/* stringlib: codec implementations */

#if !STRINGLIB_IS_UNICODE
# error "codecs.h is specific to Unicode"
#endif

/* Mask to quickly check whether a C 'long' contains a
 non-ASCII, UTF8-encoded char. */
#if (SIZEOF_LONG == 8)
# define ASCII_CHAR_MASK 0x8080808080808080UL
#elif (SIZEOF_LONG == 4)
# define ASCII_CHAR_MASK 0x80808080UL
#else
# error C 'long' size should be either 4 or 8!
#endif

/* 10xxxxxx */
#define IS_CONTINUATION_BYTE(ch) ((ch) >= 0x80 && (ch) < 0xC0)

Py_LOCAL_INLINE(Py_UCS4)
STRINGLIB(utf8_decode)(const char **inptr, const char *end,
 STRINGLIB_CHAR *dest,
 Py_ssize_t *outpos)
{
 Py_UCS4 ch;
 const char *s = *inptr;
 const char *aligned_end = (const char *) _Py_ALIGN_DOWN(end, SIZEOF_LONG);
 STRINGLIB_CHAR *p = dest + *outpos;

 while (s < end) {
 ch = (unsigned char)*s;

 if (ch < 0x80) {
 /* Fast path for runs of ASCII characters. Given that common UTF-8
 input will consist of an overwhelming majority of ASCII
 characters, we try to optimize for this case by checking
 as many characters as a C 'long' can contain.
 First, check if we can do an aligned read, as most CPUs have
 a penalty for unaligned reads.
 */
 if (_Py_IS_ALIGNED(s, SIZEOF_LONG)) {
 /* Help register allocation */
 const char *_s = s;
 STRINGLIB_CHAR *_p = p;
 while (_s < aligned_end) {
 /* Read a whole long at a time (either 4 or 8 bytes),
 and do a fast unrolled copy if it only contains ASCII
 characters. */
 unsigned long value = *(const unsigned long *) _s;
 if (value & ASCII_CHAR_MASK)
 break;
#if PY_LITTLE_ENDIAN
 _p[0] = (STRINGLIB_CHAR)(value & 0xFFu);
 _p[1] = (STRINGLIB_CHAR)((value >> 8) & 0xFFu);
 _p[2] = (STRINGLIB_CHAR)((value >> 16) & 0xFFu);
 _p[3] = (STRINGLIB_CHAR)((value >> 24) & 0xFFu);
# if SIZEOF_LONG == 8
 _p[4] = (STRINGLIB_CHAR)((value >> 32) & 0xFFu);
 _p[5] = (STRINGLIB_CHAR)((value >> 40) & 0xFFu);
 _p[6] = (STRINGLIB_CHAR)((value >> 48) & 0xFFu);
 _p[7] = (STRINGLIB_CHAR)((value >> 56) & 0xFFu);
# endif
#else
# if SIZEOF_LONG == 8
 _p[0] = (STRINGLIB_CHAR)((value >> 56) & 0xFFu);
 _p[1] = (STRINGLIB_CHAR)((value >> 48) & 0xFFu);
 _p[2] = (STRINGLIB_CHAR)((value >> 40) & 0xFFu);
 _p[3] = (STRINGLIB_CHAR)((value >> 32) & 0xFFu);
 _p[4] = (STRINGLIB_CHAR)((value >> 24) & 0xFFu);
 _p[5] = (STRINGLIB_CHAR)((value >> 16) & 0xFFu);
 _p[6] = (STRINGLIB_CHAR)((value >> 8) & 0xFFu);
 _p[7] = (STRINGLIB_CHAR)(value & 0xFFu);
# else
 _p[0] = (STRINGLIB_CHAR)((value >> 24) & 0xFFu);
 _p[1] = (STRINGLIB_CHAR)((value >> 16) & 0xFFu);
 _p[2] = (STRINGLIB_CHAR)((value >> 8) & 0xFFu);
 _p[3] = (STRINGLIB_CHAR)(value & 0xFFu);
# endif
#endif
 _s += SIZEOF_LONG;
 _p += SIZEOF_LONG;
 }
 s = _s;
 p = _p;
 if (s == end)
 break;
 ch = (unsigned char)*s;
 }
 if (ch < 0x80) {
 s++;
 *p++ = ch;
 continue;
 }
 }

