initial commit

main.odin

@@ -0,0 +1,119 @@
+package main
+
+import "base:runtime"
+import "base:intrinsics"
+import "core:fmt"
+import "core:slice"
+import "core:time"
+import "core:encoding/endian"
+import "core:sys/posix"
+import "core:os/os2"
+
+import "shared:alsa"
+
+DEVICE :: "default"
+OUTPUT_FILE :: "capture"
+FRAMES :: 128
+FORMAT: alsa.pcm_format_t : .S16_LE
+BITS_PER_SAMPLE :: 16
+CHANNELS :: 1
+SAMPLE_RATE :: 22050
+
+WAV_HEADER_SIZE :: 44
+
+interrupted := false
+
+main :: proc() {
+    handle: ^alsa.pcm_t
+
+    alsa_err := alsa.pcm_open(&handle, DEVICE, .CAPTURE, .BLOCK)
+    if alsa_err < 0 {
+        fmt.eprintln("Failed to open default capture device.")
+        os2.exit(1)
+    }
+    defer alsa.pcm_close(handle)
+
+    now := time.now()
+    year, month, day := time.date(now)
+    hour, minute, second := time.clock_from_time(now)
+
+    out, err := os2.open(fmt.tprintf("%v_%v-%02d-%02dT%02d:%02d:%02d.wav", OUTPUT_FILE, year, int(month), day, hour, minute, second), {.Write, .Create, .Trunc}, 0o644)
+    if err != nil {
+        fmt.eprintln("Failed to open output file:", err)
+        os2.exit(1)
+    }
+    defer os2.close(out)
+
+    alsa_err = alsa.pcm_set_params(handle, FORMAT, .RW_INTERLEAVED, CHANNELS, SAMPLE_RATE, 1, 500000)
+    if alsa_err < 0 {
+        fmt.eprintln("Failed to set the HW params")
+        os2.exit(1)
+    }
+
+    alsa_err = alsa.pcm_prepare(handle)
+    if alsa_err < 0 {
+        fmt.eprintln("Failed to prepare audio device for capture.")
+        os2.exit(1)
+    }
+
+    samples := make([]u8, FRAMES * CHANNELS * alsa.pcm_format_width(FORMAT) / 8)
+
+    fmt.println("Capturing audio")
+
+    action: posix.sigaction_t
+    action.sa_handler = proc "c" (signal: posix.Signal) {
+        context = runtime.default_context()
+        fmt.println("\nCaught SIGINT. Exiting gracefully")
+        intrinsics.atomic_store(&interrupted, true)
+    }
+    posix.sigaction(.SIGINT, &action, nil)
+
+    four_byte_slice := make([]byte, 4)
+    two_byte_slice := make([]byte, 2)
+    defer delete(four_byte_slice)
+    defer delete(two_byte_slice)
+
+    os2.write(out, []byte{'R', 'I', 'F', 'F'}) // Riff file
+    os2.write(out, []byte{0,0,0,0})            // File size - 8 bytes. To be filled in later
+    os2.write(out, []byte{'W', 'A', 'V', 'E'}) // WAVE data
+    os2.write(out, []byte{'f', 'm', 't', ' '}) // Format chunk marker with NUL byte
+    endian.put_i32(four_byte_slice, .Little, 16)
+    os2.write(out, four_byte_slice)            // Chunk size: 16 for PCM
+    endian.put_i16(two_byte_slice, .Little, 1)
+    os2.write(out, two_byte_slice)             // Audio format: 1 for PCM
+    os2.write(out, two_byte_slice)             // Number of channels
+    endian.put_i32(four_byte_slice, .Little, SAMPLE_RATE)
+    os2.write(out, four_byte_slice)            // Sample rate
+    endian.put_i32(four_byte_slice, .Little, SAMPLE_RATE * CHANNELS * BITS_PER_SAMPLE / 8)
+    os2.write(out, four_byte_slice)            // Byte rate
+    endian.put_i16(two_byte_slice, .Little, CHANNELS * BITS_PER_SAMPLE / 8)
+    os2.write(out, two_byte_slice)             // Block align
+    endian.put_i16(two_byte_slice, .Little, BITS_PER_SAMPLE)
+    os2.write(out, two_byte_slice)             // Bits per sample
+    os2.write(out, []byte{'d', 'a', 't', 'a'}) // Data chunk header
+
+    size_written := 0
+
+    os2.write(out, []byte{0,0,0,0}) // Length of data. To be filled in later
+
+    for !intrinsics.atomic_load(&interrupted) {
+        read := alsa.pcm_readi(handle, raw_data(samples), FRAMES)
+        if read != FRAMES {
+            fmt.eprintfln("Didn't read %v frames", FRAMES)
+            os2.exit(1)
+        }
+
+        n, err := os2.write(out, samples) // Write the data
+        if err != nil {
+            fmt.eprintln("Failed to write sample data to file:", err)
+            os2.exit(1)
+        }
+        size_written += n
+    }
+
+    endian.put_i32(four_byte_slice, .Little, i32(size_written + WAV_HEADER_SIZE - 8))
+    os2.write_at(out, four_byte_slice, 4) // Overall size - 8 bytes
+
+    endian.put_i32(four_byte_slice, .Little, i32(size_written))
+    os2.write_at(out, four_byte_slice, 40) // Data size
+}