shithub: femtolisp

ref: 14c196a5da48284123d615418c80b6fbc87d7f46
dir: /ios.c/

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#include "flisp.h"
#include "timefuncs.h"

#define MOST_OF(x) ((x) - ((x)>>4))

static char emptystr[] = "";

ios_t *ios_stdin = nil;
ios_t *ios_stdout = nil;
ios_t *ios_stderr = nil;

/* OS-level primitive wrappers */

void *
llt_memrchr(const void *s, int c, size_t n)
{
	const uint8_t *src = (const uint8_t*)s + n;
	uint8_t uc = c;
	while(--src >= (uint8_t*)s)
		if(*src == uc)
			return (void *)src;
	return nil;
}

#if !defined(__plan9__)
static int
_enonfatal(int err)
{
	return err == 0 || err == EAGAIN || err == EINPROGRESS || err == EINTR || err == EWOULDBLOCK;
}
#define SLEEP_TIME 5//ms
#endif

// return error code, #bytes read in *nread
// these wrappers retry operations until success or a fatal error
static int
_os_read(int fd, uint8_t *buf, size_t n, size_t *nread)
{
	ssize_t r;

	while(1){
#if !defined(__plan9__)
		errno = 0;
#endif
		r = read(fd, buf, n);
		if(r > -1){
			*nread = (size_t)r;
			break;
		}
#if defined(__plan9__)
		return r;
#else
		if(!_enonfatal(errno)){
			*nread = 0;
			return errno;
		}
		sleep_ms(SLEEP_TIME);
#endif
	}
	return 0;
}

static int
_os_read_all(int fd, uint8_t *buf, size_t n, size_t *nread)
{
	size_t got;

	*nread = 0;

	while(n > 0){
		int err = _os_read(fd, buf, n, &got);
		n -= got;
		*nread += got;
		buf += got;
		if(err || got == 0)
			return err;
	}
	return 0;
}

static int
_os_write(int fd, const void *buf, size_t n, size_t *nwritten)
{
	ssize_t r;

	while(1){
#if !defined(__plan9__)
		errno = 0;
#endif
		r = write(fd, buf, n);
		if(r > -1){
			*nwritten = (size_t)r;
			break;
		}
#if defined(__plan9__)
		return r;
#else
		if(!_enonfatal(errno)){
			*nwritten = 0;
			return errno;
		}
		sleep_ms(SLEEP_TIME);
#endif
	}
	return 0;
}

static int
_os_write_all(int fd, const uint8_t *buf, size_t n, size_t *nwritten)
{
	size_t wrote;

	*nwritten = 0;
	while(n > 0){
		int err = _os_write(fd, buf, n, &wrote);
		n -= wrote;
		*nwritten += wrote;
		buf += wrote;
		if(err)
			return err;
	}
	return 0;
}


/* internal utility functions */

static uint8_t *
_buf_realloc(ios_t *s, size_t sz)
{
	uint8_t *temp;

	if((s->buf == nil || s->buf == &s->local[0]) && sz <= IOS_INLSIZE){
		/* TODO: if we want to allow shrinking, see if the buffer shrank
		   down to this size, in which case we need to copy. */
		s->buf = &s->local[0];
		s->maxsize = IOS_INLSIZE;
		s->ownbuf = 1;
		return s->buf;
	}

	if(sz <= s->maxsize)
		return s->buf;

	if(s->ownbuf && s->buf != &s->local[0]){
		// if we own the buffer we're free to resize it
		// always allocate 1 bigger in case user wants to add a NUL
		// terminator after taking over the buffer
		temp = MEM_REALLOC(s->buf, sz);
		if(temp == nil)
			return nil;
	}else{
		temp = MEM_ALLOC(sz);
		if(temp == nil)
			return nil;
		s->ownbuf = 1;
		if(s->size > 0)
			memcpy(temp, s->buf, s->size);
	}

	s->buf = temp;
	s->maxsize = sz;
	return s->buf;
}

// write a block of data into the buffer at the current position, resizing
// if necessary. returns # written.
static size_t
_write_grow(ios_t *s, const void *data, size_t n)
{
	size_t amt;
	size_t newsize;

	if(n == 0)
		return 0;

