ref: ec5f2d23637dadf6d2893bf6f2f829b070ec3b34
dir: /lib/bio/bio.myr/
use std
pkg bio =
type mode = int
const Rd : mode = 1
const Wr : mode = 2
const Rw : mode = 1 | 2
type file = struct
/* backing fd */
fd : std.fd
mode : mode
lasterr : std.errno
/* read buffer */
rbuf : byte[:]
rstart : std.size
rend : std.size
/* write buffer */
wbuf : byte[:]
wend : std.size
;;
type status(@a) = union
`Eof
`Ok @a
`Err ioerr
;;
type ioerr = union
`Ebadfile
`Ebadbuf
`Ebadfd
`Eioerr
;;
/* creation */
const mkfile : (fd : std.fd, mode : mode -> file#)
const open : (path : byte[:], mode : mode -> std.result(file#, byte[:]))
const dial : (srv : byte[:], mode : mode -> std.result(file#, byte[:]))
const create : (path : byte[:], mode : mode, perm : int -> std.result(file#, byte[:]))
const close : (f : file# -> bool)
const free : (f : file# -> void)
/* basic i/o. Returns sub-buffer when applicable. */
const write : (f : file#, src : byte[:] -> status(std.size))
const read : (f : file#, dst : byte[:] -> status(byte[:]))
const flush : (f : file# -> bool)
/* seeking */
const seek : (f : file#, std.off -> std.result(std.off, ioerr))
/* single unit operations */
const putb : (f : file#, b : byte -> status(std.size))
const putc : (f : file#, c : char -> status(std.size))
const getb : (f : file# -> status(byte))
const getc : (f : file# -> status(char))
/* peeking */
const peekb : (f : file# -> status(byte))
const peekc : (f : file# -> status(char))
/* delimited read; returns freshly allocated buffer. */
const readln : (f : file# -> status(byte[:]))
const readto : (f : file#, delim : byte[:] -> status(byte[:]))
const skipto : (f : file#, delim : byte[:] -> bool)
const skipspace : (f : file# -> bool)
/* formatted i/o */
const put : (f : file#, fmt : byte[:], args : ... -> status(std.size))
/* pkg funcs */
pkglocal const ensureread : (f : file#, n : std.size -> status(std.size))
pkglocal const ensurewrite : (f : file#, n : std.size -> status(std.size))
;;
const Bufsz = 16*std.KiB
const Small = 512
/* Creates a file from an fd, opened in the given mode. */
const mkfile = {fd, mode
var f
f = std.alloc()
f.fd = fd
f.mode = mode
f.lasterr = 0
if mode & Rd != 0
f.rbuf = std.slalloc(Bufsz)
f.rstart = 0
f.rend = 0
;;
if mode & Wr != 0
f.wbuf = std.slalloc(Bufsz)
f.wend = 0
;;
-> f
}
/* Opens a file with mode provided. */
const open = {path, mode
-> sysopen(path, mode, sysmode(mode), 0o777)
}
/*
Creates a file for the provided path, with opened in
the requested mode, with the requested permissions
*/
const create = {path, mode, perm
-> sysopen(path, mode, sysmode(mode) | std.Ocreat | std.Otrunc, perm)
}
/* dial the server, and open a file using the returned fd */
const dial = {srv, mode
match std.dial(srv)
| `std.Ok sock: -> `std.Ok mkfile(sock, mode)
| `std.Fail m: -> `std.Fail m
;;
}
/* map from the bio modes to the unix open modes */
const sysmode = {mode
match mode
| Rd: -> std.Ordonly
| Wr: -> std.Owronly
| Rw: -> std.Ordwr
| _: std.fatal("bio: bad file mode")
;;
-> 0
}
/* open the file, and return it */
const sysopen = {path, mode, openmode, perm
match std.openmode(path, openmode, (perm : int64))
| `std.Ok fd: -> `std.Ok mkfile(fd, mode)
| `std.Fail e: -> `std.Fail "could not open fd"
;;
}
/* closes a file, flushing it to the output fd */
const close = {f
var fd
fd = f.fd
free(f)
-> std.close(fd) == 0
}
const free = {f
flush(f)
if f.mode & Rd != 0
std.slfree(f.rbuf)
;;
if f.mode & Wr != 0
std.slfree(f.wbuf)
;;
std.free(f)
}
/*
writes to as much from `src` as possible to a file,
returning the number of bytes written.
