bpo-28749: Fixed the documentation of the mapping codec APIs. (#487) (#714)

Added the documentation for PyUnicode_Translate().
(cherry picked from commit c85a26628ceb9624c96c3064e8b99033c026d8a3)

1 files changed, 18 insertions, 27 deletions

diff --git a/Include/unicodeobject.h b/Include/unicodeobject.h
index 587cf03e36..2d0d77e804 100644
--- a/Include/unicodeobject.h
+++ b/Include/unicodeobject.h
@@ -1609,50 +1609,41 @@ PyAPI_FUNC(PyObject*) PyUnicode_EncodeASCII(
 
    This codec uses mappings to encode and decode characters.
 
-   Decoding mappings must map single string characters to single
-   Unicode characters, integers (which are then interpreted as Unicode
-   ordinals) or None (meaning "undefined mapping" and causing an
-   error).
-
-   Encoding mappings must map single Unicode characters to single
-   string characters, integers (which are then interpreted as Latin-1
-   ordinals) or None (meaning "undefined mapping" and causing an
-   error).
-
-   If a character lookup fails with a LookupError, the character is
-   copied as-is meaning that its ordinal value will be interpreted as
-   Unicode or Latin-1 ordinal resp. Because of this mappings only need
-   to contain those mappings which map characters to different code
-   points.
+   Decoding mappings must map byte 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 mapped to None, 0xFFFE or '\ufffe' are treated as "undefined
+   mapping" and cause an error.
+
+   Encoding mappings 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.
 
 */
 
 PyAPI_FUNC(PyObject*) PyUnicode_DecodeCharmap(
     const char *string,         /* Encoded string */
     Py_ssize_t length,          /* size of string */
-    PyObject *mapping,          /* character mapping
-                                   (char ordinal -> unicode ordinal) */
+    PyObject *mapping,          /* decoding mapping */
     const char *errors          /* error handling */
     );
 
 PyAPI_FUNC(PyObject*) PyUnicode_AsCharmapString(
     PyObject *unicode,          /* Unicode object */
-    PyObject *mapping           /* character mapping
-                                   (unicode ordinal -> char ordinal) */
+    PyObject *mapping           /* encoding mapping */
     );
 
 #ifndef Py_LIMITED_API
 PyAPI_FUNC(PyObject*) PyUnicode_EncodeCharmap(
     const Py_UNICODE *data,     /* Unicode char buffer */
     Py_ssize_t length,          /* Number of Py_UNICODE chars to encode */
-    PyObject *mapping,          /* character mapping
-                                   (unicode ordinal -> char ordinal) */
+    PyObject *mapping,          /* encoding mapping */
     const char *errors          /* error handling */
     );
 PyAPI_FUNC(PyObject*) _PyUnicode_EncodeCharmap(
     PyObject *unicode,          /* Unicode object */
-    PyObject *mapping,          /* character mapping
-                                   (unicode ordinal -> char ordinal) */
+    PyObject *mapping,          /* encoding mapping */
     const char *errors          /* error handling */
     );
 #endif
@@ -1661,8 +1652,8 @@ PyAPI_FUNC(PyObject*) _PyUnicode_EncodeCharmap(
    character mapping table to it and return the resulting Unicode
    object.
 
-   The mapping table must map Unicode ordinal integers to Unicode
-   ordinal integers or None (causing deletion of the character).
+   The mapping table must map Unicode ordinal integers to Unicode strings,
+   Unicode ordinal integers or None (causing deletion of the character).
 
    Mapping tables may be dictionaries or sequences. Unmapped character
    ordinals (ones which cause a LookupError) are left untouched and
@@ -1960,8 +1951,8 @@ PyAPI_FUNC(PyObject*) PyUnicode_RSplit(
 /* Translate a string by applying a character mapping table to it and
    return the resulting Unicode object.
 
-   The mapping table must map Unicode ordinal integers to Unicode
-   ordinal integers or None (causing deletion of the character).
+   The mapping table must map Unicode ordinal integers to Unicode strings,
+   Unicode ordinal integers or None (causing deletion of the character).
 
    Mapping tables may be dictionaries or sequences. Unmapped character
    ordinals (ones which cause a LookupError) are left untouched and