Include/cpython/unicodeobject.h

#ifndef Py_CPYTHON_UNICODEOBJECT_H
#  error "this header file must not be included directly"
#endif

/* Py_UNICODE was the native Unicode storage format (code unit) used by
   Python and represents a single Unicode element in the Unicode type.
   With PEP 393, Py_UNICODE is deprecated and replaced with a
   typedef to wchar_t. */
#define PY_UNICODE_TYPE wchar_t
/* Py_DEPRECATED(3.3) */ typedef wchar_t Py_UNICODE;

/* --- Internal Unicode Operations ---------------------------------------- */

#ifndef USE_UNICODE_WCHAR_CACHE
#  define USE_UNICODE_WCHAR_CACHE 1
#endif /* USE_UNICODE_WCHAR_CACHE */

/* Since splitting on whitespace is an important use case, and
   whitespace in most situations is solely ASCII whitespace, we
   optimize for the common case by using a quick look-up table
   _Py_ascii_whitespace (see below) with an inlined check.

 */
#define Py_UNICODE_ISSPACE(ch) \
    ((Py_UCS4)(ch) < 128U ? _Py_ascii_whitespace[(ch)] : _PyUnicode_IsWhitespace(ch))

#define Py_UNICODE_ISLOWER(ch) _PyUnicode_IsLowercase(ch)
#define Py_UNICODE_ISUPPER(ch) _PyUnicode_IsUppercase(ch)
#define Py_UNICODE_ISTITLE(ch) _PyUnicode_IsTitlecase(ch)
#define Py_UNICODE_ISLINEBREAK(ch) _PyUnicode_IsLinebreak(ch)

#define Py_UNICODE_TOLOWER(ch) _PyUnicode_ToLowercase(ch)
#define Py_UNICODE_TOUPPER(ch) _PyUnicode_ToUppercase(ch)
#define Py_UNICODE_TOTITLE(ch) _PyUnicode_ToTitlecase(ch)

#define Py_UNICODE_ISDECIMAL(ch) _PyUnicode_IsDecimalDigit(ch)
#define Py_UNICODE_ISDIGIT(ch) _PyUnicode_IsDigit(ch)
#define Py_UNICODE_ISNUMERIC(ch) _PyUnicode_IsNumeric(ch)
#define Py_UNICODE_ISPRINTABLE(ch) _PyUnicode_IsPrintable(ch)

#define Py_UNICODE_TODECIMAL(ch) _PyUnicode_ToDecimalDigit(ch)
#define Py_UNICODE_TODIGIT(ch) _PyUnicode_ToDigit(ch)
#define Py_UNICODE_TONUMERIC(ch) _PyUnicode_ToNumeric(ch)

#define Py_UNICODE_ISALPHA(ch) _PyUnicode_IsAlpha(ch)

#define Py_UNICODE_ISALNUM(ch) \
   (Py_UNICODE_ISALPHA(ch) || \
    Py_UNICODE_ISDECIMAL(ch) || \
    Py_UNICODE_ISDIGIT(ch) || \
    Py_UNICODE_ISNUMERIC(ch))

/* macros to work with surrogates */
#define Py_UNICODE_IS_SURROGATE(ch) (0xD800 <= (ch) && (ch) <= 0xDFFF)
#define Py_UNICODE_IS_HIGH_SURROGATE(ch) (0xD800 <= (ch) && (ch) <= 0xDBFF)
#define Py_UNICODE_IS_LOW_SURROGATE(ch) (0xDC00 <= (ch) && (ch) <= 0xDFFF)
/* Join two surrogate characters and return a single Py_UCS4 value. */
#define Py_UNICODE_JOIN_SURROGATES(high, low)  \
    (((((Py_UCS4)(high) & 0x03FF) << 10) |      \
      ((Py_UCS4)(low) & 0x03FF)) + 0x10000)
/* high surrogate = top 10 bits added to D800 */
#define Py_UNICODE_HIGH_SURROGATE(ch) (0xD800 - (0x10000 >> 10) + ((ch) >> 10))
/* low surrogate = bottom 10 bits added to DC00 */
#define Py_UNICODE_LOW_SURROGATE(ch) (0xDC00 + ((ch) & 0x3FF))

/* --- Unicode Type ------------------------------------------------------- */

/* ASCII-only strings created through PyUnicode_New use the PyASCIIObject
   structure. state.ascii and state.compact are set, and the data
   immediately follow the structure. utf8_length and wstr_length can be found
   in the length field; the utf8 pointer is equal to the data pointer. */
typedef struct {
    /* There are 4 forms of Unicode strings:

       - compact ascii:

         * structure = PyASCIIObject
         * test: PyUnicode_IS_COMPACT_ASCII(op)
         * kind = PyUnicode_1BYTE_KIND
         * compact = 1
         * ascii = 1
         * ready = 1
         * (length is the length of the utf8 and wstr strings)
         * (data starts just after the structure)
         * (since ASCII is decoded from UTF-8, the utf8 string are the data)

       - compact:

         * structure = PyCompactUnicodeObject
         * test: PyUnicode_IS_COMPACT(op) && !PyUnicode_IS_ASCII(op)
         * kind = PyUnicode_1BYTE_KIND, PyUnicode_2BYTE_KIND or
           PyUnicode_4BYTE_KIND
         * compact = 1
         * ready = 1
         * ascii = 0
         * utf8 is not shared with data
         * utf8_length = 0 if utf8 is NULL
         * wstr is shared with data and wstr_length=length
           if kind=PyUnicode_2BYTE_KIND and sizeof(wchar_t)=2
           or if kind=PyUnicode_4BYTE_KIND and sizeof(wchar_t)=4
         * wstr_length = 0 if wstr is NULL
         * (data starts just after the structure)

       - legacy string, not ready:

         * structure = PyUnicodeObject
         * test: kind == PyUnicode_WCHAR_KIND
         * length = 0 (use wstr_length)
         * hash = -1
         * kind = PyUnicode_WCHAR_KIND
         * compact = 0
         * ascii = 0
         * ready = 0
         * interned = SSTATE_NOT_INTERNED
         * wstr is not NULL
         * data.any is NULL
         * utf8 is NULL
         * utf8_length = 0