	if(s->bpos + n > s->size){
		if(s->bpos + n > s->maxsize){
			/* TODO: here you might want to add a mechanism for limiting
			   the growth of the stream. */
			newsize = s->maxsize ? s->maxsize * 2 : 8;
			while(s->bpos + n > newsize)
				newsize *= 2;
			if(_buf_realloc(s, newsize) == nil){
				/* no more space; write as much as we can */
				amt = s->maxsize - s->bpos;
				if(amt > 0)
					memcpy(&s->buf[s->bpos], data, amt);
				s->bpos += amt;
				s->size = s->maxsize;
				return amt;
			}
		}
		s->size = s->bpos + n;
	}
	memcpy(s->buf + s->bpos, data, n);
	s->bpos += n;

	return n;
}


/* interface functions, low level */

static size_t
_ios_read(ios_t *s, uint8_t *dest, size_t n, int all)
{
	size_t tot = 0;
	size_t got, avail;

	while(n > 0){
		avail = s->size - s->bpos;

		if(avail > 0){
			size_t ncopy = avail >= n ? n : avail;
			memcpy(dest, s->buf + s->bpos, ncopy);
			s->bpos += ncopy;
			if(ncopy >= n){
				s->state = bst_rd;
				return tot+ncopy;
			}
		}
		if(s->bm == bm_mem || s->fd == -1){
			// can't get any more data
			s->state = bst_rd;
			if(avail == 0)
				s->_eof = 1;
			return avail;
		}

		dest += avail;
		n -= avail;
		tot += avail;

		ios_flush(s);
		s->bpos = s->size = 0;
		s->state = bst_rd;

		s->fpos = -1;
		if(n > MOST_OF(s->maxsize)){
			// doesn't fit comfortably in buffer; go direct
			if(all)
				_os_read_all(s->fd, dest, n, &got);
			else
				_os_read(s->fd, dest, n, &got);
			tot += got;
			if(got == 0)
				s->_eof = 1;
			return tot;
		}else{
			// refill buffer
			if(_os_read(s->fd, s->buf, s->maxsize, &got)){
				s->_eof = 1;
				return tot;
			}
			if(got == 0){
				s->_eof = 1;
				return tot;
			}
			s->size = got;
		}
	}

	return tot;
}

size_t
ios_read(ios_t *s, void *dest, size_t n)
{
	return _ios_read(s, dest, n, 0);
}

size_t
ios_readprep(ios_t *s, size_t n)
{
	if(s->state == bst_wr && s->bm != bm_mem){
		ios_flush(s);
		s->bpos = s->size = 0;
	}
	size_t space = s->size - s->bpos;
	s->state = bst_rd;
	if(space >= n || s->bm == bm_mem || s->fd == -1)
		return space;
	if(s->maxsize < s->bpos+n){
		// it won't fit. grow buffer or move data back.
		if(n <= s->maxsize && space <= ((s->maxsize)>>2)){
			if(space)
				memmove(s->buf, s->buf+s->bpos, space);
			s->size -= s->bpos;
			s->bpos = 0;
		}
		else {
			if(_buf_realloc(s, s->bpos + n) == nil)
				return space;
		}
	}
	size_t got;
	int result = _os_read(s->fd, s->buf+s->size, s->maxsize - s->size, &got);
	if(result)
		return space;
	s->size += got;
	return s->size - s->bpos;
}

static void
_write_update_pos(ios_t *s)
{
	if(s->bpos > s->ndirty)
		s->ndirty = s->bpos;
	if(s->bpos > s->size)
		s->size = s->bpos;
}

size_t
ios_write(ios_t *s, const void *data, size_t n)
{
	if(s->readonly)
		return 0;
	if(n == 0)
		return 0;
	size_t space;
	size_t wrote = 0;

	if(s->state == bst_none)
		s->state = bst_wr;
	if(s->state == bst_rd){
		if(!s->rereadable){
			s->size = 0;
			s->bpos = 0;
		}
		space = s->size - s->bpos;
	}else{
		space = s->maxsize - s->bpos;
	}

