// Copyright (c) 2000 - 2026 kio@little-bat.de // BSD-2-Clause license // https://opensource.org/licenses/BSD-2-Clause #pragma once #include "zxsp_types.h" /* Buffer for csw bytes: runlength encoded compressed square wave data. Stores an audio signal as one-bit samples, and compacts this further by storing the run length (sample count) of each phase only. Definitions: pulse: sequence of samples with all the same phase phase: boolean value: sample<0 ? 0 : 1 The buffer may be in one of 7 modes: - stopped: tape operations like cueing are possible playing: - samples: play into a sample buffer for audio output - edges: peek into the data with input(Time) instructions - pulses: retrieve complete pulses for data conversion (export) recording: - samples: record from a sample buffer from audio input - edges: store signal edges from output(Time) instructions - pulses: store complete pulses for data conversion (import) Compression scheme: 1 byte: 1 to 255 samples 5 bytes: 0 or more than 255 samples: char(0) char(m) char(m>>8) char(m>>16 + e<<4) --> count = (m+$100000)<0. due to rounding akku may refer ±0.5 into the opposite pulse. */ /* Notes: total samples = 2^32-1 == 20 minutes at 3.5MHz pre-growing with 1100000 pulses is almost always sufficient (zxsp, 64k) pre-growing with 2600000 pulses is almost always sufficient (zx81, 16k) or pre-grow with 10000+16*size_of_tap_file (zxsp) purge buffer before writing rewind or seek position before reading pulses longer than 0xFFFF samples are split and interleaved with 0-len opposite pulses Read and write with CPU input / output: --------------------------------------- Write to tape with CPU output: 1. create new CswBuffer or purge existing buffer 2. pre-grow buffer (optional) 3. startRecording(CC) 4a. output(CC,bit) for every output instruction 4b. seek(CC) for audioBufferEnd() or videoFrameEnd() to update current CC 5. stopRecording(CC) Read from tape with CPU input: 1. create and fill CswBuffer from TapeData 2. rewind() or seek(CC) tape 3a. input(CC) for every input instruction 3b. seek(CC) for audioBufferEnd() or videoFrameEnd() to update current CC Read and write pulses --------------------- this is for converting to or from TapeData. */ namespace zxsp { using CC = uint32; class CswBuffer { friend class TapeFileDataBlock; friend class TapeRecorder; uint16* data; // buffer uint32 max; // allocated size uint32 end; // used size CC cc_end; // total samples up to 'end' uint32 ccps; // ccps = (nominelle) CPU-Clock der laufenden Maschine bool recording; mutable uint32 pos; // current index in 'data' mutable CC cc_pos; // total samples up to 'pos' (excl.) mutable bool phase; // current phase mutable CC cc_offset; // current CC offset inside current sample void skip() const noexcept; void rskip() const noexcept; void grow(uint32); public: ~CswBuffer() noexcept { delete[] data; } CswBuffer(uint32 ccps, bool phase0, int foo); CswBuffer(const TapData&, uint32 ccps); // implemented in TapData.cpp CswBuffer(const TzxData&, uint32 ccps); // implemented in TzxData.cpp CswBuffer(const O80Data&, uint32 ccps); // implemented in O80Data.cpp CswBuffer(const RlesData&, uint32 ccps); // implemented in RlesData.cpp CswBuffer(const AudioData&, uint32 ccps); // implemented in AudioData.cpp CswBuffer(const TapeData&, uint32 ccps); CswBuffer(const CswBuffer&, uint32 ccps); CswBuffer(const int16* samples, uint32 count, uint32 sps, uint32 ccps); CswBuffer(const CswBuffer&) = delete; CswBuffer& operator=(const CswBuffer&) = delete; void growBuffer(uint32); void purge() noexcept; void shrinkToFit() noexcept; uint32 ccPerSecond() const noexcept { return ccps; } bool isAtStart() const noexcept { return cc_pos + cc_offset == 0; } bool isAtEnd() const noexcept { return pos >= end; } void seekStart() const noexcept; void seekEnd() const noexcept; CC seekCc(CC) const noexcept; void seekPos(uint32) const noexcept; Time seekTime(Time t) const noexcept { seekCc(t * ccps); return t; } CC getTotalCc() const noexcept { return cc_end; } Time getTotalTime() const noexcept { return Time(cc_end) / ccps; } uint32 getTotalPulses() const noexcept { return end; } uint32 getCurrentPos() const noexcept { return pos; } CC getCurrentCc() const noexcept { return cc_pos + cc_offset; } Time getCurrentTime() const noexcept { return Time(cc_pos + cc_offset) / ccps; } bool getCurrentPhase() const noexcept { return phase; } bool getPhase0() const noexcept { return (pos & 1) ^ phase; } bool getFinalPhase() const noexcept { return ((end - pos) & 1) ^ phase; } uint16*& getData() noexcept { return data; } cu16ptr getData() const noexcept { return data; } void invertPolarity() noexcept { phase ^= 1; } // polarity of entire buffer! CswBuffer* normalize() noexcept; bool is_normalized() const noexcept; bool isSilenceOrNoise() const noexcept; void splitAtCurrentPos(CswBuffer&); void addToAudioBuffer( StereoSample*, uint count, double samples_per_second, double& zpos, uint32& qpos, double& qoffs, Sample volume = 0.32f); // 0.32 ~ -10dB // read / write with CPU input / output: bool isRecording() const noexcept { return recording; } bool isPlaying() const noexcept { return !recording; } bool inputCc(CC) const noexcept; void outputCc(CC, bool); void stopRecording(CC); void startRecording(CC) noexcept; bool inputTime(Time) const noexcept; void outputTime(Time, bool); // read / write pulses: // for TapeData conversion CC readPulse() const noexcept; void putbackPulse() const noexcept; void skipSilence(uint N = 7) const noexcept; void setPhase(bool); void writePulseCc(CC); void appendToPulseCc(CC); void writePulseCc(CC, bool); void writePulse(Time s) { writePulseCc(CC(s * ccps + 0.5)); } void writePulse(Time s, bool p) { writePulseCc(CC(s * ccps + 0.5), p); } void appendToPulse(Time s) { appendToPulseCc(CC(s * ccps + 0.5)); } void writePureTone(uint32 num_pulses, Time seconds_per_pulse); void writePureData(cu8ptr bu, uint32 total_bits, Time bit0, Time bit1); void writeTzxPause(Time); }; } // namespace zxsp