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python/Objects/stringlib/string_format.h at master · broncodans/python · GitHub
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/*
string_format.h -- implementation of string.format().
It uses the Objects/stringlib conventions, so that it can be
compiled for both unicode and string objects.
*/
/* Defines for Python 2.6 compatability */
#if
PY_VERSION_HEX
<
0x03000000
#define
PyLong_FromSsize_t
_PyLong_FromSsize_t
#endif
/* Defines for more efficiently reallocating the string buffer */
#define
INITIAL_SIZE_INCREMENT
100
#define
SIZE_MULTIPLIER
2
#define
MAX_SIZE_INCREMENT
3200
/************************************************************************/
/*********** Global data structures and forward declarations *********/
/************************************************************************/
/*
A SubString consists of the characters between two string or
unicode pointers.
*/
typedef
struct
{
STRINGLIB_CHAR
*
ptr
;
STRINGLIB_CHAR
*
end
;
}
SubString
;
/* forward declaration for recursion */
static
PyObject
*
build_string
(
SubString
*
input
,
PyObject
*
args
,
PyObject
*
kwargs
,
int
recursion_depth
);
/************************************************************************/
/************************** Utility functions ************************/
/************************************************************************/
/* fill in a SubString from a pointer and length */
Py_LOCAL_INLINE
(
void
)
SubString_init
(
SubString
*
str
,
STRINGLIB_CHAR
*
p
,
Py_ssize_t
len
)
{
str
->
ptr
=
p
;
if
(
p
==
NULL
)
str
->
end
=
NULL
;
else
str
->
end
=
str
->
ptr
+
len
;
}
/* return a new string. if str->ptr is NULL, return None */
Py_LOCAL_INLINE
(
PyObject
*
)
SubString_new_object
(
SubString
*
str
)
{
if
(
str
->
ptr
==
NULL
) {
Py_INCREF
(
Py_None
);
return
Py_None
;
}
return
STRINGLIB_NEW
(
str
->
ptr
,
str
->
end
-
str
->
ptr
);
}
/* return a new string. if str->ptr is NULL, return None */
Py_LOCAL_INLINE
(
PyObject
*
)
SubString_new_object_or_empty
(
SubString
*
str
)
{
if
(
str
->
ptr
==
NULL
) {
return
STRINGLIB_NEW
(
NULL
,
0
);
}
return
STRINGLIB_NEW
(
str
->
ptr
,
str
->
end
-
str
->
ptr
);
}
/************************************************************************/
/*********** Output string management functions ****************/
/************************************************************************/
typedef
struct
{
STRINGLIB_CHAR
*
ptr
;
STRINGLIB_CHAR
*
end
;
PyObject
*
obj
;
Py_ssize_t
size_increment
;
}
OutputString
;
/* initialize an OutputString object, reserving size characters */
static
int
output_initialize
(
OutputString
*
output
,
Py_ssize_t
size
)
{
output
->
obj
=
STRINGLIB_NEW
(
NULL
,
size
);
if
(
output
->
obj
==
NULL
)
return
0
;
output
->
ptr
=
STRINGLIB_STR
(
output
->
obj
);
output
->
end
=
STRINGLIB_LEN
(
output
->
obj
)
+
output
->
ptr
;
output
->
size_increment
=
INITIAL_SIZE_INCREMENT
;
return
1
;
}
/*
output_extend reallocates the output string buffer.
It returns a status: 0 for a failed reallocation,
1 for success.
*/
static
int
output_extend
(
OutputString
*
output
,
Py_ssize_t
count
)
{
STRINGLIB_CHAR
*
startptr
=
STRINGLIB_STR
(
output
->
obj
);
Py_ssize_t
curlen
=
output
->
ptr
-
startptr
;
Py_ssize_t
maxlen
=
curlen
+
count
+
output
->
size_increment
;
if
(
STRINGLIB_RESIZE
(
&
output
->
obj
,
maxlen
)
<
0
)
return
0
;
startptr
=
STRINGLIB_STR
(
output
->
obj
);
output
->
ptr
=
startptr
+
curlen
;
output
->
end
=
startptr
+
maxlen
;
if
(
output
->
size_increment
<
MAX_SIZE_INCREMENT
)
output
->
size_increment
*=
SIZE_MULTIPLIER
;
return
1
;
}
/*
output_data dumps characters into our output string
buffer.
