Add matriseq, a step sequencer for the Novation Launchpad.

git-svn-id: http://svn.drobilla.net/lad/trunk/plugins/matriseq@4512 a436a847-0d15-0410-975c-d299462d15a1

9 files changed, 1036 insertions, 0 deletions

diff --git a/manifest.ttl.in b/manifest.ttl.in
new file mode 100644
index 0000000..4c08639
--- /dev/null
+++ b/manifest.ttl.in
@@ -0,0 +1,8 @@
+@prefix lv2:  <http://lv2plug.in/ns/lv2core#> .
+@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
+@prefix ui:   <http://lv2plug.in/ns/extensions/ui#> .
+
+<http://drobilla.net/plugins/matriseq>
+	a lv2:Plugin ;
+	lv2:binary <matriseq@LIB_EXT@> ;
+	rdfs:seeAlso <matriseq.ttl> .
diff --git a/matriseq.c b/matriseq.c
new file mode 100644
index 0000000..bb9c1fe
--- /dev/null
+++ b/matriseq.c
@@ -0,0 +1,341 @@
+/*
+  Copyright 2012 David Robillard <d@drobilla.net>
+
+  Permission to use, copy, modify, and/or distribute this software for any
+  purpose with or without fee is hereby granted, provided that the above
+  copyright notice and this permission notice appear in all copies.
+
+  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+
+#include <math.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "naub/naub.h"
+#include "zix/thread.h"
+#include "zix/ring.h"
+
+#include "lv2/lv2plug.in/ns/ext/atom/forge.h"
+#include "lv2/lv2plug.in/ns/ext/log/log.h"
+#include "lv2/lv2plug.in/ns/ext/midi/midi.h"
+#include "lv2/lv2plug.in/ns/ext/urid/urid.h"
+#include "lv2/lv2plug.in/ns/lv2core/lv2.h"
+
+#define MATRISEQ_URI "http://drobilla.net/plugins/matriseq"
+
+static const uint32_t STEP_TYPE = 8;
+static const uint32_t RING_SIZE = 4096;
+
+typedef enum {
+	MATRISEQ_IN  = 0,
+	MATRISEQ_OUT = 1
+} PortIndex;
+
+// URIDs used by this plugin
+typedef struct {
+	LV2_URID log_Error;
+	LV2_URID midi_MidiEvent;
+} MatriseqURIs;
+
+typedef struct {
+	// Port buffers
+	LV2_Atom_Sequence* in;
+	LV2_Atom_Sequence* out;
+
+	// Features
+	LV2_URID_Map* map;
+	LV2_Log_Log*  log;
+
+	// LV2 stuff
+	LV2_Atom_Forge forge;
+	MatriseqURIs   uris;
+
+	// USB stuff
+	NaubWorld* naub;
+	ZixThread  thread;
+	ZixRing*   ring;
+	bool       exit;
+
+	// State
+	uint32_t time_frames;
+	uint8_t  grid[8][8];
+	uint32_t step;
+	double   rate;
+	float    bpm;
+} Matriseq;
+
+// Log a message to the host if available, or stderr otherwise.
+LV2_LOG_FUNC(3, 4)
+static void
+print(Matriseq* self, LV2_URID type, const char* fmt, ...)
