Here is a patch and benchmark script. This required more time than I thought.

Benchmark results:

Unpatched:

5.3     read(1)
0.5     read(10)
0.049   read(100)
0.013   read(1000)
0.009   read(10000)
0.0085  read(100000)
0.0082  read()
5       read1(1)
0.47    read1(10)
0.046   read1(100)
0.012   read1(1000)
0.0089  read1(10000)
0.0084  read1(100000)
0.0082  read1()
0.15    readline()

Patched:

0.73    read(1)
0.082   read(10)
0.015   read(100)
0.0089  read(1000)
0.0082  read(10000)
0.0084  read(100000)
0.0083  read()
0.78    read1(1)
0.087   read1(10)
0.016   read1(100)
0.0089  read1(1000)
0.0082  read1(10000)
0.0082  read1(100000)
0.008   read1()
0.14    readline()