initial commit

12 files changed, 1080 insertions, 0 deletions

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..20e1c2d
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,20 @@
+*.class
+*.log
+
+# sbt specific
+dist/*
+target/
+lib_managed/
+src_managed/
+project/boot/
+project/plugins/project/
+
+# Scala-IDE specific
+.scala_dependencies
+.project
+.classpath
+.cache
+
+# Native
+*.o
+*.so
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..01c1b6a
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,19 @@
+TARGET=target
+SCALA_VERSION=2.10
+CLASSPATH=$(TARGET)/scala-$(SCALA_VERSION)/classes
+TARGETDIR=target
+
+all: flow.so
+
+javah: $(CLASSPATH)
+	javah -d src/main/c/ -classpath $(CLASSPATH) com.github.jodersky.flow.NativeSerial
+
+flow.o:
+	gcc -I$(JAVA_HOME)/include -I$(JAVA_HOME)/include/linux -fPIC -c src/main/c/flow.c -o flow.o
+
+flow.so: flow.o
+	gcc -shared -Wl,-soname,libflow.so.1 -o libflow.so $< -lc
+
+clean:
+	rm -f *.o
+	rm -f *.so
diff --git a/build.sbt b/build.sbt
new file mode 100644
index 0000000..0ae0f6f
--- /dev/null
+++ b/build.sbt
@@ -0,0 +1,9 @@
+name := "flow"
+
+scalaVersion := "2.10.1"
+
+fork := true
+
+connectInput in run := true
+
+javaOptions in run += "-Djava.library.path=."
\ No newline at end of file
diff --git a/src/main/c/com_github_jodersky_flow_NativeSerial.h b/src/main/c/com_github_jodersky_flow_NativeSerial.h
new file mode 100644
index 0000000..e89652c
--- /dev/null
+++ b/src/main/c/com_github_jodersky_flow_NativeSerial.h
@@ -0,0 +1,73 @@
+/* DO NOT EDIT THIS FILE - it is machine generated */
+#include <jni.h>
+/* Header for class com_github_jodersky_flow_NativeSerial */
+
+#ifndef _Included_com_github_jodersky_flow_NativeSerial
+#define _Included_com_github_jodersky_flow_NativeSerial
+#ifdef __cplusplus
+extern "C" {
+#endif
+#undef com_github_jodersky_flow_NativeSerial_E_PERMISSION
+#define com_github_jodersky_flow_NativeSerial_E_PERMISSION -1L
+#undef com_github_jodersky_flow_NativeSerial_E_OPEN
+#define com_github_jodersky_flow_NativeSerial_E_OPEN -2L
+#undef com_github_jodersky_flow_NativeSerial_E_BUSY
+#define com_github_jodersky_flow_NativeSerial_E_BUSY -3L
+#undef com_github_jodersky_flow_NativeSerial_E_BAUD
+#define com_github_jodersky_flow_NativeSerial_E_BAUD -4L
+#undef com_github_jodersky_flow_NativeSerial_E_PIPE
+#define com_github_jodersky_flow_NativeSerial_E_PIPE -5L
+#undef com_github_jodersky_flow_NativeSerial_E_MALLOC
+#define com_github_jodersky_flow_NativeSerial_E_MALLOC -6L
+#undef com_github_jodersky_flow_NativeSerial_E_POINTER
+#define com_github_jodersky_flow_NativeSerial_E_POINTER -7L
+#undef com_github_jodersky_flow_NativeSerial_E_POLL
+#define com_github_jodersky_flow_NativeSerial_E_POLL -8L
+#undef com_github_jodersky_flow_NativeSerial_E_IO
+#define com_github_jodersky_flow_NativeSerial_E_IO -9L
+#undef com_github_jodersky_flow_NativeSerial_E_CLOSE
+#define com_github_jodersky_flow_NativeSerial_E_CLOSE -10L
+/*
+ * Class:     com_github_jodersky_flow_NativeSerial
+ * Method:    open
+ * Signature: (Ljava/lang/String;I[J)I
+ */
+JNIEXPORT jint JNICALL Java_com_github_jodersky_flow_NativeSerial_open
+  (JNIEnv *, jclass, jstring, jint, jlongArray);
+
+/*
+ * Class:     com_github_jodersky_flow_NativeSerial
+ * Method:    read
+ * Signature: (J[B)I
+ */
+JNIEXPORT jint JNICALL Java_com_github_jodersky_flow_NativeSerial_read
+  (JNIEnv *, jclass, jlong, jbyteArray);
+
+/*
+ * Class:     com_github_jodersky_flow_NativeSerial
+ * Method:    write
+ * Signature: (J[B)I
+ */
+JNIEXPORT jint JNICALL Java_com_github_jodersky_flow_NativeSerial_write
+  (JNIEnv *, jclass, jlong, jbyteArray);
+
+/*
+ * Class:     com_github_jodersky_flow_NativeSerial
+ * Method:    close
+ * Signature: (J)V
+ */
