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authorRaymond Hettinger <python@rcn.com>2008-01-04 00:01:15 +0000
committerRaymond Hettinger <python@rcn.com>2008-01-04 00:01:15 +0000
commit2f6621cce7846a221b81e4dcb113824b08a9a12f (patch)
tree290e0fe79a45c1bf6fec21accd320cf5113cfa80 /Lib/struct.py
parent076d9eef7bb49eaf0381a6e6f6f5ea71167cd504 (diff)
downloadcpython-git-2f6621cce7846a221b81e4dcb113824b08a9a12f.tar.gz
Finish-up the struct module optimizations started at the Iceland NFS sprint.
Diffstat (limited to 'Lib/struct.py')
-rw-r--r--Lib/struct.py100
1 files changed, 1 insertions, 99 deletions
diff --git a/Lib/struct.py b/Lib/struct.py
index 07c21bf9bc..297e7d0d90 100644
--- a/Lib/struct.py
+++ b/Lib/struct.py
@@ -1,99 +1 @@
-"""
-Functions to convert between Python values and C structs.
-Python strings are used to hold the data representing the C struct
-and also as format strings to describe the layout of data in the C struct.
-
-The optional first format char indicates byte order, size and alignment:
- @: native order, size & alignment (default)
- =: native order, std. size & alignment
- <: little-endian, std. size & alignment
- >: big-endian, std. size & alignment
- !: same as >
-
-The remaining chars indicate types of args and must match exactly;
-these can be preceded by a decimal repeat count:
- x: pad byte (no data); c:char; b:signed byte; B:unsigned byte;
- h:short; H:unsigned short; i:int; I:unsigned int;
- l:long; L:unsigned long; f:float; d:double.
-Special cases (preceding decimal count indicates length):
- s:string (array of char); p: pascal string (with count byte).
-Special case (only available in native format):
- P:an integer type that is wide enough to hold a pointer.
-Special case (not in native mode unless 'long long' in platform C):
- q:long long; Q:unsigned long long
-Whitespace between formats is ignored.
-
-The variable struct.error is an exception raised on errors.
-"""
-__version__ = '0.1'
-
-from _struct import Struct, error
-
-_MAXCACHE = 100
-_cache = {}
-
-def _compile(fmt):
- # Internal: compile struct pattern
- if len(_cache) >= _MAXCACHE:
- _cache.clear()
- s = Struct(fmt)
- _cache[fmt] = s
- return s
-
-def calcsize(fmt):
- """
- Return size of C struct described by format string fmt.
- See struct.__doc__ for more on format strings.
- """
- try:
- o = _cache[fmt]
- except KeyError:
- o = _compile(fmt)
- return o.size
-
-def pack(fmt, *args):
- """
- Return string containing values v1, v2, ... packed according to fmt.
- See struct.__doc__ for more on format strings.
- """
- try:
- o = _cache[fmt]
- except KeyError:
- o = _compile(fmt)
- return o.pack(*args)
-
-def pack_into(fmt, buf, offset, *args):
- """
- Pack the values v1, v2, ... according to fmt, write
- the packed bytes into the writable buffer buf starting at offset.
- See struct.__doc__ for more on format strings.
- """
- try:
- o = _cache[fmt]
- except KeyError:
- o = _compile(fmt)
- return o.pack_into(buf, offset, *args)
-
-def unpack(fmt, s):
- """
- Unpack the string, containing packed C structure data, according
- to fmt. Requires len(string)==calcsize(fmt).
- See struct.__doc__ for more on format strings.
- """
- try:
- o = _cache[fmt]
- except KeyError:
- o = _compile(fmt)
- return o.unpack(s)
-
-def unpack_from(fmt, buf, offset=0):
- """
- Unpack the buffer, containing packed C structure data, according to
- fmt starting at offset. Requires len(buffer[offset:]) >= calcsize(fmt).
- See struct.__doc__ for more on format strings.
- """
- try:
- o = _cache[fmt]
- except KeyError:
- o = _compile(fmt)
- return o.unpack_from(buf, offset)
+from _struct import *