Get printvideo audio working on Windows and MacOS

dsp/audio/BUILD.mk

@@ -0,0 +1,56 @@
+#-*-mode:makefile-gmake;indent-tabs-mode:t;tab-width:8;coding:utf-8-*-┐
+#── vi: set noet ft=make ts=8 sw=8 fenc=utf-8 :vi ────────────────────┘
+
+PKGS += DSP_AUDIO
+
+DSP_AUDIO_ARTIFACTS += DSP_AUDIO_A
+DSP_AUDIO = $(DSP_AUDIO_A_DEPS) $(DSP_AUDIO_A)
+DSP_AUDIO_A = o/$(MODE)/dsp/audio/audio.a
+DSP_AUDIO_A_FILES := $(wildcard dsp/audio/*)
+DSP_AUDIO_A_HDRS = $(filter %.h,$(DSP_AUDIO_A_FILES)) dsp/audio/cosmoaudio/cosmoaudio.h
+DSP_AUDIO_A_SRCS = $(filter %.c,$(DSP_AUDIO_A_FILES))
+
+DSP_AUDIO_A_DATA =				\
+	dsp/audio/cosmoaudio/miniaudio.h	\
+	dsp/audio/cosmoaudio/cosmoaudio.c	\
+	dsp/audio/cosmoaudio/cosmoaudio.h	\
+	dsp/audio/cosmoaudio/cosmoaudio.dll	\
+
+DSP_AUDIO_A_OBJS =				\
+	$(DSP_AUDIO_A_SRCS:%.c=o/$(MODE)/%.o)	\
+	$(DSP_AUDIO_A_DATA:%=o/$(MODE)/%.zip.o)	\
+
+DSP_AUDIO_A_CHECKS =				\
+	$(DSP_AUDIO_A).pkg			\
+	$(DSP_AUDIO_A_HDRS:%=o/$(MODE)/%.ok)
+
+DSP_AUDIO_A_DIRECTDEPS =			\
+	LIBC_CALLS				\
+	LIBC_DLOPEN				\
+	LIBC_INTRIN				\
+	LIBC_NEXGEN32E				\
+	LIBC_STR				\
+	LIBC_SYSV				\
+	LIBC_PROC				\
+	LIBC_THREAD				\
+
+DSP_AUDIO_A_DEPS :=				\
+	$(call uniq,$(foreach x,$(DSP_AUDIO_A_DIRECTDEPS),$($(x))))
+
+$(DSP_AUDIO_A):	dsp/audio/			\
+		$(DSP_AUDIO_A).pkg		\
+		$(DSP_AUDIO_A_OBJS)
+
+$(DSP_AUDIO_A).pkg:				\
+		$(DSP_AUDIO_A_OBJS)		\
+		$(foreach x,$(DSP_AUDIO_A_DIRECTDEPS),$($(x)_A).pkg)
+
+DSP_AUDIO_LIBS = $(foreach x,$(DSP_AUDIO_ARTIFACTS),$($(x)))
+DSP_AUDIO_SRCS = $(foreach x,$(DSP_AUDIO_ARTIFACTS),$($(x)_SRCS))
+DSP_AUDIO_HDRS = $(foreach x,$(DSP_AUDIO_ARTIFACTS),$($(x)_HDRS))
+DSP_AUDIO_CHECKS = $(foreach x,$(DSP_AUDIO_ARTIFACTS),$($(x)_CHECKS))
+DSP_AUDIO_OBJS = $(foreach x,$(DSP_AUDIO_ARTIFACTS),$($(x)_OBJS))
+$(DSP_AUDIO_OBJS): $(BUILD_FILES) dsp/audio/BUILD.mk
+
+.PHONY: o/$(MODE)/dsp/audio
+o/$(MODE)/dsp/audio: $(DSP_AUDIO_CHECKS)

dsp/audio/audio.c

@@ -0,0 +1,353 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│ vi: set et ft=c ts=2 sts=2 sw=2 fenc=utf-8                               :vi │
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2024 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ 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.      │
+│                                                                              │
+│ THE 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 "dsp/audio/cosmoaudio/cosmoaudio.h"
+#include "libc/calls/calls.h"
+#include "libc/calls/struct/stat.h"
+#include "libc/calls/struct/timespec.h"
+#include "libc/dce.h"
+#include "libc/dlopen/dlfcn.h"
+#include "libc/errno.h"
+#include "libc/limits.h"
+#include "libc/proc/posix_spawn.h"
+#include "libc/runtime/runtime.h"
+#include "libc/str/str.h"
+#include "libc/sysv/consts/o.h"
+#include "libc/temp.h"
+#include "libc/thread/thread.h"
+
+__static_yoink("dsp/audio/cosmoaudio/miniaudio.h");
+__static_yoink("dsp/audio/cosmoaudio/cosmoaudio.h");
+__static_yoink("dsp/audio/cosmoaudio/cosmoaudio.c");