+JNIEXPORT void JNICALL Java_com_github_jodersky_flow_NativeSerial_close
+  (JNIEnv *, jclass, jlong);
+
+/*
+ * Class:     com_github_jodersky_flow_NativeSerial
+ * Method:    debug
+ * Signature: (Z)V
+ */
+JNIEXPORT void JNICALL Java_com_github_jodersky_flow_NativeSerial_debug
+  (JNIEnv *, jclass, jboolean);
+
+#ifdef __cplusplus
+}
+#endif
+#endif
diff --git a/src/main/c/flow-aio.c b/src/main/c/flow-aio.c
new file mode 100644
index 0000000..86e1747
--- /dev/null
+++ b/src/main/c/flow-aio.c
@@ -0,0 +1,149 @@
+#include <termios.h>
+#include <stdio.h>
+#include <stdbool.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/signal.h>
+#include <sys/types.h>
+#include <sys/file.h>
+#include <errno.h>
+#include <sys/epoll.h>
+#include "com_github_jodersky_flow_NativeSerial.h"
+
+#define BUFSIZE 128
+
+/* return values:
+ * >0 fd
+ * -1 can't get file descriptor
+ * -2 device busy
+ * -3 invalid baudrate
+ * */
+int serial_open(const char* device, int baud) {
+  
+  int fd = open(device, O_RDWR | O_NOCTTY);
+  
+  if (fd < 0) {
+    perror(device);
+    return -1;
+  }
+  
+  if (flock(fd, LOCK_EX | LOCK_NB) < 0) {
+    perror(device);
+    return -2;
+  }
+  
+  speed_t bd;
+  switch (baud) {
+    case 50: bd = B50; break;
+    case 75: bd = B75; break;
+    case 110: bd = B110; break;
+    case 134: bd = B134; break;
+    case 150: bd = B150; break;
+    case 200: bd = B200; break;
+    case 300: bd = B300; break;
+    case 600: bd = B600; break;
+    case 1200: bd = B1200; break;
+    case 1800: bd = B1800; break;
+    case 2400: bd = B2400; break;
+    case 4800: bd = B4800; break;
+    case 9600: bd = B9600; break;
+    case 19200: bd = B19200; break;
+    case 38400: bd = B38400; break;
+    case 57600: bd = B57600; break;
+    case 115200: bd = B115200; break;
+    case 230400: bd = B230400; break;
+    default: puts("invalid baudrate"); return -3; break;
+  }
+  
+  struct aiocb my_aiocb;
+  
+  /* Zero out the aiocb structure (recommended) */
+  bzero( (char *)&my_aiocb, sizeof(struct aiocb) );
+
+  /* Allocate a data buffer for the aiocb request */
+  my_aiocb.aio_buf = malloc(BUFSIZE+1);
+  if (!my_aiocb.aio_buf) perror("malloc");
+
+  /* Initialize the necessary fields in the aiocb */
+  my_aiocb.aio_fildes = fd;
+  my_aiocb.aio_nbytes = BUFSIZE;
+  my_aiocb.aio_offset = 0;
+  
+  /* configure new port settings */
+  struct termios newtio;  
+  newtio.c_cflag &= ~PARENB;
+  newtio.c_cflag &= ~CSTOPB;
+  newtio.c_cflag &= ~CSIZE;
+  newtio.c_cflag |= CS8;
+  // no flow control
+  newtio.c_cflag &= ~CRTSCTS;
+  newtio.c_cflag &= ~HUPCL; // disable hang-up-on-close to avoid reset
+  newtio.c_cflag |= CREAD | CLOCAL; // turn on READ & ignore ctrl lines
+  newtio.c_iflag &= ~(IXON | IXOFF | IXANY); // turn off s/w flow ctrl
+  newtio.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG); // make raw
+  newtio.c_oflag &= ~OPOST; // make raw
+
+  // see: http://unixwiz.net/techtips/termios-vmin-vtime.html
+  newtio.c_cc[VMIN] = 1;
+  newtio.c_cc[VTIME] = 2*10/baud;
+  cfsetspeed(&newtio, bd);
+  
+  /* load new settings to port */
+  tcflush(fd, TCIFLUSH);
+  tcsetattr(fd,TCSANOW,&newtio);
+  
+  int ret = aio_read( &my_aiocb );
+  if (ret < 0) perror("aio_read");
+
+
+  struct aiocb *cblist[1];
+  /* Clear the list. */
+  bzero( (char *)cblist, sizeof(cblist) );
+
+  /* Load one or more references into the list */
+  cblist[0] = &my_aiocb;
+  aio_suspend(cblist, 1, NULL);
+  //while ( aio_error( &my_aiocb ) == EINPROGRESS ) ;
+
+  if ((ret = aio_return(&my_aiocb )) > 0) {
+    /* got ret bytes on the read */
+    puts("yeah, got bytes");
+  } else {
+    puts("hmmmmmm, couldn't read bytes");
+  }
+    
+  return fd;
+}
+
+void serial_close(int fd) {
+  if (flock(fd, LOCK_UN) < 0 ) {