+{
+	va_list args;
+	va_start(args, fmt);
+	if (self->log) {
+		self->log->vprintf(self->log->handle, type, fmt, args);
+	} else {
+		vfprintf(stderr, fmt, args);
+	}
+	va_end(args);
+}
+
+static LV2_Handle
+instantiate(const LV2_Descriptor*     descriptor,
+            double                    rate,
+            const char*               bundle_path,
+            const LV2_Feature* const* features)
+{
+	Matriseq* self = (Matriseq*)calloc(1, sizeof(Matriseq));
+	if (!self) {
+		return NULL;
+	}
+
+	// Get features
+	for (int i = 0; features[i]; ++i) {
+		if (!strcmp(features[i]->URI, LV2_URID__map)) {
+			self->map = (LV2_URID_Map*)features[i]->data;
+		} else if (!strcmp(features[i]->URI, LV2_LOG__log)) {
+			self->log = (LV2_Log_Log*)features[i]->data;
+		}
+	}
+	if (!self->map) {
+		print(self, self->uris.log_Error, "Missing feature urid:map.\n");
+		free(self);
+		return NULL;
+	}
+
+	// Initialise LV2 stuff
+	LV2_URID_Map* map = self->map;
+	self->uris.log_Error      = map->map(map->handle, LV2_LOG__Error);
+	self->uris.midi_MidiEvent = map->map(map->handle, LV2_MIDI__MidiEvent);
+	lv2_atom_forge_init(&self->forge, self->map);
+
+	if (self) {
+		self->ring = zix_ring_new(RING_SIZE);
+		self->rate = rate;
+		self->bpm  = 140.0f;
+
+		zix_ring_mlock(self->ring);
+	}
+
+	return (LV2_Handle)self;
+}
+
+static void
+connect_port(LV2_Handle instance,
+             uint32_t   port,
+             void*      data)
+{
+	Matriseq* self = (Matriseq*)instance;
+
+	switch ((PortIndex)port) {
+	case MATRISEQ_IN:
+		self->in = (LV2_Atom_Sequence*)data;
+		break;
+	case MATRISEQ_OUT:
+		self->out = (LV2_Atom_Sequence*)data;
+		break;
+	}
+}
+
+static void
+set_button(Matriseq* self, NaubControlID control, bool active)
+{
+	int32_t value = 0;
+	if (self->grid[control.y][control.x]) {
+		value = active ? naub_rgb(1, 0, 0) : naub_rgb(1, 1, 0);
+	} else {
+		value = active ? naub_rgb(0, 0.4, 0) : naub_rgb(0, 0, 0);
+	}
+	naub_set_control(self->naub, control, value);
+}
+
+static void
+naub_event(void*            instance,
+           const NaubEvent* event)
+{
+	Matriseq* self = (Matriseq*)instance;
+	if (event->type != NAUB_EVENT_BUTTON) {  // Odd...
+		return;
+	}
+
+	const NaubControlID control = event->button.control;
+	if (control.group != 0) {
+		return;
+	}
+
+	/*
+	fprintf(stderr, "PRESS %d:%d.%d.%d\n",
+	        control.device,
+	        control.group,
+	        control.x,
+	        control.y);
+	*/
+
+	if (event->button.pressed) {
+		naub_set_control(self->naub, control, naub_rgb(1, 0, 0));
+	} else {
+		uint8_t* cell = &self->grid[control.y][control.x];
+		*cell = *cell ? 0 : 1;
+		set_button(self, control, self->step == control.y);
+	}
+
+	naub_flush(self->naub);
+}
+
+static void*
+thread_run(void* instance)
+{
+	Matriseq* self = (Matriseq*)instance;
+	uint32_t  step = self->step;
+
+	while (!naub_handle_events_timeout(self->naub, 10) && !self->exit) {
+		uint32_t new_step;
+		if (zix_ring_read_space(self->ring) >= sizeof(new_step)) {
+			zix_ring_read(self->ring, &new_step, sizeof(new_step));
+
+			// De-highlight old active row
+			for (int y = 0; y < 8; ++y) {
+				const NaubControlID control = { 0, 0, step, y };
+				set_button(self, control, false);
+			}
+
+			// Highlight new active row
+			for (int y = 0; y < 8; ++y) {
+				const NaubControlID control = { 0, 0, new_step, y };
+				set_button(self, control, true);
+			}
+
+			// Send bulk update to device
+			naub_flush(self->naub);
+
+			step = new_step;
+		}
+	}
