PythonUnicode对象和编码解码器

Unicode类型¶

These are the basic Unicode object types used for the Unicode implementation in

Python:

Py_UCS4¶

Py_UCS2¶

Py_UCS1¶

These types are typedefs for unsigned integer types wide enough to contain

characters of 32 bits, 16 bits and 8 bits, respectively. When dealing with

single Unicode characters, use Py_UCS4.

3.3 新版功能.

Py_UNICODE¶

This is a typedef of wchar_t, which is a 16-bit type or 32-bit type

depending on the platform.

在 3.3 版更改: In previous versions, this was a 16-bit type or a 32-bit type depending on

whether you selected a "narrow" or "wide" Unicode version of Python at

build time.

PyASCIIObject¶

PyCompactUnicodeObject¶

PyUnicodeObject¶

These subtypes of PyObject represent a Python Unicode object. In

almost all cases, they shouldn't be used directly, since all API functions

that deal with Unicode objects take and return PyObject pointers.

3.3 新版功能.

PyTypeObject PyUnicode_Type¶

This instance of PyTypeObject represents the Python Unicode type. It

is exposed to Python code as str.

The following APIs are really C macros and can be used to do fast checks and to

access internal read-only data of Unicode objects:

int PyUnicode_Check(PyObject *o)¶

Return true if the object o is a Unicode object or an instance of a Unicode

subtype.

int PyUnicode_CheckExact(PyObject *o)¶

Return true if the object o is a Unicode object, but not an instance of a

subtype.

int PyUnicode_READY(PyObject *o)¶

Ensure the string object o is in the "canonical" representation. This is

required before using any of the access macros described below.

Returns 0 on success and -1 with an exception set on failure, which in

particular happens if memory allocation fails.

3.3 新版功能.

Py_ssize_t PyUnicode_GET_LENGTH(PyObject *o)¶

Return the length of the Unicode string, in code points. o has to be a

Unicode object in the "canonical" representation (not checked).

3.3 新版功能.

Py_UCS1* PyUnicode_1BYTE_DATA(PyObject *o)¶

Py_UCS2* PyUnicode_2BYTE_DATA(PyObject *o)¶

Py_UCS4* PyUnicode_4BYTE_DATA(PyObject *o)¶

Return a pointer to the canonical representation cast to UCS1, UCS2 or UCS4

integer types for direct character access. No checks are performed if the

canonical representation has the correct character size; use

PyUnicode_KIND() to select the right macro. Make sure

PyUnicode_READY() has been called before accessing this.

3.3 新版功能.

PyUnicode_WCHAR_KIND¶

PyUnicode_1BYTE_KIND¶

PyUnicode_2BYTE_KIND¶

PyUnicode_4BYTE_KIND¶

Return values of the PyUnicode_KIND() macro.

3.3 新版功能.

int PyUnicode_KIND(PyObject *o)¶

Return one of the PyUnicode kind constants (see above) that indicate how many

bytes per character this Unicode object uses to store its data. o has to

be a Unicode object in the "canonical" representation (not checked).

3.3 新版功能.

void* PyUnicode_DATA(PyObject *o)¶

Return a void pointer to the raw Unicode buffer. o has to be a Unicode

object in the "canonical" representation (not checked).

3.3 新版功能.

void PyUnicode_WRITE(int kind, void *data, Py_ssize_t index, Py_UCS4 value)¶

Write into a canonical representation data (as obtained with

PyUnicode_DATA()). This macro does not do any sanity checks and is

intended for usage in loops. The caller should cache the kind value and

data pointer as obtained from other macro 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.

3.3 新版功能.

Py_UCS4 PyUnicode_READ(int kind, void *data, Py_ssize_t index)¶

Read a code point from a canonical representation data (as obtained with

PyUnicode_DATA()). No checks or ready calls are performed.

3.3 新版功能.

Py_UCS4 PyUnicode_READ_CHAR(PyObject *o, Py_ssize_t index)¶

Read a character from a Unicode object o, which must be in the "canonical"

representation. This is less efficient than PyUnicode_READ() if you

do multiple consecutive reads.

3.3 新版功能.

PyUnicode_MAX_CHAR_VALUE(PyObject *o)¶

Return the maximum code point that is suitable for creating another string

based on o, which must be in the "canonical" representation. This is

always an approximation but more efficient than iterating over the string.

3.3 新版功能.

int PyUnicode_ClearFreeList()¶

清空释放列表。 返回所释放的条目数。

Py_ssize_t PyUnicode_GET_SIZE(PyObject *o)¶

Return the size of the deprecated Py_UNICODE representation, in

code units (this includes surrogate pairs as 2 units). o has to be a

Unicode object (not checked).

Deprecated since version 3.3, will be removed in version 4.0: Part of the old-style Unicode API, please migrate to using

PyUnicode_GET_LENGTH().

Py_ssize_t PyUnicode_GET_DATA_SIZE(PyObject *o)¶

Return the size of the deprecated Py_UNICODE representation in

bytes. o has to be a Unicode object (not checked).

Deprecated since version 3.3, will be removed in version 4.0: Part of the old-style Unicode API, please migrate to using

PyUnicode_GET_LENGTH().

Py_UNICODE* PyUnicode_AS_UNICODE(PyObject *o)¶

const char* PyUnicode_AS_DATA(PyObject *o)¶

Return a pointer to a Py_UNICODE representation of the object. The

returned buffer is always terminated with an extra null code point. It

may also contain embedded null code points, which would cause the string

to be truncated when used in most C functions. The AS_DATA form

casts the pointer to constchar*. The o argument has to be

a Unicode object (not checked).

在 3.3 版更改: This macro is now inefficient -- because in many cases the

Py_UNICODE representation does not exist and needs to be created

-- and can fail (return NULL with an exception set). Try to port the

code to use the new PyUnicode_nBYTE_DATA() macros or use

PyUnicode_WRITE() or PyUnicode_READ().