+    perror("");
+  }
+  if (close(fd) < 0 ) {
+    perror("");
+  }
+}
+
+
+// JNI bindings
+// ============
+
+JNIEXPORT jint JNICALL Java_com_github_jodersky_flow_NativeSerial_open
+  (JNIEnv *env, jclass clazz, jstring device, jint baud, jobject reader)
+{
+  const char *dev = (*env)->GetStringUTFChars(env, device, 0);
+  int r = serial_open(dev, baud);
+  (*env)->ReleaseStringUTFChars(env, device, dev);
+  return r;
+}
+
+/*
+ * Class:     com_github_jodersky_flow_NativeSerial
+ * Method:    close
+ * Signature: (I)I
+ */
+JNIEXPORT void JNICALL Java_com_github_jodersky_flow_NativeSerial_close
+  (JNIEnv * env, jclass clazz, jint fd)
+{
+  serial_close(fd);
+}
diff --git a/src/main/c/flow-epoll.c b/src/main/c/flow-epoll.c
new file mode 100644
index 0000000..c9bb728
--- /dev/null
+++ b/src/main/c/flow-epoll.c
@@ -0,0 +1,220 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <errno.h>
+#include <termios.h>
+#include <fcntl.h>
+//#include <sys/signal.h>
+//#include <sys/types.h>
+//#include <sys/file.h>
+#include <sys/epoll.h>
+#include <sys/eventfd.h>
+#include "com_github_jodersky_flow_NativeSerial.h"
+
+//contains file descriptors used in managing a serial port
+struct serial_config {
+  
+  int fd; //serial port
+  int efd; //event
+  int epfd; //file descriptor for epoll
+  
+};
+
+/* return values:
+ * >0 fd
+ * -1 can't get file descriptor
+ * -2 device busy
+ * -3 invalid baudrate
+ * -4 can't open pipe for graceful closing
+ * -5 can't create epoll
+ * -6 can't add event to epoll
+ * */
+int serial_open(const char* device, int baud, struct serial_config** serial) {
+  
+  int fd = open(device, O_RDWR | O_NOCTTY | O_NONBLOCK);
+  
+  if (fd < 0) {
+    perror(device);
+    return -1;
+  }
+  
+  if (flock(fd, LOCK_EX | LOCK_NB) < 0) {
+    perror(device);
+    return -2;
+  }
+  
+  speed_t bd;
+  switch (baud) {
+    case 50: bd = B50; break;
+    case 75: bd = B75; break;
+    case 110: bd = B110; break;
+    case 134: bd = B134; break;
+    case 150: bd = B150; break;
+    case 200: bd = B200; break;
+    case 300: bd = B300; break;
+    case 600: bd = B600; break;
+    case 1200: bd = B1200; break;
+    case 1800: bd = B1800; break;
+    case 2400: bd = B2400; break;
+    case 4800: bd = B4800; break;
+    case 9600: bd = B9600; break;
+    case 19200: bd = B19200; break;
+    case 38400: bd = B38400; break;
+    case 57600: bd = B57600; break;
+    case 115200: bd = B115200; break;
+    case 230400: bd = B230400; break;
+    default: puts("invalid baudrate"); return -3; break;
+  }
+
+  /* configure new port settings */
+  struct termios newtio;  
+  newtio.c_cflag &= ~PARENB;
+  newtio.c_cflag &= ~CSTOPB;
+  newtio.c_cflag &= ~CSIZE;
+  newtio.c_cflag |= CS8;
+  // no flow control
+  newtio.c_cflag &= ~CRTSCTS;
+  newtio.c_cflag &= ~HUPCL; // disable hang-up-on-close to avoid reset
+  newtio.c_cflag |= CREAD | CLOCAL; // turn on READ & ignore ctrl lines
+  newtio.c_iflag &= ~(IXON | IXOFF | IXANY); // turn off s/w flow ctrl
+  newtio.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG); // make raw
+  newtio.c_oflag &= ~OPOST; // make raw
+
+  // see: http://unixwiz.net/techtips/termios-vmin-vtime.html
+  newtio.c_cc[VMIN] = 1;
+  newtio.c_cc[VTIME] = 2*10/baud;
+  cfsetspeed(&newtio, bd);
+  
+  /* load new settings to port */
+  tcflush(fd, TCIFLUSH);
+  tcsetattr(fd,TCSANOW,&newtio);
+  
+  int efd = eventfd(0, EFD_NONBLOCK);
+  
+  int epfd = epoll_create(1);
+  if (epfd < 0) {
+    perror(device);
+    return -5;
+  }
+  
+  struct epoll_event serial_event;
+  serial_event.data.fd = fd;
+  serial_event.events = EPOLLIN;
+  
+  struct epoll_event efd_event = {0};
+  efd_event.data.fd = efd;
+  efd_event.events = EPOLLIN | EPOLLET  | EPOLLONESHOT;