	if(s->bm == bm_mem){
		wrote = _write_grow(s, data, n);
	}else if(s->bm == bm_none){
		s->fpos = -1;
		_os_write_all(s->fd, data, n, &wrote);
		return wrote;
	}else if(n <= space){
		if(s->bm == bm_line){
			char *nl;
			if((nl = llt_memrchr(data, '\n', n)) != nil){
				size_t linesz = nl-(char*)data+1;
				s->bm = bm_block;
				wrote += ios_write(s, data, linesz);
				ios_flush(s);
				s->bm = bm_line;
				n -= linesz;
				data = (char*)data + linesz;
			}
		}
		memcpy(s->buf + s->bpos, data, n);
		s->bpos += n;
		wrote += n;
	}else{
		s->state = bst_wr;
		ios_flush(s);
		if(n > MOST_OF(s->maxsize)){
			_os_write_all(s->fd, data, n, &wrote);
			return wrote;
		}
		return ios_write(s, data, n);
	}
	_write_update_pos(s);
	return wrote;
}

off_t
ios_seek(ios_t *s, off_t pos)
{
	s->_eof = 0;
	if(s->bm == bm_mem){
		if((size_t)pos > s->size)
			return -1;
		s->bpos = pos;
	}else{
		ios_flush(s);
		off_t fdpos = lseek(s->fd, pos, SEEK_SET);
		if(fdpos == (off_t)-1)
			return fdpos;
		s->bpos = s->size = 0;
	}
	return 0;
}

off_t
ios_seek_end(ios_t *s)
{
	s->_eof = 1;
	if(s->bm == bm_mem){
		s->bpos = s->size;
	}else{
		ios_flush(s);
		off_t fdpos = lseek(s->fd, 0, SEEK_END);
		if(fdpos == (off_t)-1)
			return fdpos;
		s->bpos = s->size = 0;
	}
	return 0;
}

off_t
ios_skip(ios_t *s, off_t offs)
{
	if(offs != 0){
		if(offs > 0){
			if(offs <= (off_t)(s->size-s->bpos)){
				s->bpos += offs;
				return 0;
			}else if(s->bm == bm_mem){
				// TODO: maybe grow buffer
				return -1;
			}
		}else if(offs < 0){
			if(-offs <= (off_t)s->bpos){
				s->bpos += offs;
				s->_eof = 0;
				return 0;
			}else if(s->bm == bm_mem){
				return -1;
			}
		}
		ios_flush(s);
		if(s->state == bst_wr)
			offs += s->bpos;
		else if(s->state == bst_rd)
			offs -= s->size - s->bpos;
		off_t fdpos = lseek(s->fd, offs, SEEK_CUR);
		if(fdpos == (off_t)-1)
			return fdpos;
		s->bpos = s->size = 0;
		s->_eof = 0;
	}
	return 0;
}

off_t
ios_pos(ios_t *s)
{
	if(s->bm == bm_mem)
		return (off_t)s->bpos;

	off_t fdpos = s->fpos;
	if(fdpos == (off_t)-1){
		fdpos = lseek(s->fd, 0, SEEK_CUR);
		if(fdpos == (off_t)-1)
			return fdpos;
		s->fpos = fdpos;
	}

	if(s->state == bst_wr)
		fdpos += s->bpos;
	else if(s->state == bst_rd)
		fdpos -= s->size - s->bpos;
	return fdpos;
}

size_t
ios_trunc(ios_t *s, size_t size)
{
	if(s->bm == bm_mem){
		if(size == s->size)
			return s->size;
		if(size < s->size){
			if(s->bpos > size)
				s->bpos = size;
		}else if(_buf_realloc(s, size) == nil)
			return s->size;
		s->size = size;
		return size;
	}
	//todo
	return 0;
}

int
ios_eof(ios_t *s)
{
	if(s->bm == bm_mem)
		return s->_eof;
	return s->fd == -1 || s->_eof;
}

int
ios_flush(ios_t *s)
{
	if(s->ndirty == 0 || s->bm == bm_mem || s->buf == nil)
		return 0;
	if(s->fd == -1)
		return -1;

	if(s->state == bst_rd){
		if(lseek(s->fd, -(off_t)s->size, SEEK_CUR) == (off_t)-1){
			// FIXME eh?
		}
	}

	size_t nw, ntowrite = s->ndirty;
	s->fpos = -1;
	int err = _os_write_all(s->fd, s->buf, ntowrite, &nw);
	// todo: try recovering from some kinds of errors (e.g. retry)