Deprecated since version 3.3, will be removed in version 4.0: Part of the old-style Unicode API, please migrate to using the

PyUnicode_nBYTE_DATA() family of macros.

Unicode字符属性¶

Unicode provides many different character properties. The most often needed ones

are available through these macros which are mapped to C functions depending on

the Python configuration.

int Py_UNICODE_ISSPACE(Py_UNICODE ch)¶

Return 1 or 0 depending on whether ch is a whitespace character.

int Py_UNICODE_ISLOWER(Py_UNICODE ch)¶

Return 1 or 0 depending on whether ch is a lowercase character.

int Py_UNICODE_ISUPPER(Py_UNICODE ch)¶

Return 1 or 0 depending on whether ch is an uppercase character.

int Py_UNICODE_ISTITLE(Py_UNICODE ch)¶

Return 1 or 0 depending on whether ch is a titlecase character.

int Py_UNICODE_ISLINEBREAK(Py_UNICODE ch)¶

Return 1 or 0 depending on whether ch is a linebreak character.

int Py_UNICODE_ISDECIMAL(Py_UNICODE ch)¶

Return 1 or 0 depending on whether ch is a decimal character.

int Py_UNICODE_ISDIGIT(Py_UNICODE ch)¶

Return 1 or 0 depending on whether ch is a digit character.

int Py_UNICODE_ISNUMERIC(Py_UNICODE ch)¶

Return 1 or 0 depending on whether ch is a numeric character.

int Py_UNICODE_ISALPHA(Py_UNICODE ch)¶

Return 1 or 0 depending on whether ch is an alphabetic character.

int Py_UNICODE_ISALNUM(Py_UNICODE ch)¶

Return 1 or 0 depending on whether ch is an alphanumeric character.

int Py_UNICODE_ISPRINTABLE(Py_UNICODE ch)¶

Return 1 or 0 depending on whether ch is a printable character.

Nonprintable characters are those characters defined in the Unicode character

database as "Other" or "Separator", excepting the ASCII space (0x20) which is

considered printable. (Note that printable characters in this context are

those which should not be escaped when repr() is invoked on a string.

It has no bearing on the handling of strings written to sys.stdout or

sys.stderr.)

These APIs can be used for fast direct character conversions:

Py_UNICODE Py_UNICODE_TOLOWER(Py_UNICODE ch)¶

Return the character ch converted to lower case.

3.3 版后已移除: This function uses simple case mappings.

Py_UNICODE Py_UNICODE_TOUPPER(Py_UNICODE ch)¶

Return the character ch converted to upper case.

3.3 版后已移除: This function uses simple case mappings.

Py_UNICODE Py_UNICODE_TOTITLE(Py_UNICODE ch)¶

Return the character ch converted to title case.

3.3 版后已移除: This function uses simple case mappings.

int Py_UNICODE_TODECIMAL(Py_UNICODE ch)¶

Return the character ch converted to a decimal positive integer. Return

-1 if this is not possible. This macro does not raise exceptions.

int Py_UNICODE_TODIGIT(Py_UNICODE ch)¶

Return the character ch converted to a single digit integer. Return -1 if

this is not possible. This macro does not raise exceptions.

double Py_UNICODE_TONUMERIC(Py_UNICODE ch)¶

Return the character ch converted to a double. Return -1.0 if this is not

possible. This macro does not raise exceptions.

These APIs can be used to work with surrogates:

Py_UNICODE_IS_SURROGATE(ch)¶

Check if ch is a surrogate (0xD800<=ch<=0xDFFF).

Py_UNICODE_IS_HIGH_SURROGATE(ch)¶

Check if ch is a high surrogate (0xD800<=ch<=0xDBFF).

Py_UNICODE_IS_LOW_SURROGATE(ch)¶

Check if ch is a low surrogate (0xDC00<=ch<=0xDFFF).

Py_UNICODE_JOIN_SURROGATES(high, low)¶

Join two surrogate characters and return a single Py_UCS4 value.

high and low are respectively the leading and trailing surrogates in a

surrogate pair.

Creating and accessing Unicode strings¶

To create Unicode objects and access their basic sequence properties, use these

APIs:

PyObject* PyUnicode_New(Py_ssize_t size, Py_UCS4 maxchar)¶

Return value: New reference.

Create a new Unicode object. maxchar should be the true maximum code point

to be placed in the string. As an approximation, it can be rounded up to the

nearest value in the sequence 127, 255, 65535, 1114111.

This is the recommended way to allocate a new Unicode object. Objects

created using this function are not resizable.

3.3 新版功能.

PyObject* PyUnicode_FromKindAndData(int kind, const void *buffer, Py_ssize_t size)¶

Return value: New reference.

Create a new Unicode object with the given kind (possible values are

PyUnicode_1BYTE_KIND etc., as returned by

PyUnicode_KIND()). The buffer must point to an array of size

units of 1, 2 or 4 bytes per character, as given by the kind.

3.3 新版功能.

PyObject* PyUnicode_FromStringAndSize(const char *u, Py_ssize_t size)¶

Return value: New reference.

Create a Unicode object from the char buffer u. The bytes will be

interpreted as being UTF-8 encoded. The buffer is copied into the new

object. If the buffer is not NULL, the return value might be a shared

object, i.e. modification of the data is not allowed.

If u is NULL, this function behaves like PyUnicode_FromUnicode()

with the buffer set to NULL. This usage is deprecated in favor of

PyUnicode_New().

PyObject *PyUnicode_FromString(const char *u)¶

Return value: New reference.

Create a Unicode object from a UTF-8 encoded null-terminated char buffer

u.

PyObject* PyUnicode_FromFormat(const char *format, ...)¶

Return value: New reference.