+	return NULL;
+}
+
+static void
+activate(LV2_Handle instance)
+{
+	Matriseq* self = (Matriseq*)instance;
+	self->naub = naub_world_new(self, naub_event);
+	if (self->naub) {
+		if (!naub_world_open(
+			    self->naub, NAUB_VENDOR_NOVATION, NAUB_PRODUCT_LAUNCHPAD)) {
+			fprintf(stderr, "Opened Launchpad\n");
+			if (zix_thread_create(&self->thread, 1024, thread_run, self)) {
+				fprintf(stderr, "Failed to create thread\n");
+				return;
+			}
+		}
+	}
+}
+
+static void
+run(LV2_Handle instance, uint32_t n_frames)
+{
+	Matriseq* self = (Matriseq*)instance;
+	const float bps = self->bpm / 60.0f;  // Beats per second
+	const float spb = 1.0 / bps;  // Seconds per beat
+	//const float spt = spb / STEP_TYPE;
+	const float spt = spb / 2;  // Seconds per tick (step)
+
+	// Prepare for writing to out port
+	const uint32_t out_capacity = self->out->atom.size;
+	lv2_atom_forge_set_buffer(&self->forge, (uint8_t*)self->out, out_capacity);
+
+	// Initialise output port to empty sequence
+	LV2_Atom_Forge_Frame out_frame;
+	lv2_atom_forge_sequence_head(&self->forge, &out_frame, 0);
+
+	//fprintf(stderr, "BPS: %f SPB: %f\n", bps, spb);
+	for (uint32_t i = 0; i < n_frames; ++i) {
+		const double   time_s = self->time_frames / self->rate;
+		const uint32_t step   = (uint32_t)(time_s / spt) % STEP_TYPE;
+		if (step != self->step) {
+			// Update step and frame time
+			self->step = step;
+			if (step == 0) {
+				self->time_frames = 0;
+			} else {
+				++self->time_frames;
+			}
+
+			// Notify USB thread of new step
+			//fprintf(stderr, "LV2 STEP %d @ %f\n", self->step, time_s);
+			zix_ring_write(self->ring, &self->step, sizeof(self->step));
+
+			// Send note ons for enabled notes this step
+			for (uint32_t y = 0; y < 8; ++y) {
+				if (self->grid[y][step]) {
+					const uint8_t note = (7 - y) + 36;
+					const uint8_t ev[] = { 0x90, note, 0x40 };
+					lv2_atom_forge_frame_time(&self->forge, i);
+					lv2_atom_forge_atom(&self->forge, 3, self->uris.midi_MidiEvent);
+					lv2_atom_forge_write(&self->forge, ev, 3);
+				}
+			}
+		} else {
+			++self->time_frames;
+		}
+	}
+}
+
+static void
+deactivate(LV2_Handle instance)
+{
+	Matriseq* self = (Matriseq*)instance;
+	self->exit = true;
+	void* thread_ret = NULL;
+	zix_thread_join(self->thread, &thread_ret);
+	naub_world_free(self->naub);
+	self->naub = NULL;
+}
+
+static void
+cleanup(LV2_Handle instance)
+{
+	Matriseq* self = (Matriseq*)instance;
+	zix_ring_free(self->ring);
+	free(self);
+}
+
+const void*
+extension_data(const char* uri)
+{
+	return NULL;
+}
+
+static const LV2_Descriptor descriptor = {
+	MATRISEQ_URI,
+	instantiate,
+	connect_port,
+	activate,
+	run,
+	deactivate,
+	cleanup,
+	extension_data
+};
+
+LV2_SYMBOL_EXPORT
+const LV2_Descriptor*
+lv2_descriptor(uint32_t index)
+{
+	switch (index) {
+	case 0:
+		return &descriptor;
+	default:
+		return NULL;
+	}
+}
diff --git a/matriseq.ttl b/matriseq.ttl
new file mode 100644
index 0000000..2abf153
--- /dev/null
+++ b/matriseq.ttl
@@ -0,0 +1,39 @@
+@prefix atom: <http://lv2plug.in/ns/ext/atom#> .
+@prefix doap: <http://usefulinc.com/ns/doap#> .
+@prefix foaf: <http://xmlns.com/foaf/0.1/> .
+@prefix lv2: <http://lv2plug.in/ns/lv2core#> .
+@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
+@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
+
+<http://drobilla.net/drobilla#me>
+	a foaf:Person ;
+	foaf:name "David Robillard" ;
+	foaf:mbox <mailto:d@drobilla.net> ;
+	rdfs:seeAlso <http://drobilla.net/drobilla> .
