feat: buffered decoding API

examples/in_memory/main.odin

@@ -0,0 +1,81 @@
+package main
+
+import "core:os"
+import "core:fmt"
+import "core:mem"
+import "core:mem/virtual"
+import "core:time"
+
+import "shared:alsa"
+import "shared:flac"
+
+DEVICE :: "default"
+
+main :: proc() {
+    if len(os.args) < 2 {
+        fmt.eprintln("Please provide a path to a flac file.")
+        os.exit(1)
+    }
+
+    handle: ^alsa.pcm_t
+
+    arena: virtual.Arena
+    arena_err := virtual.arena_init_growing(&arena, mem.Megabyte * 8)
+    if arena_err != nil {
+        fmt.eprintln("Failed to alloc memory")
+        return
+    }
+    allocator := virtual.arena_allocator(&arena)
+
+    alsa_err := alsa.pcm_open(&handle, DEVICE, .PLAYBACK, .BLOCK)
+    if alsa_err < 0 {
+        fmt.eprintln("Failed to initialize audio device: ", alsa.strerror(alsa_err))
+        os.exit(1)
+    }
+
+    start := time.now()
+    flac_data, err := flac.load_from_file(os.args[1], allocator = allocator)
+    if err != nil {
+        fmt.eprintln(err)
+        if err == .MD5_Mismatch {
+            fmt.printfln("Expected: %v, got: %v", flac_data.metadata.expected_md5, flac_data.metadata.calculated_md5)
+        }
+        os.exit(1)
+    }
+    defer flac.destroy(flac_data, allocator = allocator)
+    end := time.now()
+
+    fmt.println(flac_data.metadata)
+
+    alsa_err = alsa.pcm_set_params(handle, .S16_LE, .RW_INTERLEAVED, u32(flac_data.metadata.channels), flac_data.metadata.sample_rate, 1, 500000)
+    if alsa_err < 0 {
+        fmt.eprintln("Playback open error:", alsa.strerror(alsa_err))
+        os.exit(1)
+    }
+
+    converted_samples := make([]i16, len(flac_data.samples))
+
+    for sample, i in flac_data.samples {
+        new_sample := sample & 0xFF
+        new_sample |= ((sample >> 8) & 0xFF) << 8
+        converted_samples[i] = i16(new_sample)
+    }
+
+    for {
+        frames := alsa.pcm_writei(handle, raw_data(converted_samples), u64(len(flac_data.samples)) / u64(flac_data.metadata.channels))
+        if frames < 0 {
+            fmt.eprintln("Error writing to PCM device:", alsa.strerror(auto_cast frames))
+            break
+        }
+        fmt.printfln("Played %d frames", frames)
+    }
+
+    alsa_err = alsa.pcm_drain(handle)
+    if alsa_err < 0 {
+        fmt.eprintln("pcm_drain failed with:", alsa.strerror(alsa_err))
+    }
+    alsa.pcm_close(handle)
+
+    elapsed := time.diff(start, end)
+    fmt.println("Decoding took", elapsed)
+}