(PyScannerObject, object_hook), READONLY, "object_hook"},
    {"object_pairs_hook", T_OBJECT, offsetof(PyScannerObject, pairs_hook), READONLY, "object_pairs_hook"},
    {"parse_float", T_OBJECT, offsetof(PyScannerObject, parse_float), READONLY, "parse_float"},
    {"parse_int", T_OBJECT, offsetof(PyScannerObject, parse_int), READONLY, "parse_int"},
    {"parse_constant", T_OBJECT, offsetof(PyScannerObject, parse_constant), READONLY, "parse_constant"},
    {NULL}
};

typedef struct _PyEncoderObject {
    PyObject_HEAD
    PyObject *markers;
    PyObject *defaultfn;
    PyObject *encoder;
    PyObject *indent;
    PyObject *key_separator;
    PyObject *item_separator;
    PyObject *sort_keys;
    PyObject *skipkeys;
    int fast_encode;
    int allow_nan;
} PyEncoderObject;

static PyMemberDef encoder_members[] = {
    {"markers", T_OBJECT, offsetof(PyEncoderObject, markers), READONLY, "markers"},
    {"default", T_OBJECT, offsetof(PyEncoderObject, defaultfn), READONLY, "default"},
    {"encoder", T_OBJECT, offsetof(PyEncoderObject, encoder), READONLY, "encoder"},
    {"indent", T_OBJECT, offsetof(PyEncoderObject, indent), READONLY, "indent"},
    {"key_separator", T_OBJECT, offsetof(PyEncoderObject, key_separator), READONLY, "key_separator"},
    {"item_separator", T_OBJECT, offsetof(PyEncoderObject, item_separator), READONLY, "item_separator"},
    {"sort_keys", T_OBJECT, offsetof(PyEncoderObject, sort_keys), READONLY, "sort_keys"},
    {"skipkeys", T_OBJECT, offsetof(PyEncoderObject, skipkeys), READONLY, "skipkeys"},
    {NULL}
};

static Py_ssize_t
ascii_escape_char(Py_UNICODE c, char *output, Py_ssize_t chars);
static PyObject *
ascii_escape_unicode(PyObject *pystr);
static PyObject *
ascii_escape_str(PyObject *pystr);
static PyObject *
py_encode_basestring_ascii(PyObject* self UNUSED, PyObject *pystr);
void init_json(void);
static PyObject *
scan_once_str(PyScannerObject *s, PyObject *pystr, Py_ssize_t idx, Py_ssize_t *next_idx_ptr);
static PyObject *
scan_once_unicode(PyScannerObject *s, PyObject *pystr, Py_ssize_t idx, Py_ssize_t *next_idx_ptr);
static PyObject *
_build_rval_index_tuple(PyObject *rval, Py_ssize_t idx);
static PyObject *
scanner_new(PyTypeObject *type, PyObject *args, PyObject *kwds);
static void
scanner_dealloc(PyObject *self);
static int
scanner_clear(PyObject *self);
static PyObject *
encoder_new(PyTypeObject *type, PyObject *args, PyObject *kwds);
static void
encoder_dealloc(PyObject *self);
static int
encoder_clear(PyObject *self);
static int
encoder_listencode_list(PyEncoderObject *s, PyObject *rval, PyObject *seq, Py_ssize_t indent_level);
static int
encoder_listencode_obj(PyEncoderObject *s, PyObject *rval, PyObject *obj, Py_ssize_t indent_level);
static int
encoder_listencode_dict(PyEncoderObject *s, PyObject *rval, PyObject *dct, Py_ssize_t indent_level);
static PyObject *
_encoded_const(PyObject *obj);
static void
raise_errmsg(char *msg, PyObject *s, Py_ssize_t end);
static PyObject *
encoder_encode_string(PyEncoderObject *s, PyObject *obj);
static int
_convertPyInt_AsSsize_t(PyObject *o, Py_ssize_t *size_ptr);
static PyObject *
_convertPyInt_FromSsize_t(Py_ssize_t *size_ptr);
static PyObject *
encoder_encode_float(PyEncoderObject *s, PyObject *obj);

#define S_CHAR(c) (c >= ' ' && c <= '~' && c != '\\' && c != '"')
#define IS_WHITESPACE(c) (((c) == ' ') || ((c) == '\t') || ((c) == '\n') || ((c) == '\r'))

#define MIN_EXPANSION 6
#ifdef Py_UNICODE_WIDE
#define MAX_EXPANSION (2 * MIN_EXPANSION)
#else
#define MAX_EXPANSION MIN_EXPANSION
#endif

static int
_convertPyInt_AsSsize_t(PyObject *o, Py_ssize_t *size_ptr)
{
    /* PyObject to Py_ssize_t converter */
    *size_ptr = PyInt_AsSsize_t(o);
    if (*size_ptr == -1 && PyErr_Occurred())
        return 0;
    return 1;
}

static PyObject *
_convertPyInt_FromSsize_t(Py_ssize_t *size_ptr)
{
    /* Py_ssize_t to PyObject converter */
    return PyInt_FromSsize_t(*size_ptr);
}

static Py_ssize_t
ascii_escape_char(Py_UNICODE c, char *output, Py_ssize_t chars)
{
    /* Escape unicode code point c to ASCII escape sequences
    in char *output. output must have at least 12 bytes unused to
    accommodate an escaped surrogate pair "\uXXXX\uXXXX" */
    output[chars++] = '\\';
    switch (c) {
        case '\\': output[chars++] = (char)c; break;
        case '"': output[chars++] = (char)c; break;
        case '\b': output[chars++] = 'b'; break;
        case '\f': output[chars++] = 'f'; break;
        case '\n': output[chars++] = 'n'; break;
        case '\r': output[chars++] = 'r'; break;
        case '\t': output[chars++] = 't'; break;
        default:
#ifdef Py_UNICODE_WIDE
            if (c >= 0x10000) {
                /* UTF-16 surrogate pair */
                Py_UNICODE v = c - 0x10000;
                c = 0xd800 | ((v >> 10) & 0x3ff);
                output[chars++] = 'u';
                output[chars++] = "0123456789abcdef"[(c >> 12) & 0xf];
                output[chars++] = "0123456789abcdef"[(c >>  8) & 0xf];
                output[chars++] = "0123456789abcdef"[(c >>  4) & 0xf];
                output[chars++] = "0123456789abcdef"[(c      ) & 0xf];
                c = 0xdc00 | (v & 0x3ff);
                output[chars++] = '\\';
            }
#endif
            output[chars++] = 'u';
            output[chars++] = "0123456789abcdef"[(c >> 12) & 0xf];
            output[chars++] = "0123456789abcdef"[(c >>  8) & 0xf];
            output[chars++] = "0123456789abcdef"[(c >>  4) & 0xf];
            output[chars++] = "0123456789abcdef"[(c      ) & 0xf];
    }
    return chars;
}

static PyObject *
ascii_escape_unicode(PyObject *pystr)
{
    /* Take a PyUnicode pystr and return a new ASCII-only escaped PyString */
    Py_ssize_t i;
    Py_ssize_t input_chars;
    Py_ssize_t output_size;
    Py_ssize_t max_output_size;
    Py_ssize_t chars;
    Py_ssize_t incr;
    PyObject *rval;
    char *output;
    Py_UNICODE *input_unicode;

    input_chars = PyUnicode_GET_SIZE(pystr);
    input_unicode = PyUnicode_AS_UNICODE(pystr);

    output_size = input_chars;
    incr = 2; /* for quotes */
    /* One char input can be up to 6 chars output, estimate 4 of these */
    incr += MIN_EXPANSION * 4;
    if (PY_SSIZE_T_MAX - incr < output_size) {
        PyErr_NoMemory();
        return NULL;
    }
    output_size += incr;
    if (PY_SSIZE_T_MAX / MAX_EXPANSION < input_chars ||
        PY_SSIZE_T_MAX - 2 < input_chars * MAX_EXPANSION)
        max_output_size = PY_SSIZE_T_MAX;
    else
        max_output_size = 2 + (input_chars * MAX_EXPANSION);
    rval = PyString_FromStringAndSize(NULL, output_size);
    if (rval == NULL) {
        return NULL;
    }
    output = PyString_AS_STRING(rval);
    chars = 0;
    output[chars++] = '"';
    for (i = 0; i < input_chars; i++) {
        Py_UNICODE c = input_unicode[i];
        if (S_CHAR(c)) {
            output[chars++] = (char)c;
        }
        else {
            chars = ascii_escape_char(c, output, chars);
        }
        if (output_size - chars < (1 + MAX_EXPANSION)) {
            if (output_size == PY_SSIZE_T_MAX) {
                Py_DECREF(rval);
                PyErr_NoMemory();
                return NULL;
            }
            /* There's more than four, so let's resize by a lot */
            if (PY_SSIZE_T_MAX / 2 >= output_size && output_size * 2 < max_output_size)
                output_size *= 2;
            else
                output_size = max_output_size;
            if (_PyString_Resize(&rval, output_size) == -1) {
                return NULL;
            }
            output = PyString_AS_STRING(rval);
        }
    }
    output[chars++] = '"';
    if (_PyString_Resize(&rval, chars) == -1) {
        return NULL;
    }
    return rval;
}

static PyObject *
ascii_escape_str(PyObject *pystr)
{
    /* Take a PyString pystr and return a new ASCII-only escaped PyString */
    Py_ssize_t i;
    Py_ssize_t input_chars;
    Py_ssize_t output_size;
    Py_ssize_t max_output_size;
    Py_ssize_t chars;
    Py_ssize_t incr;
    PyObject *rval;
    char *output;
    char *input_str;

    input_chars = PyString_GET_SIZE(pystr);
    input_str = PyString_AS_STRING(pystr);

