84 lines
2.2 KiB
Python
84 lines
2.2 KiB
Python
from io import BytesIO
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import threading
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import functools
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def synchronized(func):
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@functools.wraps(func)
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def wrapper(self, *args, **kwargs):
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with self.lock:
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return func(self, *args, **kwargs)
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return wrapper
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class StreamCache:
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def __init__(self, maxbytes):
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self.lock = threading.Lock()
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self.bytesio = BytesIO()
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self.writeSeek = 0
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self.readSeek = 0
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self.maxbytes = maxbytes
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self.idle = 0
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@synchronized
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def write(self, bs):
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# print("写:{},{}".format(len(bs),bs), end=' ')
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if self.idle >= self.maxbytes:
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print("缓存区不够用")
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self.bytesio.seek(self.writeSeek)
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if self.writeSeek + len(bs) <= self.maxbytes:
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self.bytesio.write(bs)
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else:
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self.bytesio.write(bs[0:self.maxbytes - self.writeSeek])
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self.bytesio.seek(0)
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self.bytesio.write(bs[self.maxbytes - self.writeSeek:])
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self.idle += len(bs)
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self.writeSeek = self.bytesio.tell()
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if self.writeSeek >= self.maxbytes - 1:
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self.writeSeek = 0
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@synchronized
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def read(self, length, exception_on_overflow = False):
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if self.idle < length:
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return None
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# print("读:{}".format(length), end=' ')
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self.bytesio.seek(self.readSeek)
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if self.readSeek + length <= self.maxbytes:
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bs = self.bytesio.read(length)
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else:
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bs = self.bytesio.read(self.maxbytes - self.readSeek)
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self.bytesio.seek(0)
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bs.append(self.bytesio.read(self.readSeek + length - self.maxbytes))
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self.idle -= length
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self.readSeek = self.bytesio.tell()
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if self.readSeek >= self.maxbytes - 1:
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self.readSeek = 0
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return bs
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@synchronized
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def clear(self):
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self.bytesio = BytesIO()
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self.writeSeek = 0
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self.readSeek = 0
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self.idle = 0
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if __name__ == '__main__':
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streamCache = StreamCache(5)
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streamCache.write(b'\x01\x02')
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streamCache.write(b'\x03\x04\x00')
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print(streamCache.read(2))
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print(streamCache.read(3))
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streamCache.write(b'\x05\x06')
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print(streamCache.read(2))
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print(streamCache.read(2))
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print(streamCache.read(3))
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