Take a C printf()-style format string and a variable number of

arguments, calculate the size of the resulting Python Unicode string and return

a string with the values formatted into it. The variable arguments must be C

types and must correspond exactly to the format characters in the format

ASCII-encoded string. The following format characters are allowed:

格式字符	类型	注释
%%	不适用	文字%字符。
%c	整型	单个字符，表示为C 语言的整型。
%d	整型	相当于 printf("%d"). 1
%u	无符号整型	相当于 printf("%u"). 1
%ld	长整型	相当于 printf("%ld"). 1
%li	长整型	相当于 printf("%li"). 1
%lu	无符号长整型	相当于 printf("%lu"). 1
%lld	long long	相当于 printf("%lld"). 1
%lli	long long	相当于 printf("%lli"). 1
%llu	无符号 long long	相当于 printf("%llu"). 1
%zd	Py_ssize_t	相当于 printf("%zd"). 1
%zi	Py_ssize_t	相当于 printf("%zi"). 1
%zu	size_t	相当于 printf("%zu"). 1
%i	整型	相当于 printf("%i"). 1
%x	整型	相当于 printf("%x"). 1
%s	const char*	以 null 为终止符的 C 字符数组。
%p	const void*	一个 C 指针的十六进制表示形式。 基本等价于 printf("%p") 但它会确保以字面值 0x 开头，不论系统平台上 printf 的输出是什么。
%A	PyObject*	ascii() 调用的结果。
%U	PyObject*	A Unicode object.
%V	PyObject*, const char*	A Unicode object (which may be NULL) and a null-terminated C character array as a second parameter (which will be used, if the first parameter is NULL).
%S	PyObject*	The result of calling PyObject_Str().
%R	PyObject*	The result of calling PyObject_Repr().

An unrecognized format character causes all the rest of the format string to be

copied as-is to the result string, and any extra arguments discarded.

注解

The width formatter unit is number of characters rather than bytes.

The precision formatter unit is number of bytes for "%s" and

"%V" (if the PyObject* argument is NULL), and a number of

characters for "%A", "%U", "%S", "%R" and "%V"

(if the PyObject* argument is not NULL).

1(1,2,3,4,5,6,7,8,9,10,11,12,13)

For integer specifiers (d, u, ld, li, lu, lld, lli, llu, zd, zi,

zu, i, x): the 0-conversion flag has effect even when a precision is given.

在 3.2 版更改: Support for "%lld" and "%llu" added.

在 3.3 版更改: Support for "%li", "%lli" and "%zi" added.

在 3.4 版更改: Support width and precision formatter for "%s", "%A", "%U",

"%V", "%S", "%R" added.

PyObject* PyUnicode_FromFormatV(const char *format, va_list vargs)¶

Return value: New reference.

Identical to PyUnicode_FromFormat() except that it takes exactly two

arguments.

PyObject* PyUnicode_FromEncodedObject(PyObject *obj, const char *encoding, const char *errors)¶

Return value: New reference.

Decode an encoded object obj to a Unicode object.

bytes, bytearray and other

bytes-like objects

are decoded according to the given encoding and using the error handling

defined by errors. Both can be NULL to have the interface use the default

values (see Built-in Codecs for details).

All other objects, including Unicode objects, cause a TypeError to be

set.

The API returns NULL if there was an error. The caller is responsible for

decref'ing the returned objects.

Py_ssize_t PyUnicode_GetLength(PyObject *unicode)¶

Return the length of the Unicode object, in code points.

3.3 新版功能.

Py_ssize_t PyUnicode_CopyCharacters(PyObject *to, Py_ssize_t to_start, PyObject *from, Py_ssize_t from_start, Py_ssize_t how_many)¶

Copy characters from one Unicode object into another. This function performs

character conversion when necessary and falls back to memcpy() if

possible. Returns -1 and sets an exception on error, otherwise returns

the number of copied characters.

3.3 新版功能.

Py_ssize_t PyUnicode_Fill(PyObject *unicode, Py_ssize_t start, Py_ssize_t length, Py_UCS4 fill_char)¶

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.

3.3 新版功能.

int PyUnicode_WriteChar(PyObject *unicode, Py_ssize_t index, Py_UCS4 character)¶

Write a character to a string. The string must have been created through

PyUnicode_New(). Since Unicode strings are supposed to be immutable,

the string must not be shared, or have been hashed yet.

This function checks that unicode is a Unicode object, that the index is

not out of bounds, and that the object can be modified safely (i.e. that it

its reference count is one).

3.3 新版功能.

Py_UCS4 PyUnicode_ReadChar(PyObject *unicode, Py_ssize_t index)¶

Read a character from a string. This function checks that unicode is a

Unicode object and the index is not out of bounds, in contrast to the macro

version PyUnicode_READ_CHAR().

3.3 新版功能.

PyObject* PyUnicode_Substring(PyObject *str, Py_ssize_t start, Py_ssize_t end)¶

Return value: New reference.

Return a substring of str, from character index start (included) to

character index end (excluded). Negative indices are not supported.

3.3 新版功能.

Py_UCS4* PyUnicode_AsUCS4(PyObject *u, Py_UCS4 *buffer, Py_ssize_t buflen, int copy_null)¶

Copy the string u into a UCS4 buffer, including a null character, if

copy_null is set. Returns NULL and sets an exception on error (in

particular, a SystemError if buflen is smaller than the length of

u). buffer is returned on success.

3.3 新版功能.

Py_UCS4* PyUnicode_AsUCS4Copy(PyObject *u)¶

Copy the string u into a new UCS4 buffer that is allocated using

PyMem_Malloc(). If this fails, NULL is returned with a

MemoryError set. The returned buffer always has an extra

null code point appended.

3.3 新版功能.

Deprecated Py_UNICODE APIs¶

These API functions are deprecated with the implementation of PEP 393.

Extension modules can continue using them, as they will not be removed in Python

3.x, but need to be aware that their use can now cause performance and memory hits.

PyObject* PyUnicode_FromUnicode(const Py_UNICODE *u, Py_ssize_t size)¶

Return value: New reference.

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. The buffer is copied into the new

object.

If the buffer is not NULL, the return value might be a shared object.

Therefore, modification of the resulting Unicode object is only allowed when

u is NULL.