+
+<http://drobilla.net/plugins/matriseq>
+	a lv2:Plugin ,
+		lv2:AmplifierPlugin ;
+	doap:maintainer <http://drobilla.net/drobilla#me> ;
+	doap:name "Matriseq" ;
+	doap:license <http://opensource.org/licenses/isc> ;
+	lv2:optionalFeature lv2:hardRTCapable ;
+	lv2:port [
+		a lv2:InputPort ,
+			atom:AtomPort ;
+		atom:bufferType atom:Sequence ;
+		atom:supports <http://lv2plug.in/ns/ext/midi#MidiEvent> ,
+			<http://lv2plug.in/ns/ext/patch#Message> ;
+		lv2:index 0 ;
+		lv2:symbol "in" ;
+		lv2:name "In"
+	] , [
+		a lv2:OutputPort ,
+			atom:AtomPort ;
+		atom:bufferType atom:Sequence ;
+		atom:supports <http://lv2plug.in/ns/ext/midi#MidiEvent> ,
+			<http://lv2plug.in/ns/ext/patch#Message> ;
+		lv2:index 1 ;
+		lv2:symbol "out" ;
+		lv2:name "Out"
+	] .
diff --git a/waf b/waf
new file mode 120000
index 0000000..59a1ac9
--- /dev/null
+++ b/waf
@@ -0,0 +1 @@
+../../waf
\ No newline at end of file
diff --git a/wscript b/wscript
new file mode 100644
index 0000000..474e96e
--- /dev/null
+++ b/wscript
@@ -0,0 +1,76 @@
+#!/usr/bin/env python
+from waflib.extras import autowaf as autowaf
+
+# Variables for 'waf dist'
+APPNAME = 'matriseq.lv2'
+VERSION = '1.0.0'
+
+# Mandatory variables
+top = '.'
+out = 'build'
+
+def options(opt):
+    opt.load('compiler_c')
+    autowaf.set_options(opt)
+
+def configure(conf):
+    conf.load('compiler_c')
+    autowaf.configure(conf)
+    autowaf.display_header('Matriseq Configuration')
+
+    if conf.env['MSVC_COMPILER']:
+        conf.env.append_unique('CFLAGS', ['-TP', '-MD'])
+    else:
+        conf.env.append_unique('CFLAGS', '-std=c99')
+
+    autowaf.check_pkg(conf, 'lv2', atleast_version='1.0.0', uselib_store='LV2')
+    autowaf.check_pkg(conf, 'naub-0', atleast_version='0.0.0', uselib_store='NAUB')
+
+    # Set env['pluginlib_PATTERN']
+    pat = conf.env['cshlib_PATTERN']
+    if pat.startswith('lib'):
+        pat = pat[3:]
+    conf.env['pluginlib_PATTERN'] = pat
+    conf.env['pluginlib_EXT'] = pat[pat.rfind('.'):]
+
+    autowaf.display_msg(conf, "LV2 bundle directory", conf.env['LV2DIR'])
+    print('')
+
+def build(bld):
+    bundle = 'matriseq.lv2'
+
+    # Build manifest.ttl by substitution (for portable lib extension)
+    bld(features     = 'subst',
+        source       = 'manifest.ttl.in',
+        target       = '%s/%s' % (bundle, 'manifest.ttl'),
+        install_path = '${LV2DIR}/%s' % bundle,
+        LIB_EXT      = bld.env['pluginlib_EXT'])
+
+    # Copy other data files to build bundle (build/matriseq.lv2)
+    for i in ['matriseq.ttl']:
+        bld(features     = 'subst',
+            source       = i,
+            target       = '%s/%s' % (bundle, i),
+            install_path = '${LV2DIR}/%s' % bundle,
+            LIB_EXT      = bld.env['pluginlib_EXT'])
+
+    # Create a build environment that builds module-style library names
+    # e.g. matriseq.so instead of libmatriseq.so
+    # Note for C++ you must set cxxshlib_PATTERN instead
+    penv                   = bld.env.derive()
+    penv['cshlib_PATTERN'] = bld.env['pluginlib_PATTERN']
+
+    includes = None
+    if autowaf.is_child:
+        includes = '../..'