 if (ch < 0xE0) {
 /* \xC2\x80-\xDF\xBF -- 0080-07FF */
 Py_UCS4 ch2;
 if (ch < 0xC2) {
 /* invalid sequence
 \x80-\xBF -- continuation byte
 \xC0-\xC1 -- fake 0000-007F */
 goto InvalidStart;
 }
 if (end - s < 2) {
 /* unexpected end of data: the caller will decide whether
 it's an error or not */
 break;
 }
 ch2 = (unsigned char)s[1];
 if (!IS_CONTINUATION_BYTE(ch2))
 /* invalid continuation byte */
 goto InvalidContinuation1;
 ch = (ch << 6) + ch2 -
 ((0xC0 << 6) + 0x80);
 assert ((ch > 0x007F) && (ch <= 0x07FF));
 s += 2;
 if (STRINGLIB_MAX_CHAR <= 0x007F ||
 (STRINGLIB_MAX_CHAR < 0x07FF && ch > STRINGLIB_MAX_CHAR))
 /* Out-of-range */
 goto Return;
 *p++ = ch;
 continue;
 }

 if (ch < 0xF0) {
 /* \xE0\xA0\x80-\xEF\xBF\xBF -- 0800-FFFF */
 Py_UCS4 ch2, ch3;
 if (end - s < 3) {
 /* unexpected end of data: the caller will decide whether
 it's an error or not */
 if (end - s < 2)
 break;
 ch2 = (unsigned char)s[1];
 if (!IS_CONTINUATION_BYTE(ch2) ||
 (ch2 < 0xA0 ? ch == 0xE0 : ch == 0xED))
 /* for clarification see comments below */
 goto InvalidContinuation1;
 break;
 }
 ch2 = (unsigned char)s[1];
 ch3 = (unsigned char)s[2];
 if (!IS_CONTINUATION_BYTE(ch2)) {
 /* invalid continuation byte */
 goto InvalidContinuation1;
 }
 if (ch == 0xE0) {
 if (ch2 < 0xA0)
 /* invalid sequence
 \xE0\x80\x80-\xE0\x9F\xBF -- fake 0000-0800 */
 goto InvalidContinuation1;
 } else if (ch == 0xED && ch2 >= 0xA0) {
 /* Decoding UTF-8 sequences in range \xED\xA0\x80-\xED\xBF\xBF
 will result in surrogates in range D800-DFFF. Surrogates are
 not valid UTF-8 so they are rejected.
 See http://www.unicode.org/versions/Unicode5.2.0/ch03.pdf
 (table 3-7) and http://www.rfc-editor.org/rfc/rfc3629.txt */
 goto InvalidContinuation1;
 }
 if (!IS_CONTINUATION_BYTE(ch3)) {
 /* invalid continuation byte */
 goto InvalidContinuation2;
 }
 ch = (ch << 12) + (ch2 << 6) + ch3 -
 ((0xE0 << 12) + (0x80 << 6) + 0x80);
 assert ((ch > 0x07FF) && (ch <= 0xFFFF));
 s += 3;
 if (STRINGLIB_MAX_CHAR <= 0x07FF ||
 (STRINGLIB_MAX_CHAR < 0xFFFF && ch > STRINGLIB_MAX_CHAR))
 /* Out-of-range */
 goto Return;
 *p++ = ch;
 continue;
 }