In some cases, it has to reallocate the string.
It returns a status: 0 for a failed reallocation,
1 for success.
*/
static
int
output_data
(
OutputString
*
output
,
const
STRINGLIB_CHAR
*
s
,
Py_ssize_t
count
)
{
if
((
count
>
output
->
end
-
output
->
ptr
)
&&
!
output_extend
(
output
,
count
))
return
0
;
memcpy
(
output
->
ptr
,
s
,
count
*
sizeof
(
STRINGLIB_CHAR
));
output
->
ptr
+=
count
;
return
1
;
}
/************************************************************************/
/*********** Format string parsing -- integers and identifiers *********/
/************************************************************************/
static
Py_ssize_t
get_integer
(
const
SubString
*
str
)
{
Py_ssize_t
accumulator
=
0
;
Py_ssize_t
digitval
;
Py_ssize_t
oldaccumulator
;
STRINGLIB_CHAR
*
p
;
/* empty string is an error */
if
(
str
->
ptr
>=
str
->
end
)
return
-1
;
for
(
p
=
str
->
ptr
;
p
<
str
->
end
;
p
++
) {
digitval
=
STRINGLIB_TODECIMAL
(
*
p
);
if
(
digitval
<
0
)
return
-1
;
/*
This trick was copied from old Unicode format code. It's cute,
but would really suck on an old machine with a slow divide
implementation. Fortunately, in the normal case we do not
expect too many digits.
*/
oldaccumulator
=
accumulator
;
accumulator
*=
10
;
if
((
accumulator
+
10
)/
10
!=
oldaccumulator
+
1
) {
PyErr_Format
(
PyExc_ValueError
,
"Too many decimal digits in format string"
);
return
-1
;
}
accumulator
+=
digitval
;
}
return
accumulator
;
}
/************************************************************************/
/******** Functions to get field objects and specification strings ******/
/************************************************************************/
/* do the equivalent of obj.name */
static
PyObject
*
getattr
(
PyObject
*
obj
,
SubString
*
name
)
{
PyObject
*
newobj
;
PyObject
*
str
=
SubString_new_object
(
name
);
if
(
str
==
NULL
)
return
NULL
;
newobj
=
PyObject_GetAttr
(
obj
,
str
);
Py_DECREF
(
str
);
return
newobj
;
}
/* do the equivalent of obj[idx], where obj is a sequence */
static
PyObject
*
getitem_sequence
(
PyObject
*
obj
,
Py_ssize_t
idx
)
{
return
PySequence_GetItem
(
obj
,
idx
);
}
/* do the equivalent of obj[idx], where obj is not a sequence */
static
PyObject
*
getitem_idx
(
PyObject
*
obj
,
Py_ssize_t
idx
)
{
PyObject
*
newobj
;
PyObject
*
idx_obj
=
PyLong_FromSsize_t
(
idx
);
if
(
idx_obj
==
NULL
)
return
NULL
;
newobj
=
PyObject_GetItem
(
obj
,
idx_obj
);
Py_DECREF
(
idx_obj
);
return
newobj
;
}
/* do the equivalent of obj[name] */
static
PyObject
*
getitem_str
(
PyObject
*
obj
,
SubString
*
name
)
{
PyObject
*
newobj
;
PyObject
*
str
=
SubString_new_object
(
name
);
if
(
str
==
NULL
)
return
NULL
;
newobj
=
PyObject_GetItem
(
obj
,
str
);
Py_DECREF
(
str
);
return
newobj
;
}
typedef
struct
{
/* the entire string we're parsing. we assume that someone else
is managing its lifetime, and that it will exist for the
lifetime of the iterator. can be empty */
SubString
str
;
/* pointer to where we are inside field_name */
STRINGLIB_CHAR
*
ptr
;
}
FieldNameIterator
;
static
int
FieldNameIterator_init
(
FieldNameIterator
*
self
,
STRINGLIB_CHAR
*
ptr
,
Py_ssize_t
len
)
{
SubString_init
(
&
self
->
str
,
ptr
,
len
);
self
->
ptr
=
self
->
str
.
