dt_mer_sort

Daylight v4.9
Release Date: 1 February 2008

Name

dt_mer_sort - initiate a sort

Generic Prototype

dt_mer_sort(dt_Handle, dt_Handle, dt_Integer, dt_Integer, dt_Integer)
=> dt_Integer

C Prototype

#include "dt_merlin.h"

dt_Integer dt_mer_sort(dt_Handle hitlist, dt_Handle column, dt_Integer sortmethod, dt_Integer direction, dt_Integer *status)

FORTRAN Prototype

include 'dt_f_merlin.inc'

integer*4 dt_f_mer_sort(hitlist, column, sortmethod, direction, status)

integer*4 hitlist
integer*4 column
integer*4 sortmethod
integer*4 direction
integer*4 status

Description

Begins a sort task on the server. The rows currently in the hitlist are sorted using the cells from the column 'column'. The data are sorted in ascending or descending order depending on the value of 'direction', which can be DX_SORT_ASCENDING or DX_SORT_DESCENDING.

Several sort methods may be used by the Merlin server, but they all share the following two characteristics:

- Sorting is stable. That is, the relative ordering of two cells will not change if the values of the cells are equal.
- The worst case time to sort is order O(n*log(n)), where n is the length of the hitlist to be sorted. In many cases searching is much faster than this.

The type of sort to be performed is controlled by the value of 'sortmethod', which may take the following values:

DX_SORT_ASC

Performs a straight ASCII sort.

DX_SORT_ANC

ASCII sort, no case. Equivalent to the conversion of all characters to upper case, followed by an ASCII sort.

DX_SORT_ANW

ASCII sort, no whitespace. Equivalent to removal of tab, space, <CR>, <NL> followed by an ASCII sort.

DX_SORT_ANP

ASCII sort, no punctuation. Equivalent to removal of all characters not in the set of [A-Za-z0-9], followed by an ASCII sort.

DX_SORT_ANCP

Combination of no case, no punctuation sort.

DX_SORT_ANCW

Combination of no case, no whitespace sort.

DX_SORT_ANPW

Combination of no punctuation, no whitespace sort.

DX_SORT_ANCPW

Combination of no case, punctuation or whitespace sort.

DX_SORT_AAZ

ASCII sort of characters only. Equivalent to removal of all characters not in the set of [A-Za-z] followed by a no-case ASCII sort.

DX_SORT_NUM

Sort numerically.

DX_SORT_NAB

Sort numerically by absolute value. Ignores sign of the numbers.

DX_SORT_CAS

Sort CAS numbers.

DX_SORT_MFM

Sort by molecular formula. Considers each element/number combination as a single token in the comparison.

DX_SORT_LEN

Sort by length. Short strings are lower than long strings.

Return Value

The status of the sort task is returned in 'status' (see dt_continue(3) for descriptions). If the hitlist is short enough that time-slicing is not required, the value of 'status' will be DX_STATUS_DONE. Otherwise, the status will be DX_STATUS_IN_PROGRESS and dt_continue(3) will be required to finish the task.