 if (ch < 0xF5) {
 /* \xF0\x90\x80\x80-\xF4\x8F\xBF\xBF -- 10000-10FFFF */
 Py_UCS4 ch2, ch3, ch4;
 if (end - s < 4) {
 /* unexpected end of data: the caller will decide whether
 it's an error or not */
 if (end - s < 2)
 break;
 ch2 = (unsigned char)s[1];
 if (!IS_CONTINUATION_BYTE(ch2) ||
 (ch2 < 0x90 ? ch == 0xF0 : ch == 0xF4))
 /* for clarification see comments below */
 goto InvalidContinuation1;
 if (end - s < 3)
 break;
 ch3 = (unsigned char)s[2];
 if (!IS_CONTINUATION_BYTE(ch3))
 goto InvalidContinuation2;
 break;
 }
 ch2 = (unsigned char)s[1];
 ch3 = (unsigned char)s[2];
 ch4 = (unsigned char)s[3];
 if (!IS_CONTINUATION_BYTE(ch2)) {
 /* invalid continuation byte */
 goto InvalidContinuation1;
 }
 if (ch == 0xF0) {
 if (ch2 < 0x90)
 /* invalid sequence
 \xF0\x80\x80\x80-\xF0\x8F\xBF\xBF -- fake 0000-FFFF */
 goto InvalidContinuation1;
 } else if (ch == 0xF4 && ch2 >= 0x90) {
 /* invalid sequence
 \xF4\x90\x80\x80- -- 110000- overflow */
 goto InvalidContinuation1;
 }
 if (!IS_CONTINUATION_BYTE(ch3)) {
 /* invalid continuation byte */
 goto InvalidContinuation2;
 }
 if (!IS_CONTINUATION_BYTE(ch4)) {
 /* invalid continuation byte */
 goto InvalidContinuation3;
 }
 ch = (ch << 18) + (ch2 << 12) + (ch3 << 6) + ch4 -
 ((0xF0 << 18) + (0x80 << 12) + (0x80 << 6) + 0x80);
 assert ((ch > 0xFFFF) && (ch <= 0x10FFFF));
 s += 4;
 if (STRINGLIB_MAX_CHAR <= 0xFFFF ||
 (STRINGLIB_MAX_CHAR < 0x10FFFF && ch > STRINGLIB_MAX_CHAR))
 /* Out-of-range */
 goto Return;
 *p++ = ch;
 continue;
 }
 goto InvalidStart;
 }
 ch = 0;
Return:
 *inptr = s;
 *outpos = p - dest;
 return ch;
InvalidStart:
 ch = 1;
 goto Return;
InvalidContinuation1:
 ch = 2;
 goto Return;
InvalidContinuation2:
 ch = 3;
 goto Return;
InvalidContinuation3:
 ch = 4;
 goto Return;
}

#undef ASCII_CHAR_MASK


/* UTF-8 encoder specialized for a Unicode kind to avoid the slow
 PyUnicode_READ() macro. Delete some parts of the code depending on the kind:
 UCS-1 strings don't need to handle surrogates for example. */
Py_LOCAL_INLINE(PyObject *)
STRINGLIB(utf8_encoder)(PyObject *unicode,
 STRINGLIB_CHAR *data,
 Py_ssize_t size,
 _Py_error_handler error_handler,
 const char *errors)
{
 Py_ssize_t i; /* index into data of next input character */
 char *p; /* next free byte in output buffer */
#if STRINGLIB_SIZEOF_CHAR > 1
 PyObject *error_handler_obj = NULL;
 PyObject *exc = NULL;
 PyObject *rep = NULL;
#endif
#if STRINGLIB_SIZEOF_CHAR == 1
 const Py_ssize_t max_char_size = 2;
#elif STRINGLIB_SIZEOF_CHAR == 2
 const Py_ssize_t max_char_size = 3;
#else /* STRINGLIB_SIZEOF_CHAR == 4 */
 const Py_ssize_t max_char_size = 4;
#endif
 _PyBytesWriter writer;

 assert(size >= 0);
 _PyBytesWriter_Init(&writer);

 if (size > PY_SSIZE_T_MAX / max_char_size) {
 /* integer overflow */
 return PyErr_NoMemory();
 }

 p = _PyBytesWriter_Alloc(&writer, size * max_char_size);
 if (p == NULL)
 return NULL;

 for (i = 0; i < size;) {
 Py_UCS4 ch = data[i++];

 if (ch < 0x80) {
 /* Encode ASCII */
 *p++ = (char) ch;

