Matching circuit and method of controlling matching circuit

A matching circuit, comprising:

• a plurality of pattern circuits each configured to match data against part of a regular expression pattern;
• and
• a signal path in which the pattern circuits are series-connected, and a given-stage pattern circuit supplies to a next-stage pattern circuit the data and a result of matching generated by the given-stage pattern circuit,
• wherein each of the pattern circuits connected to a preceding-stage pattern circuit through the signal path is settable in a first operation mode and in a second operation mode,
• wherein each of the pattern circuits in the first operation mode generates a result of matching which is to be supplied to a next-stage pattern circuit in response to both a result of matching supplied from the preceding-stage pattern circuit and a result obtained by matching the data supplied from the preceding-stage pattern circuit against part of a regular expression pattern, and
• wherein each of the pattern circuits in the second operation mode generates a result of matching which is to be supplied to the next-stage pattern circuit in response to a result obtained by matching the data supplied from the preceding-stage pattern circuit against part of a regular expression pattern, without relying on a result of matching supplied from the preceding-stage pattern circuit.