cut: make memory allocation independent of range width

The current implementation of cut, uses a bit array,
an array of `struct range_pair's, and (when --output-delimiter
is specified) a hash_table.  The new implementation will use
only an array of `struct range_pair's.
The old implementation is memory inefficient because:
 1. When -b with a big num is specified, it allocates a lot of
    memory for `printable_field'.
 2. When --output-delimiter is specified, it will allocate 31 buckets.
    Even if only a few ranges are specified.

Note CPU overhead is increased to determine if an item is to be printed,
as shown by:

$ yes abcdfeg | head -n1MB > big-file
$ for c in with-bitarray without-bitarray; do
    src/cut-$c 2>/dev/null
    echo -ne "\n== $c =="
    time src/cut-$c -b1,3 big-file > /dev/null
  done

== with-bitarray ==
real    0m0.084s
user    0m0.078s
sys     0m0.006s

== without-bitarray ==
real    0m0.111s
user    0m0.108s
sys     0m0.002s

Subsequent patches will reduce this overhead.

* src/cut.c (set_fields): Set and initialize RP
instead of printable_field.
* src/cut.c (is_range_start_index): Use CURRENT_RP rather than a hash.
* tests/misc/cut.pl: Check if `eol_range_start' is set correctly.
* tests/misc/cut-huge-range.sh: Rename from cut-huge-to-eol-range.sh,
and add a test to verify large amounts of mem aren't allocated.
Fixes http://bugs.gnu.org/13127

1 files changed, 34 insertions, 0 deletions

diff --git a/tests/misc/cut-huge-range.sh b/tests/misc/cut-huge-range.sh
new file mode 100755
index 000000000..8783e96ad
--- /dev/null
+++ b/tests/misc/cut-huge-range.sh
@@ -0,0 +1,34 @@
+#!/bin/sh
+# Ensure that cut does not allocate mem for a range like -b9999999999999-
+
+# Copyright (C) 2012-2013 Free Software Foundation, Inc.
+
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+. "${srcdir=.}/tests/init.sh"; path_prepend_ ./src
+print_ver_ cut
+require_ulimit_v_
+getlimits_
+
+# From coreutils-8.10 through 8.20, this would make cut try to allocate
+# a 256MiB bit vector.  With a 20MB limit on VM, the following would fail.
+(ulimit -v 20000; : | cut -b$INT_MAX- > err 2>&1) || fail=1
+
+# Up to and including coreutils-8.21, cut would allocate possibly needed
+# memory upfront.  Subsequently memory is allocated as required.
+(ulimit -v 20000; : | cut -b1-$INT_MAX > err 2>&1) || fail=1
+
+compare /dev/null err || fail=1
+
+Exit $fail