 }
 else
#if STRINGLIB_SIZEOF_CHAR > 1
 if (ch < 0x0800)
#endif
 {
 /* Encode Latin-1 */
 *p++ = (char)(0xc0 | (ch >> 6));
 *p++ = (char)(0x80 | (ch & 0x3f));
 }
#if STRINGLIB_SIZEOF_CHAR > 1
 else if (Py_UNICODE_IS_SURROGATE(ch)) {
 Py_ssize_t startpos, endpos, newpos;
 Py_ssize_t k;
 if (error_handler == _Py_ERROR_UNKNOWN) {
 error_handler = _Py_GetErrorHandler(errors);
 }

 startpos = i-1;
 endpos = startpos+1;

 while ((endpos < size) && Py_UNICODE_IS_SURROGATE(data[endpos]))
 endpos++;

 /* Only overallocate the buffer if it's not the last write */
 writer.overallocate = (endpos < size);

 switch (error_handler)
 {
 case _Py_ERROR_REPLACE:
 memset(p, '?', endpos - startpos);
 p += (endpos - startpos);
 /* fall through */
 case _Py_ERROR_IGNORE:
 i += (endpos - startpos - 1);
 break;

 case _Py_ERROR_SURROGATEPASS:
 for (k=startpos; k<endpos; k++) {
 ch = data[k];
 *p++ = (char)(0xe0 | (ch >> 12));
 *p++ = (char)(0x80 | ((ch >> 6) & 0x3f));
 *p++ = (char)(0x80 | (ch & 0x3f));
 }
 i += (endpos - startpos - 1);
 break;

 case _Py_ERROR_BACKSLASHREPLACE:
 /* subtract preallocated bytes */
 writer.min_size -= max_char_size * (endpos - startpos);
 p = backslashreplace(&writer, p,
 unicode, startpos, endpos);
 if (p == NULL)
 goto error;
 i += (endpos - startpos - 1);
 break;

 case _Py_ERROR_XMLCHARREFREPLACE:
 /* subtract preallocated bytes */
 writer.min_size -= max_char_size * (endpos - startpos);
 p = xmlcharrefreplace(&writer, p,
 unicode, startpos, endpos);
 if (p == NULL)
 goto error;
 i += (endpos - startpos - 1);
 break;

 case _Py_ERROR_SURROGATEESCAPE:
 for (k=startpos; k<endpos; k++) {
 ch = data[k];
 if (!(0xDC80 <= ch && ch <= 0xDCFF))
 break;
 *p++ = (char)(ch & 0xff);
 }
 if (k >= endpos) {
 i += (endpos - startpos - 1);
 break;
 }
 startpos = k;
 assert(startpos < endpos);
 /* fall through */
 default:
 rep = unicode_encode_call_errorhandler(
 errors, &error_handler_obj, "utf-8", "surrogates not allowed",
 unicode, &exc, startpos, endpos, &newpos);
 if (!rep)
 goto error;

 /* subtract preallocated bytes */
 writer.min_size -= max_char_size * (newpos - startpos);

 if (PyBytes_Check(rep)) {
 p = _PyBytesWriter_WriteBytes(&writer, p,
 PyBytes_AS_STRING(rep),
 PyBytes_GET_SIZE(rep));
 }
 else {
 /* rep is unicode */
 if (PyUnicode_READY(rep) < 0)
 goto error;

 if (!PyUnicode_IS_ASCII(rep)) {
 raise_encode_exception(&exc, "utf-8", unicode,
 startpos, endpos,
 "surrogates not allowed");
 goto error;
 }

