Files
reasampler/src/core/capture/tail_control.cpp
T

120 lines
3.8 KiB
C++

// tail_control — pure implementation. See tail_control.h.
#include "core/capture/tail_control.h"
#include <algorithm>
#include <cstdio>
#include "core/json/json.h"
namespace reasampler::capture {
TailMode cycleTailMode(TailMode current) {
switch (current) {
case TailMode::None: return TailMode::Auto;
case TailMode::Auto: return TailMode::Manual;
case TailMode::Manual: return TailMode::None;
}
return TailMode::None; // unreachable for a valid enum; fail to the safe default
}
double clampManualMs(double manualMs) {
return std::clamp(manualMs, 0.0, kMaxTailMs);
}
double adjustManualMs(double current, int notches, double stepMs) {
return clampManualMs(current + notches * stepMs);
}
std::string tailToggleLabel(const TailSetting& setting) {
switch (setting.mode) {
case TailMode::None: return "Tail: Off";
case TailMode::Auto: return "Tail: Auto";
case TailMode::Manual: {
// Clamped so the readout can't show an over-cap value even if
// manualMs was stored past the cap.
const double seconds = clampManualMs(setting.manualMs) / 1000.0;
char buf[32];
std::snprintf(buf, sizeof(buf), "Tail: Manual %.1fs", seconds);
return std::string(buf);
}
}
return "Tail: Off"; // unreachable for a valid enum; fail to the safe default
}
// --- JSON round-trip ---------------------------------------------------------
// manualMs round-trips exactly (json::numToStr uses the shortest %.17g-class
// form for doubles); deserialize returns nullopt on any parse failure.
namespace {
// The persisted integer for a mode. Stable forever (stored in the .rpp): never
// renumber these values or an already-saved project reads back the wrong mode.
int modeToInt(TailMode m) {
switch (m) {
case TailMode::None: return 0;
case TailMode::Auto: return 1;
case TailMode::Manual: return 2;
}
return 0;
}
std::optional<TailMode> modeFromInt(int v) {
switch (v) {
case 0: return TailMode::None;
case 1: return TailMode::Auto;
case 2: return TailMode::Manual;
default: return std::nullopt; // unknown enumerant -> malformed -> default
}
}
} // namespace
std::string serializeTailSetting(const TailSetting& setting) {
// Byte-identical to the former snprintf writer: {"mode":%d,"manualMs":%.17g}.
std::string out;
{
json::Writer w(out);
w.keyRaw("mode", json::numToStr(modeToInt(setting.mode)));
w.keyRaw("manualMs", json::numToStr(setting.manualMs));
} // Writer closes the object here (see bank_model's NRVO note)
return out;
}
std::optional<TailSetting> deserializeTailSetting(const std::string& blob) {
json::Reader r(blob);
if (!r.consume('{')) return std::nullopt;
int modeInt = 0;
double ms = 0.0;
bool haveMode = false, haveMs = false;
r.skipWs();
if (!r.consume('}')) {
do {
std::string key;
if (!r.parseKey(key)) return std::nullopt;
if (key == "mode") {
if (!r.parseInt(modeInt)) return std::nullopt;
haveMode = true;
} else if (key == "manualMs") {
if (!r.parseDouble(ms)) return std::nullopt;
haveMs = true;
} else {
if (!r.skipValue()) return std::nullopt; // forward-compat
}
} while (r.consume(','));
if (!r.consume('}')) return std::nullopt;
}
if (!haveMode || !haveMs) return std::nullopt; // absent key -> malformed -> default
const std::optional<TailMode> mode = modeFromInt(modeInt);
if (!mode) return std::nullopt;
TailSetting out;
out.mode = *mode;
out.manualMs = ms;
return out;
}
} // namespace reasampler::capture