QSORT - sort an array of things.

Alternate Entry Name: .QSORT

Usage:

B:
   qsort(vec, n, bytes [, compare])

/* C users use the C "qsort" */

Where:

vec

is a pointer to the array to be sorted.

n

is the actual number of items to be sorted.

bytes

is the size of each item in bytes.

compare

is an optional function to compare two elements of "vec". It will be called with "compare(p, q, s)", where:

p

is a byte pointer (upper 20 bits) to an element.

q

is a byte pointer to another element.

s

is a copy of the "bytes" argument to QSORT.

"compare" should return a negative, zero or positive value depending on whether the element pointed to by "p" is less than, equal to or greater than the element pointed to by "q". If "compare" is omitted, QSORT will do a logical byte string compare between elements.

Description:

QSORT is used to sort an array of byte vectors. The array elements can be any number of bytes long, and thus may lie on any byte boundary. Because of this, "compare" is passed C type byte pointers, so it may be necessary to shift these down by 18 bits to use them as B pointers.

Currently, QSORT uses the "Shell sort" algorithm.

See Also:

expl b lib shells

for a routine that just sorts word quantities.

Copyright © 1996, Thinkage Ltd.