+  
+  
+  if (epoll_ctl(epfd, EPOLL_CTL_ADD, fd, &serial_event) < 0 ||  epoll_ctl(epfd, EPOLL_CTL_ADD, efd, &efd_event) < 0) {
+    perror(device);
+    return -6;
+  }
+  
+  struct serial_config* s = malloc(sizeof(s));
+  s->fd = fd;
+  s->efd = efd;
+  s->epfd = epfd;
+  (*serial) = s;
+  
+  return 0;
+}
+/*
+int serial_pipe() {
+  int p = pipe();
+  if (p < 0) {
+    perror("create pipe");
+  }
+  return p;
+}
+
+int serial_add_epoll(int fd, int pipe) {
+  int epfd = epoll_create(1);
+  
+  struct epoll_event event;
+  event.data.fd = fd;
+  event.events = EPOLLIN;
+  
+  if (epoll_ctl (epfd, EPOLL_CTL_ADD, fd, &event)) {
+    perror (device);
+  }
+  
+  return epfd;
+}
+
+*/
+void serial_close(struct serial_config* serial) {
+  
+  if (serial == NULL) return;
+  
+  //write to pipe to wake up any blocked read thread (self-pipe trick)
+  eventfd_write(serial->efd, 1);
+  
+  close(serial->efd);
+  flock(serial->fd, LOCK_UN);
+  close(serial->fd);
+  close(serial->epfd);
+  
+  free(serial);
+}
+
+int serial_read(struct serial_config* serial) {
+  struct epoll_event events[10];// = malloc (sizeof (struct epoll_event) * 10);
+  int nr_events = epoll_wait(serial->epfd, events, 10, -1);
+  if (nr_events < 0) {
+    perror("read");
+  }
+  
+  int i;
+  for (i = 0; i < nr_events; i++) {
+    //printf ("event=%d on fd=%d\n", events[i].events, events[i].data.fd);
+    
+    if (events[i].data.fd == serial->fd) puts("from serial");
+    else if (events[i].data.fd == serial->efd) puts("from pipe");
+    else puts("from ???");
+  }
+  /*
+  int buffer[256];
+  int x = read(fd, buffer, 255);
+  if (x < 0) {
+    perror("read");
+  }*/
+  return nr_events;
+}
+
+
+// JNI bindings
+// ============
+
+inline struct serial_config* j2s(jlong pointer) {
+  return (struct serial_config*) pointer;
+}
+
+inline jlong s2j(struct serial_config* pointer) {
+  return (jlong) pointer;
+}
+
+JNIEXPORT jlong JNICALL Java_com_github_jodersky_flow_NativeSerial_open
+  (JNIEnv *env, jclass clazz, jstring device, jint baud)
+{
+  const char *dev = (*env)->GetStringUTFChars(env, device, 0);
+  
+  struct serial_config* serial;
+  serial_open(dev, baud, &serial);
+  
+  (*env)->ReleaseStringUTFChars(env, device, dev);
+  
+  return s2j(serial);
+}
+
+JNIEXPORT void JNICALL Java_com_github_jodersky_flow_NativeSerial_close
+  (JNIEnv * env, jclass clazz, jlong serial)
+{
+  serial_close(j2s(serial));
+}
+
+JNIEXPORT jint JNICALL Java_com_github_jodersky_flow_NativeSerial_read
+  (JNIEnv * env, jclass clazz, jlong serial)
+{
+  return serial_read(j2s(serial));
+}
diff --git a/src/main/c/flow-signal.c b/src/main/c/flow-signal.c
new file mode 100644
index 0000000..f3f6e7d
--- /dev/null
+++ b/src/main/c/flow-signal.c
@@ -0,0 +1,153 @@
+#include <termios.h>
+#include <stdio.h>
+#include <stdbool.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/signal.h>
+#include <sys/types.h>
+#include <sys/file.h>
+#include "com_github_jodersky_flow_NativeSerial.h"
+
+
+static JavaVM *jvm = NULL;
+static jobject callback = NULL;
+
+void signal_handler(int signum) {
+  puts("got data");
+  if(jvm == NULL)
+        return ;
+    if(callback == NULL)
+        return ;
+
+    JNIEnv *env = NULL;
+    jint res;
+    res = (*jvm)->AttachCurrentThread(jvm, (void **)&env, NULL);
+    if(res < 0)
+    {
+        fprintf(stderr, "Attach VM Thread failed\n");
+        return ;
+    }
+
+    jclass cls = (*env)->GetObjectClass(env, callback);
+    jmethodID mid = (*env)->GetMethodID(env, cls, "onRead", "()V");
+    (*env)->CallVoidMethod(env, callback, mid);
+    (*jvm)->DetachCurrentThread(jvm);
+}
+
+/* return values:
+ * >0 fd
+ * -1 can't get file descriptor
+ * -2 device busy
+ * -3 invalid baudrate
