Function AppendHeader

src/brpc/redis_command.cpp:53–60

This function is the hotspot of RedisCommandFormatV() when format is short or does not have many %. In a 100K-time call to formating of "GET key1", the time spent on RedisRequest.AddCommand() are ~700ns vs. ~400ns while using snprintf() vs. AppendDecimal() respectively.

// "GET key1", the time spent on RedisRequest.AddCommand() are ~700ns
// vs. ~400ns while using snprintf() vs. AppendDecimal() respectively.
inline void AppendHeader(std::string& buf, char fc, unsigned long value) {
    char header[32];
    header[0] = fc;
    size_t len = AppendDecimal(header + 1, value);
    header[len + 1] = '\r';
    header[len + 2] = '\n';
    buf.append(header, len + 3);
}
inline void AppendHeader(butil::IOBuf& buf, char fc, unsigned long value) {
    char header[32];
    header[0] = fc;