Merge bitcoin/bitcoin#19690: util: improve FindByte() performance

72efc26439 util: improve streams.h:FindByte() performance (Larry Ruane)
604df63f6c [bench] add streams findbyte (gzhao408)

Pull request description:

  This PR is strictly a performance improvement; there is no functional change. The `CBufferedFile::FindByte()` method searches for the next occurrence of the given byte in the file. Currently, this is done by explicitly inspecting each byte in turn. This PR takes advantage of `std::find()` to do the same more efficiently, improving its CPU runtime by a factor of about 25 in typical use.

ACKs for top commit:
  achow101:
    re-ACK 72efc26439
  stickies-v:
    re-ACK 72efc26439

Tree-SHA512: ddf0bff335cc8aa34f911aa4e0558fa77ce35d963d602e4ab1c63090b4a386faf074548daf06ee829c7f2c760d06eed0125cf4c34e981c6129cea1804eb3b719
This commit is contained in:
Andrew Chow
2023-05-10 17:40:42 -04:00
6 changed files with 50 additions and 8 deletions

View File

@@ -4565,7 +4565,7 @@ void Chainstate::LoadExternalBlockFile(
try {
// locate a header
unsigned char buf[CMessageHeader::MESSAGE_START_SIZE];
blkdat.FindByte(params.MessageStart()[0]);
blkdat.FindByte(std::byte(params.MessageStart()[0]));
nRewind = blkdat.GetPos() + 1;
blkdat >> buf;
if (memcmp(buf, params.MessageStart(), CMessageHeader::MESSAGE_START_SIZE)) {