ptr
;
return
1
;
}
static
int
_FieldNameIterator_attr
(
FieldNameIterator
*
self
,
SubString
*
name
)
{
STRINGLIB_CHAR
c
;
name
->
ptr
=
self
->
ptr
;
/* return everything until '.' or '[' */
while
(
self
->
ptr
<
self
->
str
.
end
) {
switch
(
c
=
*
self
->
ptr
++
) {
case
'['
:
case
'.'
:
/* backup so that we this character will be seen next time */
self
->
ptr
--
;
break
;
default
:
continue
;
}
break
;
}
/* end of string is okay */
name
->
end
=
self
->
ptr
;
return
1
;
}
static
int
_FieldNameIterator_item
(
FieldNameIterator
*
self
,
SubString
*
name
)
{
int
bracket_seen
=
0
;
STRINGLIB_CHAR
c
;
name
->
ptr
=
self
->
ptr
;
/* return everything until ']' */
while
(
self
->
ptr
<
self
->
str
.
end
) {
switch
(
c
=
*
self
->
ptr
++
) {
case
']'
:
bracket_seen
=
1
;
break
;
default
:
continue
;
}
break
;
}
/* make sure we ended with a ']' */
if
(!
bracket_seen
) {
PyErr_SetString
(
PyExc_ValueError
,
"Missing ']' in format string"
);
return
0
;
}
/* end of string is okay */
/* don't include the ']' */
name
->
end
=
self
->
ptr
-
1
;
return
1
;
}
/* returns 0 on error, 1 on non-error termination, and 2 if it returns a value */
static
int
FieldNameIterator_next
(
FieldNameIterator
*
self
,
int
*
is_attribute
,
Py_ssize_t
*
name_idx
,
SubString
*
name
)
{
/* check at end of input */
if
(
self
->
ptr
>=
self
->
str
.
end
)
return
1
;
switch
(
*
self
->
ptr
++
) {
case
'.'
:
*
is_attribute
=
1
;
if
(
_FieldNameIterator_attr
(
self
,
name
)
==
0
)
return
0
;
*
name_idx
=
-1
;
break
;
case
'['
:
*
is_attribute
=
0
;
if
(
_FieldNameIterator_item
(
self
,
name
)
==
0
)
return
0
;
*
name_idx
=
get_integer
(
name
);
break
;
default
:
/* interal error, can't get here */
assert
(
0
);
return
0
;
}
/* empty string is an error */
if
(
name
->
ptr
==
name
->
end
) {
PyErr_SetString
(
PyExc_ValueError
,
"Empty attribute in format string"
);
return
0
;
}
return
2
;
}
/* input: field_name
output: 'first' points to the part before the first '[' or '.'
'first_idx' is -1 if 'first' is not an integer, otherwise
it's the value of first converted to an integer
'rest' is an iterator to return the rest
*/
static
int
field_name_split
(
STRINGLIB_CHAR
*
ptr
,
Py_ssize_t
len
,
SubString
*
first
,
Py_ssize_t
*
first_idx
,
FieldNameIterator
*
rest
)
{
STRINGLIB_CHAR
c
;
STRINGLIB_CHAR
*
p
=
ptr
;
STRINGLIB_CHAR
*
end
=
ptr
+
len
;
/* find the part up until the first '.' or '[' */
while
(
p
<
end
) {
switch
(
c
=
*
p
++
) {
case
'['
:
case
'.'