+ * */
+int serial_open(const char* device, int baud) {
+  
+  int fd = open(device, O_RDWR | O_NOCTTY | O_NONBLOCK);
+  
+  if (fd < 0) {
+    perror(device);
+    return -1;
+  }
+  
+  if (flock(fd, LOCK_EX | LOCK_NB) < 0) {
+    perror(device);
+    return -2;
+  }
+  
+  speed_t bd;
+  switch (baud) {
+    case 50: bd = B50; break;
+    case 75: bd = B75; break;
+    case 110: bd = B110; break;
+    case 134: bd = B134; break;
+    case 150: bd = B150; break;
+    case 200: bd = B200; break;
+    case 300: bd = B300; break;
+    case 600: bd = B600; break;
+    case 1200: bd = B1200; break;
+    case 1800: bd = B1800; break;
+    case 2400: bd = B2400; break;
+    case 4800: bd = B4800; break;
+    case 9600: bd = B9600; break;
+    case 19200: bd = B19200; break;
+    case 38400: bd = B38400; break;
+    case 57600: bd = B57600; break;
+    case 115200: bd = B115200; break;
+    case 230400: bd = B230400; break;
+    default: puts("invalid baudrate"); return -3; break;
+  }
+  
+  struct sigaction saio;
+  saio.sa_handler = signal_handler;
+  sigemptyset(&saio.sa_mask);
+  saio.sa_flags = 0;
+  saio.sa_restorer = NULL;
+  sigaction(SIGIO,&saio,NULL);
+  
+  /* allow the process to receive SIGIO */
+  fcntl(fd, F_SETOWN, getpid());
+  
+  /* send SIGIO whenever input or output becomes available */
+  fcntl(fd, F_SETFL, FASYNC);
+  
+  /* configure new port settings */
+  struct termios newtio;  
+  newtio.c_cflag &= ~PARENB;
+  newtio.c_cflag &= ~CSTOPB;
+  newtio.c_cflag &= ~CSIZE;
+  newtio.c_cflag |= CS8;
+  // no flow control
+  newtio.c_cflag &= ~CRTSCTS;
+  newtio.c_cflag &= ~HUPCL; // disable hang-up-on-close to avoid reset
+  newtio.c_cflag |= CREAD | CLOCAL; // turn on READ & ignore ctrl lines
+  newtio.c_iflag &= ~(IXON | IXOFF | IXANY); // turn off s/w flow ctrl
+  newtio.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG); // make raw
+  newtio.c_oflag &= ~OPOST; // make raw
+
+  // see: http://unixwiz.net/techtips/termios-vmin-vtime.html
+  newtio.c_cc[VMIN] = 1;
+  newtio.c_cc[VTIME] = 2*10/baud;
+  cfsetspeed(&newtio, bd);
+  
+  /* load new settings to port */
+  tcflush(fd, TCIFLUSH);
+  tcsetattr(fd,TCSANOW,&newtio);
+    
+  return fd;
+}
+
+void serial_close(int fd) {
+  if (flock(fd, LOCK_UN) < 0 ) {
+    perror("");
+  }
+  if (close(fd) < 0 ) {
+    perror("");
+  }
+}
+
+
+// JNI bindings
+// ============
+
+JNIEXPORT jint JNICALL Java_com_github_jodersky_flow_NativeSerial_open
+  (JNIEnv *env, jclass clazz, jstring device, jint baud, jobject reader)
+{
+  const char *dev = (*env)->GetStringUTFChars(env, device, 0);
+  int r = serial_open(dev, baud);
+  (*env)->ReleaseStringUTFChars(env, device, dev);
+  (*env)->GetJavaVM(env, &jvm);
+  /* upgrade callback to global ref */
+  callback = (*env)->NewGlobalRef(env, reader);
+  return r;
+}
+
+/*
+ * Class:     com_github_jodersky_flow_NativeSerial
+ * Method:    close
+ * Signature: (I)I
+ */
+JNIEXPORT void JNICALL Java_com_github_jodersky_flow_NativeSerial_close
+  (JNIEnv * env, jclass clazz, jint fd)
+{
+  serial_close(fd);
+}
diff --git a/src/main/c/flow.c b/src/main/c/flow.c
new file mode 100644
index 0000000..3ed66b6
--- /dev/null
+++ b/src/main/c/flow.c
@@ -0,0 +1,292 @@
+/*
+ * Copyright (C) 2013 Jakob Odersky
+ * 
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ * 
+ * * Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above
+ *   copyright notice, this list of conditions and the following disclaimer
+ *   in the documentation and/or other materials provided with the
+ *   distribution.
+ * * Neither the name of the  nor the names of its
+ *   contributors may be used to endorse or promote products derived from
+ *   this software without specific prior written permission.
