PNG
IHDR x sBIT|d pHYs + tEXtSoftware www.inkscape.org< ,tEXtComment
File Manager
File Manager
Viewing File: streaming.py
#
# This file is part of pyasn1 software.
#
# Copyright (c) 2005-2019, Ilya Etingof <etingof@gmail.com>
# License: https://pyasn1.readthedocs.io/en/latest/license.html
#
import io
import os
from pyasn1 import error
from pyasn1.type import univ
class CachingStreamWrapper(io.IOBase):
"""Wrapper around non-seekable streams.
Note that the implementation is tied to the decoder,
not checking for dangerous arguments for the sake
of performance.
The read bytes are kept in an internal cache until
setting _markedPosition which may reset the cache.
"""
def __init__(self, raw):
self._raw = raw
self._cache = io.BytesIO()
self._markedPosition = 0
def peek(self, n):
result = self.read(n)
self._cache.seek(-len(result), os.SEEK_CUR)
return result
def seekable(self):
return True
def seek(self, n=-1, whence=os.SEEK_SET):
# Note that this not safe for seeking forward.
return self._cache.seek(n, whence)
def read(self, n=-1):
read_from_cache = self._cache.read(n)
if n != -1:
n -= len(read_from_cache)
if not n: # 0 bytes left to read
return read_from_cache
read_from_raw = self._raw.read(n)
self._cache.write(read_from_raw)
return read_from_cache + read_from_raw
@property
def markedPosition(self):
"""Position where the currently processed element starts.
This is used for back-tracking in SingleItemDecoder.__call__
and (indefLen)ValueDecoder and should not be used for other purposes.
The client is not supposed to ever seek before this position.
"""
return self._markedPosition
@markedPosition.setter
def markedPosition(self, value):
# By setting the value, we ensure we won't seek back before it.
# `value` should be the same as the current position
# We don't check for this for performance reasons.
self._markedPosition = value
# Whenever we set _marked_position, we know for sure
# that we will not return back, and thus it is
# safe to drop all cached data.
if self._cache.tell() > io.DEFAULT_BUFFER_SIZE:
self._cache = io.BytesIO(self._cache.read())
self._markedPosition = 0
def tell(self):
return self._cache.tell()
def asSeekableStream(substrate):
"""Convert object to seekable byte-stream.
Parameters
----------
substrate: :py:class:`bytes` or :py:class:`io.IOBase` or :py:class:`univ.OctetString`
Returns
-------
: :py:class:`io.IOBase`
Raises
------
: :py:class:`~pyasn1.error.PyAsn1Error`
If the supplied substrate cannot be converted to a seekable stream.
"""
if isinstance(substrate, io.BytesIO):
return substrate
elif isinstance(substrate, bytes):
return io.BytesIO(substrate)
elif isinstance(substrate, univ.OctetString):
return io.BytesIO(substrate.asOctets())
try:
if substrate.seekable(): # Will fail for most invalid types
return substrate
else:
return CachingStreamWrapper(substrate)
except AttributeError:
raise error.UnsupportedSubstrateError(
"Cannot convert " + substrate.__class__.__name__ +
" to a seekable bit stream.")
def isEndOfStream(substrate):
"""Check whether we have reached the end of a stream.
Although it is more effective to read and catch exceptions, this
function
Parameters
----------
substrate: :py:class:`IOBase`
Stream to check
Returns
-------
: :py:class:`bool`
"""
if isinstance(substrate, io.BytesIO):
cp = substrate.tell()
substrate.seek(0, os.SEEK_END)
result = substrate.tell() == cp
substrate.seek(cp, os.SEEK_SET)
yield result
else:
received = substrate.read(1)
if received is None:
yield
if received:
substrate.seek(-1, os.SEEK_CUR)
yield not received
def peekIntoStream(substrate, size=-1):
"""Peek into stream.
Parameters
----------
substrate: :py:class:`IOBase`
Stream to read from.
size: :py:class:`int`
How many bytes to peek (-1 = all available)
Returns
-------
: :py:class:`bytes` or :py:class:`str`
The return type depends on Python major version
"""
if hasattr(substrate, "peek"):
received = substrate.peek(size)
if received is None:
yield
while len(received) < size:
yield
yield received
else:
current_position = substrate.tell()
try:
for chunk in readFromStream(substrate, size):
yield chunk
finally:
substrate.seek(current_position)
def readFromStream(substrate, size=-1, context=None):
"""Read from the stream.