       - legacy string, ready:

         * structure = PyUnicodeObject structure
         * test: !PyUnicode_IS_COMPACT(op) && kind != PyUnicode_WCHAR_KIND
         * kind = PyUnicode_1BYTE_KIND, PyUnicode_2BYTE_KIND or
           PyUnicode_4BYTE_KIND
         * compact = 0
         * ready = 1
         * data.any is not NULL
         * utf8 is shared and utf8_length = length with data.any if ascii = 1
         * utf8_length = 0 if utf8 is NULL
         * wstr is shared with data.any and wstr_length = length
           if kind=PyUnicode_2BYTE_KIND and sizeof(wchar_t)=2
           or if kind=PyUnicode_4BYTE_KIND and sizeof(wchar_4)=4
         * wstr_length = 0 if wstr is NULL

       Compact strings use only one memory block (structure + characters),
       whereas legacy strings use one block for the structure and one block
       for characters.

       Legacy strings are created by PyUnicode_FromUnicode() and
       PyUnicode_FromStringAndSize(NULL, size) functions. They become ready
       when PyUnicode_READY() is called.

       See also _PyUnicode_CheckConsistency().
    */
    PyObject_HEAD
    Py_ssize_t length;          /* Number of code points in the string */
    Py_hash_t hash;             /* Hash value; -1 if not set */
    struct {
        /*
           SSTATE_NOT_INTERNED (0)
           SSTATE_INTERNED_MORTAL (1)
           SSTATE_INTERNED_IMMORTAL (2)

           If interned != SSTATE_NOT_INTERNED, the two references from the
           dictionary to this object are *not* counted in ob_refcnt.
         */
        unsigned int interned:2;
        /* Character size:

           - PyUnicode_WCHAR_KIND (0):

             * character type = wchar_t (16 or 32 bits, depending on the
               platform)

           - PyUnicode_1BYTE_KIND (1):

             * character type = Py_UCS1 (8 bits, unsigned)
             * all characters are in the range U+0000-U+00FF (latin1)
             * if ascii is set, all characters are in the range U+0000-U+007F
               (ASCII), otherwise at least one character is in the range
               U+0080-U+00FF

           - PyUnicode_2BYTE_KIND (2):

             * character type = Py_UCS2 (16 bits, unsigned)
             * all characters are in the range U+0000-U+FFFF (BMP)
             * at least one character is in the range U+0100-U+FFFF

           - PyUnicode_4BYTE_KIND (4):

             * character type = Py_UCS4 (32 bits, unsigned)
             * all characters are in the range U+0000-U+10FFFF
             * at least one character is in the range U+10000-U+10FFFF
         */
        unsigned int kind:3;
        /* Compact is with respect to the allocation scheme. Compact unicode
           objects only require one memory block while non-compact objects use
           one block for the PyUnicodeObject struct and another for its data
           buffer. */
        unsigned int compact:1;
        /* The string only contains characters in the range U+0000-U+007F (ASCII)
           and the kind is PyUnicode_1BYTE_KIND. If ascii is set and compact is
           set, use the PyASCIIObject structure. */
        unsigned int ascii:1;
        /* The ready flag indicates whether the object layout is initialized
           completely. This means that this is either a compact object, or
           the data pointer is filled out. The bit is redundant, and helps
           to minimize the test in PyUnicode_IS_READY(). */
        unsigned int ready:1;
        /* Padding to ensure that PyUnicode_DATA() is always aligned to
           4 bytes (see issue #19537 on m68k). */
        unsigned int :24;
    } state;
    wchar_t *wstr;              /* wchar_t representation (null-terminated) */
} PyASCIIObject;

/* Non-ASCII strings allocated through PyUnicode_New use the
   PyCompactUnicodeObject structure. state.compact is set, and the data
   immediately follow the structure. */
typedef struct {
    PyASCIIObject _base;
    Py_ssize_t utf8_length;     /* Number of bytes in utf8, excluding the
                                 * terminating \0. */
    char *utf8;                 /* UTF-8 representation (null-terminated) */
    Py_ssize_t wstr_length;     /* Number of code points in wstr, possible
                                 * surrogates count as two code points. */
} PyCompactUnicodeObject;

/* Strings allocated through PyUnicode_FromUnicode(NULL, len) use the
   PyUnicodeObject structure. The actual string data is initially in the wstr
   block, and copied into the data block using _PyUnicode_Ready. */
typedef struct {
    PyCompactUnicodeObject _base;
    union {
        void *any;
        Py_UCS1 *latin1;
        Py_UCS2 *ucs2;
        Py_UCS4 *ucs4;
    } data;                     /* Canonical, smallest-form Unicode buffer */
} PyUnicodeObject;

PyAPI_FUNC(int) _PyUnicode_CheckConsistency(
    PyObject *op,
    int check_content);


#define _PyASCIIObject_CAST(op) \
    (assert(PyUnicode_Check(op)), \
     _Py_CAST(PyASCIIObject*, (op)))
#define _PyCompactUnicodeObject_CAST(op) \
    (assert(PyUnicode_Check(op)), \
     _Py_CAST(PyCompactUnicodeObject*, (op)))
#define _PyUnicodeObject_CAST(op) \
    (assert(PyUnicode_Check(op)), \
     _Py_CAST(PyUnicodeObject*, (op)))


/* --- Flexible String Representation Helper Macros (PEP 393) -------------- */

/* Values for PyASCIIObject.state: */

/* Interning state. */
#define SSTATE_NOT_INTERNED 0
#define SSTATE_INTERNED_MORTAL 1
#define SSTATE_INTERNED_IMMORTAL 2

/* Use only if you know it's a string */
static inline unsigned int PyUnicode_CHECK_INTERNED(PyObject *op) {
    return _PyASCIIObject_CAST(op)->state.interned;
}
#if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 < 0x030b0000
#  define PyUnicode_CHECK_INTERNED(op) PyUnicode_CHECK_INTERNED(_PyObject_CAST(op))
#endif

