def __init__( self, file, size, cache_size=DEFAULT_CACHE_SIZE,
block_size=DEFAULT_BLOCK_SIZE ):
"""
Create a new `FileCache` wrapping the file-like object `file` that
has total size `size` and caching blocks of size `block_size`.
"""
self.file = file
self.size = size
self.cache_size = cache_size
self.block_size = block_size
# Setup the cache
self.nblocks = ( self.size // self.block_size ) + 1
self.cache = LRUCache( self.cache_size )
# Position in file
self.dirty = True
self.at_eof = False
self.file_pos = 0
self.current_block_index = -1
self.current_block = None
def __init__(self, f, cache=32):
# If cache=None, then everything is allowed to stay in memory,
# this is the default behavior.
self.f = f
M, V, max_size, bin_size, nbins = read_packed(f, ">5I")
assert M == MAGIC
# assert version less than max supported
assert V <= VERSION, "File is version %d but I don't know about anything beyond %d" % (
V, VERSION)
self.max_size = max_size
self.bin_size = bin_size
self.nbins = nbins
self.bins = LRUCache(size=cache)
# Read typecode
if V >= 1:
self.typecode = unpack('c', f.read(1))[0]
else:
self.typecode = 'f'
# Read compression type
if V >= 2:
self.comp_type = f.read(4).strip()
else:
self.comp_type = 'zlib'
self.decompress = comp_types[self.comp_type][1]
# Read default value
s = f.read(calcsize(self.typecode))
a = fromstring(s, self.typecode)
if platform_is_little_endian:
a = a.byteswap()
self.default = a[0]
# Read bin sizes and offsets
self.bin_pos = []
self.bin_sizes = []
for i in range(nbins):
pos, size = read_packed(f, ">2I")
self.bin_pos.append(pos)
self.bin_sizes.append(size)