Unicode对象和编码解码器

Unicode对象

自从python3.3中实现了 PEP 393 以来，Unicode对象在内部使用各种表示形式，以便在保持内存效率的同时处理完整范围的Unicode字符。对于所有代码点都低于128、256或65536的字符串，有一些特殊情况；否则，代码点必须低于1114112（这是完整的Unicode范围）。

UTF-8 表示将按需创建并缓存在 Unicode 对象中。

备注

Py_UNICODE 表示形式在 Python 3.12 中同被弃用的 API 一起被移除了，查阅 PEP 623 以获得更多信息。

Unicode类型

以下是用于Python中Unicode实现的基本Unicode对象类型：

type Py_UCS4

type Py_UCS2

type Py_UCS1

Part of the Stable ABI.

这些类型是无符号整数类型的类型定义，其宽度足以分别包含 32 位、16 位和 8 位字符。 当需要处理单个 Unicode 字符时，请使用 Py_UCS4。

3.3 新版功能.

type Py_UNICODE

这是 wchar_t 的类型定义，根据平台的不同它可能为 16 位类型或 32 位类型。

在 3.3 版更改: 在以前的版本中，这是16位类型还是32位类型，这取决于您在构建时选择的是“窄”还是“宽”Unicode版本的Python。

type PyASCIIObject

type PyCompactUnicodeObject

type PyUnicodeObject

这些关于 PyObject 的子类型表示了一个 Python Unicode 对象。 在几乎所有情形下，它们不应该被直接使用，因为所有处理 Unicode 对象的 API 函数都接受并返回 PyObject 类型的指针。

3.3 新版功能.

PyTypeObject PyUnicode_Type

Part of the Stable ABI.

这个 PyTypeObject 实例代表 Python Unicode 类型。 它作为 str 公开给 Python 代码。

以下API是C宏和静态内联函数，用于快速检查和访问Unicode对象的内部只读数据：

int PyUnicode_Check(PyObject *o)

如果对象*o*是Unicode对象或Unicode子类型的实例，则返回“真”。此函数始终成功。

int PyUnicode_CheckExact(PyObject *o)

如果对象*o*是Unicode对象，但不是子类型的实例，则返回“真”。此函数始终成功。

int PyUnicode_READY(PyObject *o)

返回 0。 此 API 仅为向下兼容而保留。

3.3 新版功能.

3.10 版后已移除: 此 API 从 Python 3.12 起将不做任何事。

Py_ssize_t PyUnicode_GET_LENGTH(PyObject *o)

返回Unicode字符串的长度（以代码点为单位）*o*必须是“规范”表达方式中的Unicode对象（未选中）。

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)

返回一个用于直接字符访问的指向转换为 UCS1、UCS2 或 UCS4 整数类型的规范表示的指针。 如果规范表示具有正确的字符大小，则不执行检查；使用 PyUnicode_KIND() 选择正确的函数。

3.3 新版功能.

PyUnicode_1BYTE_KIND

PyUnicode_2BYTE_KIND

PyUnicode_4BYTE_KIND

返回 PyUnicode_KIND() 宏的值。

3.3 新版功能.

在 3.12 版更改: PyUnicode_WCHAR_KIND 已被移除。

int PyUnicode_KIND(PyObject *o)

返回一个PyUnicode类常量（见上文），指示此Unicode对象用于存储其数据的每个字符的字节数*o*必须是“规范”表达方式中的Unicode对象（未选中）。

3.3 新版功能.

void *PyUnicode_DATA(PyObject *o)

返回指向原始Unicode缓冲区的空指针*o*必须是“规范”表达方式中的Unicode对象（未选中）。

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 function performs no sanity checks, and is intended for usage in loops. The caller should cache the kind value and data pointer as obtained from other 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.

Py_UCS4 PyUnicode_MAX_CHAR_VALUE(PyObject *o)

返回适合于基于*o*创建另一个字符串的最大代码点，该字符串必须在“规范”表达方式中。这始终是一种近似，但比在字符串上迭代更有效。

3.3 新版功能.

int PyUnicode_IsIdentifier(PyObject *o)

Part of the Stable ABI.

如果字符串按照语言定义是合法的标识符则返回 1，参见 标识符和关键字 小节。 否则返回 0。

在 3.9 版更改: The function does not call Py_FatalError() anymore if the string is not ready.

