[Octave-bug-tracker] [bug #53391] Memory overallocation in io package, function xlsread

[anonymous]

URL:
  <http://savannah.gnu.org/bugs/?53391>

                 Summary: Memory overallocation in io package, function
xlsread
                 Project: GNU Octave
            Submitted by: None
            Submitted on: Tue 20 Mar 2018 07:11:09 PM UTC
                Category: Octave Forge Package
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: Performance
                  Status: None
             Assigned to: None
         Originator Name: Peter Giles
        Originator Email: address@hidden
             Open/Closed: Open
         Discussion Lock: Any
                 Release: 4.0.0
        Operating System: Microsoft Windows

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Details:

io package version 2.4.8
module __OCT_xls2oct__.m
line 134 - this is within the code section that is marked with comment "##
2.B. Shared strings"

current code:
ctext = cell (numel (strings));

proposed code:
ctext = cell (numel (strings), 1);

>From an inspection of the code that follows line 134, it appears that the only
part of ctext that is actually used is the first column. The current code
allocates a square matrix of size numel(strings), which allocates a factor of
numel(strings) more memory than required. This causes the code to fail with
out-of-memory error when reading spreadsheets of modest-to-large size. 

I have tried the change noted above, and it works for the examples I have
tried, but it has not been tested extensively.





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