Calculating cyclic redundancy checks over overlapping windows of streaming data

摘要

To calculate sequential CRCs, a CRC pipeline may be used to calculate the sequential CRCs for a block of data The CRC pipeline includes a plurality of stages, where, in each subsequent stage a CRC calculated from a previous stage is used to calculate an offset CRC. For example, using at least one CRC calculator and CRC shifter, a stage in the pipeline removes an effect of first portion of the data represented by a previously calculated CRC from the CRC and then adds an effect of a second portion of data neighboring the first portion in a received data block to yield an offset CRC. For example, a stage may change CRC(0:63) to CRC(32:95) by removing the effect of bytes 0:31 and adding the effect of bytes 64:95. At each stage, the byte offset may get smaller until all the sequential CRCs have been calculated.

主权项

1. A cyclic redundancy check (CRC) pipeline comprising:
a first stage configured to receive a data block and calculate a first CRC value for a first portion of the data block; and a plurality of subsequent stages configured to calculate a plurality of sequential CRC values representing overlapping portions of the data block, wherein each of the plurality of subsequent stages comprises at least one CRC calculator and CRC shifter configured to modify the first CRC value such that an effect of a sub-portion of the first portion is removed from the first CRC value to yield a temporary CRC value and an effect of a second portion of the data block neighboring the first portion of the data block is added to the temporary CRC value to yield a second, offset CRC value, wherein a data size of the sub-portion and the second portion is the same and defines a predetermined offset value.