ref: 1018d7a7091fd5e0433f501a3474cdc3fec322cc
dir: /appl/cmd/read.b/
implement Read; include "sys.m"; sys: Sys; include "draw.m"; Read: module { init: fn(nil: ref Draw->Context, argv: list of string); }; usage() { sys->fprint(sys->fildes(2), "usage: read [-[ero] offset] count\n"); raise "fail:usage"; } init(nil: ref Draw->Context, argv: list of string) { sys = load Sys Sys->PATH; # usage: read [-[ero] offset] count count := Sys->ATOMICIO; offset := big 0; seeking := -1; if (argv != nil) argv = tl argv; if (argv != nil && hd argv != nil && (hd argv)[0] == '-') { if (tl argv == nil) usage(); case hd argv { "-o" => seeking = Sys->SEEKSTART; "-e" => seeking = Sys->SEEKEND; "-r" => seeking = Sys->SEEKRELA; * => usage(); } offset = big hd tl argv; argv = tl tl argv; } if (argv != nil) { if (tl argv != nil) usage(); count = int hd argv; } fd := sys->fildes(0); if (seeking != -1) sys->seek(fd, offset, seeking); if (count == 0) return; buf := array[count] of byte; n := sys->read(fd, buf, len buf); if (n > 0) sys->write(sys->fildes(1), buf, n); else { if (n == -1) { sys->fprint(sys->fildes(2), "read: read error: %r\n"); raise "fail:error"; } raise "fail:eof"; } }