+
+    # Build plugin library
+    obj = bld(features     = 'c cshlib',
+              env          = penv,
+              source       = ['matriseq.c', 'zix/ring.c'],
+              name         = 'matriseq',
+              target       = '%s/matriseq' % bundle,
+              install_path = '${LV2DIR}/%s' % bundle,
+              includes     = includes)
+    autowaf.use_lib(bld, obj, 'LV2 NAUB')
+
diff --git a/zix/common.h b/zix/common.h
new file mode 100644
index 0000000..59e1f55
--- /dev/null
+++ b/zix/common.h
@@ -0,0 +1,83 @@
+/*
+  Copyright 2011 David Robillard <http://drobilla.net>
+
+  Permission to use, copy, modify, and/or distribute this software for any
+  purpose with or without fee is hereby granted, provided that the above
+  copyright notice and this permission notice appear in all copies.
+
+  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+
+#ifndef ZIX_COMMON_H
+#define ZIX_COMMON_H
+
+/**
+   @addtogroup zix
+   @{
+*/
+
+/** @cond */
+#ifdef ZIX_SHARED
+#    ifdef _WIN32
+#        define ZIX_LIB_IMPORT __declspec(dllimport)
+#        define ZIX_LIB_EXPORT __declspec(dllexport)
+#    else
+#        define ZIX_LIB_IMPORT __attribute__((visibility("default")))
+#        define ZIX_LIB_EXPORT __attribute__((visibility("default")))
+#    endif
+#    ifdef ZIX_INTERNAL
+#        define ZIX_API ZIX_LIB_EXPORT
+#    else
+#        define ZIX_API ZIX_LIB_IMPORT
+#    endif
+#else
+#    define ZIX_API
+#endif
+/** @endcond */
+
+#ifdef __cplusplus
+extern "C" {
+#else
+#    include <stdbool.h>
+#endif
+
+typedef enum {
+	ZIX_STATUS_SUCCESS,
+	ZIX_STATUS_ERROR,
+	ZIX_STATUS_NO_MEM,
+	ZIX_STATUS_NOT_FOUND,
+	ZIX_STATUS_EXISTS,
+	ZIX_STATUS_BAD_ARG,
+	ZIX_STATUS_BAD_PERMS,
+} ZixStatus;
+
+/**
+   Function for comparing two elements.
+*/
+typedef int (*ZixComparator)(const void* a, const void* b, void* user_data);
+
+/**
+   Function for testing equality of two elements.
+*/
+typedef bool (*ZixEqualFunc)(const void* a, const void* b);
+
+/**
+   Function to destroy an element.
+*/
+typedef void (*ZixDestroyFunc)(void* ptr);
+
+/**
+   @}
+*/
+
+#ifdef __cplusplus
+}  /* extern "C" */
+#endif
+
+#endif  /* ZIX_COMMON_H */
diff --git a/zix/ring.c b/zix/ring.c
new file mode 100644
index 0000000..7ebbe67
--- /dev/null
+++ b/zix/ring.c
@@ -0,0 +1,225 @@
+/*
+  Copyright 2011 David Robillard <http://drobilla.net>
+
+  Permission to use, copy, modify, and/or distribute this software for any
+  purpose with or without fee is hereby granted, provided that the above
+  copyright notice and this permission notice appear in all copies.
