diff --git a/contrib/android/Android.mk b/contrib/android/Android.mk
index 61961a0..d2d8cd1 100644
--- a/contrib/android/Android.mk
+++ b/contrib/android/Android.mk
@@ -36,6 +36,7 @@ LOCAL_SRC_FILES := \
src/diverite_nitekq_parser.c \
src/divesystem_idive.c \
src/divesystem_idive_parser.c \
+ src/hdlc.c \
src/hw_frog.c \
src/hw_ostc3.c \
src/hw_ostc.c \
diff --git a/contrib/msvc/libdivecomputer.vcxproj b/contrib/msvc/libdivecomputer.vcxproj
index 406c577..6497705 100644
--- a/contrib/msvc/libdivecomputer.vcxproj
+++ b/contrib/msvc/libdivecomputer.vcxproj
@@ -204,6 +204,7 @@
+
@@ -331,6 +332,7 @@
+
diff --git a/src/Makefile.am b/src/Makefile.am
index 9234ba7..1b37d9c 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -80,6 +80,7 @@ libdivecomputer_la_SOURCES = \
deepblu_cosmiq.h deepblu_cosmiq.c deepblu_cosmiq_parser.c \
oceans_s1_common.h oceans_s1_common.c \
oceans_s1.h oceans_s1.c oceans_s1_parser.c \
+ hdlc.h hdlc.c \
socket.h socket.c \
irda.c \
usb.c \
diff --git a/src/hdlc.c b/src/hdlc.c
new file mode 100644
index 0000000..40e1ae7
--- /dev/null
+++ b/src/hdlc.c
@@ -0,0 +1,406 @@
+/*
+ * libdivecomputer
+ *
+ * Copyright (C) 2023 Jef Driesen
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301 USA
+ */
+
+#include // malloc, free
+
+#include "hdlc.h"
+
+#include "iostream-private.h"
+#include "common-private.h"
+#include "context-private.h"
+
+#define END 0x7E
+#define ESC 0x7D
+#define ESC_BIT 0x20
+
+static dc_status_t dc_hdlc_set_timeout (dc_iostream_t *abstract, int timeout);
+static dc_status_t dc_hdlc_set_break (dc_iostream_t *abstract, unsigned int value);
+static dc_status_t dc_hdlc_set_dtr (dc_iostream_t *abstract, unsigned int value);
+static dc_status_t dc_hdlc_set_rts (dc_iostream_t *abstract, unsigned int value);
+static dc_status_t dc_hdlc_get_lines (dc_iostream_t *abstract, unsigned int *value);
+static dc_status_t dc_hdlc_configure (dc_iostream_t *abstract, unsigned int baudrate, unsigned int databits, dc_parity_t parity, dc_stopbits_t stopbits, dc_flowcontrol_t flowcontrol);
+static dc_status_t dc_hdlc_poll (dc_iostream_t *abstract, int timeout);
+static dc_status_t dc_hdlc_read (dc_iostream_t *abstract, void *data, size_t size, size_t *actual);
+static dc_status_t dc_hdlc_write (dc_iostream_t *abstract, const void *data, size_t size, size_t *actual);
+static dc_status_t dc_hdlc_ioctl (dc_iostream_t *abstract, unsigned int request, void *data, size_t size);
+static dc_status_t dc_hdlc_flush (dc_iostream_t *abstract);
+static dc_status_t dc_hdlc_purge (dc_iostream_t *abstract, dc_direction_t direction);
+static dc_status_t dc_hdlc_sleep (dc_iostream_t *abstract, unsigned int milliseconds);
+static dc_status_t dc_hdlc_close (dc_iostream_t *abstract);
+
+typedef struct dc_hdlc_t {
+ /* Base class. */
+ dc_iostream_t base;
+ /* Internal state. */
+ dc_context_t *context;
+ dc_iostream_t *iostream;
+ unsigned char *rbuf;
+ unsigned char *wbuf;
+ size_t rbuf_size;
+ size_t rbuf_offset;
+ size_t rbuf_available;
+ size_t wbuf_size;
+ size_t wbuf_offset;
+} dc_hdlc_t;
+
+static const dc_iostream_vtable_t dc_hdlc_vtable = {
+ sizeof(dc_hdlc_t),
+ dc_hdlc_set_timeout, /* set_timeout */
+ dc_hdlc_set_break, /* set_break */
+ dc_hdlc_set_dtr, /* set_dtr */
+ dc_hdlc_set_rts, /* set_rts */
+ dc_hdlc_get_lines, /* get_lines */
+ NULL, /* get_available */
+ dc_hdlc_configure, /* configure */
+ dc_hdlc_poll, /* poll */
+ dc_hdlc_read, /* read */
+ dc_hdlc_write, /* write */
+ dc_hdlc_ioctl, /* ioctl */
+ dc_hdlc_flush, /* flush */
+ dc_hdlc_purge, /* purge */
+ dc_hdlc_sleep, /* sleep */
+ dc_hdlc_close, /* close */
+};
+
+dc_status_t
+dc_hdlc_open (dc_iostream_t **out, dc_context_t *context, dc_iostream_t *base, size_t isize, size_t osize)
+{
+ dc_status_t status = DC_STATUS_SUCCESS;
+ dc_hdlc_t *hdlc = NULL;
+
+ if (out == NULL)
+ return DC_STATUS_INVALIDARGS;
+
+ if (base == NULL || isize == 0 || osize == 0)
+ return DC_STATUS_INVALIDARGS;
+
+ dc_transport_t transport = dc_iostream_get_transport (base);
+
+ // Allocate memory.