    /* Fast path for a string that's already ASCII */
    for (i = 0; i < input_chars; i++) {
        Py_UNICODE c = (Py_UNICODE)(unsigned char)input_str[i];
        if (!S_CHAR(c)) {
            /* If we have to escape something, scan the string for unicode */
            Py_ssize_t j;
            for (j = i; j < input_chars; j++) {
                c = (Py_UNICODE)(unsigned char)input_str[j];
                if (c > 0x7f) {
                    /* We hit a non-ASCII character, bail to unicode mode */
                    PyObject *uni;
                    uni = PyUnicode_DecodeUTF8(input_str, input_chars, "strict");
                    if (uni == NULL) {
                        return NULL;
                    }
                    rval = ascii_escape_unicode(uni);
                    Py_DECREF(uni);
                    return rval;
                }
            }
            break;
        }
    }

    output_size = input_chars;
    incr = 2; /* for quotes */
    if (i != input_chars) {
        /* One char input can be up to 6 chars output, estimate 4 of these */
        incr += MIN_EXPANSION * 4;
    }
    if (PY_SSIZE_T_MAX - incr < output_size) {
        PyErr_NoMemory();
        return NULL;
    }
    output_size += incr;
    if (PY_SSIZE_T_MAX / MIN_EXPANSION < input_chars ||
        PY_SSIZE_T_MAX - 2 < input_chars * MIN_EXPANSION)
        max_output_size = PY_SSIZE_T_MAX;
    else
        max_output_size = 2 + (input_chars * MIN_EXPANSION);
    rval = PyString_FromStringAndSize(NULL, output_size);
    if (rval == NULL) {
        return NULL;
    }
    output = PyString_AS_STRING(rval);
    output[0] = '"';

    /* We know that everything up to i is ASCII already */
    chars = i + 1;
    memcpy(&output[1], input_str, i);

    for (; i < input_chars; i++) {
        Py_UNICODE c = (Py_UNICODE)(unsigned char)input_str[i];
        if (S_CHAR(c)) {
            output[chars++] = (char)c;
        }
        else {
            chars = ascii_escape_char(c, output, chars);
        }
        /* An ASCII char can't possibly expand to a surrogate! */
        if (output_size - chars < (1 + MIN_EXPANSION)) {
            if (output_size == PY_SSIZE_T_MAX) {
                Py_DECREF(rval);
                PyErr_NoMemory();
                return NULL;
            }
            /* There's more than four, so let's resize by a lot */
            if (PY_SSIZE_T_MAX / 2 >= output_size && output_size * 2 < max_output_size)
                output_size *= 2;
            else
                output_size = max_output_size;
            if (_PyString_Resize(&rval, output_size) == -1) {
                return NULL;
            }
            output = PyString_AS_STRING(rval);
        }
    }
    output[chars++] = '"';
    if (_PyString_Resize(&rval, chars) == -1) {
        return NULL;
    }
    return rval;
}

static void
raise_errmsg(char *msg, PyObject *s, Py_ssize_t end)
{
    /* Use the Python function json.decoder.errmsg to raise a nice
    looking ValueError exception */
    static PyObject *errmsg_fn = NULL;
    PyObject *pymsg;
    if (errmsg_fn == NULL) {
        PyObject *decoder = PyImport_ImportModule("json.decoder");
        if (decoder == NULL)
            return;
        errmsg_fn = PyObject_GetAttrString(decoder, "errmsg");
        Py_DECREF(decoder);
        if (errmsg_fn == NULL)
            return;
    }
    pymsg = PyObject_CallFunction(errmsg_fn, "(zOO&)", msg, s, _convertPyInt_FromSsize_t, &end);
    if (pymsg) {
        PyErr_SetObject(PyExc_ValueError, pymsg);
        Py_DECREF(pymsg);
    }
}

static PyObject *
join_list_unicode(PyObject *lst)
{
    /* return u''.join(lst) */
    static PyObject *joinfn = NULL;
    if (joinfn == NULL) {
        PyObject *ustr = PyUnicode_FromUnicode(NULL, 0);
        if (ustr == NULL)
            return NULL;

        joinfn = PyObject_GetAttrString(ustr, "join");
        Py_DECREF(ustr);
        if (joinfn == NULL)
            return NULL;
    }
    return PyObject_CallFunctionObjArgs(joinfn, lst, NULL);
}

static PyObject *
_build_rval_index_tuple(PyObject *rval, Py_ssize_t idx) {
    /* return (rval, idx) tuple, stealing reference to rval */
    PyObject *tpl;
    PyObject *pyidx;
    /*
    steal a reference to rval, returns (rval, idx)
    */
    if (rval == NULL) {
        return NULL;
    }
    pyidx = PyInt_FromSsize_t(idx);
    if (pyidx == NULL) {
        Py_DECREF(rval);
        return NULL;
    }
    tpl = PyTuple_New(2);
    if (tpl == NULL) {
        Py_DECREF(pyidx);
        Py_DECREF(rval);
        return NULL;
    }
    PyTuple_SET_ITEM(tpl, 0, rval);
    PyTuple_SET_ITEM(tpl, 1, pyidx);
    return tpl;
}

static PyObject *
scanstring_str(PyObject *pystr, Py_ssize_t end, char *encoding, int strict, Py_ssize_t *next_end_ptr)
{
    /* Read the JSON string from PyString pystr.
    end is the index of the first character after the quote.
    encoding is the encoding of pystr (must be an ASCII superset)
    if strict is zero then literal control characters are allowed
    *next_end_ptr is a return-by-reference index of the character
        after the end quote

    Return value is a new PyString (if ASCII-only) or PyUnicode
    */
    PyObject *rval;
    Py_ssize_t len = PyString_GET_SIZE(pystr);
    Py_ssize_t begin = end - 1;
    Py_ssize_t next;
    char *buf = PyString_AS_STRING(pystr);
    PyObject *chunks = PyList_New(0);
    if (chunks == NULL) {
        goto bail;
    }
    if (end < 0 || len <= end) {
        PyErr_SetString(PyExc_ValueError, "end is out of bounds");
        goto bail;
    }
    while (1) {
        /* Find the end of the string or the next escape */
        Py_UNICODE c = 0;
        PyObject *chunk = NULL;
        for (next = end; next < len; next++) {
            c = (unsigned char)buf[next];
            if (c == '"' || c == '\\') {
                break;
            }
            else if (strict && c <= 0x1f) {
                raise_errmsg("Invalid control character at", pystr, next);
                goto bail;
            }
        }
        if (!(c == '"' || c == '\\')) {
            raise_errmsg("Unterminated string starting at", pystr, begin);
            goto bail;
        }
        /* Pick up this chunk if it's not zero length */
        if (next != end) {
            PyObject *strchunk = PyString_FromStringAndSize(&buf[end], next - end);
            if (strchunk == NULL) {
                goto bail;
            }
            chunk = PyUnicode_FromEncodedObject(strchunk, encoding, NULL);
            Py_DECREF(strchunk);
            if (chunk == NULL) {
                goto bail;
            }
            if (PyList_Append(chunks, chunk)) {
                Py_DECREF(chunk);
                goto bail;
            }
            Py_DECREF(chunk);
        }
        next++;
        if (c == '"') {
            end = next;
            break;
        }
        if (next == len) {
            raise_errmsg("Unterminated string starting at", pystr, begin);
            goto bail;
        }
        c = buf[next];
        if (c != 'u') {
            /* Non-unicode backslash escapes */
            end = next + 1;
            switch (c) {
                case '"': break;
                case '\\': break;
                case '/': break;
                case 'b': c = '\b'; break;
                case 'f': c = '\f'; break;
                case 'n': c = '\n'; break;
                case 'r': c = '\r'; break;
                case 't': c = '\t'; break;
                default: c = 0;
            }
            if (c == 0) {
                raise_errmsg("Invalid \\escape", pystr, end - 2);
                goto bail;
            }
        }
        else {
            c = 0;
            next++;
            end = next + 4;
            if (end >= len) {
                raise_errmsg("Invalid \\uXXXX escape", pystr, next - 1);
                goto bail;
            }
            /* Decode 4 hex digits */
            for (; next < end; next++) {
                Py_UNICODE digit = buf[next];
                c <<= 4;
                switch (digit) {
                    case '0': case '1': case '2': case '3': case '4':
                    case '5': case '6': case '7': case '8': case '9':
                        c |= (digit - '0'); break;
                    case 'a': case 'b': case 'c': case 'd': case 'e':
                    case 'f':
                        c |= (digit - 'a' + 10); break;
                    case 'A': case 'B': case 'C': case 'D': case 'E':
                    case 'F':
                        c |= (digit - 'A' + 10); break;
                    default:
                        raise_errmsg("Invalid \\uXXXX escape", pystr, end - 5);
                        goto bail;
                }
            }
#ifdef Py_UNICODE_WIDE
            /* Surrogate pair */
            if ((c & 0xfc00) == 0xd800 && end + 6 < len &&
                buf[next++] == '\\' &&
                buf[next++] == 'u') {
                Py_UNICODE c2 = 0;
                end += 6;
                /* Decode 4 hex digits */
                for (; next < end; next++) {
                    Py_UNICODE digit = buf[next];
                    c2 <<= 4;
                    switch (digit) {
                        case '0': case '1': case '2': case '3': case '4':
                        case '5': case '6': case '7': case '8': case '9':
                            c2 |= (digit - '0'); break;
                        case 'a': case 'b': case 'c': case 'd': case 'e':
                        case 'f':
                            c2 |= (digit - 'a' + 10); break;
                        case 'A': case 'B': case 'C': case 'D': case 'E':
                        case 'F':
                            c2 |= (digit - 'A' + 10); break;
                        default:
                            raise_errmsg("Invalid \\uXXXX escape", pystr, end - 5);
                            goto bail;
                    }
                }
                if ((c2 & 0xfc00) == 0xdc00)
                    c = 0x10000 + (((c - 0xd800) << 10) | (c2 - 0xdc00));
                else
                    end -= 6;
            }
#endif
        }
        chunk = PyUnicode_FromUnicode(&c, 1);
        if (chunk == NULL) {
            goto bail;
        }
        if (PyList_Append(chunks, chunk)) {
            Py_DECREF(chunk);
            goto bail;
        }
        Py_DECREF(chunk);
    }

    rval = join_list_unicode(chunks);
    if (rval == NULL) {
        goto bail;
    }
    Py_CLEAR(chunks);
    *next_end_ptr = end;
    return rval;
bail:
    *next_end_ptr = -1;
    Py_XDECREF(chunks);
    return NULL;
}


static PyObject *
scanstring_unicode(PyObject *pystr, Py_ssize_t end, int strict, Py_ssize_t *next_end_ptr)
{
    /* Read the JSON string from PyUnicode pystr.
    end is the index of the first character after the quote.
    if strict is zero then literal control characters are allowed
    *next_end_ptr is a return-by-reference index of the character
        after the end quote

