Use @scanner << readline instead of @scanner.string = @scanner.rest + readline

[naitoh]

Why

JRuby's StringScanner#<< and StringScanner#scan OutOfMemoryError has been resolved in strscan gem 3.0.9.

ruby/strscan#83

Benchmark

RUBYLIB= BUNDLER_ORIG_RUBYLIB= /Users/naitoh/.rbenv/versions/3.3.0/bin/ruby -v -S benchmark-driver /Users/naitoh/ghq/github.com/naitoh/rexml/benchmark/parse.yaml
ruby 3.3.0 (2023-12-25 revision 5124f9ac75) [arm64-darwin22]
Calculating -------------------------------------
                         before       after  before(YJIT)  after(YJIT)
                 dom     10.958      11.044        16.615       16.783 i/s -     100.000 times in 9.126104s 9.055023s 6.018799s 5.958437s
                 sax     29.624      29.609        44.390       45.370 i/s -     100.000 times in 3.375641s 3.377372s 2.252774s 2.204080s
                pull     33.868      34.695        51.173       53.492 i/s -     100.000 times in 2.952679s 2.882229s 1.954138s 1.869422s
              stream     31.719      32.351        43.604       45.403 i/s -     100.000 times in 3.152713s 3.091052s 2.293356s 2.202514s

Comparison:
                              dom
         after(YJIT):        16.8 i/s
        before(YJIT):        16.6 i/s - 1.01x  slower
               after:        11.0 i/s - 1.52x  slower
              before:        11.0 i/s - 1.53x  slower

                              sax
         after(YJIT):        45.4 i/s
        before(YJIT):        44.4 i/s - 1.02x  slower
              before:        29.6 i/s - 1.53x  slower
               after:        29.6 i/s - 1.53x  slower

                             pull
         after(YJIT):        53.5 i/s
        before(YJIT):        51.2 i/s - 1.05x  slower
               after:        34.7 i/s - 1.54x  slower
              before:        33.9 i/s - 1.58x  slower

                           stream
         after(YJIT):        45.4 i/s
        before(YJIT):        43.6 i/s - 1.04x  slower
               after:        32.4 i/s - 1.40x  slower
              before:        31.7 i/s - 1.43x  slower

• YJIT=ON : 1.01x - 1.05x faster
• YJIT=OFF : 1.00x - 1.02x faster

[kou]

Thanks!