+
+  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+
+#ifdef HAVE_MLOCK
+#    include <sys/mman.h>
+#    define ZIX_MLOCK(ptr, size) mlock((ptr), (size))
+#elif defined(_WIN32)
+#    include <windows.h>
+#    define ZIX_MLOCK(ptr, size) VirtualLock((ptr), (size))
+#else
+#    pragma message("warning: No memory locking, possible RT violations")
+#    define ZIX_MLOCK(ptr, size)
+#endif
+
+#if defined(__APPLE__)
+#    include <libkern/OSAtomic.h>
+#    define ZIX_FULL_BARRIER() OSMemoryBarrier()
+#elif defined(_WIN32)
+#    include <windows.h>
+#    define ZIX_FULL_BARRIER() MemoryBarrier()
+#elif (__GNUC__ > 4) || (__GNUC__ == 4 && __GNUC_MINOR__ >= 1)
+#    define ZIX_FULL_BARRIER() __sync_synchronize()
+#else
+#    pragma message("warning: No memory barriers, possible SMP bugs")
+#    define ZIX_FULL_BARRIER()
+#endif
+
+/* No support for any systems with separate read and write barriers */
+#define ZIX_READ_BARRIER() ZIX_FULL_BARRIER()
+#define ZIX_WRITE_BARRIER() ZIX_FULL_BARRIER()
+
+#include "zix/ring.h"
+
+struct ZixRingImpl {
+	uint32_t write_head;  ///< Read index into buf
+	uint32_t read_head;   ///< Write index into buf
+	uint32_t size;        ///< Size (capacity) in bytes
+	uint32_t size_mask;   ///< Mask for fast modulo
+	char*    buf;         ///< Contents
+};
+
+static inline uint32_t
+next_power_of_two(uint32_t size)
+{
+	// http://graphics.stanford.edu/~seander/bithacks.html#RoundUpPowerOf2
+	size--;
+	size |= size >> 1;
+	size |= size >> 2;
+	size |= size >> 4;
+	size |= size >> 8;
+	size |= size >> 16;
+	size++;
+	return size;
+}
+
+ZixRing*
+zix_ring_new(uint32_t size)
+{
+	ZixRing* ring = (ZixRing*)malloc(sizeof(ZixRing));
+	ring->write_head = 0;
+	ring->read_head  = 0;
+	ring->size       = next_power_of_two(size);
+	ring->size_mask  = ring->size - 1;
+	ring->buf        = (char*)malloc(ring->size);
+	return ring;
+}
+
+void
+zix_ring_free(ZixRing* ring)
+{
+	free(ring->buf);
+	free(ring);
+}
+
+void
+zix_ring_mlock(ZixRing* ring)
+{
+	ZIX_MLOCK(ring, sizeof(ZixRing));
+	ZIX_MLOCK(ring->buf, ring->size);
+}
+
+void
+zix_ring_reset(ZixRing* ring)
+{
+	ring->write_head = 0;
+	ring->read_head  = 0;
+}
+
+static inline uint32_t
+read_space_internal(const ZixRing* ring, uint32_t r, uint32_t w)
+{
+	if (r < w) {
+		return w - r;
+	} else {
+		return (w - r + ring->size) & ring->size_mask;
+	}
+}
+
+uint32_t
+zix_ring_read_space(const ZixRing* ring)
+{
+	return read_space_internal(ring, ring->read_head, ring->write_head);
+}
+
+static inline uint32_t
+write_space_internal(const ZixRing* ring, uint32_t r, uint32_t w)
+{
+	if (r == w) {
+		return ring->size - 1;
+	} else if (r < w) {
+		return ((r - w + ring->size) & ring->size_mask) - 1;
+	} else {
+		return (r - w) - 1;
+	}
+}
+
+uint32_t
+zix_ring_write_space(const ZixRing* ring)
+{
+	return write_space_internal(ring, ring->read_head, ring->write_head);
+}
+
+uint32_t
+zix_ring_capacity(const ZixRing* ring)
+{
+	return ring->size - 1;
+}
+
+static inline uint32_t
+peek_internal(const ZixRing* ring, uint32_t r, uint32_t w,
+              uint32_t size, void* dst)
+{
+	if (read_space_internal(ring, r, w) < size) {
+		return 0;
+	}
+
+	if (r + size < ring->size) {
+		memcpy(dst, &ring->buf[r], size);
+	} else {
+		const uint32_t first_size = ring->size - r;
+		memcpy(dst, &ring->buf[r], first_size);
+		memcpy((char*)dst + first_size, &ring->buf[0], size - first_size);
+	}
+
+	return size;
+}
+
+uint32_t
+zix_ring_peek(ZixRing* ring, void* dst, uint32_t size)
+{
+	const uint32_t r = ring->read_head;
+	const uint32_t w = ring->write_head;
+
+	return peek_internal(ring, r, w, size, dst);