+__static_yoink("dsp/audio/cosmoaudio/cosmoaudio.dll");
+
+static const struct Source {
+  const char *zip;
+  const char *name;
+} srcs[] = {
+    {"/zip/dsp/audio/cosmoaudio/miniaudio.h", "miniaudio.h"},
+    {"/zip/dsp/audio/cosmoaudio/cosmoaudio.h", "cosmoaudio.h"},
+    {"/zip/dsp/audio/cosmoaudio/cosmoaudio.c", "cosmoaudio.c"},  // must last
+};
+
+static struct {
+  pthread_once_t once;
+  typeof(cosmoaudio_open) *open;
+  typeof(cosmoaudio_close) *close;
+  typeof(cosmoaudio_write) *write;
+  typeof(cosmoaudio_read) *read;
+} g_audio;
+
+static const char *get_tmp_dir(void) {
+  const char *tmpdir;
+  if (!(tmpdir = getenv("TMPDIR")) || !*tmpdir)
+    if (!(tmpdir = getenv("HOME")) || !*tmpdir)
+      tmpdir = ".";
+  return tmpdir;
+}
+
+static bool get_app_dir(char *path, size_t size) {
+  strlcpy(path, get_tmp_dir(), size);
+  strlcat(path, "/.cosmo/", size);
+  if (makedirs(path, 0755))
+    return false;
+  return true;
+}
+
+static bool get_dso_path(char *path, size_t size) {
+  if (!get_app_dir(path, size))
+    return false;
+  strlcat(path, "cosmoaudio", size);
+  if (IsWindows()) {
+    strlcat(path, ".dll", size);
+  } else if (IsXnu()) {
+    strlcat(path, ".dylib", size);
+  } else {
+    strlcat(path, ".so", size);
+  }
+  return true;
+}
+
+static int is_file_newer_than_time(const char *path, const char *other) {
+  struct stat st1, st2;
+  if (stat(path, &st1))
+    // PATH should always exist when calling this function
+    return -1;
+  if (stat(other, &st2)) {
+    if (errno == ENOENT) {
+      // PATH should replace OTHER because OTHER doesn't exist yet
+      return true;
+    } else {
+      // some other error happened, so we can't do anything
+      return -1;
+    }
+  }
+  // PATH should replace OTHER if PATH was modified more recently
+  return timespec_cmp(st1.st_mtim, st2.st_mtim) > 0;
+}
+
+static int is_file_newer_than_bytes(const char *path, const char *other) {
+  int other_fd;
+  if ((other_fd = open(other, O_RDONLY | O_CLOEXEC)) == -1) {
+    if (errno == ENOENT) {
+      return true;
+    } else {
+      return -1;
+    }
+  }
+  int path_fd;
+  if ((path_fd = open(path, O_RDONLY | O_CLOEXEC)) == -1) {
+    close(other_fd);
+    return -1;
+  }
+  int res;
+  long i = 0;
+  for (;;) {
+    char path_buf[512];
+    ssize_t path_rc = pread(path_fd, path_buf, sizeof(path_buf), i);
+    if (path_rc == -1) {
+      res = -1;
+      break;
+    }
+    char other_buf[512];
+    ssize_t other_rc = pread(other_fd, other_buf, sizeof(other_buf), i);
+    if (other_rc == -1) {
+      res = -1;
+      break;
+    }
+    if (!path_rc || !other_rc) {
+      if (!path_rc && !other_rc)
+        res = false;
+      else
+        res = true;
+      break;
+    }
+    size_t size = path_rc;
+    if (other_rc < path_rc)
+      size = other_rc;
+    if (memcmp(path_buf, other_buf, size)) {
+      res = true;
+      break;
+    }
+    i += size;
+  }
+  if (close(path_fd))
+    res = -1;
+  if (close(other_fd))