Parameters
----------
substrate: :py:class:`IOBase`
Stream to read from.
Keyword parameters
------------------
size: :py:class:`int`
How many bytes to read (-1 = all available)
context: :py:class:`dict`
Opaque caller context will be attached to exception objects created
by this function.
Yields
------
: :py:class:`bytes` or :py:class:`str` or :py:class:`SubstrateUnderrunError`
Read data or :py:class:`~pyasn1.error.SubstrateUnderrunError`
object if no `size` bytes is readily available in the stream. The
data type depends on Python major version
Raises
------
: :py:class:`~pyasn1.error.EndOfStreamError`
Input stream is exhausted
"""
while True:
# this will block unless stream is non-blocking
received = substrate.read(size)
if received is None: # non-blocking stream can do this
yield error.SubstrateUnderrunError(context=context)
elif not received and size != 0: # end-of-stream
raise error.EndOfStreamError(context=context)
elif len(received) < size:
substrate.seek(-len(received), os.SEEK_CUR)
# behave like a non-blocking stream
yield error.SubstrateUnderrunError(context=context)
else:
break
yield received
b IDATxytVսϓ22 A@IR :hCiZ[v*E:WũZA ^dQeQ @ !jZ'>gsV仿$|?g)&x-E IENT ; @x T.i%-X} SvS5.r/ UHz^_$-W" w)Ɗ/ @Z &IoX P$K} JzX:;` &, ŋui,e6mX
Եr Kb1ԗ) D A D A D A D A D A D A D A D A D A D A D A D A D A D A D A D A D A D A D A D A D A D A D A D A D A D A D A D A D A D A D A D A D A D A D A D A D A D A D A D A D A D A ݀!I*]R;I2$eZ#ORZSrr 6mteffu*((Pu'v{ DIߔ4^pIm '77WEEE;vƎ 4- $]'RI{\I&G :IHJ
DWBB=\WRm
o$K(V 9 ABB.}jѢv `^?IOȅ} ڶmG }T#FJ`5 6$- ھ}FI&v;0(h; Б 38CӧOWf!; A
i:F _m9s&|q%=# wZprrrla
A & P\\СC[A#! { olF}
`E2} MK/vV )i{ 4BffV\|ۭX `b@kɶ@%i$K z5zhmX [IXZ ` 'b%$r5 M4º /l
ԃ ߖ xhʔ)[@=}
K6IM}^ 5k㏷݆z
ΗÿO:gdGBmyT/@+Vɶ纽zl.yit뭷zV 0[Y^>Wsqs}\/@$(T7f.Inݺi R$푔n.~?H))\Z RW'Mo~v
Ov6oԃ xz! S,&xm/yɞԟ?'uaSѽb, 8GלKboi&3 t7Y,)JJ c[nzӳdE&KsZLӄ I ?@ & %ӟ۶mSMMњ0 iؐSZ, |J+N