Unicode字符属性

Unicode提供了许多不同的字符特性。最常需要的宏可以通过这些宏获得，这些宏根据Python配置映射到C函数。

int Py_UNICODE_ISSPACE(Py_UCS4 ch)

根据 ch 是否为空白字符返回 1 或 0。

int Py_UNICODE_ISLOWER(Py_UCS4 ch)

根据 ch 是否为小写字符返回 1 或 0。

int Py_UNICODE_ISUPPER(Py_UCS4 ch)

根据 ch 是否为大写字符返回 1 或 0

int Py_UNICODE_ISTITLE(Py_UCS4 ch)

根据 ch 是否为标题化的大小写返回 1 或 0。

int Py_UNICODE_ISLINEBREAK(Py_UCS4 ch)

根据 ch 是否为换行类字符返回 1 或 0。

int Py_UNICODE_ISDECIMAL(Py_UCS4 ch)

根据 ch 是否为十进制数字符返回 1 或 0。

int Py_UNICODE_ISDIGIT(Py_UCS4 ch)

根据 ch 是否为数码类字符返回 1 或 0。

int Py_UNICODE_ISNUMERIC(Py_UCS4 ch)

根据 ch 是否为数值类字符返回 1 或 0。

int Py_UNICODE_ISALPHA(Py_UCS4 ch)

根据 ch 是否为字母类字符返回 1 或 0。

int Py_UNICODE_ISALNUM(Py_UCS4 ch)

根据 ch 是否为字母数字类字符返回 1 或 0。

int Py_UNICODE_ISPRINTABLE(Py_UCS4 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_UCS4 Py_UNICODE_TOLOWER(Py_UCS4 ch)

Return the character ch converted to lower case.

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

Py_UCS4 Py_UNICODE_TOUPPER(Py_UCS4 ch)

Return the character ch converted to upper case.

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

Py_UCS4 Py_UNICODE_TOTITLE(Py_UCS4 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_UCS4 ch)

Return the character ch converted to a decimal positive integer. Return -1 if this is not possible. This function does not raise exceptions.

int Py_UNICODE_TODIGIT(Py_UCS4 ch)

Return the character ch converted to a single digit integer. Return -1 if this is not possible. This function does not raise exceptions.

double Py_UNICODE_TONUMERIC(Py_UCS4 ch)

Return the character ch converted to a double. Return -1.0 if this is not possible. This function does not raise exceptions.

These APIs can be used to work with surrogates:

int Py_UNICODE_IS_SURROGATE(Py_UCS4 ch)

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

int Py_UNICODE_IS_HIGH_SURROGATE(Py_UCS4 ch)

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

int Py_UNICODE_IS_LOW_SURROGATE(Py_UCS4 ch)

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

Py_UCS4 Py_UNICODE_JOIN_SURROGATES(Py_UCS4 high, Py_UCS4 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. high must be in the range [0xD800; 0xDBFF] and low must be in the range [0xDC00; 0xDFFF].

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)

返回值：新的引用。

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)

返回值：新的引用。

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.

If necessary, the input buffer is copied and transformed into the canonical representation. For example, if the buffer is a UCS4 string (PyUnicode_4BYTE_KIND) and it consists only of codepoints in the UCS1 range, it will be transformed into UCS1 (PyUnicode_1BYTE_KIND).

3.3 新版功能.

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

返回值：新的引用。 Part of the Stable ABI.

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. The return value might be a shared object, i.e. modification of the data is not allowed.

This function raises SystemError when:

• size < 0,

• u is NULL and size > 0

在 3.12 版更改: u == NULL with size > 0 is not allowed anymore.

PyObject *PyUnicode_FromString(const char *u)

返回值：新的引用。 Part of the Stable ABI.

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

PyObject *PyUnicode_FromFormat(const char *format, …)

返回值：新的引用。 Part of the Stable ABI.

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.

转换标记符包含两个或更多字符并具有以下组成，且必须遵循此处规定的顺序：

1. '%' 字符，用于标记转换符的起始。

2. 转换旗标（可选），用于影响某些转换类型的结果。

3. Minimum field width (optional). If specified as an '*' (asterisk), the actual width is given in the next argument, which must be of type int, and the object to convert comes after the minimum field width and optional precision.

4. Precision (optional), given as a '.' (dot) followed by the precision. If specified as '*' (an asterisk), the actual precision is given in the next argument, which must be of type int, and the value to convert comes after the precision.

