US 10,095,680 B1Granted

Systems and methods for reduced memory usage when processing spreadsheet files

AssigneeServiceNow, Inc.

InventorAzfar Kazmi

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Abstract

A method and associated apparatus provide for accessing contents of a worksheet file comprising a worksheet structure file and a shared strings table file. The method comprises processing the shared strings table file by opening the shared strings table file, and identifying a plurality of shared strings within the opened shared strings table file, and, for each shared string, creating an access record in an access table comprising a shared string identifier, a starting offset into a shared string text file, and a length, and retrieving data for a requested cell by obtaining a requested cell shared string identifier from the worksheet structure file, locating a requested cell access record in the access table, retrieving a requested cell string from the shared string text file at a position indicated by the starting offset and for a length indicated by the record length, and outputting the retrieved string.

Claims18

Dependent claims

An apparatus for accessing contents of a worksheet file, comprising:

a processor;
a non-volatile hardware disk device accessible by the processor and storing the worksheet file;
and
a memory accessible by the processor and comprising a worksheet processing module;
wherein:
the worksheet file comprises:
a worksheet structure file that includes shared string identifiers for one or more cells of the worksheet file;
and
a shared strings table file that contains a plurality of shared strings associated with the one or more cells of the worksheet file;
and
the worksheet processing module comprises instructions that:
process the shared strings table file by executing instructions that:
open the shared strings table file;
write each of the plurality of shared strings of the shared strings table file to an indexed shared string text file on the non-volatile hardware disk device;
and
for each of the plurality of shared strings, create an access record in an access table in memory, wherein each access record comprises:
a shared string identifier, a starting offset into the indexed shared string text file, and a length;
and
retrieve data for a requested cell by executing instructions that:
obtain a requested cell shared string identifier for the requested cell from the worksheet structure file;
locate a requested cell access record in the access table based on the requested cell shared string identifier;
and
retrieve a requested cell string from the indexed shared string text file at a position indicated by the starting offset of the requested cell access record and for the length indicated by the requested cell access record;
and
output the retrieved requested cell string as the data for the requested cell.

22 more elements

A non-transitory computer-readable storage medium, comprising executable instructions that, when executed by a processor, facilitate performance of operations for accessing contents of a worksheet file stored on a non-volatile hardware disk device, wherein the worksheet file comprises:

a worksheet structure file that includes shared string identifiers for one or more cells of the worksheet file;
a shared strings table file that contains a plurality of shared strings associated with the one or more cells of the worksheet file;
and
the operations comprising:
processing the shared strings table file by:
opening the shared strings table file;
writing each of the plurality of shared strings to an indexed shared string text file on the non-volatile hardware disk device;
and
for each of the plurality of shared strings, creating an access record in an access table in a volatile memory, wherein each access record comprises:
a shared string identifier, a starting offset into the indexed shared string text file, and a length;
and
retrieving data for a requested cell by:
obtaining a requested cell shared string identifier from the worksheet structure file for the requested cell;
locating a requested cell access record in the access table based on the requested cell shared string identifier;
retrieving a requested cell string from the indexed shared string text file at a position indicated by the starting offset of the requested cell access record and for the length indicated by the requested cell access record;
and
outputting the retrieved requested cell string as the data for the requested cell.

14 more elements

Dependencies are inferred from the claim text.