micropython/stm/printf.c

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C
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#include <stdarg.h>
#include "std.h"
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#include "misc.h"
#include "lcd.h"
#include "usb.h"
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#define PF_FLAG_LEFT_ADJUST (0x01)
#define PF_FLAG_SHOW_SIGN (0x02)
#define PF_FLAG_SPACE_SIGN (0x04)
#define PF_FLAG_NO_TRAILZ (0x08)
#define PF_FLAG_ZERO_PAD (0x10)
// tricky; we compute pad string by: pad_chars + (flags & PF_FLAG_ZERO_PAD)
#define PF_PAD_SIZE PF_FLAG_ZERO_PAD
static const char *pad_chars = " 0000000000000000";
typedef struct _pfenv_t {
void *data;
void (*print_strn)(void *, const char *str, unsigned int len);
} pfenv_t;
static void print_str_dummy(void *data, const char *str, unsigned int len) {
}
const pfenv_t pfenv_dummy = {0, print_str_dummy};
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static int pfenv_print_strn(const pfenv_t *pfenv, const char *str, unsigned int len, int flags, int width) {
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int pad = width - len;
if (pad > 0 && (flags & PF_FLAG_LEFT_ADJUST) == 0) {
while (pad > 0) {
int p = pad;
if (p > PF_PAD_SIZE)
p = PF_PAD_SIZE;
pfenv->print_strn(pfenv->data, pad_chars + (flags & PF_FLAG_ZERO_PAD), p);
pad -= p;
}
}
pfenv->print_strn(pfenv->data, str, len);
while (pad > 0) {
int p = pad;
if (p > PF_PAD_SIZE)
p = PF_PAD_SIZE;
pfenv->print_strn(pfenv->data, pad_chars, p);
pad -= p;
}
return len;
}
// enough room for 32 signed number
#define INT_BUF_SIZE (12)
static int pfenv_print_int(const pfenv_t *pfenv, unsigned int x, int sgn, int base, int base_char, int flags, int width) {
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char sign = 0;
if (sgn) {
if ((int)x < 0) {
sign = '-';
x = -x;
} else if (flags & PF_FLAG_SHOW_SIGN) {
sign = '+';
} else if (flags & PF_FLAG_SPACE_SIGN) {
sign = ' ';
}
}
char buf[INT_BUF_SIZE];
char *b = buf + INT_BUF_SIZE;
if (x == 0) {
*(--b) = '0';
} else {
do {
int c = x % base;
x /= base;
if (c >= 10) {
c += base_char - 10;
} else {
c += '0';
}
*(--b) = c;
} while (b > buf && x != 0);
}
if (b > buf && sign != 0) {
*(--b) = sign;
}
return pfenv_print_strn(pfenv, b, buf + INT_BUF_SIZE - b, flags, width);
}
void pfenv_prints(const pfenv_t *pfenv, const char *str) {
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pfenv->print_strn(pfenv->data, str, strlen(str));
}
int pfenv_printf(const pfenv_t *pfenv, const char *fmt, va_list args) {
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int chrs = 0;
for (;;) {
{
const char *f = fmt;
while (*f != '\0' && *f != '%') {
++f; // XXX UTF8 advance char
}
if (f > fmt) {
pfenv->print_strn(pfenv->data, fmt, f - fmt);
chrs += f - fmt;
fmt = f;
}
}
if (*fmt == '\0') {
break;
}
// move past % character
++fmt;
// parse flags, if they exist
int flags = 0;
while (*fmt != '\0') {
if (*fmt == '-') flags |= PF_FLAG_LEFT_ADJUST;
else if (*fmt == '+') flags |= PF_FLAG_SHOW_SIGN;
else if (*fmt == ' ') flags |= PF_FLAG_SPACE_SIGN;
else if (*fmt == '!') flags |= PF_FLAG_NO_TRAILZ;
else if (*fmt == '0') flags |= PF_FLAG_ZERO_PAD;
else break;
++fmt;
}
// parse width, if it exists
int width = 0;
for (; '0' <= *fmt && *fmt <= '9'; ++fmt) {
width = width * 10 + *fmt - '0';