    Return value is a new PyUnicode
    */
    PyObject *rval;
    Py_ssize_t len = PyUnicode_GET_SIZE(pystr);
    Py_ssize_t begin = end - 1;
    Py_ssize_t next;
    const Py_UNICODE *buf = PyUnicode_AS_UNICODE(pystr);
    PyObject *chunks = PyList_New(0);
    if (chunks == NULL) {
        goto bail;
    }
    if (end < 0 || len <= end) {
        PyErr_SetString(PyExc_ValueError, "end is out of bounds");
        goto bail;
    }
    while (1) {
        /* Find the end of the string or the next escape */
        Py_UNICODE c = 0;
        PyObject *chunk = NULL;
        for (next = end; next < len; next++) {
            c = buf[next];
            if (c == '"' || c == '\\') {
                break;
            }
            else if (strict && c <= 0x1f) {
                raise_errmsg("Invalid control character at", pystr, next);
                goto bail;
            }
        }
        if (!(c == '"' || c == '\\')) {
            raise_errmsg("Unterminated string starting at", pystr, begin);
            goto bail;
        }
        /* Pick up this chunk if it's not zero length */
        if (next != end) {
            chunk = PyUnicode_FromUnicode(&buf[end], next - end);
            if (chunk == NULL) {
                goto bail;
            }
            if (PyList_Append(chunks, chunk)) {
                Py_DECREF(chunk);
                goto bail;
            }
            Py_DECREF(chunk);
        }
        next++;
        if (c == '"') {
            end = next;
            break;
        }
        if (next == len) {
            raise_errmsg("Unterminated string starting at", pystr, begin);
            goto bail;
        }
        c = buf[next];
        if (c != 'u') {
            /* Non-unicode backslash escapes */
            end = next + 1;
            switch (c) {
                case '"': break;
                case '\\': break;
                case '/': break;
                case 'b': c = '\b'; break;
                case 'f': c = '\f'; break;
                case 'n': c = '\n'; break;
                case 'r': c = '\r'; break;
                case 't': c = '\t'; break;
                default: c = 0;
            }
            if (c == 0) {
                raise_errmsg("Invalid \\escape", pystr, end - 2);
                goto bail;
            }
        }
        else {
            c = 0;
            next++;
            end = next + 4;
            if (end >= len) {
                raise_errmsg("Invalid \\uXXXX escape", pystr, next - 1);
                goto bail;
            }
            /* Decode 4 hex digits */
            for (; next < end; next++) {
                Py_UNICODE digit = buf[next];
                c <<= 4;
                switch (digit) {
                    case '0': case '1': case '2': case '3': case '4':
                    case '5': case '6': case '7': case '8': case '9':
                        c |= (digit - '0'); break;
                    case 'a': case 'b': case 'c': case 'd': case 'e':
                    case 'f':
                        c |= (digit - 'a' + 10); break;
                    case 'A': case 'B': case 'C': case 'D': case 'E':
                    case 'F':
                        c |= (digit - 'A' + 10); break;
                    default:
                        raise_errmsg("Invalid \\uXXXX escape", pystr, end - 5);
                        goto bail;
                }
            }
#ifdef Py_UNICODE_WIDE
            /* Surrogate pair */
            if ((c & 0xfc00) == 0xd800 && end + 6 < len &&
                buf[next++] == '\\' && buf[next++] == 'u') {
                Py_UNICODE c2 = 0;
                end += 6;
                /* Decode 4 hex digits */
                for (; next < end; next++) {
                    Py_UNICODE digit = buf[next];
                    c2 <<= 4;
                    switch (digit) {
                        case '0': case '1': case '2': case '3': case '4':
                        case '5': case '6': case '7': case '8': case '9':
                            c2 |= (digit - '0'); break;
                        case 'a': case 'b': case 'c': case 'd': case 'e':
                        case 'f':
                            c2 |= (digit - 'a' + 10); break;
                        case 'A': case 'B': case 'C': case 'D': case 'E':
                        case 'F':
                            c2 |= (digit - 'A' + 10); break;
                        default:
                            raise_errmsg("Invalid \\uXXXX escape", pystr, end - 5);
                            goto bail;
                    }
                }
                if ((c2 & 0xfc00) == 0xdc00)
                    c = 0x10000 + (((c - 0xd800) << 10) | (c2 - 0xdc00));
                else
                    end -= 6;
            }
#endif
        }
        chunk = PyUnicode_FromUnicode(&c, 1);
        if (chunk == NULL) {
            goto bail;
        }
        if (PyList_Append(chunks, chunk)) {
            Py_DECREF(chunk);
            goto bail;
        }
        Py_DECREF(chunk);
    }

    rval = join_list_unicode(chunks);
    if (rval == NULL) {
        goto bail;
    }
    Py_DECREF(chunks);
    *next_end_ptr = end;
    return rval;
bail:
    *next_end_ptr = -1;
    Py_XDECREF(chunks);
    return NULL;
}

PyDoc_STRVAR(pydoc_scanstring,
    "scanstring(basestring, end, encoding, strict=True) -> (str, end)\n"
    "\n"
    "Scan the string s for a JSON string. End is the index of the\n"
    "character in s after the quote that started the JSON string.\n"
    "Unescapes all valid JSON string escape sequences and raises ValueError\n"
    "on attempt to decode an invalid string. If strict is False then literal\n"
    "control characters are allowed in the string.\n"
    "\n"
    "Returns a tuple of the decoded string and the index of the character in s\n"
    "after the end quote."
);

static PyObject *
py_scanstring(PyObject* self UNUSED, PyObject *args)
{
    PyObject *pystr;
    PyObject *rval;
    Py_ssize_t end;
    Py_ssize_t next_end = -1;
    char *encoding = NULL;
    int strict = 1;
    if (!PyArg_ParseTuple(args, "OO&|zi:scanstring", &pystr, _convertPyInt_AsSsize_t, &end, &encoding, &strict)) {
        return NULL;
    }
    if (encoding == NULL) {
        encoding = DEFAULT_ENCODING;
    }
    if (PyString_Check(pystr)) {
        rval = scanstring_str(pystr, end, encoding, strict, &next_end);
    }
    else if (PyUnicode_Check(pystr)) {
        rval = scanstring_unicode(pystr, end, strict, &next_end);
    }
    else {
        PyErr_Format(PyExc_TypeError,
                     "first argument must be a string, not %.80s",
                     Py_TYPE(pystr)->tp_name);
        return NULL;
    }
    return _build_rval_index_tuple(rval, next_end);
}

PyDoc_STRVAR(pydoc_encode_basestring_ascii,
    "encode_basestring_ascii(basestring) -> str\n"
    "\n"
    "Return an ASCII-only JSON representation of a Python string"
);

static PyObject *
py_encode_basestring_ascii(PyObject* self UNUSED, PyObject *pystr)
{
    /* Return an ASCII-only JSON representation of a Python string */
    /* METH_O */
    if (PyString_Check(pystr)) {
        return ascii_escape_str(pystr);
    }
    else if (PyUnicode_Check(pystr)) {
        return ascii_escape_unicode(pystr);
    }
    else {
        PyErr_Format(PyExc_TypeError,
                     "first argument must be a string, not %.80s",
                     Py_TYPE(pystr)->tp_name);
        return NULL;
    }
}

static void
scanner_dealloc(PyObject *self)
{
    /* bpo-31095: UnTrack is needed before calling any callbacks */
    PyObject_GC_UnTrack(self);
    scanner_clear(self);
    Py_TYPE(self)->tp_free(self);
}

static int
scanner_traverse(PyObject *self, visitproc visit, void *arg)
{
    PyScannerObject *s;
    assert(PyScanner_Check(self));
    s = (PyScannerObject *)self;
    Py_VISIT(s->encoding);
    Py_VISIT(s->strict);
    Py_VISIT(s->object_hook);
    Py_VISIT(s->pairs_hook);
    Py_VISIT(s->parse_float);
    Py_VISIT(s->parse_int);
    Py_VISIT(s->parse_constant);
    return 0;
}

static int
scanner_clear(PyObject *self)
{
    PyScannerObject *s;
    assert(PyScanner_Check(self));
    s = (PyScannerObject *)self;
    Py_CLEAR(s->encoding);
    Py_CLEAR(s->strict);
    Py_CLEAR(s->object_hook);
    Py_CLEAR(s->pairs_hook);
    Py_CLEAR(s->parse_float);
    Py_CLEAR(s->parse_int);
    Py_CLEAR(s->parse_constant);
    return 0;
}

static PyObject *
_parse_object_str(PyScannerObject *s, PyObject *pystr, Py_ssize_t idx, Py_ssize_t *next_idx_ptr) {
    /* Read a JSON object from PyString pystr.
    idx is the index of the first character after the opening curly brace.
    *next_idx_ptr is a return-by-reference index to the first character after
        the closing curly brace.