~,0A 0!5%Q-YQQa 3 }$_vVr f9f?S 8` z D A D A D A D A D A D A D A D A D A dqP,تmMmg 1V?rSI꒟]u|l
RCyEf٢9 jURbztѰ!m5~tGj2DhG*{H9)꒟ר3:(+3\?/;TUݭʴ~S6lڧUJ*i$d(#=Yݺd{,p|3B)) q:vN0Y.jkק6;SɶVzHJJЀ-utѹսk>QUU \~]fFnK?&ߡ5b=z9)^|u_k-[ y%ZNU6 7Mi:]ۦ tk[n
X(e6 Bb."8cۭ|~teuuw|ήI-5"~Uk;ZicEmN/:]M>
cQ^uiƞ??Ң pc# TUU3UakNwA`:Y_V-8.KKfRi tv*
9S6ֿj,ՃNOMߤ]z^fOh|<>@Å5 _/Iu?{SY4hK/2]4%it5q]GGe2%iR|
W&f*^]??vq[LgE_3f}Fxu~}qd-ږFxu~I N >\;͗O֊:̗WJ@ Bh W=y|GgwܷH_NY?)Tdi'?խwhlmQi !SUUsw4kӺe4rfxu-[nHtMFj}H_u~w>)oV}(T'ebʒv3_[+vn @Ȭ\S}ot}w=k HFnxg S 0eޢm~l}uqZfF oZuuEg
`zt~? b;t%>WTkķh[ 2eG8LIWx,^\thrl^Ϊ{=dž<}qV@ ⠨Wy^LF_>0UkD uʫuCs$)I v:IK; 6ֲ4{^6 եm+l 3>݆uM 9u ?>Zc }g~qhKwڭ e FMM~pМuqǿz6Tb@8 @Y|jx](^]gf}M"tG
-w.@ vOqh~/HII` S[l.6nØXL9vU cOoB\xoǤ'T&I ǍQw_wpv[kmO{w~>#=P1Pɞa-we:iǏlHo꒟f9SzH?+shk%Fs:q VhqY `jvO'ρ?PyX3lх]˾uV{ݞ]1,MzYNW~̈́ joYn}ȚF߾mS]F z+EDxm/d{F{-W-4wY듏:??_gPf
^3ecg ҵs8R2מz@TA NGj)}CNi/R~}c:5{! ZHӋӾ6}T] G]7W6^n
9*,YqOZj :P?Q D FL|?-^.Ɵ7}fFhxe2Ps cz1&5\cn[=Vn[ĶE鎀uˌd3GII k;lNmشOuuRVfBE]ۣe Ӷu
:X-[(er4~LHi6:Ѻ@ԅr ST0 trk%$Č0 ez" *z " T/X9|8.C5Feg} C Q%͞ˣJvL/? j^ h & 9xF`њZ( & yF&Iݻfg #W;3^{Wo^4'v V[[K';+mӍִ] AC @ W?1^{එyh +^]fm~iԵ] AB @WTk̏t uR?l.OIHiYyԶ] Aˀ 7c:q}ힽaf6Z~қm(+sK4{^6}T *UUu]n.:kx{:2 _m=sAߤU@? Z-Vކе z왍Nэ{|5 pڶn b
p-@sPg]0G7fy-M{GCF'%{4` =$-Ge\ eU:m+Zt'WjO!OAF @ik&t݆ϥ_
e}=]" Wz_.͜E3leW Fih|t-wZۍ-uw=6 YN {6|} | *={Ѽn.S .z1z jۻTH]흾 D uDvmvK .` V]yY~sI@t?/ϓ. m&[ " +P?MzovVЫG3- G RR[(!!\_,^%?v@ ҵő
m`Y)tem8GM x.))A]Y i`ViW`?^~! S#^+ѽGZj?Vģ 0.))AlzL*]OXrY `DBBLOj{-MH'ii-ϰ ok7^
)쭡b]UXSְmռY|5 *cֽk0B7镹%ڽP# 8nȎq}mJr23_>lE5$iwui+ H~F`IjƵ@q
\ @#qG 0" . 0" l ` . 0! , AQHN6qzkKJ#o;`Xv2>,tێJJ7Z/*A .@fفjMzkg @TvZH3Zxu6Ra'%O?/d Q5x YkU]Rֽkق@ DaS^RSּ5|BeHNN͘p
HvcYcC5:y
#`οb; z2 .!kr}gUWkyZn=f Pvsn3p~;4p˚=ē~NmI] ¾ 0lH[_L hs h_ ғߤc_њe c) g 7VIZ5 yrgk̞W#IjӪv>՞y睝M8[ |]\շ 8M 6%|@P ZڨI-m>=k= 'aiRo-x?>Q. }`Ȏ:Wsmu u >
.@,&;+!!˱tﭧD QwRW\vF\~Q7>sp Yw$%A~;~}6 ¾ g &if_=j,v+U L1(tW ake:@Ș>j$Gq2t7S?vL|]u/ .(0 E 6Mk6hiۺzښOrifޱxm/Gx> Lal%%~{lBsR4* }{0Z/ tNIɚpV ^# Lf:u@k#RSu