+ hdlc = (dc_hdlc_t *) dc_iostream_allocate (NULL, &dc_hdlc_vtable, transport);
+ if (hdlc == NULL) {
+ ERROR (context, "Failed to allocate memory.");
+ status = DC_STATUS_NOMEMORY;
+ goto error_exit;
+ }
+
+ // Allocate the read buffer.
+ hdlc->rbuf = malloc (isize);
+ if (hdlc->rbuf == NULL) {
+ ERROR (context, "Failed to allocate memory.");
+ status = DC_STATUS_NOMEMORY;
+ goto error_free;
+ }
+
+ // Allocate the write buffer.
+ hdlc->wbuf = malloc (osize);
+ if (hdlc->wbuf == NULL) {
+ ERROR (context, "Failed to allocate memory.");
+ status = DC_STATUS_NOMEMORY;
+ goto error_free_rbuf;
+ }
+
+ hdlc->context = context;
+ hdlc->iostream = base;
+ hdlc->rbuf_size = isize;
+ hdlc->rbuf_offset = 0;
+ hdlc->rbuf_available = 0;
+ hdlc->wbuf_size = osize;
+ hdlc->wbuf_offset = 0;
+
+ *out = (dc_iostream_t *) hdlc;
+
+ return DC_STATUS_SUCCESS;
+
+error_free_rbuf:
+ free (hdlc->rbuf);
+error_free:
+ dc_iostream_deallocate ((dc_iostream_t *) hdlc);
+error_exit:
+ return status;
+}
+
+static dc_status_t
+dc_hdlc_set_timeout (dc_iostream_t *abstract, int timeout)
+{
+ dc_hdlc_t *hdlc = (dc_hdlc_t *) abstract;
+
+ return dc_iostream_set_timeout (hdlc->iostream, timeout);
+}
+
+static dc_status_t
+dc_hdlc_set_break (dc_iostream_t *abstract, unsigned int value)
+{
+ dc_hdlc_t *hdlc = (dc_hdlc_t *) abstract;
+
+ return dc_iostream_set_break (hdlc->iostream, value);
+}
+
+static dc_status_t
+dc_hdlc_set_dtr (dc_iostream_t *abstract, unsigned int value)
+{
+ dc_hdlc_t *hdlc = (dc_hdlc_t *) abstract;
+
+ return dc_iostream_set_dtr (hdlc->iostream, value);
+}
+
+static dc_status_t
+dc_hdlc_set_rts (dc_iostream_t *abstract, unsigned int value)
+{
+ dc_hdlc_t *hdlc = (dc_hdlc_t *) abstract;
+
+ return dc_iostream_set_rts (hdlc->iostream, value);
+}
+
+static dc_status_t
+dc_hdlc_get_lines (dc_iostream_t *abstract, unsigned int *value)
+{
+ dc_hdlc_t *hdlc = (dc_hdlc_t *) abstract;
+
+ return dc_iostream_get_lines (hdlc->iostream, value);
+}
+
+static dc_status_t
+dc_hdlc_configure (dc_iostream_t *abstract, unsigned int baudrate, unsigned int databits, dc_parity_t parity, dc_stopbits_t stopbits, dc_flowcontrol_t flowcontrol)
+{
+ dc_hdlc_t *hdlc = (dc_hdlc_t *) abstract;
+
+ return dc_iostream_configure (hdlc->iostream, baudrate, databits, parity, stopbits, flowcontrol);
+}
+
+static dc_status_t
+dc_hdlc_poll (dc_iostream_t *abstract, int timeout)
+{
+ dc_hdlc_t *hdlc = (dc_hdlc_t *) abstract;
+
+ if (hdlc->rbuf_available) {
+ return DC_STATUS_SUCCESS;
+ }
+
+ return dc_iostream_poll (hdlc->iostream, timeout);
+}
+
+static dc_status_t
+dc_hdlc_read (dc_iostream_t *abstract, void *data, size_t size, size_t *actual)
+{
+ dc_status_t status = DC_STATUS_SUCCESS;
+ dc_hdlc_t *hdlc = (dc_hdlc_t *) abstract;
+ size_t nbytes = 0;
+
+ unsigned int initialized = 0;
+ unsigned int escaped = 0;
+
+ while (1) {
+ if (hdlc->rbuf_available == 0) {
+ // Read a packet into the cache.