+    res = -1;
+  return res;
+}
+
+static int is_file_newer_than(const char *path, const char *other) {
+  if (startswith(path, "/zip/"))
+    // to keep builds deterministic, embedded zip files always have
+    // the same timestamp from back in 2022 when it was implemented
+    return is_file_newer_than_bytes(path, other);
+  else
+    return is_file_newer_than_time(path, other);
+}
+
+static bool extract(const char *zip, const char *to) {
+  int fdin, fdout;
+  char stage[PATH_MAX];
+  strlcpy(stage, to, sizeof(stage));
+  if (strlcat(stage, ".XXXXXX", sizeof(stage)) >= sizeof(stage)) {
+    errno = ENAMETOOLONG;
+    return false;
+  }
+  if ((fdout = mkostemp(stage, O_CLOEXEC)) == -1) {
+    return false;
+  }
+  if ((fdin = open(zip, O_RDONLY | O_CLOEXEC)) == -1) {
+    close(fdout);
+    unlink(stage);
+    return false;
+  }
+  if (copyfd(fdin, fdout, -1) == -1) {
+    close(fdin);
+    close(fdout);
+    unlink(stage);
+    return false;
+  }
+  if (close(fdout)) {
+    close(fdin);
+    unlink(stage);
+    return false;
+  }
+  if (close(fdin)) {
+    unlink(stage);
+    return false;
+  }
+  if (rename(stage, to)) {
+    unlink(stage);
+    return false;
+  }
+  return true;
+}
+
+static bool deploy(const char *dso) {
+  switch (is_file_newer_than("/zip/dsp/audio/cosmoaudio/cosmoaudio.dll", dso)) {
+    case 0:
+      return true;
+    case 1:
+      return extract("/zip/dsp/audio/cosmoaudio/cosmoaudio.dll", dso);
+    default:
+      return false;
+  }
+}
+
+static bool build(const char *dso) {
+
+  // extract source code
+  char src[PATH_MAX];
+  bool needs_rebuild = false;
+  for (int i = 0; i < sizeof(srcs) / sizeof(*srcs); ++i) {
+    get_app_dir(src, PATH_MAX);
+    strlcat(src, srcs[i].name, sizeof(src));
+    switch (is_file_newer_than(srcs[i].zip, src)) {
+      case -1:
+        return false;
+      case 0:
+        break;
+      case 1:
+        needs_rebuild = true;
+        if (!extract(srcs[i].zip, src))
+          return false;
+        break;
+      default:
+        __builtin_unreachable();
+    }
+  }
+
+  // determine if we need to build
+  if (!needs_rebuild) {
+    switch (is_file_newer_than(src, dso)) {
+      case -1:
+        return false;
+      case 0:
+        break;
+      case 1:
+        needs_rebuild = true;
+        break;
+      default:
+        __builtin_unreachable();
+    }
+  }
+
+  // compile dynamic shared object
+  if (needs_rebuild) {
+    int fd;
+    char tmpdso[PATH_MAX];
+    strlcpy(tmpdso, dso, sizeof(tmpdso));
+    strlcat(tmpdso, ".XXXXXX", sizeof(tmpdso));
+    if ((fd = mkostemp(tmpdso, O_CLOEXEC)) != -1) {
+      close(fd);
+    } else {
+      return false;
+    }
+    char *args[] = {
+        "cc",                                       //
+        "-I.",                                      //
+        "-O2",                                      //
+        "-fPIC",                                    //
+        "-shared",                                  //