    Returns a new PyObject (usually a dict, but object_hook can change that)
    */
    char *str = PyString_AS_STRING(pystr);
    Py_ssize_t end_idx = PyString_GET_SIZE(pystr) - 1;
    PyObject *rval;
    PyObject *pairs;
    PyObject *item;
    PyObject *key = NULL;
    PyObject *val = NULL;
    char *encoding = PyString_AS_STRING(s->encoding);
    int strict = PyObject_IsTrue(s->strict);
    Py_ssize_t next_idx;

    if (strict < 0)
        return NULL;

    pairs = PyList_New(0);
    if (pairs == NULL)
        return NULL;

    /* skip whitespace after { */
    while (idx <= end_idx && IS_WHITESPACE(str[idx])) idx++;

    /* only loop if the object is non-empty */
    if (idx <= end_idx && str[idx] != '}') {
        while (idx <= end_idx) {
            /* read key */
            if (str[idx] != '"') {
                raise_errmsg("Expecting property name", pystr, idx);
                goto bail;
            }
            key = scanstring_str(pystr, idx + 1, encoding, strict, &next_idx);
            if (key == NULL)
                goto bail;
            idx = next_idx;

            /* skip whitespace between key and : delimiter, read :, skip whitespace */
            while (idx <= end_idx && IS_WHITESPACE(str[idx])) idx++;
            if (idx > end_idx || str[idx] != ':') {
                raise_errmsg("Expecting : delimiter", pystr, idx);
                goto bail;
            }
            idx++;
            while (idx <= end_idx && IS_WHITESPACE(str[idx])) idx++;

            /* read any JSON data type */
            val = scan_once_str(s, pystr, idx, &next_idx);
            if (val == NULL)
                goto bail;

            item = PyTuple_Pack(2, key, val);
            if (item == NULL)
                goto bail;
            Py_CLEAR(key);
            Py_CLEAR(val);
            if (PyList_Append(pairs, item) == -1) {
                Py_DECREF(item);
                goto bail;
            }
            Py_DECREF(item);
            idx = next_idx;

            /* skip whitespace before } or , */
            while (idx <= end_idx && IS_WHITESPACE(str[idx])) idx++;

            /* bail if the object is closed or we didn't get the , delimiter */
            if (idx > end_idx) break;
            if (str[idx] == '}') {
                break;
            }
            else if (str[idx] != ',') {
                raise_errmsg("Expecting , delimiter", pystr, idx);
                goto bail;
            }
            idx++;

            /* skip whitespace after , delimiter */
            while (idx <= end_idx && IS_WHITESPACE(str[idx])) idx++;
        }
    }
    /* verify that idx < end_idx, str[idx] should be '}' */
    if (idx > end_idx || str[idx] != '}') {
        raise_errmsg("Expecting object", pystr, end_idx);
        goto bail;
    }

    /* if pairs_hook is not None: rval = object_pairs_hook(pairs) */
    if (s->pairs_hook != Py_None) {
        val = PyObject_CallFunctionObjArgs(s->pairs_hook, pairs, NULL);
        if (val == NULL)
            goto bail;
        Py_DECREF(pairs);
        *next_idx_ptr = idx + 1;
        return val;
    }

    rval = PyObject_CallFunctionObjArgs((PyObject *)(&PyDict_Type), 
                                         pairs, NULL);
    if (rval == NULL)
        goto bail;
    Py_CLEAR(pairs);

    /* if object_hook is not None: rval = object_hook(rval) */
    if (s->object_hook != Py_None) {
        val = PyObject_CallFunctionObjArgs(s->object_hook, rval, NULL);
        if (val == NULL)
            goto bail;
        Py_DECREF(rval);
        rval = val;
        val = NULL;
    }
    *next_idx_ptr = idx + 1;
    return rval;
bail:
    Py_XDECREF(key);
    Py_XDECREF(val);
    Py_XDECREF(pairs);
    return NULL;
}

static PyObject *
_parse_object_unicode(PyScannerObject *s, PyObject *pystr, Py_ssize_t idx, Py_ssize_t *next_idx_ptr) {
    /* Read a JSON object from PyUnicode pystr.
    idx is the index of the first character after the opening curly brace.
    *next_idx_ptr is a return-by-reference index to the first character after
        the closing curly brace.

    Returns a new PyObject (usually a dict, but object_hook can change that)
    */
    Py_UNICODE *str = PyUnicode_AS_UNICODE(pystr);
    Py_ssize_t end_idx = PyUnicode_GET_SIZE(pystr) - 1;
    PyObject *rval;
    PyObject *pairs;
    PyObject *item;
    PyObject *key = NULL;
    PyObject *val = NULL;
    int strict = PyObject_IsTrue(s->strict);
    Py_ssize_t next_idx;

    if (strict < 0)
        return NULL;

    pairs = PyList_New(0);
    if (pairs == NULL)
        return NULL;

    /* skip whitespace after { */
    while (idx <= end_idx && IS_WHITESPACE(str[idx])) idx++;

    /* only loop if the object is non-empty */
    if (idx <= end_idx && str[idx] != '}') {
        while (idx <= end_idx) {
            /* read key */
            if (str[idx] != '"') {
                raise_errmsg("Expecting property name enclosed in double quotes", pystr, idx);
                goto bail;
            }
            key = scanstring_unicode(pystr, idx + 1, strict, &next_idx);
            if (key == NULL)
                goto bail;
            idx = next_idx;

            /* skip whitespace between key and : delimiter, read :, skip whitespace */
            while (idx <= end_idx && IS_WHITESPACE(str[idx])) idx++;
            if (idx > end_idx || str[idx] != ':') {
                raise_errmsg("Expecting ':' delimiter", pystr, idx);
                goto bail;
            }
            idx++;
            while (idx <= end_idx && IS_WHITESPACE(str[idx])) idx++;

            /* read any JSON term */
            val = scan_once_unicode(s, pystr, idx, &next_idx);
            if (val == NULL)
                goto bail;

            item = PyTuple_Pack(2, key, val);
            if (item == NULL)
                goto bail;
            Py_CLEAR(key);
            Py_CLEAR(val);
            if (PyList_Append(pairs, item) == -1) {
                Py_DECREF(item);
                goto bail;
            }
            Py_DECREF(item);
            idx = next_idx;

            /* skip whitespace before } or , */
            while (idx <= end_idx && IS_WHITESPACE(str[idx])) idx++;

            /* bail if the object is closed or we didn't get the , delimiter */
            if (idx > end_idx) break;
            if (str[idx] == '}') {
                break;
            }
            else if (str[idx] != ',') {
                raise_errmsg("Expecting ',' delimiter", pystr, idx);
                goto bail;
            }
            idx++;

            /* skip whitespace after , delimiter */
            while (idx <= end_idx && IS_WHITESPACE(str[idx])) idx++;
        }
    }

    /* verify that idx < end_idx, str[idx] should be '}' */
    if (idx > end_idx || str[idx] != '}') {
        raise_errmsg("Expecting object", pystr, end_idx);
        goto bail;
    }

    /* if pairs_hook is not None: rval = object_pairs_hook(pairs) */
    if (s->pairs_hook != Py_None) {
        val = PyObject_CallFunctionObjArgs(s->pairs_hook, pairs, NULL);
        if (val == NULL)
            goto bail;
        Py_DECREF(pairs);
        *next_idx_ptr = idx + 1;
        return val;
    }

    rval = PyObject_CallFunctionObjArgs((PyObject *)(&PyDict_Type), 
                                         pairs, NULL);
    if (rval == NULL)
        goto bail;
    Py_CLEAR(pairs);

    /* if object_hook is not None: rval = object_hook(rval) */
    if (s->object_hook != Py_None) {
        val = PyObject_CallFunctionObjArgs(s->object_hook, rval, NULL);
        if (val == NULL)
            goto bail;
        Py_DECREF(rval);
        rval = val;
        val = NULL;
    }
    *next_idx_ptr = idx + 1;
    return rval;
bail:
    Py_XDECREF(key);
    Py_XDECREF(val);
    Py_XDECREF(pairs);
    return NULL;
}

static PyObject *
_parse_array_str(PyScannerObject *s, PyObject *pystr, Py_ssize_t idx, Py_ssize_t *next_idx_ptr) {
    /* Read a JSON array from PyString pystr.
    idx is the index of the first character after the opening brace.
    *next_idx_ptr is a return-by-reference index to the first character after
        the closing brace.

    Returns a new PyList
    */
    char *str = PyString_AS_STRING(pystr);
    Py_ssize_t end_idx = PyString_GET_SIZE(pystr) - 1;
    PyObject *val = NULL;
    PyObject *rval = PyList_New(0);
    Py_ssize_t next_idx;
    if (rval == NULL)
        return NULL;

    /* skip whitespace after [ */
    while (idx <= end_idx && IS_WHITESPACE(str[idx])) idx++;

    /* only loop if the array is non-empty */
    if (idx <= end_idx && str[idx] != ']') {
        while (idx <= end_idx) {

            /* read any JSON term and de-tuplefy the (rval, idx) */
            val = scan_once_str(s, pystr, idx, &next_idx);
            if (val == NULL)
                goto bail;

            if (PyList_Append(rval, val) == -1)
                goto bail;

            Py_CLEAR(val);
            idx = next_idx;

            /* skip whitespace between term and , */
            while (idx <= end_idx && IS_WHITESPACE(str[idx])) idx++;

            /* bail if the array is closed or we didn't get the , delimiter */
            if (idx > end_idx) break;
            if (str[idx] == ']') {
                break;
            }
            else if (str[idx] != ',') {
                raise_errmsg("Expecting , delimiter", pystr, idx);
                goto bail;
            }
            idx++;

            /* skip whitespace after , */
            while (idx <= end_idx && IS_WHITESPACE(str[idx])) idx++;
        }
    }

    /* verify that idx < end_idx, str[idx] should be ']' */
    if (idx > end_idx || str[idx] != ']') {
        raise_errmsg("Expecting object", pystr, end_idx);
        goto bail;
    }
    *next_idx_ptr = idx + 1;
    return rval;
bail:
    Py_XDECREF(val);
    Py_DECREF(rval);
    return NULL;
}

static PyObject *
_parse_array_unicode(PyScannerObject *s, PyObject *pystr, Py_ssize_t idx, Py_ssize_t *next_idx_ptr) {
    /* Read a JSON array from PyString pystr.
    idx is the index of the first character after the opening brace.
    *next_idx_ptr is a return-by-reference index to the first character after
        the closing brace.