:
/* backup so that we this character is available to the
"rest" iterator */
p
--
;
break
;
default
:
continue
;
}
break
;
}
/* set up the return values */
SubString_init
(
first
,
ptr
,
p
-
ptr
);
FieldNameIterator_init
(
rest
,
p
,
end
-
p
);
/* see if "first" is an integer, in which case it's used as an index */
*
first_idx
=
get_integer
(
first
);
/* zero length string is an error */
if
(
first
->
ptr
>=
first
->
end
) {
PyErr_SetString
(
PyExc_ValueError
,
"empty field name"
);
goto
error
;
}
return
1
;
error
:
return
0
;
}
/*
get_field_object returns the object inside {}, before the
format_spec. It handles getindex and getattr lookups and consumes
the entire input string.
*/
static
PyObject
*
get_field_object
(
SubString
*
input
,
PyObject
*
args
,
PyObject
*
kwargs
)
{
PyObject
*
obj
=
NULL
;
int
ok
;
int
is_attribute
;
SubString
name
;
SubString
first
;
Py_ssize_t
index
;
FieldNameIterator
rest
;
if
(!
field_name_split
(
input
->
ptr
,
input
->
end
-
input
->
ptr
,
&
first
,
&
index
,
&
rest
)) {
goto
error
;
}
if
(
index
==
-1
) {
/* look up in kwargs */
PyObject
*
key
=
SubString_new_object
(
&
first
);
if
(
key
==
NULL
)
goto
error
;
if
((
kwargs
==
NULL
)
||
(
obj
=
PyDict_GetItem
(
kwargs
,
key
))
==
NULL
) {
PyErr_SetObject
(
PyExc_KeyError
,
key
);
Py_DECREF
(
key
);
goto
error
;
}
Py_DECREF
(
key
);
Py_INCREF
(
obj
);
}
else
{
/* look up in args */
obj
=
PySequence_GetItem
(
args
,
index
);
if
(
obj
==
NULL
)
goto
error
;
}
/* iterate over the rest of the field_name */
while
((
ok
=
FieldNameIterator_next
(
&
rest
,
&
is_attribute
,
&
index
,
&
name
))
==
2
) {
PyObject
*
tmp
;
if
(
is_attribute
)
/* getattr lookup "." */
tmp
=
getattr
(
obj
,
&
name
);
else
/* getitem lookup "[]" */
if
(
index
==
-1
)
tmp
=
getitem_str
(
obj
,
&
name
);
else
if
(
PySequence_Check
(
obj
))
tmp
=
getitem_sequence
(
obj
,
index
);
else
/* not a sequence */
tmp
=
getitem_idx
(
obj
,
index
);
if
(
tmp
==
NULL
)
goto
error
;
/* assign to obj */
Py_DECREF
(
obj
);
obj
=
tmp
;
}
/* end of iterator, this is the non-error case */
if
(
ok
==
1
)
return
obj
;
error
:
Py_XDECREF
(
obj
);
return
NULL
;
}
/************************************************************************/
/***************** Field rendering functions **************************/
/************************************************************************/
/*
render_field() is the main function in this section. It takes the
field object and field specification string generated by
get_field_and_spec, and renders the field into the output string.
render_field calls fieldobj.__format__(format_spec) method, and
appends to the output.
*/
static
int
render_field
(
PyObject
*
fieldobj
,
SubString
*
format_spec
,
OutputString
*
output
)
{
int
ok
=
0
;
PyObject
*
result
=
NULL
;
PyObject
*
format_spec_object
=
NULL
;
PyObject
*
(
*
formatter
)(
PyObject
*
,
STRINGLIB_CHAR
*
,
Py_ssize_t
)
=
NULL
;
STRINGLIB_CHAR
*
format_spec_start
=
format_spec
->
ptr
?
format_spec
->
ptr
:
NULL
;
Py_ssize_t
format_spec_len
=
format_spec
->
ptr
?