*/
const write = {f, src
std.assert(f.mode & Wr != 0, "File is not in write mode")
/*
Tack small writes onto the buffer end. Big ones
flush the buffer and then go right to kernel.
*/
if src.len <= (f.wbuf.len - f.wend)
std.slcp(f.wbuf[f.wend:f.wend+src.len], src)
f.wend += src.len
-> `Ok src.len
else
flush(f)
-> writebuf(f.fd, src)
;;
}
/*
reads as much into 'dst' as possible, up to the size of 'dst',
returning the number of bytes read.
*/
const read = {f, dst
var count, cap : std.size
var d : byte[:]
/* Clear the error state so we can retry */
if f.lasterr != 0
-> `Err geterr(f)
;;
/*
a zero byte read always succeeds, reading 0 bytes; since
there are an infinite number of zero byte reads you can do
from anywhere in the file, including the end, this is not
an EOF condition.
*/
if dst.len == 0
-> `Ok dst
;;
std.assert(f.mode & Rd != 0, "File is not in read mode")
/*
small reads should try to fill, so we don't have to make a
syscall for every read
*/
cap = f.rend - f.rstart
if dst.len < Small && cap < dst.len
fill(f, dst.len)
;;
/* Read as much as we can from the buffer */
count = std.min(dst.len, f.rend - f.rstart)
std.slcp(dst[:count], f.rbuf[f.rstart:f.rstart+count])
f.rstart += count
/* if we drained the buffer, reset it */
if f.rstart == f.rend
f.rstart = 0
f.rend = 0
;;
/* Read the rest directly from the fd */
d = dst[count:]
while d.len > 0
match std.read(f.fd, d)
| `std.Ok 0:
break
| `std.Ok n:
count += n
d = d[n:]
| `std.Fail err:
if count == 0
-> `Err errtype(err)
else
f.lasterr = err
;;
break
;;
;;
if count == 0
-> `Eof
else
-> `Ok dst[:count]
;;
}
/* flushes f out to the backing fd */
const flush = {f
var ret
ret = true
if f.mode & Wr != 0
match writebuf(f.fd, f.wbuf[:f.wend])
| `Ok n: ret = (n == f.wend)
| _: ret = false
;;
;;
f.wend = 0
-> ret
}
const seek = {f, off
flush(f)
f.rstart = f.rend = 0
match std.seek(f.fd, off, std.Seekset)
| `std.Ok ret: -> `std.Ok ret
| `std.Fail e: -> `std.Fail errtype(e)
;;
}
/* writes a single byte to the output stream */
const putb = {f, b
match ensurewrite(f, 1)
| `Eof: -> `Eof
| `Err e: -> `Err e
| `Ok n:
f.wbuf[f.wend++] = b
-> `Ok 1
;;
}
/* writes a single character to the output stream, encoded in utf8 */
const putc = {f, c
var sz
sz = std.charlen(c)
match ensurewrite(f, sz)
| `Eof: -> `Eof
| `Err e: -> `Err e
| `Ok n:
std.encode(f.wbuf[f.wend:], c)
f.wend += sz
-> `Ok sz
;;
}
/* reads a single byte from the input stream */
const getb = {f
match ensureread(f, 1)
| `Eof: -> `Eof
| `Err e: -> `Err e
| `Ok n:
-> `Ok f.rbuf[f.rstart++]
;;
}
/* reads a single character from the input stream, encoded in utf8 */
const getc = {f
var c
match ensurecodepoint(f)
| `Eof: -> `Eof
| `Err e: -> `Err e
| `Ok n:
c = std.decode(f.rbuf[f.rstart:f.rend])
f.rstart += std.charlen(c)
-> `Ok c
;;
}
/* ensures we have enough to read a single codepoint in the buffer */
const ensurecodepoint : (f : file# -> status(std.size)) = {f
var b
var len
match ensureread(f, 1)
| `Eof: -> `Eof
| `Err e: -> `Err e
| `Ok n:
b = f.rbuf[f.rstart]
if b & 0x80 == 0 /* 0b0xxx_xxxx */
