VocalEasel/Sources/VLPitchName.cpp
2011-08-27 18:06:28 +02:00

123 lines
3.7 KiB
C++

//
// File: VLPitchName.cpp - Translate between (MIDI) pitches and their UTF-8 representation
//
// Author(s):
//
// (MN) Matthias Neeracher
//
// Copyright © 2011 Matthias Neeracher
//
#include "VLPitchName.h"
#include "VLModel.h"
const char * kVLSharpStr = "\xE2\x99\xAF";
const char * kVLFlatStr = "\xE2\x99\xAD";
const char * kVL2SharpStr = "\xF0\x9D\x84\xAA";
const char * kVL2FlatStr = "\xF0\x9D\x84\xAB";
const char * kVLNaturalStr = "\xE2\x99\xAE";
static const char kScale[] = "C D EF G A B";
static const char * kFancyAccidental[] =
{
kVL2SharpStr, kVLSharpStr, "", kVLFlatStr, kVL2FlatStr
};
const int8_t kAccidentalBase = 2;
std::string VLPitchName(int8_t pitch, uint16_t accidental)
{
if (pitch == VLNote::kNoPitch)
return "r";
int8_t adjust;
accidental &= VLNote::kAccidentalsMask;
switch (accidental) {
case VLNote::kWant2Flat:
adjust = 2;
break;
case VLNote::kWantFlat:
adjust = 1;
break;
case VLNote::kWantSharp:
adjust = -1;
break;
case VLNote::kWant2Sharp:
adjust = -2;
break;
default:
adjust = 0;
break;
}
pitch += adjust;
pitch %= 12;
//
// Will either succeed immediately, or after one adjustment
//
if (kScale[pitch] == ' ')
if (adjust < 0 || (accidental & VLNote::kPreferFlats) == VLNote::kPreferFlats) {
++adjust;
pitch = (pitch+1)%12;
} else {
--adjust;
pitch = (pitch+11)%12;
}
std::string name = std::string(1, kScale[pitch]);
if (adjust)
return name+kFancyAccidental[adjust+kAccidentalBase];
else if ((accidental & VLNote::kWantNatural) == VLNote::kWantNatural)
return name+kVLNaturalStr;
else
return name;
}
static bool TestAccidental(uint16_t acc, int8_t adjust, std::string & str, size_t at,
const char * fancyStr, const char * asciiString,
int8_t & pitch, uint16_t * accidental)
{
size_t sz = str.size()-at;
size_t fancySz = strlen(fancyStr);
if (sz >= fancySz && !memcmp(fancyStr, &str[at], fancySz)) {
pitch += adjust;
*accidental = acc;
str.erase(at, fancySz);
return true;
}
size_t asciiSz = strlen(asciiString);
if (!asciiSz || sz < asciiSz)
return false;
for (size_t cmp = at; *asciiString; )
if (std::toupper(str[cmp++]) != *asciiString++)
return false;
pitch += adjust;
*accidental = acc;
str.erase(at, asciiSz);
return true;
}
int8_t VLParsePitch(std::string & str, size_t at, uint16_t * accidental)
{
int8_t pitch = VLNote::kNoPitch;
//
// Determine key
//
if (const char * key = strchr(kScale, std::toupper(str[at]))) {
pitch = key-kScale+VLNote::kMiddleC;
} else if (str[at] == 'r' || str[at] == 's') {
str.erase(at, 1); // Rest
return VLNote::kNoPitch;
} else
return kPitchError;
str.erase(at, 1);
//
// Look for accidentals
//
TestAccidental(VLNote::kWant2Flat, -2, str, at, kVL2FlatStr, "BB", pitch, accidental) ||
TestAccidental(VLNote::kWantFlat, -1, str, at, kVLFlatStr, "B", pitch, accidental) ||
TestAccidental(VLNote::kWantNatural, 0, str, at, kVLNaturalStr, "", pitch, accidental) ||
TestAccidental(VLNote::kWant2Sharp, 2, str, at, kVL2SharpStr, "##", pitch, accidental) ||
TestAccidental(VLNote::kWantSharp, 1, str, at, kVLSharpStr, "#", pitch, accidental) ||
(*accidental = 0);
return pitch;
}