 p = _PyBytesWriter_WriteBytes(&writer, p,
 PyUnicode_DATA(rep),
 PyUnicode_GET_LENGTH(rep));
 }

 if (p == NULL)
 goto error;
 Py_CLEAR(rep);

 i = newpos;
 }

 /* If overallocation was disabled, ensure that it was the last
 write. Otherwise, we missed an optimization */
 assert(writer.overallocate || i == size);
 }
 else
#if STRINGLIB_SIZEOF_CHAR > 2
 if (ch < 0x10000)
#endif
 {
 *p++ = (char)(0xe0 | (ch >> 12));
 *p++ = (char)(0x80 | ((ch >> 6) & 0x3f));
 *p++ = (char)(0x80 | (ch & 0x3f));
 }
#if STRINGLIB_SIZEOF_CHAR > 2
 else /* ch >= 0x10000 */
 {
 assert(ch <= MAX_UNICODE);
 /* Encode UCS4 Unicode ordinals */
 *p++ = (char)(0xf0 | (ch >> 18));
 *p++ = (char)(0x80 | ((ch >> 12) & 0x3f));
 *p++ = (char)(0x80 | ((ch >> 6) & 0x3f));
 *p++ = (char)(0x80 | (ch & 0x3f));
 }
#endif /* STRINGLIB_SIZEOF_CHAR > 2 */
#endif /* STRINGLIB_SIZEOF_CHAR > 1 */
 }

#if STRINGLIB_SIZEOF_CHAR > 1
 Py_XDECREF(error_handler_obj);
 Py_XDECREF(exc);
#endif
 return _PyBytesWriter_Finish(&writer, p);

#if STRINGLIB_SIZEOF_CHAR > 1
 error:
 Py_XDECREF(rep);
 Py_XDECREF(error_handler_obj);
 Py_XDECREF(exc);
 _PyBytesWriter_Dealloc(&writer);
 return NULL;
#endif
}

/* The pattern for constructing UCS2-repeated masks. */
#if SIZEOF_LONG == 8
# define UCS2_REPEAT_MASK 0x0001000100010001ul
#elif SIZEOF_LONG == 4
# define UCS2_REPEAT_MASK 0x00010001ul
#else
# error C 'long' size should be either 4 or 8!
#endif

/* The mask for fast checking. */
#if STRINGLIB_SIZEOF_CHAR == 1
/* The mask for fast checking of whether a C 'long' contains a
 non-ASCII or non-Latin1 UTF16-encoded characters. */
# define FAST_CHAR_MASK (UCS2_REPEAT_MASK * (0xFFFFu & ~STRINGLIB_MAX_CHAR))
#else
/* The mask for fast checking of whether a C 'long' may contain
 UTF16-encoded surrogate characters. This is an efficient heuristic,
 assuming that non-surrogate characters with a code point >= 0x8000 are
 rare in most input.
*/
# define FAST_CHAR_MASK (UCS2_REPEAT_MASK * 0x8000u)
#endif
/* The mask for fast byte-swapping. */
#define STRIPPED_MASK (UCS2_REPEAT_MASK * 0x00FFu)
/* Swap bytes. */
#define SWAB(value) ((((value) >> 8) & STRIPPED_MASK) | \
 (((value) & STRIPPED_MASK) << 8))

Py_LOCAL_INLINE(Py_UCS4)
STRINGLIB(utf16_decode)(const unsigned char **inptr, const unsigned char *e,
 STRINGLIB_CHAR *dest, Py_ssize_t *outpos,
 int native_ordering)
{
 Py_UCS4 ch;
 const unsigned char *aligned_end =
 (const unsigned char *) _Py_ALIGN_DOWN(e, SIZEOF_LONG);
 const unsigned char *q = *inptr;
 STRINGLIB_CHAR *p = dest + *outpos;
 /* Offsets from q for retrieving byte pairs in the right order. */
#if PY_LITTLE_ENDIAN
 int ihi = !!native_ordering, ilo = !native_ordering;
#else
 int ihi = !native_ordering, ilo = !!native_ordering;
#endif
 --e;