format_spec
->
end
-
format_spec
->
ptr
:
0
;
/* If we know the type exactly, skip the lookup of __format__ and just
call the formatter directly. */
#if
STRINGLIB_IS_UNICODE
if
(
PyUnicode_CheckExact
(
fieldobj
))
formatter
=
_PyUnicode_FormatAdvanced
;
/* Unfortunately, there's a problem with checking for int, long,
and float here. If we're being included as unicode, their
formatters expect string format_spec args. For now, just skip
this optimization for unicode. This could be fixed, but it's a
hassle. */
#else
if
(
PyString_CheckExact
(
fieldobj
))
formatter
=
_PyBytes_FormatAdvanced
;
else
if
(
PyInt_CheckExact
(
fieldobj
))
formatter
=
_PyInt_FormatAdvanced
;
else
if
(
PyLong_CheckExact
(
fieldobj
))
formatter
=
_PyLong_FormatAdvanced
;
else
if
(
PyFloat_CheckExact
(
fieldobj
))
formatter
=
_PyFloat_FormatAdvanced
;
#endif
if
(
formatter
) {
/* we know exactly which formatter will be called when __format__ is
looked up, so call it directly, instead. */
result
=
formatter
(
fieldobj
,
format_spec_start
,
format_spec_len
);
}
else
{
/* We need to create an object out of the pointers we have, because
__format__ takes a string/unicode object for format_spec. */
format_spec_object
=
STRINGLIB_NEW
(
format_spec_start
,
format_spec_len
);
if
(
format_spec_object
==
NULL
)
goto
done
;
result
=
PyObject_Format
(
fieldobj
,
format_spec_object
);
}
if
(
result
==
NULL
)
goto
done
;
#if
PY_VERSION_HEX
>=
0x03000000
assert
(
PyUnicode_Check
(
result
));
#else
assert
(
PyString_Check
(
result
)
||
PyUnicode_Check
(
result
));
/* Convert result to our type. We could be str, and result could
be unicode */
{
PyObject
*
tmp
=
STRINGLIB_TOSTR
(
result
);
if
(
tmp
==
NULL
)
goto
done
;
Py_DECREF
(
result
);
result
=
tmp
;
}
#endif
ok
=
output_data
(
output
,
STRINGLIB_STR
(
result
),
STRINGLIB_LEN
(
result
));
done
:
Py_XDECREF
(
format_spec_object
);
Py_XDECREF
(
result
);
return
ok
;
}
static
int
parse_field
(
SubString
*
str
,
SubString
*
field_name
,
SubString
*
format_spec
,
STRINGLIB_CHAR
*
conversion
)
{
STRINGLIB_CHAR
c
=
0
;
/* initialize these, as they may be empty */
*
conversion
=
'\0'
;
SubString_init
(
format_spec
,
NULL
,
0
);
/* search for the field name. it's terminated by the end of the
string, or a ':' or '!' */
field_name
->
ptr
=
str
->
ptr
;
while
(
str
->
ptr
<
str
->
end
) {
switch
(
c
=
*
(
str
->
ptr
++
)) {
case
':'
:
case
'!'
:
break
;
default
:
continue
;
}
break
;
}
if
(
c
==
'!'
||
c
==
':'
) {
/* we have a format specifier and/or a conversion */
/* don't include the last character */
field_name
->
end
=
str
->
ptr
-
1
;
/* the format specifier is the rest of the string */
format_spec
->
ptr
=
str
->
ptr
;
format_spec
->
end
=
str
->
end
;
/* see if there's a conversion specifier */
if
(
c
==
'!'
