The 'store' package provides efficient binary serialization. There are a couple features that particularly distinguish it from most prior Haskell serialization libraries:
Its primary goal is speed. By default, direct machine
representations are used for things like numeric values (Int
,
Double
, Word32
, etc) and buffers (Text
, ByteString
,
Vector
, etc). This means that much of serialization uses the
equivalent of memcpy
.
We have plans for supporting architecture independent serialization - see #36 and #31. This plan makes little endian the default, so that the most common endianness has no overhead.
Integer
serialized with the integer-simple
flag enabled
are not compatible with those serialized without the flag enabled.Instead of implementing lazy serialization / deserialization
involving multiple input / output buffers, peek
and poke
always
work with a single buffer. This buffer is allocated by asking the
value for its size before encoding. This simplifies the encoding
logic, and allows for highly optimized tight loops.
store
can optimize size computations by knowing when some types
always use the same number of bytes. This allows us to compute the
byte size of a Vector Int32
by just doing length v * 4
.
It also features:
Optimized serialization instances for many types from base, vector, bytestring, text, containers, time, template-haskell, and more.
TH and GHC Generics based generation of Store instances for datatypes.
TH generation of testcases.
Utilities for streaming encoding / decoding of Store encoded
messages, via the store-streaming
package.
Store is best used for communication between trusted processes and local caches. It can certainly be used for other purposes, but the builtin set of instances have some gotchas to be aware of:
Store's builtin instances serialize in a format which depends on machine endianness.
Store's builtin instances trust the data when deserializing. For
example, the deserialization of Vector
will read the vector's
length from the first 8 bytes. It will then allocate enough memory
to store all the elements. Malicious or malformed input could cause
allocation of large amounts of memory. See issue #122.
Serialization may vary based on the version of datatypes. For
example, Text
serialized from text < 2
will not be compatible
with Text
from text >= 2
, because the internal representation
switched from UTF-16 to UTF-8.
store
.