=S^ZyuR/.@n&z~B=0eg뺆#,Þ[ B/?H uUf7y
Wy}Bwegל`Wh(||`l`.;Ws?V@" c:iɍL֯PGv6zctM̠':wuW;d=;EveD}9J@ B(0iհ bvP1{\P&G7DIy_$-Q jm~Yrr&]CDv%bh|Yzni _ R ;kg}nJOIIwy uL}{ЌNj}:+3Y?:WJ/N+Rzd=hb;dj͒suݔ@NKMԄ jqzC5 @y°hL m;*5ezᕏ=ep
XL n?מ:r`۵tŤZ|1v`V뽧_csج'ߤ%oTuumk%%%h)uy]Nk[n
'b2 l.=͜E%gf$[c;s:V-͞WߤWh-j7]4=F-X]>ZLSi[Y*We; Zan(Ӈ W|e(HNNP5[=
r4tP
&0< pc# `vTNV
GFqvTi * Tyam$ߏWyE* VJKMTfFw >'$-ؽ.Ho.8c"@ D A D A D A D A D A D A D A D A D A~j*֘, N;Pi3599h=g oض L giJ5փy~}&Zd9 p֚
e:|hL``b/d9 p? fgg+%%hMg Xosج, ΩOl0Zh=x djL mhݻo O [g_l, 8a]٭+ӧ0 $I] c]:粹:Teꢢ"5a^Kgh,&= =՟ ^߶ߢE ܹS J}I%:8
IDAT~,9/ʃ PW'Mo }zNƍ쨓zPb NZ~^z=4mswg;5 Y~SVMR XUյڱRf?s:w
; 6H:º i 5 -maM &O3; 1IKeam Zh͛7+##v+c ~u~ca] GnF'ټL~ PPPbn
v oC 4R,ӟgg %hq} @#M4IÇ Oy^xM Zx
) yO w @HkN˖-Sǎ mb]X@n+i͖ !++K3gd\$mt$^ YfJ \8PRF )77Wא!Cl $i: @@_oG I{$# 8磌ŋ9 1A (Im7 ֭>}ߴJq7ޗt^ -[ԩSj*}%]&'
- ɓ'ꫯVzzvB#; a
7@GxI{jƌ.LÇWBB7 `O"I$ /@R @ eee@۷ >}0 ,ɒ2$53Xs|cS~r pTYYY} k Hc %&k.], @ A D A D A D A D A D A D A D A D A @lT<%''*Lo^={رc5h %$+CnܸQ3fҥK}vUVVs9G
R,_{ xˇ3 o߾;TTTd}馛]uuuG~iԩ@4 bnvmvfϞ /Peeeq}}z a
I~,誫{UWW뮻}_~YƍSMMMYχ ֝waw \ ď cxꩧtEƍկ_?۷5@u ?1kNׯWzz/wy>}zj3 k (ٺu q_Zvf̘:~ AB Q&r| ! %KҥKg Ԟ={<_X-z ! CyFUUz~ AB QIIIjݺW $ UXXDٳZ~ AB QƍecW $<(~<RSSvZujjjԧO ZQu@4 8m&&&jԩg $ ď 1h ͟?_{768@ g
=@ `)))5o6m 3 ) ѣƌJ;wҿUTT /KZR{~a=@ 0o<*狔iFɶ[ˎ ;T]] OX@ ?K.ۈxN p p p p p p p p p p p p p p p p pP fl߾] ,{ｧk۶mڿo5 BTӦMӴiӴ|r D B2e |An!D y'tkΝ[A $***t5'
" !駟oaD nΝ:t֭[gD ШQ0 6qD;@ x M6v( PiizmZ 4ew" @ ̴ixf [~-F ٱc&IZ 2|n!?$ @{[HTɏ #@h Ȏ I# _m (F /6Z3 z'\r, r!;w2Z3j=~G Y 7"I$i I. p_" ? p N` y D D ?: _ G ÿa b7 J ! Bx @0 Bo
cG @`1C [ @0G
@`0C _ u V1 aC X > W ` | `! < S `" <. `# c `? cA C 4
? c p# ~ @0 ?: 0 8& _ M Q1 J h# ? /` 7; I q 7 a w Q A 1 H p
! #< 8/# @1Ul7 =S=K.4Z?E _$i@ ! 1!E 4? ` P_ @B ă 1 0# : " aU,xb F Y1
[n |n
#' v EH:`x b
# v D 4 Y hi.i& EΖv# O H 4IŶ}:Ik h @tZRF # (tXҙzZ ? I3l7 q@õ|ۍ 1,GpuY Ꮿ@ hJv# x xk$
v# 9 5 }_$ c S#=+"K {F*m7`# %H:NRS p6I?sIՖ{Ap$I$I:QRv2$Z @UJ*$]<FO4 IENDB`