/* Fast check to determine whether an object is ready. Equivalent to:
   PyUnicode_IS_COMPACT(op) || _PyUnicodeObject_CAST(op)->data.any */
static inline unsigned int PyUnicode_IS_READY(PyObject *op) {
    return _PyASCIIObject_CAST(op)->state.ready;
}
#if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 < 0x030b0000
#  define PyUnicode_IS_READY(op) PyUnicode_IS_READY(_PyObject_CAST(op))
#endif

/* Return true if the string contains only ASCII characters, or 0 if not. The
   string may be compact (PyUnicode_IS_COMPACT_ASCII) or not, but must be
   ready. */
static inline unsigned int PyUnicode_IS_ASCII(PyObject *op) {
    assert(PyUnicode_IS_READY(op));
    return _PyASCIIObject_CAST(op)->state.ascii;
}
#if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 < 0x030b0000
#  define PyUnicode_IS_ASCII(op) PyUnicode_IS_ASCII(_PyObject_CAST(op))
#endif

/* Return true if the string is compact or 0 if not.
   No type checks or Ready calls are performed. */
static inline unsigned int PyUnicode_IS_COMPACT(PyObject *op) {
    return _PyASCIIObject_CAST(op)->state.compact;
}
#if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 < 0x030b0000
#  define PyUnicode_IS_COMPACT(op) PyUnicode_IS_COMPACT(_PyObject_CAST(op))
#endif

/* Return true if the string is a compact ASCII string (use PyASCIIObject
   structure), or 0 if not.  No type checks or Ready calls are performed. */
static inline int PyUnicode_IS_COMPACT_ASCII(PyObject *op) {
    return (_PyASCIIObject_CAST(op)->state.ascii && PyUnicode_IS_COMPACT(op));
}
#if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 < 0x030b0000
#  define PyUnicode_IS_COMPACT_ASCII(op) PyUnicode_IS_COMPACT_ASCII(_PyObject_CAST(op))
#endif

enum PyUnicode_Kind {
/* String contains only wstr byte characters.  This is only possible
   when the string was created with a legacy API and _PyUnicode_Ready()
   has not been called yet.  */
    PyUnicode_WCHAR_KIND = 0,
/* Return values of the PyUnicode_KIND() function: */
    PyUnicode_1BYTE_KIND = 1,
    PyUnicode_2BYTE_KIND = 2,
    PyUnicode_4BYTE_KIND = 4
};

/* Return one of the PyUnicode_*_KIND values defined above. */
#define PyUnicode_KIND(op) \
    (assert(PyUnicode_IS_READY(op)), \
     _PyASCIIObject_CAST(op)->state.kind)

/* Return a void pointer to the raw unicode buffer. */
static inline void* _PyUnicode_COMPACT_DATA(PyObject *op) {
    if (PyUnicode_IS_ASCII(op)) {
        return _Py_STATIC_CAST(void*, (_PyASCIIObject_CAST(op) + 1));
    }
    return _Py_STATIC_CAST(void*, (_PyCompactUnicodeObject_CAST(op) + 1));
}

static inline void* _PyUnicode_NONCOMPACT_DATA(PyObject *op) {
    void *data;
    assert(!PyUnicode_IS_COMPACT(op));
    data = _PyUnicodeObject_CAST(op)->data.any;
    assert(data != NULL);
    return data;
}

static inline void* PyUnicode_DATA(PyObject *op) {
    if (PyUnicode_IS_COMPACT(op)) {
        return _PyUnicode_COMPACT_DATA(op);
    }
    return _PyUnicode_NONCOMPACT_DATA(op);
}
#if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 < 0x030b0000
#  define PyUnicode_DATA(op) PyUnicode_DATA(_PyObject_CAST(op))
#endif

/* Return pointers to the canonical representation cast to unsigned char,
   Py_UCS2, or Py_UCS4 for direct character access.
   No checks are performed, use PyUnicode_KIND() before to ensure
   these will work correctly. */

#define PyUnicode_1BYTE_DATA(op) _Py_STATIC_CAST(Py_UCS1*, PyUnicode_DATA(op))
#define PyUnicode_2BYTE_DATA(op) _Py_STATIC_CAST(Py_UCS2*, PyUnicode_DATA(op))
#define PyUnicode_4BYTE_DATA(op) _Py_STATIC_CAST(Py_UCS4*, PyUnicode_DATA(op))

/* Returns the length of the unicode string. The caller has to make sure that
   the string has it's canonical representation set before calling
   this function.  Call PyUnicode_(FAST_)Ready to ensure that. */
static inline Py_ssize_t PyUnicode_GET_LENGTH(PyObject *op) {
    assert(PyUnicode_IS_READY(op));
    return _PyASCIIObject_CAST(op)->length;
}
#if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 < 0x030b0000
#  define PyUnicode_GET_LENGTH(op) PyUnicode_GET_LENGTH(_PyObject_CAST(op))
#endif

/* Write into the canonical representation, this function does not do any sanity
   checks and is intended for usage in loops.  The caller should cache the
   kind and data pointers obtained from other function calls.
   index is the index in the string (starts at 0) and value is the new
   code point value which should be written to that location. */
static inline void PyUnicode_WRITE(int kind, void *data,
                                   Py_ssize_t index, Py_UCS4 value)
{
    if (kind == PyUnicode_1BYTE_KIND) {
        assert(value <= 0xffU);
        _Py_STATIC_CAST(Py_UCS1*, data)[index] = _Py_STATIC_CAST(Py_UCS1, value);
    }
    else if (kind == PyUnicode_2BYTE_KIND) {
        assert(value <= 0xffffU);
        _Py_STATIC_CAST(Py_UCS2*, data)[index] = _Py_STATIC_CAST(Py_UCS2, value);
    }
    else {
        assert(kind == PyUnicode_4BYTE_KIND);
        assert(value <= 0x10ffffU);
        _Py_STATIC_CAST(Py_UCS4*, data)[index] = value;
    }
}
#if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 < 0x030b0000
#define PyUnicode_WRITE(kind, data, index, value) \
    PyUnicode_WRITE(_Py_STATIC_CAST(int, kind), _Py_CAST(void*, data), \
                    (index), _Py_STATIC_CAST(Py_UCS4, value))
#endif