+ * 
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * 
+ */
+ 
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdbool.h>
+#include <unistd.h>
+#include <errno.h>
+#include <termios.h>
+#include <fcntl.h>
+#include <poll.h>
+#include "com_github_jodersky_flow_NativeSerial.h"
+
+#define E_PERMISSION -1
+#define E_OPEN -2
+#define E_BUSY -3
+#define E_BAUD -4
+#define E_PIPE -5
+#define E_MALLOC -6
+#define E_POINTER -7
+#define E_POLL -8
+#define E_IO -9
+#define E_CLOSE -10
+
+
+static bool debug = false;
+#define DEBUG(f) if (debug) {f;}
+
+//contains file descriptors used in managing a serial port
+struct serial_config {
+  
+  int fd; //serial port
+  int pipe_read; //event
+  int pipe_write; //event
+  
+};
+
+/* return values:
+ * 0 ok
+ * E_PERMISSION don't have permission to open
+ * E_OPEN can't get file descriptor
+ * E_BUSY device busy
+ * E_BAUD invalid baudrate
+ * E_PIPE can't open pipe for graceful closing
+ * E_MALLOC malloc error
+ */
+int serial_open(const char* device, int baud, struct serial_config** serial) {
+  
+  int fd = open(device, O_RDWR | O_NOCTTY | O_NONBLOCK);
+  
+  if (fd < 0) {
+    DEBUG(perror(device));
+    if (errno == EACCES) return E_PERMISSION;
+    else return E_OPEN;
+  }
+  
+  if (flock(fd, LOCK_EX | LOCK_NB) < 0) {
+    DEBUG(perror(device));
+    return E_BUSY;
+  }
+  
+  speed_t bd;
+  switch (baud) {
+    case 50: bd = B50; break;
+    case 75: bd = B75; break;
+    case 110: bd = B110; break;
+    case 134: bd = B134; break;
+    case 150: bd = B150; break;
+    case 200: bd = B200; break;
+    case 300: bd = B300; break;
+    case 600: bd = B600; break;
+    case 1200: bd = B1200; break;
+    case 1800: bd = B1800; break;
+    case 2400: bd = B2400; break;
+    case 4800: bd = B4800; break;
+    case 9600: bd = B9600; break;
+    case 19200: bd = B19200; break;
+    case 38400: bd = B38400; break;
+    case 57600: bd = B57600; break;
+    case 115200: bd = B115200; break;
+    case 230400: bd = B230400; break;
+    default: return E_BAUD; break;
+  }
+
+  /* configure new port settings */
+  struct termios newtio;
+  newtio.c_cflag &= ~(PARENB | CSTOPB | CSIZE | CRTSCTS); // 8N1
+  newtio.c_cflag |= CS8 | CREAD | CLOCAL;
+  newtio.c_iflag &= ~(IXON | IXOFF | IXANY); // turn off s/w flow ctrl
+  newtio.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG); // make raw
+  newtio.c_oflag &= ~OPOST; // make raw
+
+  // see: http://unixwiz.net/techtips/termios-vmin-vtime.html
+  //newtio.c_cc[VMIN] = 1;
+  //newtio.c_cc[VTIME] = 2*10/baud;
+  cfsetspeed(&newtio, bd);
+  
+  /* load new settings to port */
+  tcflush(fd, TCIOFLUSH);
+  tcsetattr(fd,TCSANOW,&newtio);
+  
+  int pipe_fd[2];
+  if (pipe2(pipe_fd, O_NONBLOCK) < 0) {
+    DEBUG(perror(device));
+    return E_PIPE;
+  }
+  
+  struct serial_config* s = malloc(sizeof(s));
+  if (s == NULL) {
+    return E_MALLOC;
+  }
+  
+  s->fd = fd;
+  s->pipe_read = pipe_fd[0];
+  s->pipe_write = pipe_fd[1];
+  (*serial) = s;
+  
+  return 0;
+}
+
+void serial_close(struct serial_config* serial) {
+  
+  if (serial == NULL) return;
+  
+  int data = 0xffffffff;
+  
+  //write to pipe to wake up any blocked read thread (self-pipe trick)
+  write(serial->pipe_write, &data, 1);
+  
+  close(serial->pipe_write);
+  close(serial->pipe_read);
+  
+  flock(serial->fd, LOCK_UN);
+  close(serial->fd);
+  
+  free(serial);
+}
+
+/* return
+ * >0 number of bytes read
+ * E_POINTER invalid serial pointer
+ * E_POLL poll error
+ * E_IO read error
+ * E_CLOSE close request
+ */
+int serial_read(struct serial_config* serial, unsigned char * buffer, size_t size) {
+  if (serial == NULL) {
+    return E_POINTER;
+  }
+  
+  struct pollfd sp; //serial poll
+  sp.fd = serial->fd;
+  sp.events = POLLIN;
+  
+  struct pollfd pp; //pipe poll
+  pp.fd = serial->pipe_read;
+  pp.events = POLLIN;
+  
+  struct pollfd poll_list[] = {sp, pp};
+  
+  int n = poll(poll_list,(unsigned long)3,-1);
+  if (n < 0) {
+    DEBUG(perror("read"));
+    return E_IO;
+  }
+  
+  if (sp.revents & POLLIN != 0) {