If the buffer is NULL, PyUnicode_READY() must be called once the

string content has been filled before using any of the access macros such as

PyUnicode_KIND().

Please migrate to using PyUnicode_FromKindAndData(),

PyUnicode_FromWideChar() or PyUnicode_New().

Py_UNICODE* PyUnicode_AsUnicode(PyObject *unicode)¶

Return a read-only pointer to the Unicode object's internal

Py_UNICODE buffer, or NULL on error. This will create the

Py_UNICODE* representation of the object if it is not yet

available. The buffer is always terminated with an extra null code point.

Note that the resulting Py_UNICODE string may also contain

embedded null code points, which would cause the string to be truncated when

used in most C functions.

Please migrate to using PyUnicode_AsUCS4(),

PyUnicode_AsWideChar(), PyUnicode_ReadChar() or similar new

APIs.

PyObject* PyUnicode_TransformDecimalToASCII(Py_UNICODE *s, Py_ssize_t size)¶

Return value: New reference.

Create a Unicode object by replacing all decimal digits in

Py_UNICODE buffer of the given size by ASCII digits 0--9

according to their decimal value. Return NULL if an exception occurs.

Py_UNICODE* PyUnicode_AsUnicodeAndSize(PyObject *unicode, Py_ssize_t *size)¶

Like PyUnicode_AsUnicode(), but also saves the Py_UNICODE()

array length (excluding the extra null terminator) in size.

Note that the resulting Py_UNICODE* string

may contain embedded null code points, which would cause the string to be

truncated when used in most C functions.

3.3 新版功能.

Py_UNICODE* PyUnicode_AsUnicodeCopy(PyObject *unicode)¶

Create a copy of a Unicode string ending with a null code point. Return NULL

and raise a MemoryError exception on memory allocation failure,

otherwise return a new allocated buffer (use PyMem_Free() to free

the buffer). Note that the resulting Py_UNICODE* string may

contain embedded null code points, which would cause the string to be

truncated when used in most C functions.

3.2 新版功能.

Please migrate to using PyUnicode_AsUCS4Copy() or similar new APIs.

Py_ssize_t PyUnicode_GetSize(PyObject *unicode)¶

Return the size of the deprecated Py_UNICODE representation, in

code units (this includes surrogate pairs as 2 units).

Please migrate to using PyUnicode_GetLength().

PyObject* PyUnicode_FromObject(PyObject *obj)¶

Return value: New reference.

Copy an instance of a Unicode subtype to a new true Unicode object if

necessary. If obj is already a true Unicode object (not a subtype),

return the reference with incremented refcount.

Objects other than Unicode or its subtypes will cause a TypeError.

Locale Encoding¶

The current locale encoding can be used to decode text from the operating

system.

PyObject* PyUnicode_DecodeLocaleAndSize(const char *str, Py_ssize_t len, const char *errors)¶

Return value: New reference.

Decode a string from UTF-8 on Android, or from the current locale encoding

on other platforms. The supported

error handlers are "strict" and "surrogateescape"

(PEP 383). The decoder uses "strict" error handler if

errors is NULL. str must end with a null character but

cannot contain embedded null characters.

Use PyUnicode_DecodeFSDefaultAndSize() to decode a string from

Py_FileSystemDefaultEncoding (the locale encoding read at

Python startup).

This function ignores the Python UTF-8 mode.

参见

The Py_DecodeLocale() function.

3.3 新版功能.

在 3.7 版更改: The function now also uses the current locale encoding for the

surrogateescape error handler, except on Android. Previously, Py_DecodeLocale()

was used for the surrogateescape, and the current locale encoding was

used for strict.

PyObject* PyUnicode_DecodeLocale(const char *str, const char *errors)¶

Return value: New reference.

Similar to PyUnicode_DecodeLocaleAndSize(), but compute the string

length using strlen().

3.3 新版功能.

PyObject* PyUnicode_EncodeLocale(PyObject *unicode, const char *errors)¶

Return value: New reference.

Encode a Unicode object to UTF-8 on Android, or to the current locale

encoding on other platforms. The

supported error handlers are "strict" and "surrogateescape"

(PEP 383). The encoder uses "strict" error handler if

errors is NULL. Return a bytes object. unicode cannot

contain embedded null characters.

Use PyUnicode_EncodeFSDefault() to encode a string to

Py_FileSystemDefaultEncoding (the locale encoding read at

Python startup).

This function ignores the Python UTF-8 mode.

参见

The Py_EncodeLocale() function.

3.3 新版功能.

在 3.7 版更改: The function now also uses the current locale encoding for the

surrogateescape error handler, except on Android. Previously,

Py_EncodeLocale()

was used for the surrogateescape, and the current locale encoding was

used for strict.

File System Encoding¶

To encode and decode file names and other environment strings,

Py_FileSystemDefaultEncoding should be used as the encoding, and

Py_FileSystemDefaultEncodeErrors should be used as the error handler

(PEP 383 and PEP 529). To encode file names to bytes during

argument parsing, the "O&" converter should be used, passing

PyUnicode_FSConverter() as the conversion function:

int PyUnicode_FSConverter(PyObject* obj, void* result)¶

ParseTuple converter: encode str objects -- obtained directly or

through the os.PathLike interface -- to bytes using

PyUnicode_EncodeFSDefault(); bytes objects are output as-is.

result must be a PyBytesObject* which must be released when it is

no longer used.

3.1 新版功能.

在 3.6 版更改: 接受一个 path-like object。

To decode file names to str during argument parsing, the "O&"

converter should be used, passing PyUnicode_FSDecoder() as the

conversion function:

int PyUnicode_FSDecoder(PyObject* obj, void* result)¶

ParseTuple converter: decode bytes objects -- obtained either

directly or indirectly through the os.PathLike interface -- to

str using PyUnicode_DecodeFSDefaultAndSize(); str

objects are output as-is. result must be a PyUnicodeObject* which

must be released when it is no longer used.

3.2 新版功能.