 while (q < e) {
 Py_UCS4 ch2;
 /* First check for possible aligned read of a C 'long'. Unaligned
 reads are more expensive, better to defer to another iteration. */
 if (_Py_IS_ALIGNED(q, SIZEOF_LONG)) {
 /* Fast path for runs of in-range non-surrogate chars. */
 const unsigned char *_q = q;
 while (_q < aligned_end) {
 unsigned long block = * (const unsigned long *) _q;
 if (native_ordering) {
 /* Can use buffer directly */
 if (block & FAST_CHAR_MASK)
 break;
 }
 else {
 /* Need to byte-swap */
 if (block & SWAB(FAST_CHAR_MASK))
 break;
#if STRINGLIB_SIZEOF_CHAR == 1
 block >>= 8;
#else
 block = SWAB(block);
#endif
 }
#if PY_LITTLE_ENDIAN
# if SIZEOF_LONG == 4
 p[0] = (STRINGLIB_CHAR)(block & 0xFFFFu);
 p[1] = (STRINGLIB_CHAR)(block >> 16);
# elif SIZEOF_LONG == 8
 p[0] = (STRINGLIB_CHAR)(block & 0xFFFFu);
 p[1] = (STRINGLIB_CHAR)((block >> 16) & 0xFFFFu);
 p[2] = (STRINGLIB_CHAR)((block >> 32) & 0xFFFFu);
 p[3] = (STRINGLIB_CHAR)(block >> 48);
# endif
#else
# if SIZEOF_LONG == 4
 p[0] = (STRINGLIB_CHAR)(block >> 16);
 p[1] = (STRINGLIB_CHAR)(block & 0xFFFFu);
# elif SIZEOF_LONG == 8
 p[0] = (STRINGLIB_CHAR)(block >> 48);
 p[1] = (STRINGLIB_CHAR)((block >> 32) & 0xFFFFu);
 p[2] = (STRINGLIB_CHAR)((block >> 16) & 0xFFFFu);
 p[3] = (STRINGLIB_CHAR)(block & 0xFFFFu);
# endif
#endif
 _q += SIZEOF_LONG;
 p += SIZEOF_LONG / 2;
 }
 q = _q;
 if (q >= e)
 break;
 }

 ch = (q[ihi] << 8) | q[ilo];
 q += 2;
 if (!Py_UNICODE_IS_SURROGATE(ch)) {
#if STRINGLIB_SIZEOF_CHAR < 2
 if (ch > STRINGLIB_MAX_CHAR)
 /* Out-of-range */
 goto Return;
#endif
 *p++ = (STRINGLIB_CHAR)ch;
 continue;
 }

 /* UTF-16 code pair: */
 if (!Py_UNICODE_IS_HIGH_SURROGATE(ch))
 goto IllegalEncoding;
 if (q >= e)
 goto UnexpectedEnd;
 ch2 = (q[ihi] << 8) | q[ilo];
 q += 2;
 if (!Py_UNICODE_IS_LOW_SURROGATE(ch2))
 goto IllegalSurrogate;
 ch = Py_UNICODE_JOIN_SURROGATES(ch, ch2);
#if STRINGLIB_SIZEOF_CHAR < 4
 /* Out-of-range */
 goto Return;
#else
 *p++ = (STRINGLIB_CHAR)ch;
#endif
 }
 ch = 0;
Return:
 *inptr = q;
 *outpos = p - dest;
 return ch;
UnexpectedEnd:
 ch = 1;
 goto Return;
IllegalEncoding:
 ch = 2;
 goto Return;
IllegalSurrogate:
 ch = 3;
 goto Return;
}
#undef UCS2_REPEAT_MASK
#undef FAST_CHAR_MASK
#undef STRIPPED_MASK
#undef SWAB