+        "-pthread",                                 //
+        "-DNDEBUG",                                 //
+        IsAarch64() ? "-ffixed-x28" : "-DIGNORE1",  //
+        src,                                        //
+        "-o",                                       //
+        tmpdso,                                     //
+        "-ldl",                                     //
+        "-lm",                                      //
+        NULL,
+    };
+    int pid, ws;
+    errno_t err = posix_spawnp(&pid, "cc", NULL, NULL, args, environ);
+    if (err)
+      return false;
+    while (waitpid(pid, &ws, 0) == -1) {
+      if (errno != EINTR)
+        return false;
+    }
+    if (ws)
+      return false;
+    if (rename(tmpdso, dso))
+      return false;
+  }
+
+  return true;
+}
+
+static void cosmoaudio_setup(void) {
+  void *handle;
+  if (!(handle = cosmo_dlopen("cosmoaudio.so", RTLD_LOCAL))) {
+    if (issetugid())
+      return;
+    char dso[PATH_MAX];
+    if (!get_dso_path(dso, sizeof(dso)))
+      return;
+    if (IsWindows())
+      if (deploy(dso))
+        if ((handle = cosmo_dlopen(dso, RTLD_LOCAL)))
+          goto WeAreGood;
+    if (!build(dso))
+      return;
+    if (!(handle = cosmo_dlopen(dso, RTLD_LOCAL)))
+      return;
+  }
+WeAreGood:
+  g_audio.open = cosmo_dlsym(handle, "cosmoaudio_open");
+  g_audio.close = cosmo_dlsym(handle, "cosmoaudio_close");
+  g_audio.write = cosmo_dlsym(handle, "cosmoaudio_write");
+  g_audio.read = cosmo_dlsym(handle, "cosmoaudio_read");
+}
+
+static void cosmoaudio_init(void) {
+  pthread_once(&g_audio.once, cosmoaudio_setup);
+}
+
+COSMOAUDIO_ABI int cosmoaudio_open(struct CosmoAudio **cap, int sampleRate,
+                                   int channels) {
+  cosmoaudio_init();
+  if (!g_audio.open)
+    return COSMOAUDIO_ERROR;
+  return g_audio.open(cap, sampleRate, channels);
+}
+
+COSMOAUDIO_ABI int cosmoaudio_close(struct CosmoAudio *ca) {
+  cosmoaudio_init();
+  if (!g_audio.close)
+    return COSMOAUDIO_ERROR;
+  return g_audio.close(ca);
+}
+
+COSMOAUDIO_ABI int cosmoaudio_write(struct CosmoAudio *ca, const float *data,
+                                    int frames) {
+  cosmoaudio_init();
+  if (!g_audio.write)
+    return COSMOAUDIO_ERROR;
+  return g_audio.write(ca, data, frames);
+}
+
+COSMOAUDIO_ABI int cosmoaudio_read(struct CosmoAudio *ca, float *data,
+                                   int frames) {
+  cosmoaudio_init();
+  if (!g_audio.read)
+    return COSMOAUDIO_ERROR;
+  return g_audio.read(ca, data, frames);
+}

dsp/audio/cosmoaudio/.gitignore

@@ -0,0 +1,3 @@
+*.o
+/Debug
+/Release

dsp/audio/cosmoaudio/Makefile.msvc

@@ -0,0 +1,86 @@
+# Makefile for MSVC x64 Command Line Developer Tools
+#
+#     nmake /f Makefile.msvc check
+#     nmake /f Makefile.msvc MODE=debug check
+#
+
+# Compiler and linker
+CC=cl
+LINK=link
+
+# Build mode (can be overridden from command line)
+!IFNDEF MODE
+MODE=release
+!ENDIF
+
+# Library dependencies.