在 3.6 版更改: 接受一个 path-like object。

PyObject* PyUnicode_DecodeFSDefaultAndSize(const char *s, Py_ssize_t size)¶

Return value: New reference.

Decode a string using Py_FileSystemDefaultEncoding and the

Py_FileSystemDefaultEncodeErrors error handler.

If Py_FileSystemDefaultEncoding is not set, fall back to the

locale encoding.

Py_FileSystemDefaultEncoding is initialized at startup from the

locale encoding and cannot be modified later. If you need to decode a string

from the current locale encoding, use

PyUnicode_DecodeLocaleAndSize().

参见

The Py_DecodeLocale() function.

在 3.6 版更改: Use Py_FileSystemDefaultEncodeErrors error handler.

PyObject* PyUnicode_DecodeFSDefault(const char *s)¶

Return value: New reference.

Decode a null-terminated string using Py_FileSystemDefaultEncoding

and the Py_FileSystemDefaultEncodeErrors error handler.

If Py_FileSystemDefaultEncoding is not set, fall back to the

locale encoding.

Use PyUnicode_DecodeFSDefaultAndSize() if you know the string length.

在 3.6 版更改: Use Py_FileSystemDefaultEncodeErrors error handler.

PyObject* PyUnicode_EncodeFSDefault(PyObject *unicode)¶

Return value: New reference.

Encode a Unicode object to Py_FileSystemDefaultEncoding with the

Py_FileSystemDefaultEncodeErrors error handler, and return

bytes. Note that the resulting bytes object may contain

null bytes.

If Py_FileSystemDefaultEncoding is not set, fall back to the

locale encoding.

Py_FileSystemDefaultEncoding is initialized at startup from the

locale encoding and cannot be modified later. If you need to encode a string

to the current locale encoding, use PyUnicode_EncodeLocale().

参见

The Py_EncodeLocale() function.

3.2 新版功能.

在 3.6 版更改: Use Py_FileSystemDefaultEncodeErrors error handler.

wchar_t Support¶

wchar_t support for platforms which support it:

PyObject* PyUnicode_FromWideChar(const wchar_t *w, Py_ssize_t size)¶

Return value: New reference.

Create a Unicode object from the wchar_t buffer w of the given size.

Passing -1 as the size indicates that the function must itself compute the length,

using wcslen.

Return NULL on failure.

Py_ssize_t PyUnicode_AsWideChar(PyObject *unicode, wchar_t *w, Py_ssize_t size)¶

Copy the Unicode object contents into the wchar_t buffer w. At most

sizewchar_t characters are copied (excluding a possibly trailing

null termination character). Return the number of wchar_t characters

copied or -1 in case of an error. Note that the resulting wchar_t*

string may or may not be null-terminated. It is the responsibility of the caller

to make sure that the wchar_t* string is null-terminated in case this is

required by the application. Also, note that the wchar_t* string

might contain null characters, which would cause the string to be truncated

when used with most C functions.

wchar_t* PyUnicode_AsWideCharString(PyObject *unicode, Py_ssize_t *size)¶

Convert the Unicode object to a wide character string. The output string

always ends with a null character. If size is not NULL, write the number

of wide characters (excluding the trailing null termination character) into

*size. Note that the resulting wchar_t string might contain

null characters, which would cause the string to be truncated when used with

most C functions. If size is NULL and the wchar_t* string

contains null characters a ValueError is raised.

Returns a buffer allocated by PyMem_Alloc() (use

PyMem_Free() to free it) on success. On error, returns NULL

and *size is undefined. Raises a MemoryError if memory allocation

is failed.

3.2 新版功能.

在 3.7 版更改: Raises a ValueError if size is NULL and the wchar_t*

string contains null characters.

Generic Codecs¶

These are the generic codec APIs:

PyObject* PyUnicode_Decode(const char *s, Py_ssize_t size, const char *encoding, const char *errors)¶

Return value: New reference.

Create a Unicode object by decoding size bytes of the encoded string s.

encoding and errors have the same meaning as the parameters of the same name

in the str() built-in function. The codec to be used is looked up

using the Python codec registry. Return NULL if an exception was raised by

the codec.

PyObject* PyUnicode_AsEncodedString(PyObject *unicode, const char *encoding, const char *errors)¶

Return value: New reference.

Encode a Unicode object and return the result as Python bytes object.

encoding and errors have the same meaning as the parameters of the same

name in the Unicode encode() method. The codec to be used is looked up

using the Python codec registry. Return NULL if an exception was raised by

the codec.

PyObject* PyUnicode_Encode(const Py_UNICODE *s, Py_ssize_t size, const char *encoding, const char *errors)¶

Return value: New reference.

Encode the Py_UNICODE buffer s of the given size and return a Python

bytes object. encoding and errors have the same meaning as the

parameters of the same name in the Unicode encode() method. The codec

to be used is looked up using the Python codec registry. Return NULL if an

exception was raised by the codec.

Deprecated since version 3.3, will be removed in version 4.0: Part of the old-style Py_UNICODE API; please migrate to using

PyUnicode_AsEncodedString().

UTF-8 Codecs¶

These are the UTF-8 codec APIs:

PyObject* PyUnicode_DecodeUTF8(const char *s, Py_ssize_t size, const char *errors)¶

Return value: New reference.

Create a Unicode object by decoding size bytes of the UTF-8 encoded string

s. Return NULL if an exception was raised by the codec.

PyObject* PyUnicode_DecodeUTF8Stateful(const char *s, Py_ssize_t size, const char *errors, Py_ssize_t *consumed)¶

Return value: New reference.

If consumed is NULL, behave like PyUnicode_DecodeUTF8(). If

consumed is not NULL, trailing incomplete UTF-8 byte sequences will not be

treated as an error. Those bytes will not be decoded and the number of bytes

that have been decoded will be stored in consumed.

PyObject* PyUnicode_AsUTF8String(PyObject *unicode)¶

Return value: New reference.