/* Read a code point from the string's canonical representation.  No checks
   or ready calls are performed. */
static inline Py_UCS4 PyUnicode_READ(int kind,
                                     const void *data, Py_ssize_t index)
{
    if (kind == PyUnicode_1BYTE_KIND) {
        return _Py_STATIC_CAST(const Py_UCS1*, data)[index];
    }
    if (kind == PyUnicode_2BYTE_KIND) {
        return _Py_STATIC_CAST(const Py_UCS2*, data)[index];
    }
    assert(kind == PyUnicode_4BYTE_KIND);
    return _Py_STATIC_CAST(const Py_UCS4*, data)[index];
}
#if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 < 0x030b0000
#define PyUnicode_READ(kind, data, index) \
    PyUnicode_READ(_Py_STATIC_CAST(int, kind), \
                   _Py_STATIC_CAST(const void*, data), \
                   (index))
#endif

/* PyUnicode_READ_CHAR() is less efficient than PyUnicode_READ() because it
   calls PyUnicode_KIND() and might call it twice.  For single reads, use
   PyUnicode_READ_CHAR, for multiple consecutive reads callers should
   cache kind and use PyUnicode_READ instead. */
static inline Py_UCS4 PyUnicode_READ_CHAR(PyObject *unicode, Py_ssize_t index)
{
    int kind;
    assert(PyUnicode_IS_READY(unicode));
    kind = PyUnicode_KIND(unicode);
    if (kind == PyUnicode_1BYTE_KIND) {
        return PyUnicode_1BYTE_DATA(unicode)[index];
    }
    if (kind == PyUnicode_2BYTE_KIND) {
        return PyUnicode_2BYTE_DATA(unicode)[index];
    }
    assert(kind == PyUnicode_4BYTE_KIND);
    return PyUnicode_4BYTE_DATA(unicode)[index];
}
#if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 < 0x030b0000
#  define PyUnicode_READ_CHAR(unicode, index) \
       PyUnicode_READ_CHAR(_PyObject_CAST(unicode), (index))
#endif

/* Return a maximum character value which is suitable for creating another
   string based on op.  This is always an approximation but more efficient
   than iterating over the string. */
static inline Py_UCS4 PyUnicode_MAX_CHAR_VALUE(PyObject *op)
{
    int kind;

    assert(PyUnicode_IS_READY(op));
    if (PyUnicode_IS_ASCII(op)) {
        return 0x7fU;
    }

    kind = PyUnicode_KIND(op);
    if (kind == PyUnicode_1BYTE_KIND) {
       return 0xffU;
    }
    if (kind == PyUnicode_2BYTE_KIND) {
        return 0xffffU;
    }
    assert(kind == PyUnicode_4BYTE_KIND);
    return 0x10ffffU;
}
#if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 < 0x030b0000
#  define PyUnicode_MAX_CHAR_VALUE(op) \
       PyUnicode_MAX_CHAR_VALUE(_PyObject_CAST(op))
#endif

/* === Public API ========================================================= */

/* --- Plain Py_UNICODE --------------------------------------------------- */

/* With PEP 393, this is the recommended way to allocate a new unicode object.
   This function will allocate the object and its buffer in a single memory
   block.  Objects created using this function are not resizable. */
PyAPI_FUNC(PyObject*) PyUnicode_New(
    Py_ssize_t size,            /* Number of code points in the new string */
    Py_UCS4 maxchar             /* maximum code point value in the string */
    );

/* Initializes the canonical string representation from the deprecated
   wstr/Py_UNICODE representation. This function is used to convert Unicode
   objects which were created using the old API to the new flexible format
   introduced with PEP 393.

   Don't call this function directly, use the public PyUnicode_READY() function
   instead. */
PyAPI_FUNC(int) _PyUnicode_Ready(
    PyObject *unicode           /* Unicode object */
    );

/* PyUnicode_READY() does less work than _PyUnicode_Ready() in the best
   case.  If the canonical representation is not yet set, it will still call
   _PyUnicode_Ready().
   Returns 0 on success and -1 on errors. */
static inline int PyUnicode_READY(PyObject *op)
{
    if (PyUnicode_IS_READY(op)) {
        return 0;
    }
    return _PyUnicode_Ready(op);
}
#if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 < 0x030b0000
#  define PyUnicode_READY(op) PyUnicode_READY(_PyObject_CAST(op))
#endif

/* Get a copy of a Unicode string. */
PyAPI_FUNC(PyObject*) _PyUnicode_Copy(
    PyObject *unicode
    );

/* Copy character from one unicode object into another, this function performs
   character conversion when necessary and falls back to memcpy() if possible.

   Fail if to is too small (smaller than *how_many* or smaller than
   len(from)-from_start), or if kind(from[from_start:from_start+how_many]) >
   kind(to), or if *to* has more than 1 reference.

   Return the number of written character, or return -1 and raise an exception
   on error.

   Pseudo-code:

       how_many = min(how_many, len(from) - from_start)
       to[to_start:to_start+how_many] = from[from_start:from_start+how_many]
       return how_many

   Note: The function doesn't write a terminating null character.
   */
PyAPI_FUNC(Py_ssize_t) PyUnicode_CopyCharacters(
    PyObject *to,
    Py_ssize_t to_start,
    PyObject *from,
    Py_ssize_t from_start,
    Py_ssize_t how_many
    );

/* Unsafe version of PyUnicode_CopyCharacters(): don't check arguments and so
   may crash if parameters are invalid (e.g. if the output string
   is too short). */
PyAPI_FUNC(void) _PyUnicode_FastCopyCharacters(
    PyObject *to,
    Py_ssize_t to_start,
    PyObject *from,
    Py_ssize_t from_start,
    Py_ssize_t how_many
    );

/* Fill a string with a character: write fill_char into
   unicode[start:start+length].

