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Description
V119 is an Assembly Language commuter module that supports eight different types of operations depending on the first parameter passed. V119 can be used to
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Data that is not part of the sort string (called satellite data) can be included at the end of the fields to be sorted. The most common example of satellite data is a record key.
Syntax
V119 (FUNCTION_CODE, SORT_FILE, BYS, JUSTS, WORK, FLAG)
16-bit OpenInsight Remarks
V119 can sort strings up to a total string length of 65,533 bytes. If the data to be sorted exceeds this length, V119 can be used to create and merge individual blocks of sort data. The blocks are temporarily stored in an operating system file.
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You can choose any operating system file you wish to hold blocks of data. However, the system function Get.Sort.File( ) can be used to return a unique filename for this purpose. Get.Sort.File( ) uses the environment setting for the sort path, and creates a temporary sort filename that includes the station number.
Parameters
V119 accepts a total of six parameters. The first parameter is a one-letter code that determines what V119 is to do. It is the only parameter that is always required.
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| Function Code | Description | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| D | causes the external sort file to be deleted.
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| E | Indicates an extract operation to return satellite data from the sort array. This is useful when the sort operation has been performed with record keys as satellite data. A list of record keys is then returned.
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| I | Initializes an operating system file that is used to hold sort data temporarily while sorting.
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| L | Indicates a list operation. This operation is similar to the Extract operation. This operation gets the keys back from the merged external sort file in blocks of 32K.
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| M | Indicates a merge operation. This operation is used to fully sort the external sort file after all of the sorted blocks of data have been written to it.
Note: This operation immediately doubles the size of the operating system file. If disk space is tight, this is the most vulnerable operation. | ||||||||||||
| S | Sorts an array of records.
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| V | Denotes a value operation. This operation is like the List operation in that it returns data in 32K blocks from an external sort file after it has been merged. However, the data returned is like that of a sort operation rather than an extract operation.
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| W | Indicates a write operation. This is used to write a block of sort data to the temporary sort file.
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See Also
Example: Sorting by One Column
| Code Block |
|---|
/* Sort by Customer Number (Right Justified), Ascending , then Descending */
declare subroutine V119
/* Customer Number, Region, Customer Name, Total Sales */
Record1 = "42" : @fm : "West" : @fm : "Acme Corporation" : @fm : 5000
Record2 = "1" : @fm : "East" : @fm : "Zeta Corporation" : @fm : 200
Record3 = "3" : @fm : "East" : @fm : "Midland Corporation" : @fm : 3500
Record4 = "2" : @fm : "West" : @fm : "Orland Corporation" : @fm : 300
SortData = Record1 : @rm : Record2 : @rm : Record3 : @rm : Record4 : @rm
/* ascending sort */
Bys = 'A'
Justs = 'R'
V119('S', '', Bys, Justs, SortData, '')
/* descending sort */
Bys = 'D'
V119('S', '', Bys, Justs, SortData, '') |
Example: Sorting by Two Columns
| Code Block |
|---|
/* Sort by Region (Ascending-Left), then Total Sales (Descending-Right) */
declare subroutine V119
/* Region, Total Sales, Customer Number, Customer Name */
Record1 = "West" : @fm : 5000 : @fm : "42" : @fm : "Acme Corporation"
Record2 = "East" : @fm : 200 : @fm : "1" : @fm : "Zeta Corporation"
Record3 = "East" : @fm : 3500 : @fm : "3" : @fm : "Midland Corporation"
Record4 = "West" : @fm : 300 : @fm : "2" : @fm : "Orland Corporation"
SortData = Record1 : @rm : Record2 : @rm : Record3 : @rm : Record4 : @rm
Bys = 'AD'
Justs = 'LR'
V119('S', '', Bys, Justs, SortData, '') |
Example: External Sort Logic
| Code Block |
|---|
/* External sort */
declare subroutine V119 , msg
declare function Get.Sort.File
$insert logical
/* Same data as Sorting by Two Columns Example */
Record1 = "West" : @fm : 5000 : @fm : "42" : @fm : "Acme Corporation"
Record2 = "East" : @fm : 200 : @fm : "1" : @fm : "Zeta Corporation"
Record3 = "East" : @fm : 3500 : @fm : "3" : @fm : "Midland Corporation"
Record4 = "West" : @fm : 300 : @fm : "2" : @fm : "Orland Corporation"
SortData = Record1 : @rm : Record2 : @rm : Record3 : @rm : Record4 : @rm
Bys = 'AD'
Justs = 'LR'
flag = ''
/* get a unique sort file name and initialize it */
SortFile = Get.Sort.File()
V119('I', SortFile, '', '', '', flag)
IF flag else
TEXT = 'Error initializing sort file.'
call msg(@window, TEXT)
return FALSE$
END
/* write the data to SortFile. May be called multiple times
if data > 32K. Need to write in chunks. */
V119('W', SortFile , '', '', SortData, flag)
if flag else
TEXT = 'Error writing to sort file.'
msg(@window, TEXT)
gosub delete_sortfile
return FALSE$
end
/* Use the 'M' argument to sort the external file, after data has been written. */
V119('M', SortFile , Bys , Justs , '', flag)
/* Use the 'L' argument to retrieve a list of sorted keys.
Use the 'E' argument to retrieve the last field, in sorted order.
*/
V119('L', SortFile , Bys , Justs , SortData , flag)
V119('E', SortFile , Bys , Justs , SortData , flag)
/* Don't forget to delete the sort file when done! */
Delete_SortFile:
V119('D', SortFile , '', '', '', flag)
IF FLAG ELSE
TEXT = 'Error deleting sort file ': SORT_FILE
call MSG(@window, TEXT)
END |
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