}
// parse precision, if it exists
int prec = -1;
if (*fmt == '.') {
++fmt;
if (*fmt == '*') {
++fmt;
prec = va_arg(args, int);
} else {
prec = 0;
for (; '0' <= *fmt && *fmt <= '9'; ++fmt) {
prec = prec * 10 + *fmt - '0';
}
}
if (prec < 0) {
prec = 0;
}
}
// parse long specifiers (current not used)
//bool long_arg = false;
if (*fmt == 'l') {
++fmt;
//long_arg = true;
}
if (*fmt == '\0') {
break;
}
switch (*fmt) {
case 'b':
if (va_arg(args, int)) {
chrs += pfenv_print_strn(pfenv, "true", 4, flags, width);
} else {
chrs += pfenv_print_strn(pfenv, "false", 5, flags, width);
}
break;
case 'c':
{
char str = va_arg(args, int);
chrs += pfenv_print_strn(pfenv, &str, 1, flags, width);
break;
}
case 's':
{
const char *str = va_arg(args, const char*);
if (str) {
if (prec < 0) {
prec = strlen(str);
}
chrs += pfenv_print_strn(pfenv, str, prec, flags, width);
} else {
chrs += pfenv_print_strn(pfenv, "(null)", 6, flags, width);
}
break;
}
case 'u':
chrs += pfenv_print_int(pfenv, va_arg(args, int), 0, 10, 'a', flags, width);
break;
case 'd':
chrs += pfenv_print_int(pfenv, va_arg(args, int), 1, 10, 'a', flags, width);
break;
case 'x':
case 'p': // ?
chrs += pfenv_print_int(pfenv, va_arg(args, int), 0, 16, 'a', flags, width);
break;
case 'X':
case 'P': // ?
chrs += pfenv_print_int(pfenv, va_arg(args, int), 0, 16, 'A', flags, width);
break;
default:
pfenv->print_strn(pfenv->data, fmt, 1);
chrs += 1;
break;
}
++fmt;
}
return chrs;
}
void stdout_print_strn(void *data, const char *str, unsigned int len) {
// send stdout to LCD and USB CDC VCP
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if (usb_vcp_is_enabled()) {
usb_vcp_send_strn(str, len);
} else {
lcd_print_strn(str, len);
}
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}
static const pfenv_t pfenv_stdout = {0, stdout_print_strn};
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int printf(const char *fmt, ...) {
va_list args;
va_start(args, fmt);
return pfenv_printf(&pfenv_stdout, fmt, args);
}
// need this because gcc optimises printf("%c", c) -> putchar(c), and printf("a") -> putchar('a')
int putchar(int c) {
char chr = c;
stdout_print_strn(0, &chr, 1);
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return chr;
}
// need this because gcc optimises printf("string\n") -> puts("string")
int puts(const char *s) {
stdout_print_strn(0, s, strlen(s));
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char chr = '\n';
stdout_print_strn(0, &chr, 1);
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return 1;
}
typedef struct _strn_pfenv_t {
char *cur;
size_t remain;
} strn_pfenv_t;
void strn_print_strn(void *data, const char *str, unsigned int len) {
strn_pfenv_t *strn_pfenv = data;
if (len > strn_pfenv->remain) {
len = strn_pfenv->remain;
}
memcpy(strn_pfenv->cur, str, len);
strn_pfenv->cur += len;
strn_pfenv->remain -= len;
}
int snprintf(char *str, size_t size, const char *fmt, ...) {
strn_pfenv_t strn_pfenv;
strn_pfenv.cur = str;
strn_pfenv.remain = size;
pfenv_t pfenv;
pfenv.data = &strn_pfenv;
pfenv.print_strn = strn_print_strn;
va_list args;
va_start(args, fmt);
int len = pfenv_printf(&pfenv, fmt, args);
// add terminating null byte
if (size > 0) {
if (strn_pfenv.remain == 0) {
strn_pfenv.cur[-1] = 0;
} else {
strn_pfenv.cur[0] = 0;
}
}
return len;
}