   Fail if fill_char is bigger than the string maximum character, or if the
   string has more than 1 reference.

   Return the number of written character, or return -1 and raise an exception
   on error. */
PyAPI_FUNC(Py_ssize_t) PyUnicode_Fill(
    PyObject *unicode,
    Py_ssize_t start,
    Py_ssize_t length,
    Py_UCS4 fill_char
    );

/* Unsafe version of PyUnicode_Fill(): don't check arguments and so may crash
   if parameters are invalid (e.g. if length is longer than the string). */
PyAPI_FUNC(void) _PyUnicode_FastFill(
    PyObject *unicode,
    Py_ssize_t start,
    Py_ssize_t length,
    Py_UCS4 fill_char
    );

/* Create a new string from a buffer of Py_UCS1, Py_UCS2 or Py_UCS4 characters.
   Scan the string to find the maximum character. */
PyAPI_FUNC(PyObject*) PyUnicode_FromKindAndData(
    int kind,
    const void *buffer,
    Py_ssize_t size);

/* Create a new string from a buffer of ASCII characters.
   WARNING: Don't check if the string contains any non-ASCII character. */
PyAPI_FUNC(PyObject*) _PyUnicode_FromASCII(
    const char *buffer,
    Py_ssize_t size);

/* Compute the maximum character of the substring unicode[start:end].
   Return 127 for an empty string. */
PyAPI_FUNC(Py_UCS4) _PyUnicode_FindMaxChar (
    PyObject *unicode,
    Py_ssize_t start,
    Py_ssize_t end);

/* --- Legacy deprecated API ---------------------------------------------- */

/* Create a Unicode Object from the Py_UNICODE buffer u of the given
   size.

   u may be NULL which causes the contents to be undefined. It is the
   user's responsibility to fill in the needed data afterwards. Note
   that modifying the Unicode object contents after construction is
   only allowed if u was set to NULL.

   The buffer is copied into the new object. */
Py_DEPRECATED(3.3) PyAPI_FUNC(PyObject*) PyUnicode_FromUnicode(
    const Py_UNICODE *u,        /* Unicode buffer */
    Py_ssize_t size             /* size of buffer */
    );

/* Return a read-only pointer to the Unicode object's internal
   Py_UNICODE buffer.
   If the wchar_t/Py_UNICODE representation is not yet available, this
   function will calculate it. */
Py_DEPRECATED(3.3) PyAPI_FUNC(Py_UNICODE *) PyUnicode_AsUnicode(
    PyObject *unicode           /* Unicode object */
    );

/* Similar to PyUnicode_AsUnicode(), but raises a ValueError if the string
   contains null characters. */
PyAPI_FUNC(const Py_UNICODE *) _PyUnicode_AsUnicode(
    PyObject *unicode           /* Unicode object */
    );

/* Return a read-only pointer to the Unicode object's internal
   Py_UNICODE buffer and save the length at size.
   If the wchar_t/Py_UNICODE representation is not yet available, this
   function will calculate it. */

Py_DEPRECATED(3.3) PyAPI_FUNC(Py_UNICODE *) PyUnicode_AsUnicodeAndSize(
    PyObject *unicode,          /* Unicode object */
    Py_ssize_t *size            /* location where to save the length */
    );


/* Fast access macros */

Py_DEPRECATED(3.3)
static inline Py_ssize_t PyUnicode_WSTR_LENGTH(PyObject *op)
{
    if (PyUnicode_IS_COMPACT_ASCII(op)) {
        return _PyASCIIObject_CAST(op)->length;
    }
    else {
        return _PyCompactUnicodeObject_CAST(op)->wstr_length;
    }
}
#if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 < 0x030b0000
#  define PyUnicode_WSTR_LENGTH(op) PyUnicode_WSTR_LENGTH(_PyObject_CAST(op))
#endif

/* Returns the deprecated Py_UNICODE representation's size in code units
   (this includes surrogate pairs as 2 units).
   If the Py_UNICODE representation is not available, it will be computed
   on request.  Use PyUnicode_GET_LENGTH() for the length in code points. */

Py_DEPRECATED(3.3)
static inline Py_ssize_t PyUnicode_GET_SIZE(PyObject *op)
{
    _Py_COMP_DIAG_PUSH
    _Py_COMP_DIAG_IGNORE_DEPR_DECLS
    if (_PyASCIIObject_CAST(op)->wstr == _Py_NULL) {
        (void)PyUnicode_AsUnicode(op);
        assert(_PyASCIIObject_CAST(op)->wstr != _Py_NULL);
    }
    return PyUnicode_WSTR_LENGTH(op);
    _Py_COMP_DIAG_POP
}
#if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 < 0x030b0000
#  define PyUnicode_GET_SIZE(op) PyUnicode_GET_SIZE(_PyObject_CAST(op))
#endif

Py_DEPRECATED(3.3)
static inline Py_ssize_t PyUnicode_GET_DATA_SIZE(PyObject *op)
{
    _Py_COMP_DIAG_PUSH
    _Py_COMP_DIAG_IGNORE_DEPR_DECLS
    return PyUnicode_GET_SIZE(op) * Py_UNICODE_SIZE;
    _Py_COMP_DIAG_POP
}
#if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 < 0x030b0000
#  define PyUnicode_GET_DATA_SIZE(op) PyUnicode_GET_DATA_SIZE(_PyObject_CAST(op))
#endif

/* Alias for PyUnicode_AsUnicode().  This will create a wchar_t/Py_UNICODE
   representation on demand.  Using this macro is very inefficient now,
   try to port your code to use the new PyUnicode_*BYTE_DATA() macros or
   use PyUnicode_WRITE() and PyUnicode_READ(). */

Py_DEPRECATED(3.3)
static inline Py_UNICODE* PyUnicode_AS_UNICODE(PyObject *op)
{
    wchar_t *wstr = _PyASCIIObject_CAST(op)->wstr;
    if (wstr != _Py_NULL) {
        return wstr;
    }