#if STRINGLIB_MAX_CHAR >= 0x80
Py_LOCAL_INLINE(Py_ssize_t)
STRINGLIB(utf16_encode)(const STRINGLIB_CHAR *in,
 Py_ssize_t len,
 unsigned short **outptr,
 int native_ordering)
{
 unsigned short *out = *outptr;
 const STRINGLIB_CHAR *end = in + len;
#if STRINGLIB_SIZEOF_CHAR == 1
 if (native_ordering) {
 const STRINGLIB_CHAR *unrolled_end = in + _Py_SIZE_ROUND_DOWN(len, 4);
 while (in < unrolled_end) {
 out[0] = in[0];
 out[1] = in[1];
 out[2] = in[2];
 out[3] = in[3];
 in += 4; out += 4;
 }
 while (in < end) {
 *out++ = *in++;
 }
 } else {
# define SWAB2(CH) ((CH) << 8) /* high byte is zero */
 const STRINGLIB_CHAR *unrolled_end = in + _Py_SIZE_ROUND_DOWN(len, 4);
 while (in < unrolled_end) {
 out[0] = SWAB2(in[0]);
 out[1] = SWAB2(in[1]);
 out[2] = SWAB2(in[2]);
 out[3] = SWAB2(in[3]);
 in += 4; out += 4;
 }
 while (in < end) {
 Py_UCS4 ch = *in++;
 *out++ = SWAB2((Py_UCS2)ch);
 }
#undef SWAB2
 }
 *outptr = out;
 return len;
#else
 if (native_ordering) {
#if STRINGLIB_MAX_CHAR < 0x10000
 const STRINGLIB_CHAR *unrolled_end = in + _Py_SIZE_ROUND_DOWN(len, 4);
 while (in < unrolled_end) {
 /* check if any character is a surrogate character */
 if (((in[0] ^ 0xd800) &
 (in[1] ^ 0xd800) &
 (in[2] ^ 0xd800) &
 (in[3] ^ 0xd800) & 0xf800) == 0)
 break;
 out[0] = in[0];
 out[1] = in[1];
 out[2] = in[2];
 out[3] = in[3];
 in += 4; out += 4;
 }
#endif
 while (in < end) {
 Py_UCS4 ch;
 ch = *in++;
 if (ch < 0xd800)
 *out++ = ch;
 else if (ch < 0xe000)
 /* reject surrogate characters (U+D800-U+DFFF) */
 goto fail;
#if STRINGLIB_MAX_CHAR >= 0x10000
 else if (ch >= 0x10000) {
 out[0] = Py_UNICODE_HIGH_SURROGATE(ch);
 out[1] = Py_UNICODE_LOW_SURROGATE(ch);
 out += 2;
 }
#endif
 else
 *out++ = ch;
 }
 } else {
#define SWAB2(CH) (((CH) << 8) | ((CH) >> 8))
#if STRINGLIB_MAX_CHAR < 0x10000
 const STRINGLIB_CHAR *unrolled_end = in + _Py_SIZE_ROUND_DOWN(len, 4);
 while (in < unrolled_end) {
 /* check if any character is a surrogate character */
 if (((in[0] ^ 0xd800) &
 (in[1] ^ 0xd800) &
 (in[2] ^ 0xd800) &
 (in[3] ^ 0xd800) & 0xf800) == 0)
 break;
 out[0] = SWAB2(in[0]);
 out[1] = SWAB2(in[1]);
 out[2] = SWAB2(in[2]);
 out[3] = SWAB2(in[3]);
 in += 4; out += 4;
 }
#endif
 while (in < end) {
 Py_UCS4 ch = *in++;
 if (ch < 0xd800)
 *out++ = SWAB2((Py_UCS2)ch);
 else if (ch < 0xe000)
 /* reject surrogate characters (U+D800-U+DFFF) */
 goto fail;
#if STRINGLIB_MAX_CHAR >= 0x10000
 else if (ch >= 0x10000) {
 Py_UCS2 ch1 = Py_UNICODE_HIGH_SURROGATE(ch);
 Py_UCS2 ch2 = Py_UNICODE_LOW_SURROGATE(ch);
 out[0] = SWAB2(ch1);
 out[1] = SWAB2(ch2);
 out += 2;
 }
#endif
 else
 *out++ = SWAB2((Py_UCS2)ch);
 }
#undef SWAB2
 }
 *outptr = out;
 return len;
 fail:
 *outptr = out;
 return len - (end - in + 1);
#endif
}

