text: /*
   * Copyright (c) 2010, 2013-2014 Wind River Systems, Inc.
   * Copyright (c) 2020 Nordic Semiconductor ASA
   * Copyright (c) 2021 BayLibre, SAS
   *
   * SPDX-License-Identifier: Apache-2.0
   */
  
  #include <stdarg.h>
  #include <stdint.h>
  #include <string.h>
  #include <sys/cbprintf.h>
  #include <sys/types.h>
  #include <sys/util.h>
  
  #ifdef CONFIG_CBPRINTF_FULL_INTEGRAL
  typedef intmax_t int_value_type;
  typedef uintmax_t uint_value_type;
  #define DIGITS_BUFLEN 21
  BUILD_ASSERT(sizeof(uint_value_type) <= 8U,
  	     "DIGITS_BUFLEN may be incorrect");
  #else
  typedef int32_t int_value_type;
  typedef uint32_t uint_value_type;
  #define DIGITS_BUFLEN 10
  #endif
  
  #define ALPHA(fmt) (((fmt) & 0x60) - '0' - 10 + 1)
  
  /* Convert value to string, storing characters downwards */
  static inline int convert_value(uint_value_type num, unsigned int base,
  				unsigned int alpha, char *buftop)
  {
  	int i = 0;
  
  	do {
  		unsigned int c = num % base;
  		if (c >= 10) {
  			c += alpha;
  		}
  		buftop[--i] = c + '0';
  		num /= base;
  	} while (num);
  
  	return -i;
  }
  
  #define OUTC(_c) do { \
  	out((int)(_c), ctx); \
  	if (IS_ENABLED(CONFIG_CBPRINTF_LIBC_SUBSTS)) { \
  		++count; \
  	} \
  } while (false)
  
  #define PAD_ZERO	BIT(0)
  #define PAD_TAIL	BIT(1)
  
  /**
   * @brief Printk internals
   *
   * See printk() for description.
   * @param fmt Format string
   * @param ap Variable parameters
   *
   * @return printed byte count if CONFIG_CBPRINTF_LIBC_SUBSTS is set
   */
  int cbvprintf(cbprintf_cb out, void *ctx, const char *fmt, va_list ap)
  {
  	size_t count = 0;
  	char buf[DIGITS_BUFLEN];
  	char *prefix, *data;
  	int min_width, precision, data_len;
  	char padding_mode, length_mod, special;
  
  	/* we pre-increment in the loop  afterwards */
  	fmt--;
  
  start:
  	while (*++fmt != '%') {
  		if (*fmt == 0) {
  			return count;
  		}
  		OUTC(*fmt);
  	}
  
  	min_width = -1;
  	precision = -1;
  	prefix = "";
  	padding_mode = 0;
  	length_mod = 0;
  	special = 0;
  
  	for (fmt++ ; ; fmt++) {
  		switch (*fmt) {
  		case 0:
  			return count;
  
  		case '%':
  			OUTC('%');
  			goto start;
  
  		case '-':
  			padding_mode = PAD_TAIL;
  			continue;
  
  		case '.':
  			precision = 0;
  			padding_mode &= ~PAD_ZERO;
  			continue;
  
  		case '0':
  			if (min_width < 0 && precision < 0 && !padding_mode) {
  				padding_mode = PAD_ZERO;
  				continue;
  			}
  			__fallthrough;
  
  		case '1':
  		case '2':
  		case '3':
  		case '4':
  		case '5':
  		case '6':
  		case '7':
  		case '8':
  		case '9':
  			if (precision >= 0) {
  				precision = 10 * precision + *fmt - '0';
  			} else {
  				if (min_width < 0) {
  					min_width = 0;
  				}
  				min_width = 10 * min_width + *fmt - '0';
  			}
  			continue;
  
  		case '*':
  			if (precision >= 0) {
  				precision = va_arg(ap, int);
  			} else {
  				min_width = va_arg(ap, int);
  				if (min_width < 0) {
  					min_width = -min_width;
  					padding_mode = PAD_TAIL;
  				}
  			}
  			continue;
  