) {
/* there must be another character present */
if
(
format_spec
->
ptr
>=
format_spec
->
end
) {
PyErr_SetString
(
PyExc_ValueError
,
"end of format while looking for conversion "
"specifier"
);
return
0
;
}
*
conversion
=
*
(
format_spec
->
ptr
++
);
/* if there is another character, it must be a colon */
if
(
format_spec
->
ptr
<
format_spec
->
end
) {
c
=
*
(
format_spec
->
ptr
++
);
if
(
c
!=
':'
) {
PyErr_SetString
(
PyExc_ValueError
,
"expected ':' after format specifier"
);
return
0
;
}
}
}
return
1
;
}
else
{
/* end of string, there's no format_spec or conversion */
field_name
->
end
=
str
->
ptr
;
return
1
;
}
}
/************************************************************************/
/******* Output string allocation and escape-to-markup processing ******/
/************************************************************************/
/* MarkupIterator breaks the string into pieces of either literal
text, or things inside {} that need to be marked up. it is
designed to make it easy to wrap a Python iterator around it, for
use with the Formatter class */
typedef
struct
{
SubString
str
;
}
MarkupIterator
;
static
int
MarkupIterator_init
(
MarkupIterator
*
self
,
STRINGLIB_CHAR
*
ptr
,
Py_ssize_t
len
)
{
SubString_init
(
&
self
->
str
,
ptr
,
len
);
return
1
;
}
/* returns 0 on error, 1 on non-error termination, and 2 if it got a
string (or something to be expanded) */
static
int
MarkupIterator_next
(
MarkupIterator
*
self
,
SubString
*
literal
,
SubString
*
field_name
,
SubString
*
format_spec
,
STRINGLIB_CHAR
*
conversion
,
int
*
format_spec_needs_expanding
)
{
int
at_end
;
STRINGLIB_CHAR
c
=
0
;
STRINGLIB_CHAR
*
start
;
int
count
;
Py_ssize_t
len
;
int
markup_follows
=
0
;
/* initialize all of the output variables */
SubString_init
(
literal
,
NULL
,
0
);
SubString_init
(
field_name
,
NULL
,
0
);
SubString_init
(
format_spec
,
NULL
,
0
);
*
conversion
=
'\0'
;
*
format_spec_needs_expanding
=
0
;
/* No more input, end of iterator. This is the normal exit
path. */
if
(
self
->
str
.
ptr
>=
self
->
str
.
end
)
return
1
;
start
=
self
->
str
.
ptr
;
/* First read any literal text. Read until the end of string, an
escaped '{' or '}', or an unescaped '{'. In order to never
allocate memory and so I can just pass pointers around, if
there's an escaped '{' or '}' then we'll return the literal
including the brace, but no format object. The next time
through, we'll return the rest of the literal, skipping past
the second consecutive brace. */
while
(
self
->
str
.
ptr
<
self
->
str
.
end
) {
switch
(
c
=
*
(
self
->
str
.
ptr
++
)) {
case
'{'
:
case
'}'
:
markup_follows
=
1
;
break
;
default
:
continue
;
}
break
;
}
at_end
=
self
->
str
.
ptr
>=
self
->
str
.
end
;
len
=
self
->
str
.
ptr
-
start
;
if
((
c
==
'}'
)
&&
(
at_end
||
(
c
!=
*
self
->
str
.
ptr
))) {
PyErr_SetString
(
PyExc_ValueError
,
"Single '}' encountered "
"in format string"
);
return
0
;
}
if
(
at_end
&&
c
==
'{'
) {
PyErr_SetString
(
PyExc_ValueError
,
"Single '{' encountered "
"in format string"
);
return
0
;
}
if
(!
at_end
) {
if
(
c
==
*
self
->
str
.
ptr
) {
/* escaped } or {, skip it in the input. there is no
markup object following us, just this literal text */
self
->
str
.
ptr
++
;
markup_follows
=
0
;
}
else
len
--
;
}
/* record the literal text */
literal
->
ptr
=
start
;
literal
->
end
=
start
+
len
;
if
(!
markup_follows
)
return
2
;
/* this is markup, find the end of the string by counting nested
braces. note that this prohibits escaped braces, so that
format_specs cannot have braces in them. */
count
=
1
;
start
=
self
->
str
.
ptr
;
/* we know we can't have a zero length string, so don't worry
about that case */
while
(
self
->
str
.
ptr
<
self
->
str
.
end
) {
switch
(
c
=
*
(
self
->
str
.
ptr
++
)) {
case
'{'
:
/* the format spec needs to be recursively expanded.
this is an optimization, and not strictly needed */
*
format_spec_needs_expanding
=
1
;
count
++
;
break
;
case
'}'
:
count
--
;
if
(
count
<=
0
) {
/* we're done. parse and get out */
SubString
s
;
SubString_init
(
&
s
,
start
,
self
->
str
.