+TEST_LIBS=OneCore.lib
+
+# Compiler flags
+CFLAGS_COMMON=/nologo /W4 /Gy /EHsc
+CFLAGS_DEBUG=/Od /Zi /MDd /D_DEBUG
+CFLAGS_RELEASE=/O2 /MD /DNDEBUG
+
+!IF "$(MODE)"=="debug"
+CFLAGS=$(CFLAGS_COMMON) $(CFLAGS_DEBUG)
+LDFLAGS=/DEBUG
+OUT_DIR=Debug
+!ELSE
+CFLAGS=$(CFLAGS_COMMON) $(CFLAGS_RELEASE) /GL
+LDFLAGS=/RELEASE /OPT:REF /OPT:ICF /LTCG /INCREMENTAL:NO
+OUT_DIR=Release
+!ENDIF
+
+# Additional flags for DLL
+DLL_CFLAGS=$(CFLAGS) /D_USRDLL /D_WINDLL
+
+# Linker flags
+LDFLAGS=/NOLOGO /SUBSYSTEM:CONSOLE $(LDFLAGS)
+
+# Output file names
+DLL_TARGET=$(OUT_DIR)\cosmoaudio.dll
+TEST_TARGET=$(OUT_DIR)\test.exe
+
+# Source files
+DLL_SOURCES=cosmoaudio.c
+TEST_SOURCES=test.c
+
+# Object files
+DLL_OBJECTS=$(OUT_DIR)\cosmoaudio.obj
+TEST_OBJECTS=$(OUT_DIR)\test.obj
+
+# Default target
+all: $(OUT_DIR) $(DLL_TARGET) $(TEST_TARGET)
+
+# Create output directory
+$(OUT_DIR):
+    if not exist $(OUT_DIR) mkdir $(OUT_DIR)
+
+# Rule to build the DLL
+$(DLL_TARGET): $(OUT_DIR) $(DLL_OBJECTS)
+    $(LINK) /DLL $(LDFLAGS) /OUT:$(DLL_TARGET) $(DLL_OBJECTS)
+
+# Rule to build the test program
+$(TEST_TARGET): $(OUT_DIR) $(TEST_OBJECTS) $(DLL_TARGET)
+    $(LINK) $(LDFLAGS) /OUT:$(TEST_TARGET) $(TEST_OBJECTS) $(DLL_TARGET:.dll=.lib) $(TEST_LIBS)
+
+# Rules to compile .c files to .obj files with header dependencies
+{.}.c{$(OUT_DIR)}.obj:
+    $(CC) $(DLL_CFLAGS) /c /Fo$(OUT_DIR)\ $<
+
+$(OUT_DIR)\test.obj: $(OUT_DIR) test.c cosmoaudio.h
+    $(CC) $(CFLAGS) /c /Fo$(OUT_DIR)\ test.c
+
+$(OUT_DIR)\cosmoaudio.obj: $(OUT_DIR) cosmoaudio.c miniaudio.h cosmoaudio.h
+    $(CC) $(DLL_CFLAGS) /c /Fo$(OUT_DIR)\ cosmoaudio.c
+
+# Clean target
+clean:
+    if exist $(OUT_DIR) rmdir /s /q $(OUT_DIR)
+
+# Run tests (now called 'check')
+check: $(TEST_TARGET)
+    $(TEST_TARGET)
+
+# Phony targets
+.PHONY: all clean check

dsp/audio/cosmoaudio/cosmoaudio.c

@@ -0,0 +1,251 @@
+#define COSMOAUDIO_BUILD
+#include "cosmoaudio.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define MA_STATIC
+#define MA_NO_DECODING
+#define MA_NO_ENCODING
+#ifdef NDEBUG
+#define MA_DR_MP3_NO_STDIO
+#endif
+#define MINIAUDIO_IMPLEMENTATION
+#include "miniaudio.h"
+
+#ifndef NDEBUG
+#define LOG(...) fprintf(stderr, __VA_ARGS__)
+#else
+#define LOG(...) (void)0
+#endif
+
+struct CosmoAudio {
+  ma_device device;
+  ma_pcm_rb input;
+  ma_pcm_rb output;
+  ma_uint32 sampleRate;
+  ma_uint32 channels;
+};
+
+static int read_ring_buffer(ma_pcm_rb* rb, float* pOutput, ma_uint32 frameCount,
+                            ma_uint32 channels) {
+  ma_result result;
+  ma_uint32 framesRead;
+  ma_uint32 framesToRead;
+  for (framesRead = 0; framesRead < frameCount; framesRead += framesToRead) {
+    framesToRead = frameCount - framesRead;
+    void* pMappedBuffer;
+    result = ma_pcm_rb_acquire_read(rb, &framesToRead, &pMappedBuffer);
+    if (result != MA_SUCCESS) {
+      LOG("ma_pcm_rb_acquire_read failed: %s\n", ma_result_description(result));