+    int r = read(sp.fd, buffer, size);
+    
+    //treat 0 bytes read as an error to avoid problems on disconnect
+    //anyway, after a poll there should be more than 0 bytes available to read
+    if (r <= 0) { 
+      if (r < 0) DEBUG(perror("read"));
+      return E_IO;
+    }
+    return r;
+  } else {
+    return E_CLOSE;
+  }
+}
+
+/*return
+ * >0 number of bytes written
+ * E_POINTER invalid serial config (null pointer)
+ * E_IO write error
+ */
+int serial_write(struct serial_config* serial, unsigned char* data, size_t size) {
+  if (serial == NULL) return E_POINTER;
+  
+  int r = write(serial->fd, data, size);
+  if (r < 0) {
+    DEBUG(perror("write"));
+    return E_IO;
+  }
+  return r;
+}
+
+
+
+// JNI bindings
+// ============
+
+inline struct serial_config* j2s(jlong pointer) {
+  return (struct serial_config*) pointer;
+}
+
+inline jlong s2j(struct serial_config* pointer) {
+  return (jlong) pointer;
+}
+
+JNIEXPORT jint JNICALL Java_com_github_jodersky_flow_NativeSerial_open
+  (JNIEnv *env, jclass clazz, jstring device, jint baud, jlongArray jserialp)
+{ 
+  const char *dev = (*env)->GetStringUTFChars(env, device, 0);
+  struct serial_config* serial;
+  int r = serial_open(dev, baud, &serial);
+  (*env)->ReleaseStringUTFChars(env, device, dev);
+  
+  long serialp = s2j(serial);
+  (*env)->SetLongArrayRegion(env, jserialp, 0, 1, &serialp);
+  
+  return r;
+}
+
+JNIEXPORT void JNICALL Java_com_github_jodersky_flow_NativeSerial_close
+  (JNIEnv * env, jclass clazz, jlong serial)
+{
+  serial_close(j2s(serial));
+}
+
+JNIEXPORT jint JNICALL Java_com_github_jodersky_flow_NativeSerial_read
+  (JNIEnv * env, jclass clazz, jlong serial, jbyteArray jbuffer)
+{
+  
+  jsize size = (*env)->GetArrayLength(env, jbuffer);
+  
+  unsigned char buffer[size];
+  int n = serial_read(j2s(serial), buffer, size);
+  if (n < 0) {
+    return n;
+  }
+  
+  (*env)->SetByteArrayRegion(env, jbuffer, 0, n, (signed char *) buffer);
+  return n;
+}
+
+JNIEXPORT jint JNICALL Java_com_github_jodersky_flow_NativeSerial_write
+  (JNIEnv * env, jclass clazz, jlong serial, jbyteArray jbuffer)
+{
+  unsigned char * buffer = (*env)->GetByteArrayElements(env, jbuffer, NULL);
+  int size = (*env)->GetArrayLength(env, jbuffer);
+  int r = serial_write(j2s(serial), buffer, size);
+  
+  (*env)->ReleaseByteArrayElements(env, jbuffer, buffer, JNI_ABORT);
+  
+  return r;
+}
+
+JNIEXPORT void JNICALL Java_com_github_jodersky_flow_NativeSerial_debug
+  (JNIEnv *env, jclass clazz, jboolean value)
+{
+  debug = (bool) value;
+}
+
diff --git a/src/main/java/com/github/jodersky/flow/NativeSerial.java b/src/main/java/com/github/jodersky/flow/NativeSerial.java
new file mode 100644
index 0000000..10a82c9
--- /dev/null
+++ b/src/main/java/com/github/jodersky/flow/NativeSerial.java
@@ -0,0 +1,49 @@
+package com.github.jodersky.flow;
+
+public class NativeSerial {
+	
+	static {
+		System.loadLibrary("flow");
+	}
+	
+	final static int E_PERMISSION = -1;
+	final static int E_OPEN = -2;
+	final static int E_BUSY = -3;
+	final static int E_BAUD = -4;
+	final static int E_PIPE = -5;
+	final static int E_MALLOC = -6;
+	final static int E_POINTER = -7;
+	final static int E_POLL = -8;
+	final static int E_IO = -9;
+	final static int E_CLOSE = -10;
+	
+
+	/* return values:
+	 * 0 ok
+	 * E_PERMISSION don't have permission to open
+	 * E_OPEN can't get file descriptor
+	 * E_BUSY device busy
+	 * E_BAUD invalid baudrate
+	 * E_PIPE can't open pipe for graceful closing
+	 * E_MALLOC malloc error */
+	native static int open(String device, int baud, long[] serial);
+	
+	/* return
+	 * >0 number of bytes read
+	 * E_POINTER invalid serial pointer
+	 * E_POLL poll error
+	 * E_IO read error
+	 * E_CLOSE close request */
+	native static int read(long serial, byte[] buffer);
+	
+	/*return
+	 * >0 number of bytes written
+	 * E_POINTER invalid serial config (null pointer)
+	 * E_IO write error */
+	native static int write(long serial, byte[] buffer);
+	
+	native static void close(long serial);
+	
