MS Win32 .readline() speedup, as discussed on Python-Dev. This is a tricky
variant that never needs to "search from the right".
Also fixed unlikely memory leak in get_line, if string size overflows INTMAX.
Also new std test test_bufio to make sure .readline() works.
diff --git a/Lib/test/test_bufio.py b/Lib/test/test_bufio.py
new file mode 100644
index 0000000..1a820d4
--- /dev/null
+++ b/Lib/test/test_bufio.py
@@ -0,0 +1,60 @@
+from test_support import TestFailed, TESTFN
+
+# Simple test to ensure that optimizations in fileobject.c deliver
+# the expected results. For best testing, run this under a debug-build
+# Python too (to exercise asserts in the C code).
+
+# Repeat string 'pattern' as often as needed to reach total length
+# 'length'. Then call try_one with that string, a string one larger
+# than that, and a string one smaller than that. The main driver
+# feeds this all small sizes and various powers of 2, so we exercise
+# all likely stdio buffer sizes, and "off by one" errors on both
+# sides.
+def drive_one(pattern, length):
+ q, r = divmod(length, len(pattern))
+ teststring = pattern * q + pattern[:r]
+ assert len(teststring) == length
+ try_one(teststring)
+ try_one(teststring + "x")
+ try_one(teststring[:-1])
+
+# Write s + "\n" + s to file, then open it and ensure that successive
+# .readline()s deliver what we wrote.
+def try_one(s):
+ # Since C doesn't guarantee we can write/read arbitrary bytes in text
+ # files, use binary mode.
+ f = open(TESTFN, "wb")
+ # write once with \n and once without
+ f.write(s)
+ f.write("\n")
+ f.write(s)
+ f.close()
+ f = open(TESTFN, "rb")
+ line = f.readline()
+ if line != s + "\n":
+ raise TestFailed("Expected %r got %r" % (s + "\n", line))
+ line = f.readline()
+ if line != s:
+ raise TestFailed("Expected %r got %r" % (s, line))
+ line = f.readline()
+ if line:
+ raise TestFailed("Expected EOF but got %r" % line)
+ f.close()
+
+# A pattern with prime length, to avoid simple relationships with
+# stdio buffer sizes.
+primepat = "1234567890\00\01\02\03\04\05\06\07"
+
+nullpat = "\0" * 1000
+
+try:
+ for size in range(1, 257) + [512, 1000, 1024, 2048, 4096, 8192, 10000,
+ 16384, 32768, 65536, 1000000]:
+ drive_one(primepat, size)
+ drive_one(nullpat, size)
+finally:
+ try:
+ import os
+ os.unlink(TESTFN)
+ except:
+ pass