121 lines
2.8 KiB
C++
121 lines
2.8 KiB
C++
#include "morse.h"
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// Each morse dit/dah is stored as a nybble
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#define dit 1
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#define dah 3
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#define Pack(a, b, c, d) ((a << 0) | (b << 2) | (c << 4) | (d << 6))
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#define Unpack(m, pos) ((m >> (pos * 2)) & 0b11)
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const uint8_t MorseLetters[] = {
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Pack(dit, dah, 0, 0), // A
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Pack(dah, dit, dit, dit), // B
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Pack(dah, dit, dah, dit), // C
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Pack(dah, dit, dit, 0), // D
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Pack(dit, 0, 0, 0), // E
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Pack(dit, dit, dah, dit), // F
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Pack(dah, dah, dit, 0), // G
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Pack(dit, dit, dit, dit), // H
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Pack(dit, dit, 0, 0), // I
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Pack(dit, dah, dah, dah), // J
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Pack(dah, dit, dah, 0), // K
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Pack(dit, dah, dit, dit), // L
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Pack(dah, dah, 0, 0), // M
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Pack(dah, dit, 0, 0), // N
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Pack(dah, dah, dah, 0), // O
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Pack(dit, dah, dah, dit), // P
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Pack(dah, dah, dit, dah), // Q
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Pack(dit, dah, dit, 0), // R
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Pack(dit, dit, dit, 0), // S
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Pack(dah, 0, 0, 0), // T
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Pack(dit, dit, dah, 0), // U
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Pack(dit, dit, dit, dah), // V
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Pack(dit, dah, dah, 0), // W
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Pack(dah, dit, dit, dah), // X
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Pack(dah, dit, dah, dah), // Y
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Pack(dah, dah, dit, dit), // Z
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};
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MorseEncoder::MorseEncoder() {
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SetText("");
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}
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MorseEncoder::MorseEncoder(const char *s) {
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SetText(s);
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}
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void MorseEncoder::SetText(const char *s) {
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p = s;
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crumb = 0;
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ticksLeft = 0;
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Transmitting = false;
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}
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void MorseEncoder::Quiet(int ticks) {
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Transmitting = false;
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ticksLeft = ticks;
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}
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bool MorseEncoder::Tick() {
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--ticksLeft;
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if (ticksLeft > 0) {
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return true;
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}
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// We're out of ticks
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if (!p || !*p) {
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return false;
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}
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// If we were just transmitting, we have to stop for at least one dit
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if (Transmitting) {
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Transmitting = false;
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ticksLeft = MORSE_DIT;
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return true;
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}
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// If that was the end of the letter, we have to pause more
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if (crumb == 4) {
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crumb = 0;
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++p;
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ticksLeft = MORSE_PAUSE_LETTER - MORSE_DIT;
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return true;
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}
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switch (*p) {
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case '\0':
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return false;
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case 'a' ... 'z':
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Transmitting = true;
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ticksLeft = Unpack(MorseLetters[*p - 'a'], crumb++);
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break;
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case 'A' ... 'Z':
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Transmitting = true;
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ticksLeft = Unpack(MorseLetters[*p - 'A'], crumb++);
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break;
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case ' ':
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crumb = 0;
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++p;
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Transmitting = false;
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ticksLeft = MORSE_PAUSE_WORD - MORSE_DIT;
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break;
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default: // this should never happen! Transmit for a word pause to indicate weirdness.
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crumb = 0;
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++p;
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Transmitting = true;
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ticksLeft = MORSE_PAUSE_WORD;
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break;
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}
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if (0 == ticksLeft) {
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// Unpack can return 0 if there are fewer than 4 emissions for a letter.
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// In that case, we 're done with the letter.
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crumb = 0;
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++p;
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Transmitting = false;
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ticksLeft = MORSE_PAUSE_LETTER - MORSE_DIT;
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}
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return true;
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}
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