+      return COSMOAUDIO_ERROR;
+    }
+    if (!framesToRead)
+      break;
+    memcpy(pOutput + framesRead * channels, pMappedBuffer,
+           framesToRead * channels * sizeof(float));
+    result = ma_pcm_rb_commit_read(rb, framesToRead);
+    if (result != MA_SUCCESS) {
+      if (result == MA_AT_END)
+        break;
+      LOG("ma_pcm_rb_commit_read failed: %s\n", ma_result_description(result));
+      return COSMOAUDIO_ERROR;
+    }
+  }
+  return framesRead;
+}
+
+static int write_ring_buffer(ma_pcm_rb* rb, const float* pInput,
+                             ma_uint32 frameCount, ma_uint32 channels) {
+  ma_result result;
+  ma_uint32 framesWritten;
+  ma_uint32 framesToWrite;
+  for (framesWritten = 0; framesWritten < frameCount;
+       framesWritten += framesToWrite) {
+    framesToWrite = frameCount - framesWritten;
+    void* pMappedBuffer;
+    result = ma_pcm_rb_acquire_write(rb, &framesToWrite, &pMappedBuffer);
+    if (result != MA_SUCCESS) {
+      LOG("ma_pcm_rb_acquire_write failed: %s\n",
+          ma_result_description(result));
+      return COSMOAUDIO_ERROR;
+    }
+    if (!framesToWrite)
+      break;
+    memcpy(pMappedBuffer, pInput + framesWritten * channels,
+           framesToWrite * channels * sizeof(float));
+    result = ma_pcm_rb_commit_write(rb, framesToWrite);
+    if (result != MA_SUCCESS) {
+      if (result == MA_AT_END)
+        break;
+      LOG("ma_pcm_rb_commit_write failed: %s\n", ma_result_description(result));
+      return COSMOAUDIO_ERROR;
+    }
+  }
+  return framesWritten;
+}
+
+static void data_callback_f32(ma_device* pDevice, float* pOutput,
+                              const float* pInput, ma_uint32 frameCount) {
+  struct CosmoAudio* ca = (struct CosmoAudio*)pDevice->pUserData;
+  read_ring_buffer(&ca->output, pOutput, frameCount, ca->channels);
+  write_ring_buffer(&ca->input, pInput, frameCount, ca->channels);
+}
+
+static void data_callback(ma_device* pDevice, void* pOutput, const void* pInput,
+                          ma_uint32 frameCount) {
+  data_callback_f32(pDevice, (float*)pOutput, (const float*)pInput, frameCount);
+}
+
+/**
+ * Opens access to speaker and microphone.
+ *
+ * @param cap will receive pointer to allocated CosmoAudio object on success,
+ *     which must be freed by caller with cosmoaudio_close()
+ * @param sampleRate is sample rate in Hz, e.g. 44100
+ * @param channels is number of channels (1 for mono, 2 for stereo)
+ * @return 0 on success, or negative error code on failure
+ */
+COSMOAUDIO_ABI int cosmoaudio_open(struct CosmoAudio** cap, int sampleRate,
+                                   int channels) {
+
+  // Allocate cosmo audio object.
+  struct CosmoAudio* ca;
+  if (!(ca = (struct CosmoAudio*)malloc(sizeof(struct CosmoAudio))))
+    return COSMOAUDIO_ERROR;
+  ca->channels = channels;
+  ca->sampleRate = sampleRate;
+
+  // Initialize device.