ptr
-
1
-
start
);
if
(
parse_field
(
&
s
,
field_name
,
format_spec
,
conversion
)
==
0
)
return
0
;
/* a zero length field_name is an error */
if
(
field_name
->
ptr
==
field_name
->
end
) {
PyErr_SetString
(
PyExc_ValueError
,
"zero length field name "
"in format"
);
return
0
;
}
/* success */
return
2
;
}
break
;
}
}
/* end of string while searching for matching '}' */
PyErr_SetString
(
PyExc_ValueError
,
"unmatched '{' in format"
);
return
0
;
}
/* do the !r or !s conversion on obj */
static
PyObject
*
do_conversion
(
PyObject
*
obj
,
STRINGLIB_CHAR
conversion
)
{
/* XXX in pre-3.0, do we need to convert this to unicode, since it
might have returned a string? */
switch
(
conversion
) {
case
'r'
:
return
PyObject_Repr
(
obj
);
case
's'
:
return
STRINGLIB_TOSTR
(
obj
);
default
:
if
(
conversion
>
32
&&
conversion
<
127
) {
/* It's the ASCII subrange; casting to char is safe
(assuming the execution character set is an ASCII
superset). */
PyErr_Format
(
PyExc_ValueError
,
"Unknown conversion specifier %c"
,
(
char
)
conversion
);
}
else
PyErr_Format
(
PyExc_ValueError
,
"Unknown conversion specifier \\x%x"
,
(
unsigned
int
)
conversion
);
return
NULL
;
}
}
/* given:
{field_name!conversion:format_spec}
compute the result and write it to output.
format_spec_needs_expanding is an optimization. if it's false,
just output the string directly, otherwise recursively expand the
format_spec string. */
static
int
output_markup
(
SubString
*
field_name
,
SubString
*
format_spec
,
int
format_spec_needs_expanding
,
STRINGLIB_CHAR
conversion
,
OutputString
*
output
,
PyObject
*
args
,
PyObject
*
kwargs
,
int
recursion_depth
)
{
PyObject
*
tmp
=
NULL
;
PyObject
*
fieldobj
=
NULL
;
SubString
expanded_format_spec
;
SubString
*
actual_format_spec
;
int
result
=
0
;
/* convert field_name to an object */
fieldobj
=
get_field_object
(
field_name
,
args
,
kwargs
);
if
(
fieldobj
==
NULL
)
goto
done
;
if
(
conversion
!=
'\0'
) {
tmp
=
do_conversion
(
fieldobj
,
conversion
);
if
(
tmp
==
NULL
)
goto
done
;
/* do the assignment, transferring ownership: fieldobj = tmp */
Py_DECREF
(
fieldobj
);
fieldobj
=
tmp
;
tmp
=
NULL
;
}
/* if needed, recurively compute the format_spec */
if
(
format_spec_needs_expanding
) {
tmp
=
build_string
(
format_spec
,
args
,
kwargs
,
recursion_depth
-
1
);
if
(
tmp
==
NULL
)
goto
done
;
/* note that in the case we're expanding the format string,
tmp must be kept around until after the call to
render_field. */
SubString_init
(
&
expanded_format_spec
,
STRINGLIB_STR
(
tmp
),
STRINGLIB_LEN
(
tmp
));
actual_format_spec
=
&
expanded_format_spec
;
}
else
actual_format_spec
=
format_spec
;
if
(
render_field
(
fieldobj
,
actual_format_spec
,
output
)
==
0
)
goto
done
;
result
=
1
;
done
:
Py_XDECREF
(
fieldobj
);
Py_XDECREF
(
tmp
);
return
result
;
}
/*
do_markup is the top-level loop for the format() method. It
searches through the format string for escapes to markup codes, and
calls other functions to move non-markup text to the output,
and to perform the markup to the output.