	if(s->state == bst_rd){
		if(lseek(s->fd, s->size - nw, SEEK_CUR) == (off_t)-1){
			// FIXME eh?
		}
	}else if(s->state == bst_wr){
		if(s->bpos != nw && lseek(s->fd, (off_t)s->bpos - (off_t)nw, SEEK_CUR) == (off_t)-1){
			// FIXME eh?
		}
		// now preserve the invariant that data to write
		// begins at the beginning of the buffer, and s->size refers
		// to how much valid file data is stored in the buffer.
		if(s->size > s->ndirty){
			size_t delta = s->size - s->ndirty;
			memmove(s->buf, s->buf + s->ndirty, delta);
		}
		s->size -= s->ndirty;
		s->bpos = 0;
	}

	s->ndirty = 0;

	if(err)
		return err;
	if(nw < ntowrite)
		return -1;
	return 0;
}

void
ios_close(ios_t *s)
{
	ios_flush(s);
	if(s->fd != -1 && s->ownfd)
		close(s->fd);
	s->fd = -1;
	if(s->buf != nil && s->ownbuf && s->buf != &s->local[0])
		MEM_FREE(s->buf);
	s->buf = nil;
	s->size = s->maxsize = s->bpos = 0;
	if(s->filename != emptystr){
		MEM_FREE(s->filename);
		s->filename = emptystr;
	}
}

static void
_buf_init(ios_t *s, bufmode_t bm)
{
	s->bm = bm;
	if(s->bm == bm_mem || s->bm == bm_none){
		s->buf = &s->local[0];
		s->maxsize = IOS_INLSIZE;
	}else{
		s->buf = nil;
		_buf_realloc(s, IOS_BUFSIZE);
	}
	s->size = s->bpos = 0;
}

uint8_t *
ios_takebuf(ios_t *s, size_t *psize)
{
	uint8_t *buf;

	ios_flush(s);

	if(s->buf == &s->local[0] || s->buf == nil || (!s->ownbuf && s->size == s->maxsize)){
		buf = MEM_ALLOC(s->size+1);
		if(buf == nil)
			return nil;
		if(s->size)
			memcpy(buf, s->buf, s->size);
	}else if(s->size == s->maxsize){
		buf = MEM_REALLOC(s->buf, s->size + 1);
		if(buf == nil)
			return nil;
	}else{
		buf = s->buf;
	}
	buf[s->size] = '\0';
	*psize = s->size + 1;

	/* empty stream and reinitialize */
	_buf_init(s, s->bm);

	return buf;
}

int
ios_setbuf(ios_t *s, uint8_t *buf, size_t size, int own)
{
	ios_flush(s);
	size_t nvalid;

	nvalid = size < s->size ? size : s->size;
	if(nvalid > 0)
		memcpy(buf, s->buf, nvalid);
	if(s->bpos > nvalid){
		// truncated
		s->bpos = nvalid;
	}
	s->size = nvalid;

	if(s->buf != nil && s->ownbuf && s->buf != &s->local[0])
		MEM_FREE(s->buf);
	s->buf = buf;
	s->maxsize = size;
	s->ownbuf = own;
	return 0;
}

int
ios_bufmode(ios_t *s, bufmode_t mode)
{
	// no fd; can only do mem-only buffering
	if(s->fd == -1 && mode != bm_mem)
		return -1;
	s->bm = mode;
	return 0;
}

void
ios_set_readonly(ios_t *s)
{
	if(s->readonly)
		return;
	ios_flush(s);
	s->state = bst_none;
	s->readonly = 1;
}

static size_t
ios_copy_(ios_t *to, ios_t *from, size_t nbytes, int all)
{
	size_t total = 0, avail;
	if(!ios_eof(from)){
		do{
			avail = ios_readprep(from, IOS_BUFSIZE/2);
			if(avail == 0){
				from->_eof = 1;
				break;
			}
			size_t written, ntowrite;
			ntowrite = (avail <= nbytes || all) ? avail : nbytes;
			written = ios_write(to, from->buf+from->bpos, ntowrite);
			// TODO: should this be +=written instead?
			from->bpos += ntowrite;
			total += written;
			if(!all){
				nbytes -= written;
				if(nbytes == 0)
					break;
			}
			if(written < ntowrite)
				break;
		}while(!ios_eof(from));
	}
	return total;
}

size_t
ios_copy(ios_t *to, ios_t *from, size_t nbytes)
{
	return ios_copy_(to, from, nbytes, 0);
}

size_t
ios_copyall(ios_t *to, ios_t *from)
{
	return ios_copy_(to, from, 0, 1);
}

