NAME

readdir - read directory and sort files

SYNOPSIS

include "readdir.m";
readdir := load Readdir Readdir->PATH;

NAME, ATIME, MTIME, SIZE, NONE: con iota;
COMPACT:    con (1<<4);
DESCENDING: con (1<<5);
init:    fn(path: string, sortkey: int): (array of ref Sys->Dir, int);
readall: fn(fd: ref Sys->FD, sortkey: int): (array of ref Sys->Dir, int);
sortdir: fn(a: array of ref Sys->Dir, key: int): (array of ref Sys->Dir, int);

DESCRIPTION

Readdir provides functions to read and sort the contents of a directory. Each function returns its result as a tuple that represents the directory contents as an array of references to Sys->Dir values, one per file (see sys-stat(2) for a description of Dir). The integer element of the tuple is the number of entries returned, or -1 if there was an error reading the directory. Readdir differs from sys-dirread (2) in returning the contents of the whole directory, not just a chunk of it, and in allowing the result to be sorted.

Init is most often used: it reads the contents of the directory path and sorts the resulting array according to sortkey.

The sorting criteria for the returned array are based on sortkey as follows:

NAME

Sort files alphabetically by name.

ATIME

Sort files by access time, most recently accessed first.

MTIME

Sort files by modification time, most recently modified first.

SIZE

Sort files by size, largest file first.

NONE

Files are left in directory order, unsorted.

If the value DESCENDING is or'd into any of the values above, except NONE, the order of sorting is reversed.

The sort used is stable, of particular importance in the presence of duplicate names in a union mount. If the value COMPACT is or'd into any of the values above, including NONE, only the first (outermost) entry with a given name will be returned from reading a union mount, if names are duplicated in the union.

Readall reads file descriptor fd which must be open on a directory, and returns the contents after applying sortkey as described above for init.

Sortdir sorts the array a according to the given key, as defined earlier, except that the COMPACT option has no effect.

SOURCE

/appl/lib/readdir.b

SEE ALSO

sys-dirread(2)

READDIR(2 )

Rev:  Tue Mar 31 02:42:39 GMT 2015