len = 1
elif b & 0xe0 == 0xc0 /* 0b110x_xxxx */
len = 2
elif b & 0xf0 == 0xe0 /* 0b1110_xxxx */
len = 3
elif b & 0xf8 == 0xf0 /* 0b1111_0xxx */
len = 4
else
len = 1 /* invalid unicode char */
;;
-> ensureread(f, len)
;;
}
/*
writes a single integer-like value to the output stream, in
little endian format
*/
generic putle = {f, v : @a::(numeric,integral)
for var i = 0; i < sizeof(@a); i++
putb(f, (v & 0xff : byte))
v >>= 8
;;
-> sizeof(@a)
}
/*
writes a single integer-like value to the output stream, in
big endian format
*/
generic putbe = {f, v : @a::(numeric,integral)
for var i = sizeof(@a); i != 0; i--
putb(f, ((v >> ((i-1)*8)) & 0xff : byte))
;;
-> sizeof(@a)
}
/* peeks a single byte from an input stream */
const peekb = {f
match ensureread(f, 1)
| `Eof: -> `Eof
| `Err e: -> `Err e
| `Ok n:
-> `Ok f.rbuf[f.rstart]
;;
}
/* peeks a single character from a utf8 encoded input stream */
const peekc = {f
match ensurecodepoint(f)
| `Eof: -> `Eof
| `Err e: -> `Err e
| `Ok n:
-> `Ok std.decode(f.rbuf[f.rstart:f.rend])
;;
}
/*
reads up to a single character delimiter. drops the delimiter
from the input stream. EOF always counts as a delimiter.
Eg, with the input "foo,bar\n"
bio.readto(f, ',') -> "foo"
bio.readto(f, ',') -> "bar\n"
*/
const readto = {f, delim
-> readdelim(f, delim, false)
}
/* same as readto, but drops the read data. */
const skipto = {f, delim
match readdelim(f, delim, true)
| `Ok ign: -> true
| `Eof: -> false
| `Err _: -> false
;;
}
const skipspace = {f
while true
match bio.peekc(f)
| `Ok c:
if !std.isspace(c)
break
;;
bio.getc(f)
| `Err e: -> false
| `Eof: break
;;
;;
-> true
}
/* Same as delim, but with special handling for '\n', '\r', and '\r\n' */
const readln = {f
var ret, c
ret = [][:]
while true
/* get at least delimiter count of characters */
match ensureread(f, 1)
| `Ok _:
| `Err e: -> `Err e
| `Eof:
ret = readinto(f, ret, f.rend - f.rstart)
if ret.len > 0
-> `Ok ret
else
-> `Eof
;;
;;
/* scan for delimiter */
for var i = f.rstart; i < f.rend; i++
c = (f.rbuf[i] : char)
if c == '\r' || c == '\n'
ret = readinto(f, ret, i - f.rstart)
f.rstart++
/* if we have '\r', we can get '\r\n'. */
if c == '\r' && unwrapc(peekc(f), -1) == '\n'
f.rstart++
;;
-> `Ok ret
;;
:nextitergetln
;;
ret = readinto(f, ret, f.rend - f.rstart)
;;
std.die("unreachable")
}
const unwrapc = {cc, v
match cc
| `Ok c: -> c
| _: -> v
;;
}
const readdelim = {f, delim, drop
var ret
ret = [][:]
while true
/* get at least delimiter count of characters */
match ensureread(f, 1)
| `Ok _:
| `Err e: -> `Err e
| `Eof:
if !drop
ret = readinto(f, ret, f.rend - f.rstart)
;;
if ret.len > 0
-> `Ok ret
else
-> `Eof
;;
;;
for var i = f.rstart; i < f.rend; i++
if f.rbuf[i] == delim[0]
for var j = 0; j < delim.len; j++
if f.rbuf[i + j] != delim[j]
goto nextiterread
;;
;;
if !drop
ret = readinto(f, ret, i - f.rstart)
;;
f.rstart += delim.len
-> `Ok ret
;;
:nextiterread
;;
if !drop
ret = readinto(f, ret, f.rend - f.rstart)
;;
;;
std.die("unreachable")
}
/*
Same as std.put, but buffered. Returns the number of bytes written.
