Allow setting the read buffer size

Author: rhpvorderman

profile_igzipreader.py

@@ -5,6 +5,7 @@
 
 
 def main():
+    igzip.READ_BUFFER_SIZE = 32 * 1024
     with igzip.open(sys.argv[1], mode="rb") as gzip_h:
         while True:
             block = gzip_h.read(32*1024)

src/isal/igzip.py

@@ -39,6 +39,8 @@
 _COMPRESS_LEVEL_TRADEOFF = isal_zlib.ISAL_DEFAULT_COMPRESSION
 _COMPRESS_LEVEL_BEST = isal_zlib.ISAL_BEST_COMPRESSION
 
+READ_BUFFER_SIZE = io.DEFAULT_BUFFER_SIZE
+
 FTEXT, FHCRC, FEXTRA, FNAME, FCOMMENT = 1, 2, 4, 8, 16
 
 try:
@@ -152,7 +154,7 @@ def __init__(self, filename=None, mode=None,
                                                   0)
         if self.mode == gzip.READ:
             raw = _IGzipReader(self.fileobj)
-            self._buffer = io.BufferedReader(raw)
+            self._buffer = io.BufferedReader(raw, buffer_size=READ_BUFFER_SIZE)
 
     def __repr__(self):
         s = repr(self.fileobj)
@@ -273,7 +275,7 @@ def read(self, size=-1):
 
             # Read a chunk of data from the file
             if self._decompressor.needs_input:
-                buf = self._fp.read(io.DEFAULT_BUFFER_SIZE)
+                buf = self._fp.read(READ_BUFFER_SIZE)
                 uncompress = self._decompressor.decompress(buf, size)
             else:
                 uncompress = self._decompressor.decompress(b"", size)
@@ -469,6 +471,8 @@ def main():
     elif not args.compress and args.file is not None:
         out_file = io.open(base, "wb")
 
+    global READ_BUFFER_SIZE
+    READ_BUFFER_SIZE = args.buffer_size
     try:
         while True:
             block = in_file.read(args.buffer_size)