62 lines
2.6 KiB
C
62 lines
2.6 KiB
C
// Copyright (c) 2026 Peter Fors
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// SPDX-License-Identifier: MIT
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//
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// Common interface every ported replayer exports. Each player's header declares
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// a `struct player_api <name>_api` global that the test player (or any host)
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// can iterate to auto-detect the right replayer for a file.
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//
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// Audio output is interleaved float stereo, nominal range [-1.0, 1.0]. Players
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// ACCUMULATE into the caller's buffer (caller must pre-clear). They do NOT
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// clip; the host is responsible for any final saturation, dithering, or
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// conversion to the audio backend's native sample format.
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#pragma once
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#include <stdint.h>
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// Optional file-loader callback used by players that read companion files
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// (IFF SMUS instrument files, Face The Music external samples, etc.). Hosts
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// that pass a loader implement `fetch` to resolve a logical name (e.g.
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// "Instruments/Bass6.instr") to a heap-allocated byte buffer + length. The
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// player calls free() on the returned pointer when done.
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struct player_loader {
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void *ctx;
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uint8_t *(*fetch)(void *ctx, const char *name, uint32_t *out_len);
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};
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struct player_api {
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const char *name;
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const char **extensions; /* null-terminated list of lowercase extensions, no dot */
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void *(*init)(void *data, uint32_t len, int32_t sample_rate);
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void (*free)(void *state);
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void (*get_audio)(void *state, float *output, int32_t frames);
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// Optional: when non-null and the host has a loader for sibling files,
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// the host should prefer this entry point. Players that don't need
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// external files leave this null and the host falls back to init().
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void *(*init_ex)(void *data, uint32_t len, int32_t sample_rate, struct player_loader *loader);
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};
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// [=]===^=[ player_get_audio_s16 ]===============================================================[=]
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// Convenience wrapper for hosts that want signed-16 PCM out. Drives the
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// player's float get_audio into the caller-supplied scratch buffer (must hold
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// at least frames * 2 floats), clears it first, then converts with hard
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// saturation into `output` (frames * 2 int16 stereo samples). The scratch is
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// caller-owned so the hot path never allocates; reuse the same buffer across
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// calls.
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#include <string.h>
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static void player_get_audio_s16(struct player_api *api, void *state, int16_t *output, float *scratch, int32_t frames) {
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int32_t samples = frames * 2;
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memset(scratch, 0, (size_t)samples * sizeof(float));
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api->get_audio(state, scratch, frames);
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for(int32_t i = 0; i < samples; ++i) {
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float v = scratch[i] * 32767.0f;
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if(v > 32767.0f) {
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v = 32767.0f;
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}
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if(v < -32768.0f) {
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v = -32768.0f;
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}
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output[i] = (int16_t)v;
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}
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}
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