Re-aligning a compressed data array

Patent metadata

Field	Value
Publication number	US-9252804-B2
Application number	US-201313745556-A
Country	US
Kind code	B2
Filing date	Jan 18, 2013
Priority date	Jan 18, 2013
Publication date	Feb 2, 2016
Grant date	Feb 2, 2016

Abstract

Some embodiments include an apparatus and a computer program product configured to re-align two-dimensional compressed data sets while preserving compression of the data. A set of one or more shifts and a corresponding set of one or more first dimension indices into a two-dimensional compressed data set for re-aligning the two-dimensional compressed data set are determined. Impact of re-aligning upon each vector in the second dimension of the two-dimensional compressed data set is determined while the two-dimensional compressed data set remains compressed. New compressed vectors are created in the second dimension resulting from re-aligning. Compression information is modified for each of the original vectors of the two-dimensional compressed data set that remain after re-aligning based, at least in part, on the new compressed vectors. A re-aligned version of the two-dimensional compressed data set is created with the new compressed vectors, and the remaining original vectors with their modified compression information.

First claim

What is claimed is:

1. A computer program product for re-aligning a compressed two-dimensional data set, the computer program product comprising:
a non-transitory computer readable storage medium having computer usable program code embodied therewith, the computer usable program code comprising a computer usable program code configured to:
determine a maximum shift value of a set of one or more shift values for re-aligning a two-dimensional data set, wherein each of the set of one or more shift values indicates shifts at a specified index into a first dimension of the two-dimensional data set, wherein the two-dimensional data set is compressed along the first dimension;
for each second dimension vector of the two-dimensional data set,
determine whether shifting for each of the set of one or more shift values at the specified index into the first dimension of the second dimension vector results in a different vector than either a previously created vector or the second dimension vector;
if shifting results in the different vector, add the different vector to a re-aligned array;
if shifting does not result in the different vector, incorporate a compressed form of the second dimension vector into the re-aligned data set.

2. The computer program product of claim 1 , wherein each of the vectors comprises an ordered set of values.

3. The computer program product of claim 1 , wherein sequential repeating instances of a set of values are represented with a single vector and compression information that indicates the repeating instances.

4. The computer program product of claim 1 , wherein the different vector indicates no data values or null values at the specified index into the different vector when shifting beyond the two-dimensional data set.

5. The computer program product of claim 1 further comprising computer usable program code configured to write values into a buffer in accordance with the shifting.

6. The computer program product of claim 5 , wherein the computer usable program code configured to write values into the buffer in accordance with the shifting comprises the computer usable program code configured to:
for each of the second dimension vectors of the two-dimensional data set,
for each position of the vector,
write a null value or no data value into a position of the buffer that corresponds to the position of the vector if the position of the vector shifts beyond the two-dimensional data set,
write a value at the position of the vector into the corresponding position of the buffer if the position of the vector is not shifted, and
write a value at the position of a different vector of the two-dimensional data set into the corresponding position of the buffer if the position of the vector is shifted.

7. The computer program product of claim 6 , wherein the computer usable program code configured to add the different vector to the re-aligned array comprises transferring contents of the buffer to the re-aligned array or creating a new vector for the re-aligned array with the contents of the buffer.

8. An apparatus comprising:
a processor; and
a compressed data set re-alignment unit operable to,
determine a set of one or more shifts and a corresponding set of one or more first dimension indices into a two-dimensional compressed data set for re-aligning the two-dimensional compressed data set;
determine impact of re-aligning upon each vector in the second dimension of the two-dimensional compressed data set while the two-dimensional compressed data set remains compressed; and
create new compressed vectors in the second dimension resulting from re-aligning;
modify compression information for each of the original vectors of the two-dimensional compressed data set that remain after re-aligning based, at least in part, on the new compressed vectors; and
create a re-aligned version of the two-dimensional compressed data set with the new compressed vectors, and the remaining original vectors with their modified compression information.

9. The apparatus of claim 8 further comprising a machine-readable storage medium having computer usable program code encoded therein, wherein the computer usable program code embodies the compressed data set re-alignment unit.

Assignees

• IBM

Inventors

• Carney Stuart E

Classifications

• G06F9/30178

  of compressed or encrypted instructions · CPC title

• H03M7/30

  Compression (speech analysis-synthesis for redundancy reduction G10L19/00; for image communication H04N); Expansion; Suppression of unnecessary data, e.g. redundancy reduction · CPC title

• G06F8/4434

  Reducing the memory space required by the program code · CPC title

• H03M7/3059

  Digital compression and data reduction techniques where the original information is represented by a subset or similar information, e.g. lossy compression · CPC title

• H03M7/3068 Primary

  Precoding preceding compression, e.g. Burrows-Wheeler transformation · CPC title