#define LINE_CHUNK_SIZE 160

size_t
ios_copyuntil(ios_t *to, ios_t *from, uint8_t delim)
{
	size_t total = 0, avail = from->size - from->bpos;
	int first = 1;
	if(!ios_eof(from)){
		do{
			if(avail == 0){
				first = 0;
				avail = ios_readprep(from, LINE_CHUNK_SIZE);
			}
			size_t written;
			uint8_t *pd = memchr(from->buf+from->bpos, delim, avail);
			if(pd == nil){
				written = ios_write(to, from->buf+from->bpos, avail);
				from->bpos += avail;
				total += written;
				avail = 0;
			}else{
				size_t ntowrite = pd - (from->buf+from->bpos) + 1;
				written = ios_write(to, from->buf+from->bpos, ntowrite);
				from->bpos += ntowrite;
				total += written;
				return total;
			}
		}while(!ios_eof(from) && (first || avail >= LINE_CHUNK_SIZE));
	}
	from->_eof = 1;
	return total;
}

static void
_ios_init(ios_t *s)
{
	// put all fields in a sane initial state
	memset(s, 0, sizeof(*s));
	s->bm = bm_block;
	s->state = bst_none;
	s->fpos = -1;
	s->fd = -1;
	s->ownbuf = 1;
	s->lineno = 1;
}

/* stream object initializers. we do no allocation. */

ios_t *
ios_file(ios_t *s, char *fname, int rd, int wr, int creat, int trunc)
{
	int fd;
	if(!(rd || wr)) // must specify read and/or write
		goto open_file_err;
	int flags = wr ? (rd ? O_RDWR : O_WRONLY) : O_RDONLY;
	if(trunc)
		flags |= O_TRUNC;
#if defined(__plan9__)
	fd = creat ? create(fname, flags, 0644) : open(fname, flags);
#else
	if(creat)
		flags |= O_CREAT;
	fd = open(fname, flags, 0644);
#endif
	s = ios_fd(s, fd, 1, 1);
	if(fd < 0)
		goto open_file_err;
	if(!wr)
		s->readonly = 1;
	s->filename = MEM_STRDUP(fname);
	return s;
open_file_err:
	s->fd = -1;
	return nil;
}

ios_t *
ios_mem(ios_t *s, size_t initsize)
{
	_ios_init(s);
	s->bm = bm_mem;
	s->filename = emptystr;
	_buf_realloc(s, initsize);
	return s;
}

ios_t *
ios_str(ios_t *s, char *str)
{
	size_t n = strlen(str);
	if(ios_mem(s, n+1) == nil)
		return nil;
	ios_write(s, str, n+1);
	ios_seek(s, 0);
	return s;
}

ios_t *
ios_static_buffer(ios_t *s, const uint8_t *buf, size_t sz)
{
	ios_mem(s, 0);
	ios_setbuf(s, (uint8_t*)buf, sz, 0);
	s->size = sz;
	ios_set_readonly(s);
	return s;
}

ios_t *
ios_fd(ios_t *s, int fd, int isfile, int own)
{
	_ios_init(s);
	s->fd = fd;
	if(isfile)
		s->rereadable = 1;
	_buf_init(s, bm_block);
	s->ownfd = own;
	if(fd == STDERR_FILENO)
		s->bm = bm_none;
	return s;
}

void
ios_init_stdstreams(void)
{
	ios_stdin = MEM_ALLOC(sizeof(ios_t));
	ios_fd(ios_stdin, STDIN_FILENO, 0, 0);
	ios_stdin->filename = MEM_STRDUP("*stdin*");

	ios_stdout = MEM_ALLOC(sizeof(ios_t));
	ios_fd(ios_stdout, STDOUT_FILENO, 0, 0);
	ios_stdout->bm = bm_line;
	ios_stdout->filename = MEM_STRDUP("*stdout*");

	ios_stderr = MEM_ALLOC(sizeof(ios_t));
	ios_fd(ios_stderr, STDERR_FILENO, 0, 0);
	ios_stderr->bm = bm_none;
	ios_stderr->filename = MEM_STRDUP("*stderr*");
}