    Returns a new PyList
    */
    Py_UNICODE *str = PyUnicode_AS_UNICODE(pystr);
    Py_ssize_t end_idx = PyUnicode_GET_SIZE(pystr) - 1;
    PyObject *val = NULL;
    PyObject *rval = PyList_New(0);
    Py_ssize_t next_idx;
    if (rval == NULL)
        return NULL;

    /* skip whitespace after [ */
    while (idx <= end_idx && IS_WHITESPACE(str[idx])) idx++;

    /* only loop if the array is non-empty */
    if (idx <= end_idx && str[idx] != ']') {
        while (idx <= end_idx) {

            /* read any JSON term  */
            val = scan_once_unicode(s, pystr, idx, &next_idx);
            if (val == NULL)
                goto bail;

            if (PyList_Append(rval, val) == -1)
                goto bail;

            Py_CLEAR(val);
            idx = next_idx;

            /* skip whitespace between term and , */
            while (idx <= end_idx && IS_WHITESPACE(str[idx])) idx++;

            /* bail if the array is closed or we didn't get the , delimiter */
            if (idx > end_idx) break;
            if (str[idx] == ']') {
                break;
            }
            else if (str[idx] != ',') {
                raise_errmsg("Expecting ',' delimiter", pystr, idx);
                goto bail;
            }
            idx++;

            /* skip whitespace after , */
            while (idx <= end_idx && IS_WHITESPACE(str[idx])) idx++;
        }
    }

    /* verify that idx < end_idx, str[idx] should be ']' */
    if (idx > end_idx || str[idx] != ']') {
        raise_errmsg("Expecting object", pystr, end_idx);
        goto bail;
    }
    *next_idx_ptr = idx + 1;
    return rval;
bail:
    Py_XDECREF(val);
    Py_DECREF(rval);
    return NULL;
}

static PyObject *
_parse_constant(PyScannerObject *s, char *constant, Py_ssize_t idx, Py_ssize_t *next_idx_ptr) {
    /* Read a JSON constant from PyString pystr.
    constant is the constant string that was found
        ("NaN", "Infinity", "-Infinity").
    idx is the index of the first character of the constant
    *next_idx_ptr is a return-by-reference index to the first character after
        the constant.

    Returns the result of parse_constant
    */
    PyObject *cstr;
    PyObject *rval;
    /* constant is "NaN", "Infinity", or "-Infinity" */
    cstr = PyString_InternFromString(constant);
    if (cstr == NULL)
        return NULL;

    /* rval = parse_constant(constant) */
    rval = PyObject_CallFunctionObjArgs(s->parse_constant, cstr, NULL);
    idx += PyString_GET_SIZE(cstr);
    Py_DECREF(cstr);
    *next_idx_ptr = idx;
    return rval;
}

static PyObject *
_match_number_str(PyScannerObject *s, PyObject *pystr, Py_ssize_t start, Py_ssize_t *next_idx_ptr) {
    /* Read a JSON number from PyString pystr.
    idx is the index of the first character of the number
    *next_idx_ptr is a return-by-reference index to the first character after
        the number.

    Returns a new PyObject representation of that number:
        PyInt, PyLong, or PyFloat.
        May return other types if parse_int or parse_float are set
    */
    char *str = PyString_AS_STRING(pystr);
    Py_ssize_t end_idx = PyString_GET_SIZE(pystr) - 1;
    Py_ssize_t idx = start;
    int is_float = 0;
    PyObject *rval;
    PyObject *numstr;

    /* read a sign if it's there, make sure it's not the end of the string */
    if (str[idx] == '-') {
        idx++;
        if (idx > end_idx) {
            PyErr_SetNone(PyExc_StopIteration);
            return NULL;
        }
    }

    /* read as many integer digits as we find as long as it doesn't start with 0 */
    if (str[idx] >= '1' && str[idx] <= '9') {
        idx++;
        while (idx <= end_idx && str[idx] >= '0' && str[idx] <= '9') idx++;
    }
    /* if it starts with 0 we only expect one integer digit */
    else if (str[idx] == '0') {
        idx++;
    }
    /* no integer digits, error */
    else {
        PyErr_SetNone(PyExc_StopIteration);
        return NULL;
    }

    /* if the next char is '.' followed by a digit then read all float digits */
    if (idx < end_idx && str[idx] == '.' && str[idx + 1] >= '0' && str[idx + 1] <= '9') {
        is_float = 1;
        idx += 2;
        while (idx <= end_idx && str[idx] >= '0' && str[idx] <= '9') idx++;
    }

    /* if the next char is 'e' or 'E' then maybe read the exponent (or backtrack) */
    if (idx < end_idx && (str[idx] == 'e' || str[idx] == 'E')) {

        /* save the index of the 'e' or 'E' just in case we need to backtrack */
        Py_ssize_t e_start = idx;
        idx++;

        /* read an exponent sign if present */
        if (idx < end_idx && (str[idx] == '-' || str[idx] == '+')) idx++;

        /* read all digits */
        while (idx <= end_idx && str[idx] >= '0' && str[idx] <= '9') idx++;

        /* if we got a digit, then parse as float. if not, backtrack */
        if (str[idx - 1] >= '0' && str[idx - 1] <= '9') {
            is_float = 1;
        }
        else {
            idx = e_start;
        }
    }

    /* copy the section we determined to be a number */
    numstr = PyString_FromStringAndSize(&str[start], idx - start);
    if (numstr == NULL)
        return NULL;
    if (is_float) {
        /* parse as a float using a fast path if available, otherwise call user defined method */
        if (s->parse_float != (PyObject *)&PyFloat_Type) {
            rval = PyObject_CallFunctionObjArgs(s->parse_float, numstr, NULL);
        }
        else {
            double d = PyOS_string_to_double(PyString_AS_STRING(numstr),
                                             NULL, NULL);
            if (d == -1.0 && PyErr_Occurred())
                return NULL;
            rval = PyFloat_FromDouble(d);
        }
    }
    else {
        /* parse as an int using a fast path if available, otherwise call user defined method */
        if (s->parse_int != (PyObject *)&PyInt_Type) {
            rval = PyObject_CallFunctionObjArgs(s->parse_int, numstr, NULL);
        }
        else {
            rval = PyInt_FromString(PyString_AS_STRING(numstr), NULL, 10);
        }
    }
    Py_DECREF(numstr);
    *next_idx_ptr = idx;
    return rval;
}

static PyObject *
_match_number_unicode(PyScannerObject *s, PyObject *pystr, Py_ssize_t start, Py_ssize_t *next_idx_ptr) {
    /* Read a JSON number from PyUnicode pystr.
    idx is the index of the first character of the number
    *next_idx_ptr is a return-by-reference index to the first character after
        the number.

    Returns a new PyObject representation of that number:
        PyInt, PyLong, or PyFloat.
        May return other types if parse_int or parse_float are set
    */
    Py_UNICODE *str = PyUnicode_AS_UNICODE(pystr);
    Py_ssize_t end_idx = PyUnicode_GET_SIZE(pystr) - 1;
    Py_ssize_t idx = start;
    int is_float = 0;
    PyObject *rval;
    PyObject *numstr;

    /* read a sign if it's there, make sure it's not the end of the string */
    if (str[idx] == '-') {
        idx++;
        if (idx > end_idx) {
            PyErr_SetNone(PyExc_StopIteration);
            return NULL;
        }
    }

    /* read as many integer digits as we find as long as it doesn't start with 0 */
    if (str[idx] >= '1' && str[idx] <= '9') {
        idx++;
        while (idx <= end_idx && str[idx] >= '0' && str[idx] <= '9') idx++;
    }
    /* if it starts with 0 we only expect one integer digit */
    else if (str[idx] == '0') {
        idx++;
    }
    /* no integer digits, error */
    else {
        PyErr_SetNone(PyExc_StopIteration);
        return NULL;
    }

    /* if the next char is '.' followed by a digit then read all float digits */
    if (idx < end_idx && str[idx] == '.' && str[idx + 1] >= '0' && str[idx + 1] <= '9') {
        is_float = 1;
        idx += 2;
        while (idx <= end_idx && str[idx] >= '0' && str[idx] <= '9') idx++;
    }

    /* if the next char is 'e' or 'E' then maybe read the exponent (or backtrack) */
    if (idx < end_idx && (str[idx] == 'e' || str[idx] == 'E')) {
        Py_ssize_t e_start = idx;
        idx++;

        /* read an exponent sign if present */
        if (idx < end_idx && (str[idx] == '-' || str[idx] == '+')) idx++;

        /* read all digits */
        while (idx <= end_idx && str[idx] >= '0' && str[idx] <= '9') idx++;

        /* if we got a digit, then parse as float. if not, backtrack */
        if (str[idx - 1] >= '0' && str[idx - 1] <= '9') {
            is_float = 1;
        }
        else {
            idx = e_start;
        }
    }

    /* copy the section we determined to be a number */
    numstr = PyUnicode_FromUnicode(&str[start], idx - start);
    if (numstr == NULL)
        return NULL;
    if (is_float) {
        /* parse as a float using a fast path if available, otherwise call user defined method */
        if (s->parse_float != (PyObject *)&PyFloat_Type) {
            rval = PyObject_CallFunctionObjArgs(s->parse_float, numstr, NULL);
        }
        else {
            rval = PyFloat_FromString(numstr, NULL);
        }
    }
    else {
        /* no fast path for unicode -> int, just call */
        rval = PyObject_CallFunctionObjArgs(s->parse_int, numstr, NULL);
    }
    Py_DECREF(numstr);
    *next_idx_ptr = idx;
    return rval;
}

static PyObject *
scan_once_str(PyScannerObject *s, PyObject *pystr, Py_ssize_t idx, Py_ssize_t *next_idx_ptr)
{
    /* Read one JSON term (of any kind) from PyString pystr.
    idx is the index of the first character of the term
    *next_idx_ptr is a return-by-reference index to the first character after
        the number.