Encode a Unicode object using UTF-8 and return the result as Python bytes

object. Error handling is "strict". Return NULL if an exception was

raised by the codec.

const char* PyUnicode_AsUTF8AndSize(PyObject *unicode, Py_ssize_t *size)¶

Return a pointer to the UTF-8 encoding of the Unicode object, and

store the size of the encoded representation (in bytes) in size. The

size argument can be NULL; in this case no size will be stored. The

returned buffer always has an extra null byte appended (not included in

size), regardless of whether there are any other null code points.

In the case of an error, NULL is returned with an exception set and no

size is stored.

This caches the UTF-8 representation of the string in the Unicode object, and

subsequent calls will return a pointer to the same buffer. The caller is not

responsible for deallocating the buffer.

3.3 新版功能.

在 3.7 版更改: The return type is now constchar* rather of char*.

const char* PyUnicode_AsUTF8(PyObject *unicode)¶

As PyUnicode_AsUTF8AndSize(), but does not store the size.

3.3 新版功能.

在 3.7 版更改: The return type is now constchar* rather of char*.

PyObject* PyUnicode_EncodeUTF8(const Py_UNICODE *s, Py_ssize_t size, const char *errors)¶

Return value: New reference.

Encode the Py_UNICODE buffer s of the given size using UTF-8 and

return a Python bytes object. Return NULL if an exception was raised by

the codec.

Deprecated since version 3.3, will be removed in version 4.0: Part of the old-style Py_UNICODE API; please migrate to using

PyUnicode_AsUTF8String(), PyUnicode_AsUTF8AndSize() or

PyUnicode_AsEncodedString().

UTF-32 Codecs¶

These are the UTF-32 codec APIs:

PyObject* PyUnicode_DecodeUTF32(const char *s, Py_ssize_t size, const char *errors, int *byteorder)¶

Return value: New reference.

Decode size bytes from a UTF-32 encoded buffer string and return the

corresponding Unicode object. errors (if non-NULL) defines the error

handling. It defaults to "strict".

If byteorder is non-NULL, the decoder starts decoding using the given byte

order:

*byteorder==-1:littleendian
*byteorder==0:nativeorder
*byteorder==1:bigendian

If *byteorder is zero, and the first four bytes of the input data are a

byte order mark (BOM), the decoder switches to this byte order and the BOM is

not copied into the resulting Unicode string. If *byteorder is -1 or

1, any byte order mark is copied to the output.

After completion, *byteorder is set to the current byte order at the end

of input data.

If byteorder is NULL, the codec starts in native order mode.

Return NULL if an exception was raised by the codec.

PyObject* PyUnicode_DecodeUTF32Stateful(const char *s, Py_ssize_t size, const char *errors, int *byteorder, Py_ssize_t *consumed)¶

Return value: New reference.

If consumed is NULL, behave like PyUnicode_DecodeUTF32(). If

consumed is not NULL, PyUnicode_DecodeUTF32Stateful() will not treat

trailing incomplete UTF-32 byte sequences (such as a number of bytes not divisible

by four) as an error. Those bytes will not be decoded and the number of bytes

that have been decoded will be stored in consumed.

PyObject* PyUnicode_AsUTF32String(PyObject *unicode)¶

Return value: New reference.

Return a Python byte string using the UTF-32 encoding in native byte

order. The string always starts with a BOM mark. Error handling is "strict".

Return NULL if an exception was raised by the codec.

PyObject* PyUnicode_EncodeUTF32(const Py_UNICODE *s, Py_ssize_t size, const char *errors, int byteorder)¶

Return value: New reference.

Return a Python bytes object holding the UTF-32 encoded value of the Unicode

data in s. Output is written according to the following byte order:

byteorder==-1:littleendian
byteorder==0:nativebyteorder(writesaBOMmark)
byteorder==1:bigendian

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.

If Py_UNICODE_WIDE is not defined, surrogate pairs will be output

as a single code point.

Return NULL if an exception was raised by the codec.

Deprecated since version 3.3, will be removed in version 4.0: Part of the old-style Py_UNICODE API; please migrate to using

PyUnicode_AsUTF32String() or PyUnicode_AsEncodedString().

UTF-16 Codecs¶

These are the UTF-16 codec APIs:

PyObject* PyUnicode_DecodeUTF16(const char *s, Py_ssize_t size, const char *errors, int *byteorder)¶

Return value: New reference.

Decode size bytes from a UTF-16 encoded buffer string and return the

corresponding Unicode object. errors (if non-NULL) defines the error

handling. It defaults to "strict".

If byteorder is non-NULL, the decoder starts decoding using the given byte

order:

*byteorder==-1:littleendian
*byteorder==0:nativeorder
*byteorder==1:bigendian

If *byteorder is zero, and the first two bytes of the input data are a

byte order mark (BOM), the decoder switches to this byte order and the BOM is

not copied into the resulting Unicode string. If *byteorder is -1 or

1, any byte order mark is copied to the output (where it will result in

either a \ufeff or a \ufffe character).

After completion, *byteorder is set to the current byte order at the end

of input data.

If byteorder is NULL, the codec starts in native order mode.

Return NULL if an exception was raised by the codec.

PyObject* PyUnicode_DecodeUTF16Stateful(const char *s, Py_ssize_t size, const char *errors, int *byteorder, Py_ssize_t *consumed)¶

Return value: New reference.

If consumed is NULL, behave like PyUnicode_DecodeUTF16(). If

consumed is not NULL, PyUnicode_DecodeUTF16Stateful() will not treat

trailing incomplete UTF-16 byte sequences (such as an odd number of bytes or a

split surrogate pair) as an error. Those bytes will not be decoded and the

number of bytes that have been decoded will be stored in consumed.

PyObject* PyUnicode_AsUTF16String(PyObject *unicode)¶

Return value: New reference.

Return a Python byte string using the UTF-16 encoding in native byte

order. The string always starts with a BOM mark. Error handling is "strict".

Return NULL if an exception was raised by the codec.