5. 长度修饰符（可选）。

6. 转换类型。

转换旗标为：

The length modifiers for following integer conversions (d, i, o, u, x, or X) specify the type of the argument (int by default):

针对以下转换 s 或 V 的长度修饰符 l 指明参数的类型为 const wchar_t*。

转换指示符如下:

备注

The width formatter unit is number of characters rather than bytes. The precision formatter unit is number of bytes or wchar_t items (if the length modifier l is used) 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).

备注

Unlike to C printf() the 0 flag has effect even when a precision is given for integer conversions (d, i, u, o, x, or X).

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.

在 3.12 版更改: Support for conversion specifiers o and X. Support for length modifiers j and t. Length modifiers are now applied to all integer conversions. Length modifier l is now applied to conversion specifiers s and V. Support for variable width and precision *. Support for flag -.

An unrecognized format character now sets a SystemError. In previous versions it caused all the rest of the format string to be copied as-is to the result string, and any extra arguments discarded.

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

返回值：新的引用。 Part of the Stable ABI.

Identical to PyUnicode_FromFormat() except that it takes exactly two arguments.

PyObject *PyUnicode_FromObject(PyObject *obj)

返回值：新的引用。 Part of the Stable ABI.

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 a new strong reference to the object.

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

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

返回值：新的引用。 Part of the Stable ABI.

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)

Part of the Stable ABI since version 3.7.

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)

Part of the Stable ABI since version 3.7.

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)

Part of the Stable ABI since version 3.7.

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 PyUnicode_READ_CHAR(), which performs no error checking.

3.3 新版功能.

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

返回值：新的引用。 Part of the Stable ABI since version 3.7.

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)

Part of the Stable ABI since version 3.7.

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)

Part of the Stable ABI since version 3.7.

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.

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)

返回值：新的引用。 Part of the Stable ABI since version 3.7.

Decode a string from UTF-8 on Android and VxWorks, 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 the filesystem encoding and error handler.

This function ignores the Python UTF-8 Mode.

参见

The Py_DecodeLocale() 函数。

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)

返回值：新的引用。 Part of the Stable ABI since version 3.7.

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)

返回值：新的引用。 Part of the Stable ABI since version 3.7.

Encode a Unicode object to UTF-8 on Android and VxWorks, 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 the filesystem encoding and error handler.

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.

文件系统编码格式

Functions encoding to and decoding from the filesystem encoding and 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)

Part of the Stable ABI.

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)

Part of the Stable ABI.

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)

返回值：新的引用。 Part of the Stable ABI.

Decode a string from the filesystem encoding and error handler.

If you need to decode a string from the current locale encoding, use PyUnicode_DecodeLocaleAndSize().

参见

The Py_DecodeLocale() 函数。

在 3.6 版更改: The filesystem error handler is now used.

PyObject *PyUnicode_DecodeFSDefault(const char *s)

返回值：新的引用。 Part of the Stable ABI.

Decode a null-terminated string from the filesystem encoding and error handler.

If the string length is known, use PyUnicode_DecodeFSDefaultAndSize().

在 3.6 版更改: The filesystem error handler is now used.

PyObject *PyUnicode_EncodeFSDefault(PyObject *unicode)

返回值：新的引用。 Part of the Stable ABI.

Encode a Unicode object to the filesystem encoding and error handler, and return bytes. Note that the resulting bytes object can contain null bytes.

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: The filesystem error handler is now used.

wchar_t Support

wchar_t support for platforms which support it:

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

返回值：新的引用。 Part of the Stable ABI.

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)

Part of the Stable ABI.

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

Part of the Stable ABI since version 3.7.

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_New (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.

Built-in Codecs

Python provides a set of built-in codecs which are written in C for speed. All of these codecs are directly usable via the following functions.

Many of the following APIs take two arguments encoding and errors, and they have the same semantics as the ones of the built-in str() string object constructor.

Setting encoding to NULL causes the default encoding to be used which is UTF-8. The file system calls should use PyUnicode_FSConverter() for encoding file names. This uses the filesystem encoding and error handler internally.

Error handling is set by errors which may also be set to NULL meaning to use the default handling defined for the codec. Default error handling for all built-in codecs is “strict” (ValueError is raised).

The codecs all use a similar interface. Only deviations from the following generic ones are documented for simplicity.