    _Py_COMP_DIAG_PUSH
    _Py_COMP_DIAG_IGNORE_DEPR_DECLS
    return PyUnicode_AsUnicode(op);
    _Py_COMP_DIAG_POP
}
#if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 < 0x030b0000
#  define PyUnicode_AS_UNICODE(op) PyUnicode_AS_UNICODE(_PyObject_CAST(op))
#endif

Py_DEPRECATED(3.3)
static inline const char* PyUnicode_AS_DATA(PyObject *op)
{
    _Py_COMP_DIAG_PUSH
    _Py_COMP_DIAG_IGNORE_DEPR_DECLS
    Py_UNICODE *data = PyUnicode_AS_UNICODE(op);
    // In C++, casting directly PyUnicode* to const char* is not valid
    return _Py_STATIC_CAST(const char*, _Py_STATIC_CAST(const void*, data));
    _Py_COMP_DIAG_POP
}
#if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 < 0x030b0000
#  define PyUnicode_AS_DATA(op) PyUnicode_AS_DATA(_PyObject_CAST(op))
#endif


/* --- _PyUnicodeWriter API ----------------------------------------------- */

typedef struct {
    PyObject *buffer;
    void *data;
    enum PyUnicode_Kind kind;
    Py_UCS4 maxchar;
    Py_ssize_t size;
    Py_ssize_t pos;

    /* minimum number of allocated characters (default: 0) */
    Py_ssize_t min_length;

    /* minimum character (default: 127, ASCII) */
    Py_UCS4 min_char;

    /* If non-zero, overallocate the buffer (default: 0). */
    unsigned char overallocate;

    /* If readonly is 1, buffer is a shared string (cannot be modified)
       and size is set to 0. */
    unsigned char readonly;
} _PyUnicodeWriter ;

/* Initialize a Unicode writer.
 *
 * By default, the minimum buffer size is 0 character and overallocation is
 * disabled. Set min_length, min_char and overallocate attributes to control
 * the allocation of the buffer. */
PyAPI_FUNC(void)
_PyUnicodeWriter_Init(_PyUnicodeWriter *writer);

/* Prepare the buffer to write 'length' characters
   with the specified maximum character.

   Return 0 on success, raise an exception and return -1 on error. */
#define _PyUnicodeWriter_Prepare(WRITER, LENGTH, MAXCHAR)             \
    (((MAXCHAR) <= (WRITER)->maxchar                                  \
      && (LENGTH) <= (WRITER)->size - (WRITER)->pos)                  \
     ? 0                                                              \
     : (((LENGTH) == 0)                                               \
        ? 0                                                           \
        : _PyUnicodeWriter_PrepareInternal((WRITER), (LENGTH), (MAXCHAR))))

/* Don't call this function directly, use the _PyUnicodeWriter_Prepare() macro
   instead. */
PyAPI_FUNC(int)
_PyUnicodeWriter_PrepareInternal(_PyUnicodeWriter *writer,
                                 Py_ssize_t length, Py_UCS4 maxchar);

/* Prepare the buffer to have at least the kind KIND.
   For example, kind=PyUnicode_2BYTE_KIND ensures that the writer will
   support characters in range U+000-U+FFFF.

   Return 0 on success, raise an exception and return -1 on error. */
#define _PyUnicodeWriter_PrepareKind(WRITER, KIND)                    \
    (assert((KIND) != PyUnicode_WCHAR_KIND),                          \
     (KIND) <= (WRITER)->kind                                         \
     ? 0                                                              \
     : _PyUnicodeWriter_PrepareKindInternal((WRITER), (KIND)))

/* Don't call this function directly, use the _PyUnicodeWriter_PrepareKind()
   macro instead. */
PyAPI_FUNC(int)
_PyUnicodeWriter_PrepareKindInternal(_PyUnicodeWriter *writer,
                                     enum PyUnicode_Kind kind);

/* Append a Unicode character.
   Return 0 on success, raise an exception and return -1 on error. */
PyAPI_FUNC(int)
_PyUnicodeWriter_WriteChar(_PyUnicodeWriter *writer,
    Py_UCS4 ch
    );

/* Append a Unicode string.
   Return 0 on success, raise an exception and return -1 on error. */
PyAPI_FUNC(int)
_PyUnicodeWriter_WriteStr(_PyUnicodeWriter *writer,
    PyObject *str               /* Unicode string */
    );

/* Append a substring of a Unicode string.
   Return 0 on success, raise an exception and return -1 on error. */
PyAPI_FUNC(int)
_PyUnicodeWriter_WriteSubstring(_PyUnicodeWriter *writer,
    PyObject *str,              /* Unicode string */
    Py_ssize_t start,
    Py_ssize_t end
    );

/* Append an ASCII-encoded byte string.
   Return 0 on success, raise an exception and return -1 on error. */
PyAPI_FUNC(int)
_PyUnicodeWriter_WriteASCIIString(_PyUnicodeWriter *writer,
    const char *str,           /* ASCII-encoded byte string */
    Py_ssize_t len             /* number of bytes, or -1 if unknown */
    );

/* Append a latin1-encoded byte string.
   Return 0 on success, raise an exception and return -1 on error. */
PyAPI_FUNC(int)
_PyUnicodeWriter_WriteLatin1String(_PyUnicodeWriter *writer,
    const char *str,           /* latin1-encoded byte string */
    Py_ssize_t len             /* length in bytes */
    );

/* Get the value of the writer as a Unicode string. Clear the
   buffer of the writer. Raise an exception and return NULL
   on error. */
PyAPI_FUNC(PyObject *)
_PyUnicodeWriter_Finish(_PyUnicodeWriter *writer);

/* Deallocate memory of a writer (clear its internal buffer). */
PyAPI_FUNC(void)
_PyUnicodeWriter_Dealloc(_PyUnicodeWriter *writer);


/* Format the object based on the format_spec, as defined in PEP 3101
   (Advanced String Formatting). */
PyAPI_FUNC(int) _PyUnicode_FormatAdvancedWriter(
    _PyUnicodeWriter *writer,
    PyObject *obj,
    PyObject *format_spec,
    Py_ssize_t start,
    Py_ssize_t end);

/* --- Manage the default encoding ---------------------------------------- */

/* Returns a pointer to the default encoding (UTF-8) of the
   Unicode object unicode.