  		case '+':
  		case ' ':
  		case '#':
  			special = *fmt;
  			continue;
  
  		case 'h':
  		case 'l':
  		case 'z':
  			if (*fmt == 'h' && length_mod == 'h') {
  				length_mod = 'H';
  			} else if (*fmt == 'l' && length_mod == 'l') {
  				length_mod = 'L';
  			} else if (length_mod == 0) {
  				length_mod = *fmt;
  			} else {
  				OUTC('%');
  				OUTC(*fmt);
  				goto start;
  			}
  			continue;
  
  		case 'd':
  		case 'i':
  		case 'u': {
  			uint_value_type d;
  
  			if (length_mod == 'z') {
  				d = va_arg(ap, ssize_t);
  			} else if (length_mod == 'l') {
  				d = va_arg(ap, long);
  			} else if (length_mod == 'L') {
  				long long lld = va_arg(ap, long long);
  
  				if (sizeof(int_value_type) < 8U &&
  				    lld != (int_value_type) lld) {
  					data = "ERR";
  					data_len = 3;
  					precision = 0;
  					break;
  				}
  				d = (uint_value_type) lld;
  			} else if (*fmt == 'u') {
  				d = va_arg(ap, unsigned int);
  			} else {
  				d = va_arg(ap, int);
  			}
  
  			if (*fmt != 'u' && (int_value_type)d < 0) {
  				d = -d;
  				prefix = "-";
  				min_width--;
  			} else if (special == ' ') {
  				prefix = " ";
  				min_width--;
  			} else if (special == '+') {
  				prefix = "+";
  				min_width--;
  			} else {
  				;
  			}
  			data_len = convert_value(d, 10, 0, buf + sizeof(buf));
  			data = buf + sizeof(buf) - data_len;
  			break;
  		}
  
  		case 'p':
  		case 'x':
  		case 'X': {
  			uint_value_type x;
  
  			if (*fmt == 'p') {
  				x = (uintptr_t)va_arg(ap, void *);
  				if (x == 0) {
  					data = "(nil)";
  					data_len = 5;
  					precision = 0;
  					break;
  				}
  				special = '#';
  			} else if (length_mod == 'l') {
  				x = va_arg(ap, unsigned long);
  			} else if (length_mod == 'L') {
  				x = va_arg(ap, unsigned long long);
  			} else {
  				x = va_arg(ap, unsigned int);
  			}
  			if (special == '#') {
  				prefix = (*fmt & 0x20) ? "0x" : "0X";
  				min_width -= 2;
  			}
  			data_len = convert_value(x, 16, ALPHA(*fmt),
  						 buf + sizeof(buf));
  			data = buf + sizeof(buf) - data_len;
  			break;
  		}
  
  		case 's': {
  			data = va_arg(ap, char *);
  			data_len = strlen(data);
  			if (precision >= 0 && data_len > precision) {
  				data_len = precision;
  			}
  			precision = 0;
  			break;
  		}
  
  		case 'c': {
  			int c = va_arg(ap, int);
  
  			buf[0] = c;
  			data = buf;
  			data_len = 1;
  			precision = 0;
  			break;
  		}
  
  		default:
  			OUTC('%');
  			OUTC(*fmt);
  			goto start;
  		}
  
  		if (precision < 0 && (padding_mode & PAD_ZERO)) {
  			precision = min_width;
  		}
  		min_width -= data_len;
  		precision -= data_len;
  		if (precision > 0) {
  			min_width -= precision;
  		}
  
  		if (!(padding_mode & PAD_TAIL)) {
  			while (--min_width >= 0) {
  				OUTC(' ');
  			}
  		}
  		while (*prefix) {
  			OUTC(*prefix++);
  		}
  		while (--precision >= 0) {
  			OUTC('0');
  		}
  		while (--data_len >= 0) {
  			OUTC(*data++);
  		}
  		while (--min_width >= 0) {
  			OUTC(' ');
  		}
  
  		goto start;
  	}
  }
  