+	native static void debug(boolean value);
+
+}
diff --git a/src/main/scala/com/github/jodersky/flow/Main.scala b/src/main/scala/com/github/jodersky/flow/Main.scala
new file mode 100644
index 0000000..feea51b
--- /dev/null
+++ b/src/main/scala/com/github/jodersky/flow/Main.scala
@@ -0,0 +1,26 @@
+package com.github.jodersky.flow
+
+import scala.concurrent._
+import scala.concurrent.ExecutionContext.Implicits.global
+
+object Main {
+
+  def main(args: Array[String]): Unit = {
+    println("opening")
+    
+    Serial.debug(true)
+    val s = Serial.open("/dev/ttyACM0", 115200){ data =>
+      println(data.mkString("[",",","]"))
+    }
+    println("press enter to write a loooooooooong array of data")
+    Console.readLine()
+    
+    val data: Array[Byte] = Array.fill(1000000)(42)
+    s.write(data).map(d => println("sent: " + d.mkString("[",",","]"))).recover{case t => println("write error")}
+    
+    println("press enter to exit")
+    Console.readLine()
+    println("exiting")
+    Console.flush()
+  }
+}
\ No newline at end of file
diff --git a/src/main/scala/com/github/jodersky/flow/Serial.scala b/src/main/scala/com/github/jodersky/flow/Serial.scala
new file mode 100644
index 0000000..7565cbd
--- /dev/null
+++ b/src/main/scala/com/github/jodersky/flow/Serial.scala
@@ -0,0 +1,63 @@
+package com.github.jodersky.flow
+
+import scala.concurrent._
+import scala.concurrent.ExecutionContext.Implicits._
+import java.io.IOException
+
+class Serial private (val port: String, private val pointer: Long, reader: Array[Byte] => Unit) {
+  future {
+    var n = 0
+    val buffer = new Array[Byte](100)
+    while (n >= 0) {
+      n = NativeSerial.read(pointer, buffer)
+      import NativeSerial._
+      n match {
+          case E_POINTER => throw new NullPointerException("pointer to native serial")
+          case E_POLL => throw new IOException(port + ": polling")
+          case E_IO => throw new IOException(port + ": reading")
+          case E_CLOSE => println("close request")
+          case x if x > 0 => reader(buffer.take(n))
+      }
+    }
+  }
+
+  private def writeBlock(data: Array[Byte]) = synchronized {
+    import NativeSerial._
+    NativeSerial.write(pointer, data) match {
+      case E_POINTER => throw new NullPointerException("pointer to native serial")
+      case E_IO => throw new IOException(port + ": writing")
+      case r => data.take(r) 
+    }
+  }
+  
+  def write(data: Array[Byte]) = future { writeBlock(data) }
+
+  def close() = synchronized {
+    NativeSerial.close(pointer)
+  }
+
+}
+
+object Serial {
+
+  def open(port: String, baud: Int)(reader: Array[Byte] => Unit) = synchronized {
+    val pointer = new Array[Long](1)
+    val result = NativeSerial.open(port, baud, pointer)
+
+    import NativeSerial._
+    result match {
+      case E_PERMISSION => throw new AccessDeniedException(port)
+      case E_OPEN => throw new NoSuchPortException(port)
+      case E_BUSY => throw new PortInUseException(port)
+      case E_BAUD => throw new IllegalArgumentException(
+        s"invalid baudrate ${baud}, use standard unix values")
+      case E_PIPE => throw new IOException("cannot create pipe")
+      case E_MALLOC => throw new IOException("cannot allocate memory")
+      case 0 => new Serial(port, pointer(0), reader)
+      case _ => throw new Exception("cannot open port")
+    }
+  }
+  
+  def debug(value: Boolean) = NativeSerial.debug(value)
+
+}
\ No newline at end of file
diff --git a/src/main/scala/com/github/jodersky/flow/exceptions.scala b/src/main/scala/com/github/jodersky/flow/exceptions.scala
new file mode 100644
index 0000000..a360079
--- /dev/null
+++ b/src/main/scala/com/github/jodersky/flow/exceptions.scala
@@ -0,0 +1,7 @@
+package com.github.jodersky.flow
+
+import java.io.IOException
+
+class NoSuchPortException(message: String) extends IOException(message)
+class PortInUseException(message: String) extends IOException(message)
+class AccessDeniedException(message: String) extends IOException(message)
\ No newline at end of file