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Add a note in PyUnicode_CopyCharacters() doc: it doesn't write null character 

Cleanup also the code (avoid the goto).
This commit is contained in:
Victor Stinner 2011-09-29 14:14:38 +02:00
parent ff1ef074ed
commit a0702ab1fe
2 changed files with 47 additions and 44 deletions
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8
Include/unicodeobject.h
View File

@ -521,9 +521,9 @@ PyAPI_FUNC(int) _PyUnicode_Ready(
/* Copy character from one unicode object into another, this function performs
character conversion when necessary and falls back to memcpy if possible.
Fail if 'to' is smaller than how_many or smaller than len(from)-from_start,
or if kind(from[from_start:from_start+how_many]) > kind(to), or if to has
more than 1 reference.
Fail if to is too small (smaller than how_many or smaller than
len(from)-from_start), or if kind(from[from_start:from_start+how_many]) >
kind(to), or if to has more than 1 reference.
Return the number of written character, or return -1 and raise an exception
on error.
@ -533,6 +533,8 @@ PyAPI_FUNC(int) _PyUnicode_Ready(
how_many = min(how_many, len(from) - from_start)
to[to_start:to_start+how_many] = from[from_start:from_start+how_many]
return how_many
Note: The function doesn't write a terminating null character.
*/
#ifndef Py_LIMITED_API
PyAPI_FUNC(Py_ssize_t) PyUnicode_CopyCharacters(

83
Objects/unicodeobject.c
View File

@ -615,8 +615,8 @@ PyUnicode_CopyCharacters(PyObject *to, Py_ssize_t to_start,
PyObject *from, Py_ssize_t from_start,
Py_ssize_t how_many)
{
unsigned int from_kind;
unsigned int to_kind;
unsigned int from_kind, to_kind;
void *from_data, *to_data;
assert(PyUnicode_Check(from));
assert(PyUnicode_Check(to));
@ -645,44 +645,20 @@ PyUnicode_CopyCharacters(PyObject *to, Py_ssize_t to_start,
_PyUnicode_DIRTY(to);
from_kind = PyUnicode_KIND(from);
from_data = PyUnicode_DATA(from);
to_kind = PyUnicode_KIND(to);
to_data = PyUnicode_DATA(to);
if (from_kind == to_kind) {
/* fast path */
Py_MEMCPY((char*)PyUnicode_DATA(to)
Py_MEMCPY((char*)to_data
+ PyUnicode_KIND_SIZE(to_kind, to_start),
(char*)PyUnicode_DATA(from)
(char*)from_data
+ PyUnicode_KIND_SIZE(from_kind, from_start),
PyUnicode_KIND_SIZE(to_kind, how_many));
return how_many;
}
if (from_kind > to_kind) {
/* slow path to check for character overflow */
const Py_UCS4 to_maxchar = PyUnicode_MAX_CHAR_VALUE(to);
void *from_data = PyUnicode_DATA(from);
void *to_data = PyUnicode_DATA(to);
Py_UCS4 ch, maxchar;
Py_ssize_t i;
int overflow;
maxchar = 0;
overflow = 0;
for (i=0; i < how_many; i++) {
ch = PyUnicode_READ(from_kind, from_data, from_start + i);
if (ch > maxchar) {
maxchar = ch;
if (maxchar > to_maxchar) {
overflow = 1;
break;
}
}
PyUnicode_WRITE(to_kind, to_data, to_start + i, ch);
}
if (!overflow)
return how_many;
}
else if (from_kind == PyUnicode_1BYTE_KIND && to_kind == PyUnicode_2BYTE_KIND)
else if (from_kind == PyUnicode_1BYTE_KIND
&& to_kind == PyUnicode_2BYTE_KIND)
{
_PyUnicode_CONVERT_BYTES(
Py_UCS1, Py_UCS2,
@ -690,7 +666,6 @@ PyUnicode_CopyCharacters(PyObject *to, Py_ssize_t to_start,
PyUnicode_1BYTE_DATA(from) + from_start + how_many,
PyUnicode_2BYTE_DATA(to) + to_start
);
return how_many;
}
else if (from_kind == PyUnicode_1BYTE_KIND
&& to_kind == PyUnicode_4BYTE_KIND)
@ -701,7 +676,6 @@ PyUnicode_CopyCharacters(PyObject *to, Py_ssize_t to_start,
PyUnicode_1BYTE_DATA(from) + from_start + how_many,
PyUnicode_4BYTE_DATA(to) + to_start
);
return how_many;
}
else if (from_kind == PyUnicode_2BYTE_KIND
&& to_kind == PyUnicode_4BYTE_KIND)
@ -712,14 +686,41 @@ PyUnicode_CopyCharacters(PyObject *to, Py_ssize_t to_start,
PyUnicode_2BYTE_DATA(from) + from_start + how_many,
PyUnicode_4BYTE_DATA(to) + to_start
);
return how_many;
}
PyErr_Format(PyExc_ValueError,
"Cannot copy UCS%u characters "
"into a string of UCS%u characters",
1 << (from_kind - 1),
1 << (to_kind -1));
return -1;
else {
int invalid_kinds;
if (from_kind > to_kind) {
/* slow path to check for character overflow */
const Py_UCS4 to_maxchar = PyUnicode_MAX_CHAR_VALUE(to);
Py_UCS4 ch, maxchar;
Py_ssize_t i;
maxchar = 0;
invalid_kinds = 0;
for (i=0; i < how_many; i++) {
ch = PyUnicode_READ(from_kind, from_data, from_start + i);
if (ch > maxchar) {
maxchar = ch;
if (maxchar > to_maxchar) {
invalid_kinds = 1;
break;
}
}
PyUnicode_WRITE(to_kind, to_data, to_start + i, ch);
}
}
else
invalid_kinds = 1;
if (invalid_kinds) {
PyErr_Format(PyExc_ValueError,
"Cannot copy UCS%u characters "
"into a string of UCS%u characters",
1 << (from_kind - 1),
1 << (to_kind -1));
return -1;
}
}
return how_many;
}
/* Find the maximum code point and count the number of surrogate pairs so a