   Like PyUnicode_AsUTF8AndSize(), this also caches the UTF-8 representation
   in the unicodeobject.

   _PyUnicode_AsString is a #define for PyUnicode_AsUTF8 to
   support the previous internal function with the same behaviour.

   Use of this API is DEPRECATED since no size information can be
   extracted from the returned data.
*/

PyAPI_FUNC(const char *) PyUnicode_AsUTF8(PyObject *unicode);

#define _PyUnicode_AsString PyUnicode_AsUTF8

/* --- UTF-7 Codecs ------------------------------------------------------- */

PyAPI_FUNC(PyObject*) _PyUnicode_EncodeUTF7(
    PyObject *unicode,          /* Unicode object */
    int base64SetO,             /* Encode RFC2152 Set O characters in base64 */
    int base64WhiteSpace,       /* Encode whitespace (sp, ht, nl, cr) in base64 */
    const char *errors          /* error handling */
    );

/* --- UTF-8 Codecs ------------------------------------------------------- */

PyAPI_FUNC(PyObject*) _PyUnicode_AsUTF8String(
    PyObject *unicode,
    const char *errors);

/* --- UTF-32 Codecs ------------------------------------------------------ */

PyAPI_FUNC(PyObject*) _PyUnicode_EncodeUTF32(
    PyObject *object,           /* Unicode object */
    const char *errors,         /* error handling */
    int byteorder               /* byteorder to use 0=BOM+native;-1=LE,1=BE */
    );

/* --- UTF-16 Codecs ------------------------------------------------------ */

/* Returns a Python string object holding the UTF-16 encoded value of
   the Unicode data.

   If byteorder is not 0, output is written according to the following
   byte order:

   byteorder == -1: little endian
   byteorder == 0:  native byte order (writes a BOM mark)
   byteorder == 1:  big endian

   If byteorder is 0, the output string will always start with the
   Unicode BOM mark (U+FEFF). In the other two modes, no BOM mark is
   prepended.
*/
PyAPI_FUNC(PyObject*) _PyUnicode_EncodeUTF16(
    PyObject* unicode,          /* Unicode object */
    const char *errors,         /* error handling */
    int byteorder               /* byteorder to use 0=BOM+native;-1=LE,1=BE */
    );

/* --- Unicode-Escape Codecs ---------------------------------------------- */

/* Variant of PyUnicode_DecodeUnicodeEscape that supports partial decoding. */
PyAPI_FUNC(PyObject*) _PyUnicode_DecodeUnicodeEscapeStateful(
        const char *string,     /* Unicode-Escape encoded string */
        Py_ssize_t length,      /* size of string */
        const char *errors,     /* error handling */
        Py_ssize_t *consumed    /* bytes consumed */
);
/* Helper for PyUnicode_DecodeUnicodeEscape that detects invalid escape
   chars. */
PyAPI_FUNC(PyObject*) _PyUnicode_DecodeUnicodeEscapeInternal(
        const char *string,     /* Unicode-Escape encoded string */
        Py_ssize_t length,      /* size of string */
        const char *errors,     /* error handling */
        Py_ssize_t *consumed,   /* bytes consumed */
        const char **first_invalid_escape  /* on return, points to first
                                              invalid escaped char in
                                              string. */
);

/* --- Raw-Unicode-Escape Codecs ---------------------------------------------- */

/* Variant of PyUnicode_DecodeRawUnicodeEscape that supports partial decoding. */
PyAPI_FUNC(PyObject*) _PyUnicode_DecodeRawUnicodeEscapeStateful(
        const char *string,     /* Unicode-Escape encoded string */
        Py_ssize_t length,      /* size of string */
        const char *errors,     /* error handling */
        Py_ssize_t *consumed    /* bytes consumed */
);

/* --- Latin-1 Codecs ----------------------------------------------------- */

PyAPI_FUNC(PyObject*) _PyUnicode_AsLatin1String(
    PyObject* unicode,
    const char* errors);

/* --- ASCII Codecs ------------------------------------------------------- */

PyAPI_FUNC(PyObject*) _PyUnicode_AsASCIIString(
    PyObject* unicode,
    const char* errors);

/* --- Character Map Codecs ----------------------------------------------- */

/* Translate an Unicode object by applying a character mapping table to
   it and return the resulting Unicode object.

   The mapping table must map Unicode ordinal integers to Unicode strings,
   Unicode ordinal integers or None (causing deletion of the character).

   Mapping tables may be dictionaries or sequences. Unmapped character
   ordinals (ones which cause a LookupError) are left untouched and
   are copied as-is.
*/
PyAPI_FUNC(PyObject*) _PyUnicode_EncodeCharmap(
    PyObject *unicode,          /* Unicode object */
    PyObject *mapping,          /* encoding mapping */
    const char *errors          /* error handling */
    );

/* --- Decimal Encoder ---------------------------------------------------- */

/* Coverts a Unicode object holding a decimal value to an ASCII string
   for using in int, float and complex parsers.
   Transforms code points that have decimal digit property to the
   corresponding ASCII digit code points.  Transforms spaces to ASCII.
   Transforms code points starting from the first non-ASCII code point that
   is neither a decimal digit nor a space to the end into '?'. */

PyAPI_FUNC(PyObject*) _PyUnicode_TransformDecimalAndSpaceToASCII(
    PyObject *unicode           /* Unicode object */
    );

/* --- Methods & Slots ---------------------------------------------------- */

PyAPI_FUNC(PyObject *) _PyUnicode_JoinArray(
    PyObject *separator,
    PyObject *const *items,
    Py_ssize_t seqlen
    );

/* Test whether a unicode is equal to ASCII identifier.  Return 1 if true,
   0 otherwise.  The right argument must be ASCII identifier.
   Any error occurs inside will be cleared before return. */
PyAPI_FUNC(int) _PyUnicode_EqualToASCIIId(
    PyObject *left,             /* Left string */
    _Py_Identifier *right       /* Right identifier */
    );

