Switching circuit implementing variable string matching

A content matching engine comprising:

• a shift register configured to receive and shift a packet in a byte-wise manner, thereby providing a pattern;
• a content addressable memory (CAM) array having a plurality of entries configured to store a corresponding plurality of strings that identify a first rule, wherein each of the entries is coupled to receive the pattern in parallel from the shift register, and assert a match output signal if the string stored in the entry matches the pattern;
• a plurality of entry counters, each being coupled to receive a match output signal from a corresponding entry of the CAM array, and each storing a count value associated with the length of the string stored in the corresponding entry of the CAM array;
• connections between output terminals of a first set of the entry counters and enable terminals of a set of the entries;
• and
• a priority encoder coupled to output terminals of a second set of the entry counters.