    Returns a new PyObject representation of the term.
    */
    PyObject *res;
    int strict;
    char *str = PyString_AS_STRING(pystr);
    Py_ssize_t length = PyString_GET_SIZE(pystr);
    if (idx < 0) {
        PyErr_SetString(PyExc_ValueError, "idx cannot be negative");
        return NULL;
    }
    if (idx >= length) {
        PyErr_SetNone(PyExc_StopIteration);
        return NULL;
    }
    switch (str[idx]) {
        case '"':
            /* string */
            strict = PyObject_IsTrue(s->strict);
            if (strict < 0)
                return NULL;
            return scanstring_str(pystr, idx + 1,
                PyString_AS_STRING(s->encoding), strict, next_idx_ptr);
        case '{':
            /* object */
            if (Py_EnterRecursiveCall(" while decoding a JSON object "
                                      "from a byte string"))
                return NULL;
            res = _parse_object_str(s, pystr, idx + 1, next_idx_ptr);
            Py_LeaveRecursiveCall();
            return res;
        case '[':
            /* array */
            if (Py_EnterRecursiveCall(" while decoding a JSON array "
                                      "from a byte string"))
                return NULL;
            res = _parse_array_str(s, pystr, idx + 1, next_idx_ptr);
            Py_LeaveRecursiveCall();
            return res;
        case 'n':
            /* null */
            if ((idx + 3 < length) && str[idx + 1] == 'u' && str[idx + 2] == 'l' && str[idx + 3] == 'l') {
                Py_INCREF(Py_None);
                *next_idx_ptr = idx + 4;
                return Py_None;
            }
            break;
        case 't':
            /* true */
            if ((idx + 3 < length) && str[idx + 1] == 'r' && str[idx + 2] == 'u' && str[idx + 3] == 'e') {
                Py_INCREF(Py_True);
                *next_idx_ptr = idx + 4;
                return Py_True;
            }
            break;
        case 'f':
            /* false */
            if ((idx + 4 < length) && str[idx + 1] == 'a' && str[idx + 2] == 'l' && str[idx + 3] == 's' && str[idx + 4] == 'e') {
                Py_INCREF(Py_False);
                *next_idx_ptr = idx + 5;
                return Py_False;
            }
            break;
        case 'N':
            /* NaN */
            if ((idx + 2 < length) && str[idx + 1] == 'a' && str[idx + 2] == 'N') {
                return _parse_constant(s, "NaN", idx, next_idx_ptr);
            }
            break;
        case 'I':
            /* Infinity */
            if ((idx + 7 < length) && str[idx + 1] == 'n' && str[idx + 2] == 'f' && str[idx + 3] == 'i' && str[idx + 4] == 'n' && str[idx + 5] == 'i' && str[idx + 6] == 't' && str[idx + 7] == 'y') {
                return _parse_constant(s, "Infinity", idx, next_idx_ptr);
            }
            break;
        case '-':
            /* -Infinity */
            if ((idx + 8 < length) && str[idx + 1] == 'I' && str[idx + 2] == 'n' && str[idx + 3] == 'f' && str[idx + 4] == 'i' && str[idx + 5] == 'n' && str[idx + 6] == 'i' && str[idx + 7] == 't' && str[idx + 8] == 'y') {
                return _parse_constant(s, "-Infinity", idx, next_idx_ptr);
            }
            break;
    }
    /* Didn't find a string, object, array, or named constant. Look for a number. */
    return _match_number_str(s, pystr, idx, next_idx_ptr);
}

static PyObject *
scan_once_unicode(PyScannerObject *s, PyObject *pystr, Py_ssize_t idx, Py_ssize_t *next_idx_ptr)
{
    /* Read one JSON term (of any kind) from PyUnicode pystr.
    idx is the index of the first character of the term
    *next_idx_ptr is a return-by-reference index to the first character after
        the number.

    Returns a new PyObject representation of the term.
    */
    PyObject *res;
    int strict;
    Py_UNICODE *str = PyUnicode_AS_UNICODE(pystr);
    Py_ssize_t length = PyUnicode_GET_SIZE(pystr);
    if (idx < 0) {
        PyErr_SetString(PyExc_ValueError, "idx cannot be negative");
        return NULL;
    }
    if (idx >= length) {
        PyErr_SetNone(PyExc_StopIteration);
        return NULL;
    }
    switch (str[idx]) {
        case '"':
            /* string */
            strict = PyObject_IsTrue(s->strict);
            if (strict < 0)
                return NULL;
            return scanstring_unicode(pystr, idx + 1, strict, next_idx_ptr);
        case '{':
            /* object */
            if (Py_EnterRecursiveCall(" while decoding a JSON object "
                                      "from a unicode string"))
                return NULL;
            res = _parse_object_unicode(s, pystr, idx + 1, next_idx_ptr);
            Py_LeaveRecursiveCall();
            return res;
        case '[':
            /* array */
            if (Py_EnterRecursiveCall(" while decoding a JSON array "
                                      "from a unicode string"))
                return NULL;
            res = _parse_array_unicode(s, pystr, idx + 1, next_idx_ptr);
            Py_LeaveRecursiveCall();
            return res;
        case 'n':
            /* null */
            if ((idx + 3 < length) && str[idx + 1] == 'u' && str[idx + 2] == 'l' && str[idx + 3] == 'l') {
                Py_INCREF(Py_None);
                *next_idx_ptr = idx + 4;
                return Py_None;
            }
            break;
        case 't':
            /* true */
            if ((idx + 3 < length) && str[idx + 1] == 'r' && str[idx + 2] == 'u' && str[idx + 3] == 'e') {
                Py_INCREF(Py_True);
                *next_idx_ptr = idx + 4;
                return Py_True;
            }
            break;
        case 'f':
            /* false */
            if ((idx + 4 < length) && str[idx + 1] == 'a' && str[idx + 2] == 'l' && str[idx + 3] == 's' && str[idx + 4] == 'e') {
                Py_INCREF(Py_False);
                *next_idx_ptr = idx + 5;
                return Py_False;
            }
            break;
        case 'N':
            /* NaN */
            if ((idx + 2 < length) && str[idx + 1] == 'a' && str[idx + 2] == 'N') {
                return _parse_constant(s, "NaN", idx, next_idx_ptr);
            }
            break;
        case 'I':
            /* Infinity */
            if ((idx + 7 < length) && str[idx + 1] == 'n' && str[idx + 2] == 'f' && str[idx + 3] == 'i' && str[idx + 4] == 'n' && str[idx + 5] == 'i' && str[idx + 6] == 't' && str[idx + 7] == 'y') {
                return _parse_constant(s, "Infinity", idx, next_idx_ptr);
            }
            break;
        case '-':
            /* -Infinity */
            if ((idx + 8 < length) && str[idx + 1] == 'I' && str[idx + 2] == 'n' && str[idx + 3] == 'f' && str[idx + 4] == 'i' && str[idx + 5] == 'n' && str[idx + 6] == 'i' && str[idx + 7] == 't' && str[idx + 8] == 'y') {
                return _parse_constant(s, "-Infinity", idx, next_idx_ptr);
            }
            break;
    }
    /* Didn't find a string, object, array, or named constant. Look for a number. */
    return _match_number_unicode(s, pystr, idx, next_idx_ptr);
}

static PyObject *
scanner_call(PyObject *self, PyObject *args, PyObject *kwds)
{
    /* Python callable interface to scan_once_{str,unicode} */
    PyObject *pystr;
    PyObject *rval;
    Py_ssize_t idx;
    Py_ssize_t next_idx = -1;
    static char *kwlist[] = {"string", "idx", NULL};
    PyScannerObject *s;
    assert(PyScanner_Check(self));
    s = (PyScannerObject *)self;
    if (!PyArg_ParseTupleAndKeywords(args, kwds, "OO&:scan_once", kwlist, &pystr, _convertPyInt_AsSsize_t, &idx))
        return NULL;

    if (PyString_Check(pystr)) {
        rval = scan_once_str(s, pystr, idx, &next_idx);
    }
    else if (PyUnicode_Check(pystr)) {
        rval = scan_once_unicode(s, pystr, idx, &next_idx);
    }
    else {
        PyErr_Format(PyExc_TypeError,
                 "first argument must be a string, not %.80s",
                 Py_TYPE(pystr)->tp_name);
        return NULL;
    }
    return _build_rval_index_tuple(rval, next_idx);
}

static PyObject *
scanner_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
{
    PyScannerObject *s;
    PyObject *ctx;
    static char *kwlist[] = {"context", NULL};

    if (!PyArg_ParseTupleAndKeywords(args, kwds, "O:make_scanner", kwlist, &ctx))
        return NULL;

    s = (PyScannerObject *)type->tp_alloc(type, 0);
    if (s == NULL)
        return NULL;

    /* PyString_AS_STRING is used on encoding */
    s->encoding = PyObject_GetAttrString(ctx, "encoding");
    if (s->encoding == NULL)
        goto bail;
    if (s->encoding == Py_None) {
        Py_DECREF(Py_None);
        s->encoding = PyString_InternFromString(DEFAULT_ENCODING);
    }
    else if (PyUnicode_Check(s->encoding)) {
        PyObject *tmp = PyUnicode_AsEncodedString(s->encoding, NULL, NULL);
        Py_SETREF(s->encoding, tmp);
    }
    if (s->encoding == NULL)
        goto bail;
    if (!PyString_Check(s->encoding)) {
	PyErr_Format(PyExc_TypeError,
		     "encoding must be a string, not %.80s",
		     Py_TYPE(s->encoding)->tp_name);
	goto bail;
    }
       

    /* All of these will fail "gracefully" so we don't need to verify them */
    s->strict = PyObject_GetAttrString(ctx, "strict");
    if (s->strict == NULL)
        goto bail;
    s->object_hook = PyObject_GetAttrString(ctx, "object_hook");
    if (s->object_hook == NULL)
        goto bail;
    s->pairs_hook = PyObject_GetAttrString(ctx, "object_pairs_hook");
    if (s->pairs_hook == NULL)
        goto bail;
    s->parse_float = PyObject_GetAttrString(ctx, "parse_float");
    if (s->parse_float == NULL)
        goto bail;
    s->parse_int = PyObject_GetAttrString(ctx, "parse_int");
    if (s->parse_int == NULL)
        goto bail;
    s->parse_constant = PyObject_GetAttrString(ctx, "parse_constant");
    if (s->parse_constant == NULL)
        goto bail;

    return (PyObject *)s;

bail:
    Py_DECREF(s);
    return NULL;
}

PyDoc_STRVAR(scanner_doc, "JSON scanner object");

static
PyTypeObject PyScannerType = {
    PyVarObject_HEAD_INIT(NULL, 0)
    "_json.Scanner",       /* tp_name */
    sizeof(PyScannerObject), /* tp_basicsize */
    0,                    /* tp_itemsize */
    scanner_dealloc, /* tp_dealloc */
    0,                    /* tp_print */
    0,                    /* tp_getattr */
    0,                    /* tp_setattr */
    0,                    /* tp_compare */
    0,                    /* tp_repr */
    0,                    /* tp_as_number */
    0,                    /* tp_as_sequence */
    0,                    /* tp_as_mapping */
    0,                    /* tp_hash */
    scanner_call,         /* tp_call */
    0,                    /* tp_str */
    0,/* PyObject_GenericGetAttr, */                    /* tp_getattro */
    0,/* PyObject_GenericSetAttr, */                    /* tp_setattro */
    0,                    /* tp_as_buffer */
    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC,   /* tp_flags */
    scanner_doc,          /* tp_doc */
    scanner_traverse,                    /* tp_traverse */
    scanner_clear,                    /* tp_clear */
    0,                    /* tp_richcompare */
    0,                    /* tp_weaklistoffset */
    0,                    /* tp_iter */
    0,                    /* tp_iternext */
    0,                    /* tp_methods */
    scanner_members,                    /* tp_members */
    0,                    /* tp_getset */
    0,                    /* tp_base */
    0,                    /* tp_dict */
    0,                    /* tp_descr_get */
    0,                    /* tp_descr_set */
    0,                    /* tp_dictoffset */
    0,                    /* tp_init */
    0,/* PyType_GenericAlloc, */        /* tp_alloc */
    scanner_new,          /* tp_new */
    0,/* PyObject_GC_Del, */              /* tp_free */
};

static PyObject *
encoder_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
{
    static char *kwlist[] = {"markers", "default", "encoder", "indent", "key_separator", "item_separator", "sort_keys", "skipkeys", "allow_nan", NULL};