+}
+
+uint32_t
+zix_ring_read(ZixRing* ring, void* dst, uint32_t size)
+{
+	const uint32_t r = ring->read_head;
+	const uint32_t w = ring->write_head;
+
+	if (peek_internal(ring, r, w, size, dst)) {
+		ZIX_READ_BARRIER();
+		ring->read_head = (r + size) & ring->size_mask;
+		return size;
+	} else {
+		return 0;
+	}
+}
+
+uint32_t
+zix_ring_skip(ZixRing* ring, uint32_t size)
+{
+	const uint32_t r = ring->read_head;
+	const uint32_t w = ring->write_head;
+	if (read_space_internal(ring, r, w) < size) {
+		return 0;
+	}
+
+	ZIX_READ_BARRIER();
+	ring->read_head = (r + size) & ring->size_mask;
+	return size;
+}
+
+uint32_t
+zix_ring_write(ZixRing* ring, const void* src, uint32_t size)
+{
+	const uint32_t r = ring->read_head;
+	const uint32_t w = ring->write_head;
+	if (write_space_internal(ring, r, w) < size) {
+		return 0;
+	}
+
+	if (w + size <= ring->size) {
+		memcpy(&ring->buf[w], src, size);
+		ZIX_WRITE_BARRIER();
+		ring->write_head = (w + size) & ring->size_mask;
+	} else {
+		const uint32_t this_size = ring->size - w;
+		memcpy(&ring->buf[w], src, this_size);
+		memcpy(&ring->buf[0], (char*)src + this_size, size - this_size);
+		ZIX_WRITE_BARRIER();
+		ring->write_head = size - this_size;
+	}
+
+	return size;
+}
diff --git a/zix/ring.h b/zix/ring.h
new file mode 100644
index 0000000..34ba2fa
--- /dev/null
+++ b/zix/ring.h
@@ -0,0 +1,130 @@
+/*
+  Copyright 2011 David Robillard <http://drobilla.net>
+
+  Permission to use, copy, modify, and/or distribute this software for any
+  purpose with or without fee is hereby granted, provided that the above
+  copyright notice and this permission notice appear in all copies.
+
+  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+
+#ifndef ZIX_RING_H
+#define ZIX_RING_H
+
+#include <stdint.h>
+
+#include "zix/common.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+   @addtogroup zix
+   @{
+   @name Ring
+   @{
+*/
+
+/**
+   A lock-free ring buffer.
+
+   Thread-safe with a single reader and single writer, and realtime safe
+   on both ends.
+*/
+typedef struct ZixRingImpl ZixRing;
+
+/**
+   Create a new ring.
+   @param size Size in bytes (note this may be rounded up).
+
+   At most @c size - 1 bytes may be stored in the ring at once.
+*/
+ZixRing*
+zix_ring_new(uint32_t size);
+
+/**
+   Destroy a ring.
+*/
+void
+zix_ring_free(ZixRing* ring);
+
+/**
+   Lock the ring data into physical memory.
+
+   This function is NOT thread safe or real-time safe, but it should be called
+   after zix_ring_new() to lock all ring memory to avoid page faults while
+   using the ring (i.e. this function MUST be called first in order for the
+   ring to be truly real-time safe).
+
+*/
+void
+zix_ring_mlock(ZixRing* ring);
+
+/**
+   Reset (empty) a ring.
+
+   This function is NOT thread-safe, it may only be called when there are no
+   readers or writers.
+*/
+void
+zix_ring_reset(ZixRing* ring);
+
+/**
+   Return the number of bytes of space available for reading.
+*/
+uint32_t
+zix_ring_read_space(const ZixRing* ring);
+
+/**
+   Return the number of bytes of space available for writing.
+*/
+uint32_t
+zix_ring_write_space(const ZixRing* ring);
+
+/**
+   Return the capacity (i.e. total write space when empty).
+*/
+uint32_t
+zix_ring_capacity(const ZixRing* ring);
+
+/**
+   Read from the ring without advancing the read head.
+*/
+uint32_t
+zix_ring_peek(ZixRing* ring, void* dst, uint32_t size);
+
+/**
+   Read from the ring and advance the read head.
+*/
+uint32_t
+zix_ring_read(ZixRing* ring, void* dst, uint32_t size);
+
+/**
+   Skip data in the ring (advance read head without reading).