*/
static
int
do_markup
(
SubString
*
input
,
PyObject
*
args
,
PyObject
*
kwargs
,
OutputString
*
output
,
int
recursion_depth
)
{
MarkupIterator
iter
;
int
format_spec_needs_expanding
;
int
result
;
SubString
literal
;
SubString
field_name
;
SubString
format_spec
;
STRINGLIB_CHAR
conversion
;
MarkupIterator_init
(
&
iter
,
input
->
ptr
,
input
->
end
-
input
->
ptr
);
while
((
result
=
MarkupIterator_next
(
&
iter
,
&
literal
,
&
field_name
,
&
format_spec
,
&
conversion
,
&
format_spec_needs_expanding
))
==
2
) {
if
(!
output_data
(
output
,
literal
.
ptr
,
literal
.
end
-
literal
.
ptr
))
return
0
;
if
(
field_name
.
ptr
!=
field_name
.
end
)
if
(!
output_markup
(
&
field_name
,
&
format_spec
,
format_spec_needs_expanding
,
conversion
,
output
,
args
,
kwargs
,
recursion_depth
))
return
0
;
}
return
result
;
}
/*
build_string allocates the output string and then
calls do_markup to do the heavy lifting.
*/
static
PyObject
*
build_string
(
SubString
*
input
,
PyObject
*
args
,
PyObject
*
kwargs
,
int
recursion_depth
)
{
OutputString
output
;
PyObject
*
result
=
NULL
;
Py_ssize_t
count
;
output
.
obj
=
NULL
;
/* needed so cleanup code always works */
/* check the recursion level */
if
(
recursion_depth
<=
0
) {
PyErr_SetString
(
PyExc_ValueError
,
"Max string recursion exceeded"
);
goto
done
;
}
/* initial size is the length of the format string, plus the size
increment. seems like a reasonable default */
if
(!
output_initialize
(
&
output
,
input
->
end
-
input
->
ptr
+
INITIAL_SIZE_INCREMENT
))
goto
done
;
if
(!
do_markup
(
input
,
args
,
kwargs
,
&
output
,
recursion_depth
)) {
goto
done
;
}
count
=
output
.
ptr
-
STRINGLIB_STR
(
output
.
obj
);
if
(
STRINGLIB_RESIZE
(
&
output
.
obj
,
count
)
<
0
) {
goto
done
;
}
/* transfer ownership to result */
result
=
output
.
obj
;
output
.
obj
=
NULL
;
done
:
Py_XDECREF
(
output
.
obj
);
return
result
;
}
/************************************************************************/
/*********** main routine ***********************************************/
/************************************************************************/
/* this is the main entry point */
static
PyObject
*
do_string_format
(
PyObject
*
self
,
PyObject
*
args
,
PyObject
*
kwargs
)
{
SubString
input
;
/* PEP 3101 says only 2 levels, so that
"{0:{1}}".format('abc', 's') # works
"{0:{1:{2}}}".format('abc', 's', '') # fails
*/
int
recursion_depth
=
2
;
SubString_init
(
&
input
,
STRINGLIB_STR
(
self
),
STRINGLIB_LEN
(
self
));
return
build_string
(
&
input
,
args
,
kwargs
,
recursion_depth
);
}
/************************************************************************/
/*********** formatteriterator ******************************************/
/************************************************************************/
/* This is used to implement string.Formatter.vparse(). It exists so
Formatter can share code with the built in unicode.format() method.
It's really just a wrapper around MarkupIterator that is callable
from Python. */
typedef
struct
{
PyObject_HEAD
STRINGLIB_OBJECT
*
str
;
MarkupIterator
it_markup
;
}
formatteriterobject
;
static
void
formatteriter_dealloc
(
formatteriterobject
*
it
)
{
Py_XDECREF
(
it
->
str
);
PyObject_FREE
(
it
);
}
/* returns a tuple:
(literal, field_name, format_spec, conversion)
literal is any literal text to output. might be zero length
field_name is the string before the ':'. might be None
format_spec is the string after the ':'. mibht be None
conversion is either None, or the string after the '!'
*/
static
PyObject
*
formatteriter_next
(
formatteriterobject
*
it
)
{
SubString
literal
;
SubString
field_name
;
SubString
format_spec
;
STRINGLIB_CHAR
conversion
;
int
format_spec_needs_expanding
;
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