    PyEncoderObject *s;
    PyObject *markers, *defaultfn, *encoder, *indent, *key_separator;
    PyObject *item_separator, *sort_keys, *skipkeys, *allow_nan_obj;
    int allow_nan;

    if (!PyArg_ParseTupleAndKeywords(args, kwds, "OOOOOOOOO:make_encoder", kwlist,
        &markers, &defaultfn, &encoder, &indent, &key_separator, &item_separator,
        &sort_keys, &skipkeys, &allow_nan_obj))
        return NULL;

    allow_nan = PyObject_IsTrue(allow_nan_obj);
    if (allow_nan < 0)
        return NULL;

    if (markers != Py_None && !PyDict_Check(markers)) {
        PyErr_Format(PyExc_TypeError,
                     "make_encoder() argument 1 must be dict or None, "
                     "not %.200s", Py_TYPE(markers)->tp_name);
        return NULL;
    }

    s = (PyEncoderObject *)type->tp_alloc(type, 0);
    if (s == NULL)
        return NULL;

    s->markers = markers;
    s->defaultfn = defaultfn;
    s->encoder = encoder;
    s->indent = indent;
    s->key_separator = key_separator;
    s->item_separator = item_separator;
    s->sort_keys = sort_keys;
    s->skipkeys = skipkeys;
    s->fast_encode = (PyCFunction_Check(s->encoder) && PyCFunction_GetFunction(s->encoder) == (PyCFunction)py_encode_basestring_ascii);
    s->allow_nan = allow_nan;

    Py_INCREF(s->markers);
    Py_INCREF(s->defaultfn);
    Py_INCREF(s->encoder);
    Py_INCREF(s->indent);
    Py_INCREF(s->key_separator);
    Py_INCREF(s->item_separator);
    Py_INCREF(s->sort_keys);
    Py_INCREF(s->skipkeys);
    return (PyObject *)s;
}

static PyObject *
encoder_call(PyObject *self, PyObject *args, PyObject *kwds)
{
    /* Python callable interface to encode_listencode_obj */
    static char *kwlist[] = {"obj", "_current_indent_level", NULL};
    PyObject *obj;
    PyObject *rval;
    Py_ssize_t indent_level;
    PyEncoderObject *s;
    assert(PyEncoder_Check(self));
    s = (PyEncoderObject *)self;
    if (!PyArg_ParseTupleAndKeywords(args, kwds, "OO&:_iterencode", kwlist,
        &obj, _convertPyInt_AsSsize_t, &indent_level))
        return NULL;
    rval = PyList_New(0);
    if (rval == NULL)
        return NULL;
    if (encoder_listencode_obj(s, rval, obj, indent_level)) {
        Py_DECREF(rval);
        return NULL;
    }
    return rval;
}

static PyObject *
_encoded_const(PyObject *obj)
{
    /* Return the JSON string representation of None, True, False */
    if (obj == Py_None) {
        static PyObject *s_null = NULL;
        if (s_null == NULL) {
            s_null = PyString_InternFromString("null");
        }
        Py_XINCREF(s_null);
        return s_null;
    }
    else if (obj == Py_True) {
        static PyObject *s_true = NULL;
        if (s_true == NULL) {
            s_true = PyString_InternFromString("true");
        }
        Py_XINCREF(s_true);
        return s_true;
    }
    else if (obj == Py_False) {
        static PyObject *s_false = NULL;
        if (s_false == NULL) {
            s_false = PyString_InternFromString("false");
        }
        Py_XINCREF(s_false);
        return s_false;
    }
    else {
        PyErr_SetString(PyExc_ValueError, "not a const");
        return NULL;
    }
}

static PyObject *
encoder_encode_float(PyEncoderObject *s, PyObject *obj)
{
    /* Return the JSON representation of a PyFloat */
    double i = PyFloat_AS_DOUBLE(obj);
    if (!Py_IS_FINITE(i)) {
        if (!s->allow_nan) {
            PyErr_SetString(PyExc_ValueError, "Out of range float values are not JSON compliant");
            return NULL;
        }
        if (i > 0) {
            return PyString_FromString("Infinity");
        }
        else if (i < 0) {
            return PyString_FromString("-Infinity");
        }
        else {
            return PyString_FromString("NaN");
        }
    }
    /* Make sure to use the base float class repr method */
    return PyFloat_Type.tp_repr(obj);
}

static PyObject *
encoder_encode_string(PyEncoderObject *s, PyObject *obj)
{
    /* Return the JSON representation of a string */
    if (s->fast_encode)
        return py_encode_basestring_ascii(NULL, obj);
    else
        return PyObject_CallFunctionObjArgs(s->encoder, obj, NULL);
}

static int
_steal_list_append(PyObject *lst, PyObject *stolen)
{
    /* Append stolen and then decrement its reference count */
    int rval = PyList_Append(lst, stolen);
    Py_DECREF(stolen);
    return rval;
}

static int
encoder_listencode_obj(PyEncoderObject *s, PyObject *rval, PyObject *obj, Py_ssize_t indent_level)
{
    /* Encode Python object obj to a JSON term, rval is a PyList */
    PyObject *newobj;
    int rv;

    if (obj == Py_None || obj == Py_True || obj == Py_False) {
        PyObject *cstr = _encoded_const(obj);
        if (cstr == NULL)
            return -1;
        return _steal_list_append(rval, cstr);
    }
    else if (PyString_Check(obj) || PyUnicode_Check(obj))
    {
        PyObject *encoded = encoder_encode_string(s, obj);
        if (encoded == NULL)
            return -1;
        return _steal_list_append(rval, encoded);
    }
    else if (_PyAnyInt_Check(obj)) {
        PyObject *encoded = PyObject_Str(obj);
        if (encoded == NULL)
            return -1;
        return _steal_list_append(rval, encoded);
    }
    else if (PyFloat_Check(obj)) {
        PyObject *encoded = encoder_encode_float(s, obj);
        if (encoded == NULL)
            return -1;
        return _steal_list_append(rval, encoded);
    }
    else if (PyList_Check(obj) || PyTuple_Check(obj)) {
        if (Py_EnterRecursiveCall(" while encoding a JSON object"))
            return -1;
        rv = encoder_listencode_list(s, rval, obj, indent_level);
        Py_LeaveRecursiveCall();
        return rv;
    }
    else if (PyDict_Check(obj)) {
        if (Py_EnterRecursiveCall(" while encoding a JSON object"))
            return -1;
        rv = encoder_listencode_dict(s, rval, obj, indent_level);
        Py_LeaveRecursiveCall();
        return rv;
    }
    else {
        PyObject *ident = NULL;
        if (s->markers != Py_None) {
            int has_key;
            ident = PyLong_FromVoidPtr(obj);
            if (ident == NULL)
                return -1;
            has_key = PyDict_Contains(s->markers, ident);
            if (has_key) {
                if (has_key != -1)
                    PyErr_SetString(PyExc_ValueError, "Circular reference detected");
                Py_DECREF(ident);
                return -1;
            }
            if (PyDict_SetItem(s->markers, ident, obj)) {
                Py_DECREF(ident);
                return -1;
            }
        }
        newobj = PyObject_CallFunctionObjArgs(s->defaultfn, obj, NULL);
        if (newobj == NULL) {
            Py_XDECREF(ident);
            return -1;
        }

        if (Py_EnterRecursiveCall(" while encoding a JSON object")) {
            Py_DECREF(newobj);
            Py_XDECREF(ident);
            return -1;
        }
        rv = encoder_listencode_obj(s, rval, newobj, indent_level);
        Py_LeaveRecursiveCall();

        Py_DECREF(newobj);
        if (rv) {
            Py_XDECREF(ident);
            return -1;
        }
        if (ident != NULL) {
            if (PyDict_DelItem(s->markers, ident)) {
                Py_XDECREF(ident);
                return -1;
            }
            Py_XDECREF(ident);
        }
        return rv;
    }
}

static int
encoder_listencode_dict(PyEncoderObject *s, PyObject *rval, PyObject *dct, Py_ssize_t indent_level)
{
    /* Encode Python dict dct a JSON term, rval is a PyList */
    static PyObject *open_dict = NULL;
    static PyObject *close_dict = NULL;
    static PyObject *empty_dict = NULL;
    PyObject *kstr = NULL;
    PyObject *ident = NULL;
    PyObject *key = NULL;
    PyObject *value = NULL;
    PyObject *it = NULL;
    int skipkeys;
    Py_ssize_t idx;

    if (open_dict == NULL || close_dict == NULL || empty_dict == NULL) {
        open_dict = PyString_InternFromString("{");
        close_dict = PyString_InternFromString("}");
        empty_dict = PyString_InternFromString("{}");
        if (open_dict == NULL || close_dict == NULL || empty_dict == NULL)
            return -1;
    }
    if (Py_SIZE(dct) == 0)
        return PyList_Append(rval, empty_dict);

    if (s->markers != Py_None) {
        int has_key;
        ident = PyLong_FromVoidPtr(dct);
        if (ident == NULL)
            goto bail;
        has_key = PyDict_Contains(s->markers, ident);
        if (has_key) {
            if (has_key != -1)
                PyErr_SetString(PyExc_ValueError, "Circular reference detected");
            goto bail;
        }
        if (PyDict_SetItem(s->markers, ident, dct)) {
            goto bail;
        }
    }

    if (PyList_Append(rval, open_dict))
        goto bail;

    if (s->indent != Py_None) {
        /* TODO: DOES NOT RUN */
        indent_level += 1;
        /*
            newline_indent = '\n' + (' ' * (_indent * _current_indent_level))
            separator = _item_separator + newline_indent
            buf += newline_indent
        */
    }