+ size_t len = 0;
+ status = dc_iostream_read (hdlc->iostream, hdlc->rbuf, hdlc->rbuf_size, &len);
+ if (status != DC_STATUS_SUCCESS) {
+ goto out;
+ }
+
+ hdlc->rbuf_available = len;
+ hdlc->rbuf_offset = 0;
+ }
+
+ while (hdlc->rbuf_available) {
+ unsigned char c = hdlc->rbuf[hdlc->rbuf_offset];
+ hdlc->rbuf_offset++;
+ hdlc->rbuf_available--;
+
+ if (c == END) {
+ if (escaped) {
+ ERROR (hdlc->context, "HDLC frame escaped the special character %02x.", c);
+ status = DC_STATUS_IO;
+ goto out;
+ }
+
+ if (initialized) {
+ goto out;
+ }
+
+ initialized = 1;
+ continue;
+ }
+
+ if (!initialized) {
+ continue;
+ }
+
+ if (c == ESC) {
+ if (escaped) {
+ ERROR (hdlc->context, "HDLC frame escaped the special character %02x.", c);
+ status = DC_STATUS_IO;
+ goto out;
+ }
+ escaped = 1;
+ continue;
+ }
+
+ if (escaped) {
+ c ^= ESC_BIT;
+ escaped = 0;
+ }
+
+ if (nbytes < size)
+ ((unsigned char *)data)[nbytes] = c;
+ nbytes++;
+ }
+ }
+
+out:
+ if (nbytes > size) {
+ ERROR (hdlc->context, "HDLC frame is too large (" DC_PRINTF_SIZE " " DC_PRINTF_SIZE ").", nbytes, size);
+ dc_status_set_error (&status, DC_STATUS_IO);
+ nbytes = size;
+ }
+
+ if (actual)
+ *actual = nbytes;
+
+ return status;
+}
+
+static dc_status_t
+dc_hdlc_write (dc_iostream_t *abstract, const void *data, size_t size, size_t *actual)
+{
+ dc_status_t status = DC_STATUS_SUCCESS;
+ dc_hdlc_t *hdlc = (dc_hdlc_t *) abstract;
+ size_t nbytes = 0;
+
+ // Clear the buffer.
+ hdlc->wbuf_offset = 0;
+
+ // Start of the packet.
+ hdlc->wbuf[hdlc->wbuf_offset++] = END;
+
+ // Flush the buffer if necessary.
+ if (hdlc->wbuf_offset >= hdlc->wbuf_size) {
+ status = dc_iostream_write (hdlc->iostream, hdlc->wbuf, hdlc->wbuf_offset, NULL);
+ if (status != DC_STATUS_SUCCESS) {
+ goto out;
+ }
+
+ hdlc->wbuf_offset = 0;
+ }
+
+ while (nbytes < size) {
+ unsigned char c = ((const unsigned char *) data)[nbytes];
+
+ if (c == END || c == ESC) {
+ // Append the escape character.
+ hdlc->wbuf[hdlc->wbuf_offset++] = ESC;
+
+ // Flush the buffer if necessary.