PyObject* PyUnicode_EncodeUTF16(const Py_UNICODE *s, Py_ssize_t size, const char *errors, int byteorder)¶

Return value: New reference.

Return a Python bytes object holding the UTF-16 encoded value of the Unicode

data in s. Output is written according to the following byte order:

byteorder==-1:littleendian
byteorder==0:nativebyteorder(writesaBOMmark)
byteorder==1:bigendian

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.

If Py_UNICODE_WIDE is defined, a single Py_UNICODE value may get

represented as a surrogate pair. If it is not defined, each Py_UNICODE

values is interpreted as a UCS-2 character.

Return NULL if an exception was raised by the codec.

Deprecated since version 3.3, will be removed in version 4.0: Part of the old-style Py_UNICODE API; please migrate to using

PyUnicode_AsUTF16String() or PyUnicode_AsEncodedString().

UTF-7 Codecs¶

These are the UTF-7 codec APIs:

PyObject* PyUnicode_DecodeUTF7(const char *s, Py_ssize_t size, const char *errors)¶

Return value: New reference.

Create a Unicode object by decoding size bytes of the UTF-7 encoded string

s. Return NULL if an exception was raised by the codec.

PyObject* PyUnicode_DecodeUTF7Stateful(const char *s, Py_ssize_t size, const char *errors, Py_ssize_t *consumed)¶

Return value: New reference.

If consumed is NULL, behave like PyUnicode_DecodeUTF7(). If

consumed is not NULL, trailing incomplete UTF-7 base-64 sections will not

be treated as an error. Those bytes will not be decoded and the number of

bytes that have been decoded will be stored in consumed.

PyObject* PyUnicode_EncodeUTF7(const Py_UNICODE *s, Py_ssize_t size, int base64SetO, int base64WhiteSpace, const char *errors)¶

Return value: New reference.

Encode the Py_UNICODE buffer of the given size using UTF-7 and

return a Python bytes object. Return NULL if an exception was raised by

the codec.

If base64SetO is nonzero, "Set O" (punctuation that has no otherwise

special meaning) will be encoded in base-64. If base64WhiteSpace is

nonzero, whitespace will be encoded in base-64. Both are set to zero for the

Python "utf-7" codec.

Deprecated since version 3.3, will be removed in version 4.0: Part of the old-style Py_UNICODE API; please migrate to using

PyUnicode_AsEncodedString().

Unicode-Escape Codecs¶

These are the "Unicode Escape" codec APIs:

PyObject* PyUnicode_DecodeUnicodeEscape(const char *s, Py_ssize_t size, const char *errors)¶

Return value: New reference.

Create a Unicode object by decoding size bytes of the Unicode-Escape encoded

string s. Return NULL if an exception was raised by the codec.

PyObject* PyUnicode_AsUnicodeEscapeString(PyObject *unicode)¶

Return value: New reference.

Encode a Unicode object using Unicode-Escape and return the result as a

bytes object. Error handling is "strict". Return NULL if an exception was

raised by the codec.

PyObject* PyUnicode_EncodeUnicodeEscape(const Py_UNICODE *s, Py_ssize_t size)¶

Return value: New reference.

Encode the Py_UNICODE buffer of the given size using Unicode-Escape and

return a bytes object. Return NULL if an exception was raised by the codec.

Deprecated since version 3.3, will be removed in version 4.0: Part of the old-style Py_UNICODE API; please migrate to using

PyUnicode_AsUnicodeEscapeString().

Raw-Unicode-Escape Codecs¶

These are the "Raw Unicode Escape" codec APIs:

PyObject* PyUnicode_DecodeRawUnicodeEscape(const char *s, Py_ssize_t size, const char *errors)¶

Return value: New reference.

Create a Unicode object by decoding size bytes of the Raw-Unicode-Escape

encoded string s. Return NULL if an exception was raised by the codec.

PyObject* PyUnicode_AsRawUnicodeEscapeString(PyObject *unicode)¶

Return value: New reference.

Encode a Unicode object using Raw-Unicode-Escape and return the result as

a bytes object. Error handling is "strict". Return NULL if an exception

was raised by the codec.

PyObject* PyUnicode_EncodeRawUnicodeEscape(const Py_UNICODE *s, Py_ssize_t size)¶

Return value: New reference.

Encode the Py_UNICODE buffer of the given size using Raw-Unicode-Escape

and return a bytes object. Return NULL if an exception was raised by the codec.

Deprecated since version 3.3, will be removed in version 4.0: Part of the old-style Py_UNICODE API; please migrate to using

PyUnicode_AsRawUnicodeEscapeString() or

PyUnicode_AsEncodedString().

Latin-1 Codecs¶

These are the Latin-1 codec APIs: Latin-1 corresponds to the first 256 Unicode

ordinals and only these are accepted by the codecs during encoding.

PyObject* PyUnicode_DecodeLatin1(const char *s, Py_ssize_t size, const char *errors)¶

Return value: New reference.

Create a Unicode object by decoding size bytes of the Latin-1 encoded string

s. Return NULL if an exception was raised by the codec.

PyObject* PyUnicode_AsLatin1String(PyObject *unicode)¶

Return value: New reference.

Encode a Unicode object using Latin-1 and return the result as Python bytes

object. Error handling is "strict". Return NULL if an exception was

raised by the codec.

PyObject* PyUnicode_EncodeLatin1(const Py_UNICODE *s, Py_ssize_t size, const char *errors)¶

Return value: New reference.

Encode the Py_UNICODE buffer of the given size using Latin-1 and

return a Python bytes object. Return NULL if an exception was raised by

the codec.

Deprecated since version 3.3, will be removed in version 4.0: Part of the old-style Py_UNICODE API; please migrate to using

PyUnicode_AsLatin1String() or

PyUnicode_AsEncodedString().

ASCII Codecs¶

These are the ASCII codec APIs. Only 7-bit ASCII data is accepted. All other

codes generate errors.

PyObject* PyUnicode_DecodeASCII(const char *s, Py_ssize_t size, const char *errors)¶

Return value: New reference.