#if STRINGLIB_SIZEOF_CHAR == 1
# define SWAB4(CH, tmp) ((CH) << 24) /* high bytes are zero */
#elif STRINGLIB_SIZEOF_CHAR == 2
# define SWAB4(CH, tmp) (tmp = (CH), \
 ((tmp & 0x00FFu) << 24) + ((tmp & 0xFF00u) << 8))
 /* high bytes are zero */
#else
# define SWAB4(CH, tmp) (tmp = (CH), \
 tmp = ((tmp & 0x00FF00FFu) << 8) + ((tmp >> 8) & 0x00FF00FFu), \
 ((tmp & 0x0000FFFFu) << 16) + ((tmp >> 16) & 0x0000FFFFu))
#endif
Py_LOCAL_INLINE(Py_ssize_t)
STRINGLIB(utf32_encode)(const STRINGLIB_CHAR *in,
 Py_ssize_t len,
 PY_UINT32_T **outptr,
 int native_ordering)
{
 PY_UINT32_T *out = *outptr;
 const STRINGLIB_CHAR *end = in + len;
 if (native_ordering) {
 const STRINGLIB_CHAR *unrolled_end = in + _Py_SIZE_ROUND_DOWN(len, 4);
 while (in < unrolled_end) {
#if STRINGLIB_SIZEOF_CHAR > 1
 /* check if any character is a surrogate character */
 if (((in[0] ^ 0xd800) &
 (in[1] ^ 0xd800) &
 (in[2] ^ 0xd800) &
 (in[3] ^ 0xd800) & 0xf800) == 0)
 break;
#endif
 out[0] = in[0];
 out[1] = in[1];
 out[2] = in[2];
 out[3] = in[3];
 in += 4; out += 4;
 }
 while (in < end) {
 Py_UCS4 ch;
 ch = *in++;
#if STRINGLIB_SIZEOF_CHAR > 1
 if (Py_UNICODE_IS_SURROGATE(ch)) {
 /* reject surrogate characters (U+D800-U+DFFF) */
 goto fail;
 }
#endif
 *out++ = ch;
 }
 } else {
 const STRINGLIB_CHAR *unrolled_end = in + _Py_SIZE_ROUND_DOWN(len, 4);
 while (in < unrolled_end) {
#if STRINGLIB_SIZEOF_CHAR > 1
 Py_UCS4 ch1, ch2, ch3, ch4;
 /* check if any character is a surrogate character */
 if (((in[0] ^ 0xd800) &
 (in[1] ^ 0xd800) &
 (in[2] ^ 0xd800) &
 (in[3] ^ 0xd800) & 0xf800) == 0)
 break;
#endif
 out[0] = SWAB4(in[0], ch1);
 out[1] = SWAB4(in[1], ch2);
 out[2] = SWAB4(in[2], ch3);
 out[3] = SWAB4(in[3], ch4);
 in += 4; out += 4;
 }
 while (in < end) {
 Py_UCS4 ch = *in++;
#if STRINGLIB_SIZEOF_CHAR > 1
 if (Py_UNICODE_IS_SURROGATE(ch)) {
 /* reject surrogate characters (U+D800-U+DFFF) */
 goto fail;
 }
#endif
 *out++ = SWAB4(ch, ch);
 }
 }
 *outptr = out;
 return len;
#if STRINGLIB_SIZEOF_CHAR > 1
 fail:
 *outptr = out;
 return len - (end - in + 1);
#endif
}
#undef SWAB4

#endif