Generic Codecs

These are the generic codec APIs:

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

返回值：新的引用。 Part of the Stable ABI.

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)

返回值：新的引用。 Part of the Stable ABI.

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.

UTF-8 编解码器

以下是 UTF-8 编解码器 API:

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

返回值：新的引用。 Part of the Stable ABI.

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)

返回值：新的引用。 Part of the Stable ABI.

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)

返回值：新的引用。 Part of the Stable ABI.

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)

Part of the Stable ABI since version 3.10.

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. The buffer is deallocated and pointers to it become invalid when the Unicode object is garbage collected.

3.3 新版功能.

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

在 3.10 版更改: This function is a part of the limited API.

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 const char * rather of char *.

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)

返回值：新的引用。 Part of the Stable ABI.

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: little endian
*byteorder == 0:  native order
*byteorder == 1:  big endian

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)

返回值：新的引用。 Part of the Stable ABI.

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)

返回值：新的引用。 Part of the Stable ABI.

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.

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)

返回值：新的引用。 Part of the Stable ABI.

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: little endian
*byteorder == 0:  native order
*byteorder == 1:  big endian

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)

返回值：新的引用。 Part of the Stable ABI.

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)

返回值：新的引用。 Part of the Stable ABI.

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.

UTF-7 Codecs

These are the UTF-7 codec APIs:

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

返回值：新的引用。 Part of the Stable ABI.

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)

返回值：新的引用。 Part of the Stable ABI.

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.

Unicode-Escape 编解码器

These are the “Unicode Escape” codec APIs:

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

返回值：新的引用。 Part of the Stable ABI.

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)

返回值：新的引用。 Part of the Stable ABI.

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.

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)

返回值：新的引用。 Part of the Stable ABI.

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)

返回值：新的引用。 Part of the Stable ABI.

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.

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)

返回值：新的引用。 Part of the Stable ABI.

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)

返回值：新的引用。 Part of the Stable ABI.

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.

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)

返回值：新的引用。 Part of the Stable ABI.

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)

返回值：新的引用。 Part of the Stable ABI.

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.

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 mappings 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)

返回值：新的引用。 Part of the Stable ABI.

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)

返回值：新的引用。 Part of the Stable ABI.

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.

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

PyObject *PyUnicode_Translate(PyObject *str, PyObject *table, const char *errors)

返回值：新的引用。 Part of the Stable ABI.

Translate a string by applying a character mapping table to it and return the resulting Unicode object. Return NULL if an exception was raised by the codec.

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

Mapping tables need only provide the __getitem__() interface; dictionaries and sequences work well. Unmapped character ordinals (ones which cause a LookupError) are left untouched and are copied as-is.

errors has the usual meaning for codecs. It may be NULL which indicates to use the default error handling.

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)

返回值：新的引用。 Part of the Stable ABI on Windows since version 3.7.

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)

返回值：新的引用。 Part of the Stable ABI on Windows since version 3.7.

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)

返回值：新的引用。 Part of the Stable ABI on Windows since version 3.7.

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)

返回值：新的引用。 Part of the Stable ABI on Windows since version 3.7.

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.

Methods & Slots

方法与槽位函数

The following APIs are capable of handling Unicode objects and strings on input (we refer to them as strings in the descriptions) and return Unicode objects or integers as appropriate.

They all return NULL or -1 if an exception occurs.

PyObject *PyUnicode_Concat(PyObject *left, PyObject *right)

返回值：新的引用。 Part of the Stable ABI.

Concat two strings giving a new Unicode string.

PyObject *PyUnicode_Split(PyObject *s, PyObject *sep, Py_ssize_t maxsplit)

返回值：新的引用。 Part of the Stable ABI.

Split a string giving a list of Unicode strings. If sep is NULL, splitting will be done at all whitespace substrings. Otherwise, splits occur at the given separator. At most maxsplit splits will be done. If negative, no limit is set. Separators are not included in the resulting list.

PyObject *PyUnicode_Splitlines(PyObject *s, int keepend)

返回值：新的引用。 Part of the Stable ABI.

Split a Unicode string at line breaks, returning a list of Unicode strings. CRLF is considered to be one line break. If keepend is 0, the line break characters are not included in the resulting strings.

PyObject *PyUnicode_Join(PyObject *separator, PyObject *seq)

返回值：新的引用。 Part of the Stable ABI.