+  ma_result result;
+  ma_device_config deviceConfig = ma_device_config_init(ma_device_type_duplex);
+  deviceConfig.sampleRate = sampleRate;
+  deviceConfig.capture.channels = channels;
+  deviceConfig.capture.format = ma_format_f32;
+  deviceConfig.capture.shareMode = ma_share_mode_shared;
+  deviceConfig.playback.channels = channels;
+  deviceConfig.playback.format = ma_format_f32;
+  deviceConfig.dataCallback = data_callback;
+  deviceConfig.pUserData = ca;
+  result = ma_device_init(NULL, &deviceConfig, &ca->device);
+  if (result != MA_SUCCESS) {
+    free(ca);
+    return COSMOAUDIO_ERROR;
+  }
+
+  // Initialize the speaker ring buffer.
+  result = ma_pcm_rb_init(ma_format_f32, channels,
+                          ca->device.playback.internalPeriodSizeInFrames * 10,
+                          NULL, NULL, &ca->output);
+  if (result != MA_SUCCESS) {
+    ma_device_uninit(&ca->device);
+    free(ca);
+    return COSMOAUDIO_ERROR;
+  }
+  ma_pcm_rb_set_sample_rate(&ca->output, sampleRate);
+
+  // Initialize the microphone ring buffer.
+  result = ma_pcm_rb_init(ma_format_f32, channels,
+                          ca->device.capture.internalPeriodSizeInFrames * 10,
+                          NULL, NULL, &ca->input);
+  if (result != MA_SUCCESS) {
+    ma_pcm_rb_uninit(&ca->output);
+    ma_device_uninit(&ca->device);
+    free(ca);
+    return COSMOAUDIO_ERROR;
+  }
+  ma_pcm_rb_set_sample_rate(&ca->output, sampleRate);
+
+  // Start audio playback.
+  if (ma_device_start(&ca->device) != MA_SUCCESS) {
+    ma_pcm_rb_uninit(&ca->input);
+    ma_pcm_rb_uninit(&ca->output);
+    ma_device_uninit(&ca->device);
+    free(ca);
+    return COSMOAUDIO_ERROR;
+  }
+
+  *cap = ca;
+  return COSMOAUDIO_SUCCESS;
+}
+
+/**
+ * Closes audio device and frees all associated resources.
+ *
+ * @param ca is CosmoAudio object returned earlier by cosmoaudio_open()
+ * @return 0 on success, or negative error code on failure
+ */
+COSMOAUDIO_ABI int cosmoaudio_close(struct CosmoAudio* ca) {
+  ma_device_uninit(&ca->device);
+  ma_pcm_rb_uninit(&ca->output);
+  free(ca);
+  return COSMOAUDIO_SUCCESS;
+}
+
+/**
+ * Writes raw audio data to speaker.
+ *
+ * The data is written to a ring buffer in real-time, which is then
+ * played back very soon on the audio device. This has tolerence for
+ * a certain amount of buffering, but expects that this function is
+ * repeatedly called at a regular time interval. The caller should
+ * have its own sleep loop for this purpose.
+ *
+ * @param ca is CosmoAudio object returned earlier by cosmoaudio_open()
+ * @param data is pointer to raw audio samples, expected to be in the range
+ *     -1.0 to 1.0, where channels are interleaved
+ * @param frames is the number of frames (i.e. number of samples divided by
+ *     number of channels) from `data` to write to audio device
+ * @return number of frames written, or negative error code on failure
+ */
+COSMOAUDIO_ABI int cosmoaudio_write(struct CosmoAudio* ca, const float* data,
+                                    int frames) {
+  return write_ring_buffer(&ca->output, data, frames, ca->channels);
+}
+
+/**
+ * Reads raw audio data from microphone.
+ *
+ * The data is read from a ring buffer in real-time, which is then
+ * played back very soon on the audio device. This has tolerence for
+ * a certain amount of buffering, but expects that this function is
+ * repeatedly called at a regular time interval. The caller should
+ * have its own sleep loop for this purpose.