FIXME: depends on std.fmt() having a flush buffer API. Until then,
we're stuck with a small static buffer.
*/
const put = {f, fmt, args
var sl, ap, n
ap = std.vastart(&args)
sl = std.fmtv(fmt, &ap)
n = write(f, sl)
std.slfree(sl)
-> n
}
/*
reads n bytes from the read buffer onto the heap-allocated slice
provided.
*/
const readinto = {f, buf, n
var ret
std.assert(f.rstart + n <= f.rend, "Reading too much from buffer")
ret = std.sljoin(&buf, f.rbuf[f.rstart:f.rstart + n])
f.rstart += n
-> ret
}
/* makes sure we can bufferedly write at least n bytes */
const ensurewrite = {f, n
std.assert(n < f.wbuf.len, "ensured write capacity > buffer size")
if n > f.wbuf.len - f.wend
match writebuf(f.fd, f.wbuf[:f.wend])
| `Ok len:
f.wend = 0
-> `Ok len
| `Err e: -> `Err e
| `Eof: -> `Eof
;;
;;
-> `Ok n
}
/*
makes sure we have at least n bytes buffered. returns true if we succeed
in buffering n bytes, false if we fail.
*/
const ensureread = {f, n
var held
std.assert(n < f.rbuf.len, "ensured read capacity > buffer size")
held = f.rend - f.rstart
if n > held
match fill(f, n)
| `Eof: -> `Eof
| `Err e: -> `Err e
| `Ok len:
if len >= n
-> `Ok len
else
-> `Eof
;;
;;
else
-> `Ok n
;;
}
/* blats a buffer to an fd */
const writebuf = {fd, src
var count
count = 0
while src.len != 0
match std.write(fd, src)
| `std.Ok 0:
-> `Eof
| `std.Ok n:
count += n
src = src[n:]
| `std.Fail e:
-> `Err errtype(e)
;;
;;
:writedone
-> `Ok count
}
/*
Reads as many bytes as possible from the file into
the read buffer.
*/
const fill = {f, min
var count, cap
count = 0
/* Clear the error state so we can retry */
if f.lasterr != 0
-> `Err geterr(f)
;;
/* if we need to shift the slice down to the start, do it */
cap = f.rend - f.rstart
if min > cap
std.slcp(f.rbuf[:cap], f.rbuf[f.rstart:f.rend])
f.rstart = 0
f.rend = cap
;;
while count < min
/*
If we've already read data, we don't want to
throw it away, so we report a successful short
read, and then error on the next read.
*/
match std.read(f.fd, f.rbuf[f.rend:])
| `std.Ok 0:
break
| `std.Ok n:
count += n
f.rend += n
| `std.Fail e:
if count > 0
f.lasterr = e
else
-> `Err errtype(e)
;;
break
;;
;;
if count == 0
-> `Eof
else
-> `Ok count
;;
}
const geterr = {f
var e
e = f.lasterr
f.lasterr = 0
-> errtype(e)
}
const errtype : (e : std.errno -> ioerr )= {e : std.errno -> ioerr
var errno
errno = (e : std.errno)
if errno == std.Ebadf
-> `Ebadfile
elif errno == std.Einval
-> `Ebadfile
elif errno == std.Efault
-> `Ebadbuf
elif errno == std.Eio
-> `Eioerr
else
-> `Eioerr
;;
}