+ if (hdlc->wbuf_offset >= hdlc->wbuf_size) {
+ status = dc_iostream_write (hdlc->iostream, hdlc->wbuf, hdlc->wbuf_offset, NULL);
+ if (status != DC_STATUS_SUCCESS) {
+ goto out;
+ }
+
+ hdlc->wbuf_offset = 0;
+ }
+
+ // Escape the character.
+ c ^= ESC_BIT;
+ }
+
+ // Append the character.
+ hdlc->wbuf[hdlc->wbuf_offset++] = c;
+
+ // Flush the buffer if necessary.
+ if (hdlc->wbuf_offset >= hdlc->wbuf_size) {
+ status = dc_iostream_write (hdlc->iostream, hdlc->wbuf, hdlc->wbuf_offset, NULL);
+ if (status != DC_STATUS_SUCCESS) {
+ goto out;
+ }
+
+ hdlc->wbuf_offset = 0;
+ }
+
+ nbytes++;
+ }
+
+ // End of the packet.
+ hdlc->wbuf[hdlc->wbuf_offset++] = END;
+
+ // Flush the buffer.
+ status = dc_iostream_write (hdlc->iostream, hdlc->wbuf, hdlc->wbuf_offset, NULL);
+ if (status != DC_STATUS_SUCCESS) {
+ goto out;
+ }
+
+ hdlc->wbuf_offset = 0;
+
+out:
+ if (actual)
+ *actual = nbytes;
+
+ return status;
+}
+
+static dc_status_t
+dc_hdlc_ioctl (dc_iostream_t *abstract, unsigned int request, void *data, size_t size)
+{
+ dc_hdlc_t *hdlc = (dc_hdlc_t *) abstract;
+
+ return dc_iostream_ioctl (hdlc->iostream, request, data, size);
+}
+
+static dc_status_t
+dc_hdlc_flush (dc_iostream_t *abstract)
+{
+ dc_hdlc_t *hdlc = (dc_hdlc_t *) abstract;
+
+ return dc_iostream_flush (hdlc->iostream);
+}
+
+static dc_status_t
+dc_hdlc_purge (dc_iostream_t *abstract, dc_direction_t direction)
+{
+ dc_hdlc_t *hdlc = (dc_hdlc_t *) abstract;
+
+ if (direction & DC_DIRECTION_INPUT) {
+ hdlc->rbuf_available = 0;
+ hdlc->rbuf_offset = 0;
+ }
+
+ return dc_iostream_purge (hdlc->iostream, direction);
+}
+
+static dc_status_t
+dc_hdlc_sleep (dc_iostream_t *abstract, unsigned int milliseconds)
+{
+ dc_hdlc_t *hdlc = (dc_hdlc_t *) abstract;
+
+ return dc_iostream_sleep (hdlc->iostream, milliseconds);
+}
+
+static dc_status_t
+dc_hdlc_close (dc_iostream_t *abstract)
+{
+ dc_hdlc_t *hdlc = (dc_hdlc_t *) abstract;
+
+ free (hdlc->wbuf);
+ free (hdlc->rbuf);
+
+ return DC_STATUS_SUCCESS;
+}
diff --git a/src/hdlc.h b/src/hdlc.h
new file mode 100644
index 0000000..aedd9b5
--- /dev/null
+++ b/src/hdlc.h
@@ -0,0 +1,50 @@
+/*
+ * libdivecomputer
+ *
+ * Copyright (C) 2023 Jef Driesen
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301 USA
+ */
+
+#ifndef DC_HDLC_H
+#define DC_HDLC_H
+
+#include
+#include
+#include
+
+#ifdef __cplusplus
+extern "C" {
+#endif /* __cplusplus */
+
+/**
+ * Create a HDLC I/O stream layered on top of another base I/O stream.
+ *
+ * @param[out] iostream A location to store the HDLC I/O stream.
+ * @param[in] context A valid context.
+ * @param[in] base A valid I/O stream.
+ * @param[in] isize The input packet size in bytes.
+ * @param[in] osize The output packet size in bytes.
+ * @returns #DC_STATUS_SUCCESS on success, or another #dc_status_t code
+ * on failure.
+ */
+dc_status_t
+dc_hdlc_open (dc_iostream_t **iostream, dc_context_t *context, dc_iostream_t *base, size_t isize, size_t osize);
+
+#ifdef __cplusplus
+}
+#endif /* __cplusplus */
+#endif /* DC_HDLC_H */