Arduinoの開発＆デバッグでよく困るのがprintf()がなかったり浮動小数点型など特定のデータ型に対応していないことだったりする。
printf()の完全実装は複雑かつ巨大すぎるので普段使いそうな機能に限定して作成してみたがコンパイル後のバイナリーには浮動小数点ライブラリがリンクされるためATmega32U4で約4K弱ほどになってしまう。もう少し小さくしたいところではあるが．．．まぁ、こんなもんかな。
組み込み系では数値を文字列に変換する関数が実装されていないことも多いため効率は良くないが標準ライブラリを使わずに変換している。
なお、書式のエラーチェックはしてないので間違った書式を指定してもエラーにはならないことに注意すること。
変換指定は次の形式をとる。（[ ]内は省略可能）
%[フラグ][0][最小フィールド幅][.精度][長さ修飾子]変換指定子
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[フラグ] -: 左詰め +: 符号付き数値 [0] 0: ゼロ詰め数値 [最小フィールド幅] *: 引数で桁数を指定 [.精度] *: 引数で桁数を指定 [長さ修飾子][変換指定子] d : 符号付き10進数 (int) ld : 符号付き10進数 (long int) lld: 符号付き10進数 (long long int) zd : 符号付き10進数 (ssize_t) ※AVRは非対応 u : 符号無し10進数 (unsigned int) lu : 符号無し10進数 (unsigned long int) llu: 符号無し10進数 (unsigned long long int) zu : 符号無し10進数 (size_t) X : 大文字16進数 (unsigned int) lX : 大文字16進数 (unsigned long int) llX: 大文字16進数 (unsigned long long int) zX : 大文字16進数 (size_t) x : 小文字16進数 (unsigned int) lx : 小文字16進数 (unsigned long int) llx: 小文字16進数 (unsigned long long int) zx : 小文字16進数 (size_t) o : 8進数 (unsigned int) lo : 8進数 (unsigned long int) llo: 8進数 (unsigned long long int) zo : 8進数 (size_t) b : 2進数 (unsigned int) lb : 2進数 (unsigned long int) llb: 2進数 (unsigned long long int) zb : 2進数 (size_t) f : 浮動小数点型10進数 (double) lf : 浮動小数点型10進数 (long double) Lf : 浮動小数点型10進数 (long double) s : 文字列 c : 文字 % : '%'文字 |
【スケッチ】
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#include "format.h" DECLARE_PRINTF(Serial) serfmt; StringFormat strfmt; void setup(void) { Serial.begin(115200); } void loop(void) { char buf[64]; strfmt.snprintf(buf, sizeof(buf), "%f\n", -123.001); Serial.print(buf); serfmt.printf("%f\n", -123.001); delay(1000); } |
【ライブラリ】
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/* format.h - String Format Library for ARDUINO Copyright (c) 2024 Sasapea's Lab. All right reserved. This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see <https://www.gnu.org/licenses/>. */ #pragma once #include <stdarg.h> #include <math.h> class Format { public: int printf(const char *format, ...) { va_list ap; va_start(ap, format); int nbytes = vprintf(format, ap); va_end(ap); return nbytes; } int vprintf(const char *format, va_list ap) { const char *p = format; char c; _count = 0; do { c = *p++; if (c == '%') { format_t option = {}; option.alignchar = (*p == '-' ? *p++ : 0); option.signchar = (*p == '+' ? *p++ : 0); option.fillchar = (*p == '0' ? *p++ : ' '); if (*p == '*') { ++p; option.width = va_arg(ap, int); } else { while (isdigit(*p)) option.width = option.width * 10 + (*p++ - '0'); } if (*p == '.') { if (*++p == '*') { ++p; option.precision = va_arg(ap, int); } else { while (isdigit(*p)) option.precision = option.precision * 10 + (*p++ - '0'); } } while ((*p == 'l') || (*p == 'L')) { ++p; ++option.type; } if (*p == 'z') { ++p; option.type = TYPE_SIZE_T; } switch (*p) { case 'd': case 'u': case 'X': case 'x': case 'o': case 'b': switch (option.type) { default: option.type = TYPE_INT; /* fall through */ case TYPE_INT : option.value.i = va_arg(ap, int); break; case TYPE_LONG_INT : option.value.li = va_arg(ap, long int); break; case TYPE_LONG_LONG_INT: option.value.lli = va_arg(ap, long long int); break; case TYPE_SIZE_T : option.value.s = va_arg(ap, size_t); break; } break; case 'f': switch (option.type) { default: option.type = TYPE_INT; /* fall through */ case TYPE_INT : option.value.f = va_arg(ap, double); break; case TYPE_LONG_INT: option.value.lf = va_arg(ap, long double); break; } option.type += TYPE_DOUBLE; break; default: option.type = TYPE_INT; break; } switch (*p++) { case 'f': /* %f - float */ case 'd': /* %d - integer */ switch (option.type) { default: /* fall through */ case TYPE_INT: if ((int)option.value.i < 0) { option.value.i = 0 - option.value.i; option.signchar = '-'; } break; case TYPE_LONG_INT: if ((long int)option.value.li < 0) { option.value.li = 0 - option.value.li; option.signchar = '-'; } break; case TYPE_LONG_LONG_INT: if ((long long int)option.value.lli < 0) { option.value.lli = 0 - option.value.lli; option.signchar = '-'; } break; #if !defined(ARDUINO_ARCH_AVR) case TYPE_SIZE_T: if ((ssize_t)option.value.s < 0) { option.value.s = 0 - option.value.s; option.signchar = '-'; } break; #endif case TYPE_DOUBLE: if (option.value.f < 