Join a sequence of strings using the given separator and return the resulting Unicode string.

Py_ssize_t PyUnicode_Tailmatch(PyObject *str, PyObject *substr, Py_ssize_t start, Py_ssize_t end, int direction)

Part of the Stable ABI.

Return 1 if substr matches str[start:end] at the given tail end (direction == -1 means to do a prefix match, direction == 1 a suffix match), 0 otherwise. Return -1 if an error occurred.

Py_ssize_t PyUnicode_Find(PyObject *str, PyObject *substr, Py_ssize_t start, Py_ssize_t end, int direction)

Part of the Stable ABI.

Return the first position of substr in str[start:end] using the given direction (direction == 1 means to do a forward search, direction == -1 a backward search). The return value is the index of the first match; a value of -1 indicates that no match was found, and -2 indicates that an error occurred and an exception has been set.

Py_ssize_t PyUnicode_FindChar(PyObject *str, Py_UCS4 ch, Py_ssize_t start, Py_ssize_t end, int direction)

Part of the Stable ABI since version 3.7.

Return the first position of the character ch in str[start:end] using the given direction (direction == 1 means to do a forward search, direction == -1 a backward search). The return value is the index of the first match; a value of -1 indicates that no match was found, and -2 indicates that an error occurred and an exception has been set.

3.3 新版功能.

在 3.7 版更改: start and end are now adjusted to behave like str[start:end].

Py_ssize_t PyUnicode_Count(PyObject *str, PyObject *substr, Py_ssize_t start, Py_ssize_t end)

Part of the Stable ABI.

Return the number of non-overlapping occurrences of substr in str[start:end]. Return -1 if an error occurred.

PyObject *PyUnicode_Replace(PyObject *str, PyObject *substr, PyObject *replstr, Py_ssize_t maxcount)

返回值：新的引用。 Part of the Stable ABI.

Replace at most maxcount occurrences of substr in str with replstr and return the resulting Unicode object. maxcount == -1 means replace all occurrences.

int PyUnicode_Compare(PyObject *left, PyObject *right)

Part of the Stable ABI.

Compare two strings and return -1, 0, 1 for less than, equal, and greater than, respectively.

This function returns -1 upon failure, so one should call PyErr_Occurred() to check for errors.

int PyUnicode_CompareWithASCIIString(PyObject *uni, const char *string)

Part of the Stable ABI.

Compare a Unicode object, uni, with string and return -1, 0, 1 for less than, equal, and greater than, respectively. It is best to pass only ASCII-encoded strings, but the function interprets the input string as ISO-8859-1 if it contains non-ASCII characters.

This function does not raise exceptions.

PyObject *PyUnicode_RichCompare(PyObject *left, PyObject *right, int op)

返回值：新的引用。 Part of the Stable ABI.

对两个 Unicode 字符串执行富比较并返回以下值之一:

• NULL in case an exception was raised

• Py_True or Py_False for successful comparisons

• Py_NotImplemented in case the type combination is unknown

Possible values for op are Py_GT, Py_GE, Py_EQ, Py_NE, Py_LT, and Py_LE.

PyObject *PyUnicode_Format(PyObject *format, PyObject *args)

返回值：新的引用。 Part of the Stable ABI.

Return a new string object from format and args; this is analogous to format % args.

int PyUnicode_Contains(PyObject *container, PyObject *element)

Part of the Stable ABI.

Check whether element is contained in container and return true or false accordingly.

element has to coerce to a one element Unicode string. -1 is returned if there was an error.

void PyUnicode_InternInPlace(PyObject **string)

Part of the Stable ABI.

Intern the argument *string in place. The argument must be the address of a pointer variable pointing to a Python Unicode string object. If there is an existing interned string that is the same as *string, it sets *string to it (releasing the reference to the old string object and creating a new strong reference to the interned string object), otherwise it leaves *string alone and interns it (creating a new strong reference). (Clarification: even though there is a lot of talk about references, think of this function as reference-neutral; you own the object after the call if and only if you owned it before the call.)

PyObject *PyUnicode_InternFromString(const char *v)

返回值：新的引用。 Part of the Stable ABI.

A combination of PyUnicode_FromString() and PyUnicode_InternInPlace(), returning either a new Unicode string object that has been interned, or a new (“owned”) reference to an earlier interned string object with the same value.