+*/
+uint32_t
+zix_ring_skip(ZixRing* ring, uint32_t size);
+
+/**
+   Write data to the ring.
+*/
+uint32_t
+zix_ring_write(ZixRing* ring, const void* src, uint32_t size);
+
+/**
+   @}
+   @}
+*/
+
+#ifdef __cplusplus
+}  /* extern "C" */
+#endif
+
+#endif  /* ZIX_RING_H */
diff --git a/zix/thread.h b/zix/thread.h
new file mode 100644
index 0000000..ff5a727
--- /dev/null
+++ b/zix/thread.h
@@ -0,0 +1,133 @@
+/*
+  Copyright 2012 David Robillard <http://drobilla.net>
+
+  Permission to use, copy, modify, and/or distribute this software for any
+  purpose with or without fee is hereby granted, provided that the above
+  copyright notice and this permission notice appear in all copies.
+
+  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+
+#ifndef ZIX_THREAD_H
+#define ZIX_THREAD_H
+
+#ifdef _WIN32
+#    include <windows.h>
+#else
+#    include <errno.h>
+#    include <pthread.h>
+#endif
+
+#include "zix/common.h"
+
+#ifdef __cplusplus
+extern "C" {
+#else
+#    include <stdbool.h>
+#endif
+
+/**
+   @addtogroup zix
+   @{
+   @name Thread
+   @{
+*/
+
+#ifdef _WIN32
+typedef HANDLE ZixThread;
+#else
+typedef pthread_t ZixThread;
+#endif
+
+/**
+   Initialize @c thread to a new thread.
+
+   The thread will immediately be launched, calling @c function with @c arg
+   as the only parameter.
+*/
+static inline ZixStatus
+zix_thread_create(ZixThread* thread,
+                  size_t     stack_size,
+                  void*      (*function)(void*),
+                  void*      arg);
+
+/**
+   Join @c thread (block until @c thread exits).
+*/
+static inline ZixStatus
+zix_thread_join(ZixThread thread, void** retval);
+
+#ifdef _WIN32
+
+static inline ZixStatus
+zix_thread_create(ZixThread* thread,
+                  size_t     stack_size,
+                  void*      (*function)(void*),
+                  void*      arg)
+{
+	*thread = CreateThread(NULL, stack_size,
+	                       (LPTHREAD_START_ROUTINE)function, arg,
+	                       0, NULL);
+	return *thread ? ZIX_STATUS_SUCCESS : ZIX_STATUS_ERROR;
+}
+
+static inline ZixStatus
+zix_thread_join(ZixThread thread, void** retval)
+{
+	return WaitForSingleObject(thread, INFINITE)
+		? ZIX_STATUS_SUCCESS : ZIX_STATUS_ERROR;
+}
+
+#else  /* !defined(_WIN32) */
+
+static inline ZixStatus
+zix_thread_create(ZixThread* thread,
+                  size_t     stack_size,
+                  void*      (*function)(void*),
+                  void*      arg)
+{
+	pthread_attr_t attr;
+	pthread_attr_init(&attr);
+	pthread_attr_setstacksize(&attr, stack_size);
+
+	const int ret = pthread_create(thread, NULL, function, arg);
+	pthread_attr_destroy(&attr);
+
+	if (ret == EAGAIN) {
+		return ZIX_STATUS_NO_MEM;
+	} else if (ret == EINVAL) {
+		return ZIX_STATUS_BAD_ARG;
+	} else if (ret == EPERM) {
+		return ZIX_STATUS_BAD_PERMS;
+	} else if (ret) {
+		return ZIX_STATUS_ERROR;
+	}
+
+	return ZIX_STATUS_SUCCESS;
+}
+
+static inline ZixStatus
+zix_thread_join(ZixThread thread, void** retval)
+{
+	return pthread_join(thread, retval)
+		? ZIX_STATUS_ERROR : ZIX_STATUS_SUCCESS;
+}
+
+#endif
+
+/**
+   @}
+   @}
+*/
+
+#ifdef __cplusplus
+}  /* extern "C" */
+#endif
+
+#endif  /* ZIX_THREAD_H */