/* Test whether a unicode is equal to ASCII string.  Return 1 if true,
   0 otherwise.  The right argument must be ASCII-encoded string.
   Any error occurs inside will be cleared before return. */
PyAPI_FUNC(int) _PyUnicode_EqualToASCIIString(
    PyObject *left,
    const char *right           /* ASCII-encoded string */
    );

/* Externally visible for str.strip(unicode) */
PyAPI_FUNC(PyObject *) _PyUnicode_XStrip(
    PyObject *self,
    int striptype,
    PyObject *sepobj
    );

/* Using explicit passed-in values, insert the thousands grouping
   into the string pointed to by buffer.  For the argument descriptions,
   see Objects/stringlib/localeutil.h */
PyAPI_FUNC(Py_ssize_t) _PyUnicode_InsertThousandsGrouping(
    _PyUnicodeWriter *writer,
    Py_ssize_t n_buffer,
    PyObject *digits,
    Py_ssize_t d_pos,
    Py_ssize_t n_digits,
    Py_ssize_t min_width,
    const char *grouping,
    PyObject *thousands_sep,
    Py_UCS4 *maxchar);

/* === Characters Type APIs =============================================== */

/* Helper array used by Py_UNICODE_ISSPACE(). */

PyAPI_DATA(const unsigned char) _Py_ascii_whitespace[];

/* These should not be used directly. Use the Py_UNICODE_IS* and
   Py_UNICODE_TO* macros instead.

   These APIs are implemented in Objects/unicodectype.c.

*/

PyAPI_FUNC(int) _PyUnicode_IsLowercase(
    Py_UCS4 ch       /* Unicode character */
    );

PyAPI_FUNC(int) _PyUnicode_IsUppercase(
    Py_UCS4 ch       /* Unicode character */
    );

PyAPI_FUNC(int) _PyUnicode_IsTitlecase(
    Py_UCS4 ch       /* Unicode character */
    );

PyAPI_FUNC(int) _PyUnicode_IsXidStart(
    Py_UCS4 ch       /* Unicode character */
    );

PyAPI_FUNC(int) _PyUnicode_IsXidContinue(
    Py_UCS4 ch       /* Unicode character */
    );

PyAPI_FUNC(int) _PyUnicode_IsWhitespace(
    const Py_UCS4 ch         /* Unicode character */
    );

PyAPI_FUNC(int) _PyUnicode_IsLinebreak(
    const Py_UCS4 ch         /* Unicode character */
    );

/* Py_DEPRECATED(3.3) */ PyAPI_FUNC(Py_UCS4) _PyUnicode_ToLowercase(
    Py_UCS4 ch       /* Unicode character */
    );

/* Py_DEPRECATED(3.3) */ PyAPI_FUNC(Py_UCS4) _PyUnicode_ToUppercase(
    Py_UCS4 ch       /* Unicode character */
    );

Py_DEPRECATED(3.3) PyAPI_FUNC(Py_UCS4) _PyUnicode_ToTitlecase(
    Py_UCS4 ch       /* Unicode character */
    );

PyAPI_FUNC(int) _PyUnicode_ToLowerFull(
    Py_UCS4 ch,       /* Unicode character */
    Py_UCS4 *res
    );

PyAPI_FUNC(int) _PyUnicode_ToTitleFull(
    Py_UCS4 ch,       /* Unicode character */
    Py_UCS4 *res
    );

PyAPI_FUNC(int) _PyUnicode_ToUpperFull(
    Py_UCS4 ch,       /* Unicode character */
    Py_UCS4 *res
    );

PyAPI_FUNC(int) _PyUnicode_ToFoldedFull(
    Py_UCS4 ch,       /* Unicode character */
    Py_UCS4 *res
    );

PyAPI_FUNC(int) _PyUnicode_IsCaseIgnorable(
    Py_UCS4 ch         /* Unicode character */
    );

PyAPI_FUNC(int) _PyUnicode_IsCased(
    Py_UCS4 ch         /* Unicode character */
    );

PyAPI_FUNC(int) _PyUnicode_ToDecimalDigit(
    Py_UCS4 ch       /* Unicode character */
    );

PyAPI_FUNC(int) _PyUnicode_ToDigit(
    Py_UCS4 ch       /* Unicode character */
    );

PyAPI_FUNC(double) _PyUnicode_ToNumeric(
    Py_UCS4 ch       /* Unicode character */
    );

PyAPI_FUNC(int) _PyUnicode_IsDecimalDigit(
    Py_UCS4 ch       /* Unicode character */
    );

PyAPI_FUNC(int) _PyUnicode_IsDigit(
    Py_UCS4 ch       /* Unicode character */
    );

PyAPI_FUNC(int) _PyUnicode_IsNumeric(
    Py_UCS4 ch       /* Unicode character */
    );

PyAPI_FUNC(int) _PyUnicode_IsPrintable(
    Py_UCS4 ch       /* Unicode character */
    );

PyAPI_FUNC(int) _PyUnicode_IsAlpha(
    Py_UCS4 ch       /* Unicode character */
    );

PyAPI_FUNC(PyObject*) _PyUnicode_FormatLong(PyObject *, int, int, int);

/* Return an interned Unicode object for an Identifier; may fail if there is no memory.*/
PyAPI_FUNC(PyObject*) _PyUnicode_FromId(_Py_Identifier*);

/* Fast equality check when the inputs are known to be exact unicode types
   and where the hash values are equal (i.e. a very probable match) */
PyAPI_FUNC(int) _PyUnicode_EQ(PyObject *, PyObject *);

/* Equality check. Returns -1 on failure. */
PyAPI_FUNC(int) _PyUnicode_Equal(PyObject *, PyObject *);

PyAPI_FUNC(int) _PyUnicode_WideCharString_Converter(PyObject *, void *);
PyAPI_FUNC(int) _PyUnicode_WideCharString_Opt_Converter(PyObject *, void *);

PyAPI_FUNC(Py_ssize_t) _PyUnicode_ScanIdentifier(PyObject *);