0) { option.value.f = 0 - option.value.f; option.signchar = '-'; } break; case TYPE_LONG_DOUBLE: if (option.value.lf < 0) { option.value.lf = 0 - option.value.lf; option.signchar = '-'; } break; } option.base = 10; nformat(option); break; case 'u': /* %u - unsigned integer */ option.base = 10; nformat(option); break; case 'X': /* %X - hex */ option.hexchar = 'A'; option.base = 16; nformat(option); break; case 'x': /* %x - hex */ option.hexchar = 'a'; option.base = 16; nformat(option); break; case 'o': /* %o - octal */ option.base = 8; nformat(option); break; case 'b': /* %b - binary */ option.base = 2; nformat(option); break; case 'c': /* %c - character */ putch_(va_arg(ap, int)); break; case 's': /* %s - string */ option.fillchar = ' '; putstr(option, va_arg(ap, char *)); break; case '%': /* %% - '%' character */ putch_('%'); break; default: putch_('?'); break; } } else if (c) putch_(c); } while (c); return _count; } protected: int _count; virtual int putch(char c) = 0; private: enum { TYPE_INT, TYPE_LONG_INT, TYPE_LONG_LONG_INT, TYPE_SIZE_T, TYPE_DOUBLE, TYPE_LONG_DOUBLE }; typedef struct { char alignchar; char signchar; char fillchar; char hexchar; unsigned char width; unsigned char precision; unsigned char type; unsigned char base; union { unsigned int i; unsigned long int li; unsigned long long int lli; size_t s; double f; long double lf; } value; } format_t; void putch_(char c) { _count += putch(c); } void putstr(format_t& option, const char *str) { if (!str) str = "(null)"; size_t i, len = strlen(str); if (option.precision && (len > option.precision)) len = option.precision; if (option.alignchar == '-') { for (i = 0; i < len; ++i) putch_(*str++); for (i = len; i < option.width; ++i) putch_(option.fillchar); } else { for (i = len; i < option.width; ++i) putch_(option.fillchar); for (i = 0; i < len; ++i) putch_(*str++); } } void nformat(format_t& option) { unsigned long int d; char buf[128], c, z, n, *p = buf + sizeof(buf); *--p = 0; switch (option.type) { case TYPE_DOUBLE: n = option.precision ? (option.precision < 9 ? option.precision : 9) : 6; z = option.precision == 0; d = pow(10, n); d = (typeof(d))(option.value.f * d + 0.5) % d; do { c = d % option.base; if (c || !z) { *--p = '0' + c; z = 0; } --n; } while (d /= option.base); if (!z) { while (n--) *--p = '0'; *--p = '.'; } option.precision = 0; option.type = TYPE_LONG_INT; option.value.li = option.value.f; break; case TYPE_LONG_DOUBLE: n = option.precision ? (option.precision < 9 ? option.precision : 9) : 6; z = option.precision == 0; d = pow(10, n); d = (typeof(d))(option.value.lf * d + 0.5) % d; do { c = d % option.base; if (c || !z) { *--p = '0' + c; z = 0; } --n; } while (d /= option.base); if (!z) { while (n--) *--p = '0'; *--p = '.'; } option.precision = 0; option.type = TYPE_LONG_LONG_INT; option.value.lli = option.value.lf; break; } do { switch (option.type) { default: /* fall through */ case TYPE_INT: c = option.value.i % option.base; z = (option.value.i /= option.base); break; case TYPE_LONG_INT: c = option.value.li % option.base; z = (option.value.li /= option.base); break; case TYPE_LONG_LONG_INT: c = option.value.lli % option.base; z = (option.value.lli /= option.base); break; case TYPE_SIZE_T: c = option.value.s % option.base; z = (option.value.s /= option.base); break; } if (c < 10) *--p = '0' + c; else *--p = option.hexchar + (c - 10); } while (z); if (option.signchar) *--p = option.signchar; putstr(option, p); } }; class StringFormat : public Format { public: int snprintf(char *buf, size_t n, const char *format, ...) { va_list ap; va_start(ap, format); int nbytes = vsnprintf(buf, n, format, ap); va_end(ap); return nbytes; } int vsnprintf(char *buf, size_t n, const char *format, va_list ap) { _buffer = buf; _length = n; int nbytes = vprintf(format, ap); buf[nbytes] = 0; return nbytes; } protected: int putch(char c) override { if (_count + 1 < _length) { *_buffer++ = c; return 1; } return 0; } private: char *_buffer; size_t _length; }; #define DECLARE_PRINTF(instance) PrintFormat<typeof(instance), instance> template<typename T, T &UART> class PrintFormat : public Format { protected: int putch(char c) override { if (c == '\n') UART.println(); else UART.print(c); return 1; } }; |