/* higher level interface */

int
ios_putc(int c, ios_t *s)
{
	char ch = c;

	if(s->state == bst_wr && s->bpos < s->maxsize && s->bm != bm_none){
		s->buf[s->bpos++] = ch;
		_write_update_pos(s);
		if(s->bm == bm_line && ch == '\n')
			ios_flush(s);
		return 1;
	}
	return ios_write(s, &ch, 1);
}

int
ios_getc(ios_t *s)
{
	uint8_t ch;
	if(s->state == bst_rd && s->bpos < s->size)
		ch = s->buf[s->bpos++];
	else if(s->_eof || ios_read(s, &ch, 1) < 1)
		return IOS_EOF;
	if(ch == '\n'){
		s->lineno++;
		s->colno = 0;
		s->colnowait = 0;
	}else if(s->colnowait > 0){
		s->colnowait--;
	}else{
		s->colno++;
		if(ch & 0x80){
			if((ch & 0xe0) == 0xc0)
				s->colnowait = 1;
			else if((ch & 0xf0) == 0xe0)
				s->colnowait = 2;
			else
				s->colnowait = 3;
		}
	}
	return ch;
}

int
ios_peekc(ios_t *s)
{
	if(s->bpos < s->size)
		return (uint8_t)s->buf[s->bpos];
	if(s->_eof)
		return IOS_EOF;
	size_t n = ios_readprep(s, 1);
	if(n == 0)
		return IOS_EOF;
	return (uint8_t)s->buf[s->bpos];
}

int
ios_wait(ios_t *s, double ws)
{
	if(s->bpos < s->size)
		return 1;
	if(s->_eof)
		return IOS_EOF;
#if defined(__plan9__)
	USED(ws);
	return 1; // FIXME(sigrid): wait for input, but not too much
#else
	struct timeval t, *pt = nil;
	if(ws >= 0){
		t.tv_sec = ws;
		t.tv_usec = (long)((ws - t.tv_sec) * 1000000.0) % 1000000;
		pt = &t;
	}
	fd_set f;
	FD_ZERO(&f);
	FD_SET(s->fd, &f);
	int r;
	while((r = select(s->fd+1, &f, nil, nil, pt)) == EINTR);
	return r && FD_ISSET(s->fd, &f);
#endif
}

int
ios_getutf8(ios_t *s, Rune *r)
{
	int c;
	size_t i;
	char buf[UTFmax];

	for(i = 0; i < sizeof(buf); i++){
		if((c = ios_getc(s)) == IOS_EOF){
			s->_eof = 1;
			return IOS_EOF;
		}
		buf[i] = c;
		if(fullrune(buf, i+1))
			break;
	}
	chartorune(r, buf);
	if(*r == Runeerror)
		return 0;
	if(*r == '\n')
		s->colno = 0;
	else
		s->colno++;
	return 1;
}

int
ios_pututf8(ios_t *s, Rune r)
{
	char buf[UTFmax];
	return ios_write(s, buf, runetochar(buf, &r));
}

void
ios_purge(ios_t *s)
{
	if(s->state == bst_rd)
		s->bpos = s->size;
}

int
ios_vprintf(ios_t *s, const char *format, va_list args)
{
	char buf[256];
	char *str;
	int c;

	/* skip allocations if no buffering needed */
	if(s->bm == bm_none && (s->state == bst_none || s->state == bst_wr))
		return vdprintf(s->fd, format, args);

	if((c = vsnprintf(buf, sizeof(buf), format, args)) < nelem(buf))
		str = buf;
	else if(s->state == bst_none || s->state == bst_wr){
		/* doesn't fit? prefer no allocations */
		ios_flush(s);
		return vdprintf(s->fd, format, args);
	}else{
		str = MEM_ALLOC(c+1);
		c = vsnprintf(str, sizeof(c+1), format, args);
	}
	if(c > 0)
		c = ios_write(s, str, c);
	if(str != buf)
		MEM_FREE(str);

	return c;
}

int
ios_printf(ios_t *s, const char *format, ...)
{
	va_list args;
	int c;

	va_start(args, format);
	c = ios_vprintf(s, format, args);
	va_end(args);
	return c;
}