+ *
+ * @param ca is CosmoAudio object returned earlier by cosmoaudio_open()
+ * @param data is pointer to raw audio samples, expected to be in the range
+ *     -1.0 to 1.0, where channels are interleaved
+ * @param frames is the number of frames (i.e. number of samples divided by
+ *     number of channels) from `data` to read from microphone
+ * @return number of frames read, or negative error code on failure
+ */
+COSMOAUDIO_ABI int cosmoaudio_read(struct CosmoAudio* ca, float* data,
+                                   int frames) {
+  int read;
+  for (int i = 0; i < frames; i += read) {
+    int remaining = frames - i;
+    read = read_ring_buffer(&ca->input, data + i * ca->channels, remaining,
+                            ca->channels);
+    if (read < 0)
+      return read;
+  }
+  return frames;
+}
+
+#ifdef _MSC_VER
+#include <Windows.h>
+BOOL APIENTRY DllMain(HMODULE hModule, DWORD ul_reason_for_call,
+                      LPVOID lpReserved) {
+  switch (ul_reason_for_call) {
+    case DLL_PROCESS_ATTACH:
+    case DLL_THREAD_ATTACH:
+    case DLL_THREAD_DETACH:
+    case DLL_PROCESS_DETACH:
+      break;
+  }
+  return TRUE;
+  (void)hModule;
+  (void)lpReserved;
+  (void)ul_reason_for_call;
+}
+#endif

dsp/audio/cosmoaudio/cosmoaudio.h

@@ -0,0 +1,41 @@
+#ifndef COSMOAUDIO_H_
+#define COSMOAUDIO_H_
+
+#ifdef _MSC_VER
+#define COSMOAUDIO_ABI
+#ifdef COSMOAUDIO_BUILD
+#define COSMOAUDIO_API __declspec(dllexport)
+#else
+#define COSMOAUDIO_API __declspec(dllimport)
+#endif
+#else
+#define COSMOAUDIO_API
+#ifdef __x86_64__
+#define COSMOAUDIO_ABI __attribute__((__ms_abi__))
+#else
+#define COSMOAUDIO_ABI
+#endif
+#endif
+
+#define COSMOAUDIO_SUCCESS 0
+#define COSMOAUDIO_ERROR   -1
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct CosmoAudio;
+
+COSMOAUDIO_API int cosmoaudio_open(struct CosmoAudio **, int,
+                                   int) COSMOAUDIO_ABI;
+COSMOAUDIO_API int cosmoaudio_close(struct CosmoAudio *) COSMOAUDIO_ABI;
+COSMOAUDIO_API int cosmoaudio_write(struct CosmoAudio *, const float *,
+                                    int) COSMOAUDIO_ABI;
+COSMOAUDIO_API int cosmoaudio_read(struct CosmoAudio *, float *,
+                                   int) COSMOAUDIO_ABI;
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* COSMOAUDIO_H_ */

dsp/audio/cosmoaudio/test.c

@@ -0,0 +1,36 @@
+#include <errno.h>
+#include <limits.h>
+#include <math.h>
+#include <stdio.h>
+#include <time.h>
+#include "cosmoaudio.h"
+
+#ifndef M_PIf
+#define M_PIf 3.14159265358979323846f
+#endif
+
+int main() {
+
+  int hz = 44100;
+  int channels = 2;
+  struct CosmoAudio *ca;
+  if (cosmoaudio_open(&ca, hz, channels) != COSMOAUDIO_SUCCESS) {
+    fprintf(stderr, "%s: failed to open audio\n", argv[0]);
+    return 1;
+  }
+
+  int n = 1000;
+  int sample = 0;
+  float *buf = (float *)malloc(sizeof(float) * channels * n);
+  for (;;) {
+    for (int i = 0; i < 128; i++) {
+      float freq = 440;
+      float t = (float)sample++ / hz;
+      if (sample == hz)
+        sample = 0;
+      buf[i * channels] = sinf(freq * 2.f * M_PIf * t);
+      buf[i * channels + 1] = sinf(freq * 2.f * M_PIf * t);
+    }
+    cosmoaudio_write(ca, buf, 128);
+  }
+}