Create a Unicode object by decoding size bytes of the ASCII encoded string

s. Return NULL if an exception was raised by the codec.

PyObject* PyUnicode_AsASCIIString(PyObject *unicode)¶

Return value: New reference.

Encode a Unicode object using ASCII and return the result as Python bytes

object. Error handling is "strict". Return NULL if an exception was

raised by the codec.

PyObject* PyUnicode_EncodeASCII(const Py_UNICODE *s, Py_ssize_t size, const char *errors)¶

Return value: New reference.

Encode the Py_UNICODE buffer of the given size using ASCII and

return a Python bytes object. Return NULL if an exception was raised by

the codec.

Deprecated since version 3.3, will be removed in version 4.0: Part of the old-style Py_UNICODE API; please migrate to using

PyUnicode_AsASCIIString() or

PyUnicode_AsEncodedString().

Character Map Codecs¶

This codec is special in that it can be used to implement many different codecs

(and this is in fact what was done to obtain most of the standard codecs

included in the encodings package). The codec uses mapping to encode and

decode characters. The mapping objects provided must support the

__getitem__() mapping interface; dictionaries and sequences work well.

These are the mapping codec APIs:

PyObject* PyUnicode_DecodeCharmap(const char *data, Py_ssize_t size, PyObject *mapping, const char *errors)¶

Return value: New reference.

Create a Unicode object by decoding size bytes of the encoded string s

using the given mapping object. Return NULL if an exception was raised

by the codec.

If mapping is NULL, Latin-1 decoding will be applied. Else

mapping must map bytes ordinals (integers in the range from 0 to 255)

to Unicode strings, integers (which are then interpreted as Unicode

ordinals) or None. Unmapped data bytes -- ones which cause a

LookupError, as well as ones which get mapped to None,

0xFFFE or '\ufffe', are treated as undefined mappings and cause

an error.

PyObject* PyUnicode_AsCharmapString(PyObject *unicode, PyObject *mapping)¶

Return value: New reference.

Encode a Unicode object using the given mapping object and return the

result as a bytes object. Error handling is "strict". Return NULL if an

exception was raised by the codec.

The mapping object must map Unicode ordinal integers to bytes objects,

integers in the range from 0 to 255 or None. Unmapped character

ordinals (ones which cause a LookupError) as well as mapped to

None are treated as "undefined mapping" and cause an error.

PyObject* PyUnicode_EncodeCharmap(const Py_UNICODE *s, Py_ssize_t size, PyObject *mapping, const char *errors)¶

Return value: New reference.

Encode the Py_UNICODE buffer of the given size using the given

mapping object and return the result as a bytes object. Return NULL if

an exception was raised by the codec.

Deprecated since version 3.3, will be removed in version 4.0: Part of the old-style Py_UNICODE API; please migrate to using

PyUnicode_AsCharmapString() or

PyUnicode_AsEncodedString().

The following codec API is special in that maps Unicode to Unicode.

PyObject* PyUnicode_Translate(PyObject *unicode, PyObject *mapping, const char *errors)¶

Return value: New reference.

Translate a Unicode object using the given mapping object and return the

resulting Unicode object. Return NULL if an exception was raised by the

codec.

The mapping object must map Unicode ordinal integers to Unicode strings,

integers (which are then interpreted as Unicode ordinals) or None

(causing deletion of the character). Unmapped character ordinals (ones

which cause a LookupError) are left untouched and are copied as-is.

PyObject* PyUnicode_TranslateCharmap(const Py_UNICODE *s, Py_ssize_t size, PyObject *mapping, const char *errors)¶

Return value: New reference.

Translate a Py_UNICODE buffer of the given size by applying a

character mapping table to it and return the resulting Unicode object.

Return NULL when an exception was raised by the codec.

Deprecated since version 3.3, will be removed in version 4.0: Part of the old-style Py_UNICODE API; please migrate to using

PyUnicode_Translate(). or generic codec based API

MBCS codecs for Windows¶

These are the MBCS codec APIs. They are currently only available on Windows and

use the Win32 MBCS converters to implement the conversions. Note that MBCS (or

DBCS) is a class of encodings, not just one. The target encoding is defined by

the user settings on the machine running the codec.

PyObject* PyUnicode_DecodeMBCS(const char *s, Py_ssize_t size, const char *errors)¶

Return value: New reference.

Create a Unicode object by decoding size bytes of the MBCS encoded string s.

Return NULL if an exception was raised by the codec.

PyObject* PyUnicode_DecodeMBCSStateful(const char *s, Py_ssize_t size, const char *errors, Py_ssize_t *consumed)¶

Return value: New reference.

If consumed is NULL, behave like PyUnicode_DecodeMBCS(). If

consumed is not NULL, PyUnicode_DecodeMBCSStateful() will not decode

trailing lead byte and the number of bytes that have been decoded will be stored

in consumed.

PyObject* PyUnicode_AsMBCSString(PyObject *unicode)¶

Return value: New reference.

Encode a Unicode object using MBCS and return the result as Python bytes

object. Error handling is "strict". Return NULL if an exception was

raised by the codec.

PyObject* PyUnicode_EncodeCodePage(int code_page, PyObject *unicode, const char *errors)¶

Return value: New reference.

Encode the Unicode object using the specified code page and return a Python

bytes object. Return NULL if an exception was raised by the codec. Use

CP_ACP code page to get the MBCS encoder.

3.3 新版功能.

PyObject* PyUnicode_EncodeMBCS(const Py_UNICODE *s, Py_ssize_t size, const char *errors)¶

Return value: New reference.

Encode the Py_UNICODE buffer of the given size using MBCS and return

a Python bytes object. Return NULL if an exception was raised by the

codec.

Deprecated since version 3.3, will be removed in version 4.0: Part of the old-style Py_UNICODE API; please migrate to using

PyUnicode_AsMBCSString(), PyUnicode_EncodeCodePage() or

PyUnicode_AsEncodedString().

Methods & Slots¶