    /* TODO: C speedup not implemented for sort_keys */

    it = PyObject_GetIter(dct);
    if (it == NULL)
        goto bail;
    skipkeys = PyObject_IsTrue(s->skipkeys);
    if (skipkeys < 0)
        goto bail;
    idx = 0;
    while ((key = PyIter_Next(it)) != NULL) {
        PyObject *encoded;

        if (PyString_Check(key) || PyUnicode_Check(key)) {
            Py_INCREF(key);
            kstr = key;
        }
        else if (PyFloat_Check(key)) {
            kstr = encoder_encode_float(s, key);
            if (kstr == NULL)
                goto bail;
        }
        else if (_PyAnyInt_Check(key)) {
            kstr = PyObject_Str(key);
            if (kstr == NULL)
                goto bail;
        }
        else if (key == Py_True || key == Py_False || key == Py_None) {
            kstr = _encoded_const(key);
            if (kstr == NULL)
                goto bail;
        }
        else if (skipkeys) {
            Py_DECREF(key);
            continue;
        }
        else {
            /* TODO: include repr of key */
            PyErr_SetString(PyExc_TypeError, "keys must be a string");
            goto bail;
        }

        if (idx) {
            if (PyList_Append(rval, s->item_separator))
                goto bail;
        }

        value = PyObject_GetItem(dct, key);
        if (value == NULL)
            goto bail;

        encoded = encoder_encode_string(s, kstr);
        Py_CLEAR(kstr);
        if (encoded == NULL)
            goto bail;
        if (PyList_Append(rval, encoded)) {
            Py_DECREF(encoded);
            goto bail;
        }
        Py_DECREF(encoded);
        if (PyList_Append(rval, s->key_separator))
            goto bail;
        if (encoder_listencode_obj(s, rval, value, indent_level))
            goto bail;
        idx += 1;
        Py_CLEAR(value);
        Py_DECREF(key);
    }
    if (PyErr_Occurred())
        goto bail;
    Py_CLEAR(it);

    if (ident != NULL) {
        if (PyDict_DelItem(s->markers, ident))
            goto bail;
        Py_CLEAR(ident);
    }
    if (s->indent != Py_None) {
        /* TODO: DOES NOT RUN */
        /*
            indent_level -= 1;

            yield '\n' + (' ' * (_indent * _current_indent_level))
        */
    }
    if (PyList_Append(rval, close_dict))
        goto bail;
    return 0;

bail:
    Py_XDECREF(it);
    Py_XDECREF(key);
    Py_XDECREF(value);
    Py_XDECREF(kstr);
    Py_XDECREF(ident);
    return -1;
}


static int
encoder_listencode_list(PyEncoderObject *s, PyObject *rval, PyObject *seq, Py_ssize_t indent_level)
{
    /* Encode Python list seq to a JSON term, rval is a PyList */
    static PyObject *open_array = NULL;
    static PyObject *close_array = NULL;
    static PyObject *empty_array = NULL;
    PyObject *ident = NULL;
    PyObject *s_fast = NULL;
    Py_ssize_t i;

    if (open_array == NULL || close_array == NULL || empty_array == NULL) {
        open_array = PyString_InternFromString("[");
        close_array = PyString_InternFromString("]");
        empty_array = PyString_InternFromString("[]");
        if (open_array == NULL || close_array == NULL || empty_array == NULL)
            return -1;
    }
    ident = NULL;
    s_fast = PySequence_Fast(seq, "_iterencode_list needs a sequence");
    if (s_fast == NULL)
        return -1;
    if (PySequence_Fast_GET_SIZE(s_fast) == 0) {
        Py_DECREF(s_fast);
        return PyList_Append(rval, empty_array);
    }

    if (s->markers != Py_None) {
        int has_key;
        ident = PyLong_FromVoidPtr(seq);
        if (ident == NULL)
            goto bail;
        has_key = PyDict_Contains(s->markers, ident);
        if (has_key) {
            if (has_key != -1)
                PyErr_SetString(PyExc_ValueError, "Circular reference detected");
            goto bail;
        }
        if (PyDict_SetItem(s->markers, ident, seq)) {
            goto bail;
        }
    }

    if (PyList_Append(rval, open_array))
        goto bail;
    if (s->indent != Py_None) {
        /* TODO: DOES NOT RUN */
        indent_level += 1;
        /*
            newline_indent = '\n' + (' ' * (_indent * _current_indent_level))
            separator = _item_separator + newline_indent
            buf += newline_indent
        */
    }
    for (i = 0; i < PySequence_Fast_GET_SIZE(s_fast); i++) {
        PyObject *obj = PySequence_Fast_GET_ITEM(s_fast, i);
        if (i) {
            if (PyList_Append(rval, s->item_separator))
                goto bail;
        }
        if (encoder_listencode_obj(s, rval, obj, indent_level))
            goto bail;
    }
    if (ident != NULL) {
        if (PyDict_DelItem(s->markers, ident))
            goto bail;
        Py_CLEAR(ident);
    }
    if (s->indent != Py_None) {
        /* TODO: DOES NOT RUN */
        /*
            indent_level -= 1;

            yield '\n' + (' ' * (_indent * _current_indent_level))
        */
    }
    if (PyList_Append(rval, close_array))
        goto bail;
    Py_DECREF(s_fast);
    return 0;

bail:
    Py_XDECREF(ident);
    Py_DECREF(s_fast);
    return -1;
}

static void
encoder_dealloc(PyObject *self)
{
    /* bpo-31095: UnTrack is needed before calling any callbacks */
    PyObject_GC_UnTrack(self);
    encoder_clear(self);
    Py_TYPE(self)->tp_free(self);
}

static int
encoder_traverse(PyObject *self, visitproc visit, void *arg)
{
    PyEncoderObject *s;
    assert(PyEncoder_Check(self));
    s = (PyEncoderObject *)self;
    Py_VISIT(s->markers);
    Py_VISIT(s->defaultfn);
    Py_VISIT(s->encoder);
    Py_VISIT(s->indent);
    Py_VISIT(s->key_separator);
    Py_VISIT(s->item_separator);
    Py_VISIT(s->sort_keys);
    Py_VISIT(s->skipkeys);
    return 0;
}

static int
encoder_clear(PyObject *self)
{
    /* Deallocate Encoder */
    PyEncoderObject *s;
    assert(PyEncoder_Check(self));
    s = (PyEncoderObject *)self;
    Py_CLEAR(s->markers);
    Py_CLEAR(s->defaultfn);
    Py_CLEAR(s->encoder);
    Py_CLEAR(s->indent);
    Py_CLEAR(s->key_separator);
    Py_CLEAR(s->item_separator);
    Py_CLEAR(s->sort_keys);
    Py_CLEAR(s->skipkeys);
    return 0;
}

PyDoc_STRVAR(encoder_doc, "_iterencode(obj, _current_indent_level) -> iterable");

static
PyTypeObject PyEncoderType = {
    PyVarObject_HEAD_INIT(NULL, 0)
    "_json.Encoder",       /* tp_name */
    sizeof(PyEncoderObject), /* tp_basicsize */
    0,                    /* tp_itemsize */
    encoder_dealloc, /* tp_dealloc */
    0,                    /* tp_print */
    0,                    /* tp_getattr */
    0,                    /* tp_setattr */
    0,                    /* tp_compare */
    0,                    /* tp_repr */
    0,                    /* tp_as_number */
    0,                    /* tp_as_sequence */
    0,                    /* tp_as_mapping */
    0,                    /* tp_hash */
    encoder_call,         /* tp_call */
    0,                    /* tp_str */
    0,                    /* tp_getattro */
    0,                    /* tp_setattro */
    0,                    /* tp_as_buffer */
    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC,   /* tp_flags */
    encoder_doc,          /* tp_doc */
    encoder_traverse,     /* tp_traverse */
    encoder_clear,        /* tp_clear */
    0,                    /* tp_richcompare */
    0,                    /* tp_weaklistoffset */
    0,                    /* tp_iter */
    0,                    /* tp_iternext */
    0,                    /* tp_methods */
    encoder_members,      /* tp_members */
    0,                    /* tp_getset */
    0,                    /* tp_base */
    0,                    /* tp_dict */
    0,                    /* tp_descr_get */
    0,                    /* tp_descr_set */
    0,                    /* tp_dictoffset */
    0,                    /* tp_init */
    0,                    /* tp_alloc */
    encoder_new,          /* tp_new */
    0,                    /* tp_free */
};

static PyMethodDef speedups_methods[] = {
    {"encode_basestring_ascii",
        (PyCFunction)py_encode_basestring_ascii,
        METH_O,
        pydoc_encode_basestring_ascii},
    {"scanstring",
        (PyCFunction)py_scanstring,
        METH_VARARGS,
        pydoc_scanstring},
    {NULL, NULL, 0, NULL}
};

PyDoc_STRVAR(module_doc,
"json speedups\n");

void
init_json(void)
{
    PyObject *m;
    if (PyType_Ready(&PyScannerType) < 0)
        return;
    if (PyType_Ready(&PyEncoderType) < 0)
        return;
    m = Py_InitModule3("_json", speedups_methods, module_doc);
    if (m == NULL)
        return;
    Py_INCREF((PyObject*)&PyScannerType);
    PyModule_AddObject(m, "make_scanner", (PyObject*)&PyScannerType);
    Py_INCREF((PyObject*)&PyEncoderType);
    PyModule_AddObject(m, "make_encoder", (PyObject*)&PyEncoderType);
}