C++ skip_atoi函数代码示例

int vtxprintf(void (*tx_byte)(unsigned char byte, void *data),
	       const char *fmt, va_list args, void *data)
{
	int len;
	unsigned long long num;
	int i, base;
	const char *s;

	int flags;		/* flags to number() */

	int field_width;	/* width of output field */
	int precision;		/* min. # of digits for integers; max
				   number of chars for from string */
	int qualifier;		/* 'h', 'H', 'l', or 'L' for integer fields */

	int count;

	for (count = 0; *fmt ; ++fmt) {
		if (*fmt != '%') {
			call_tx(*fmt), count++;
			continue;
		}

		/* process flags */
		flags = 0;
repeat:
			++fmt;		/* this also skips first '%' */
			switch (*fmt) {
				case '-': flags |= LEFT; goto repeat;
				case '+': flags |= PLUS; goto repeat;
				case ' ': flags |= SPACE; goto repeat;
				case '#': flags |= SPECIAL; goto repeat;
				case '0': flags |= ZEROPAD; goto repeat;
				}

		/* get field width */
		field_width = -1;
		if (is_digit(*fmt)) {
			field_width = skip_atoi(&fmt);
		} else if (*fmt == '*') {
			++fmt;
			/* it's the next argument */
			field_width = va_arg(args, int);
			if (field_width < 0) {
				field_width = -field_width;
				flags |= LEFT;
			}
		}

		/* get the precision */
		precision = -1;
		if (*fmt == '.') {
			++fmt;
			if (is_digit(*fmt)) {
				precision = skip_atoi(&fmt);
			} else if (*fmt == '*') {
				++fmt;
				/* it's the next argument */
				precision = va_arg(args, int);
			}

int vsprintf(char* buf, const char* fmt, va_list args)
{
	int len;
	long num;
	int i;
	int base;
	char* str;
	const char* s;

	int flags;		/* flags to number() */

	int field_width;	/* width of output field */
	int precision;		/* min. # of digits for integers; max
					   number of chars for from string */
	int qualifier;		/* 'h', 'l', or 'q' for integer fields */

	for (str = buf; *fmt; ++fmt) {
		if (*fmt != '%') {
			*str++ = *fmt;
			continue;
		}

		/* process flags */
		flags = 0;
repeat:
		++fmt;		/* this also skips first '%' */
		switch (*fmt) {
			case '-': flags |= LEFT; goto repeat;
			case '+': flags |= PLUS; goto repeat;
			case ' ': flags |= SPACE; goto repeat;
			case '#': flags |= SPECIAL; goto repeat;
			case '0': flags |= ZEROPAD; goto repeat;
		}

		/* get field width */
		field_width = -1;
		if (is_digit(*fmt)) {
			field_width = skip_atoi(&fmt);
		} else if (*fmt == '*') {
			++fmt;
			/* it's the next argument */
			field_width = va_arg(args, int);
			if (field_width < 0) {
				field_width = -field_width;
				flags |= LEFT;
			}
		}

		/* get the precision */
		precision = -1;
		if (*fmt == '.') {
			++fmt;
			if (is_digit(*fmt)) {
				precision = skip_atoi(&fmt);
			} else if (*fmt == '*') {
				++fmt;
				/* it's the next argument */
				precision = va_arg(args, int);
			}

static int vsprintf(char *buff, const char *format, va_list args)
{
	int len;
	int i;
	char *str;
	char *s;
	int *ip;

	int flags;		// flags to number()

	int field_width;	// width of output field
	int precision;		// min. # of digits for integers; max number of chars for from string

	for (str = buff ; *format ; ++format) {
		if (*format != '%') {
			*str++ = *format;
			continue;
		}

		flags = 0;
		repeat:
			++format;		// this also skips first '%'
			switch (*format) {
				case '-': flags |= LEFT;
					  goto repeat;
				case '+': flags |= PLUS;
					  goto repeat;
				case ' ': flags |= SPACE;
					  goto repeat;
				case '#': flags |= SPECIAL;
					  goto repeat;
				case '0': flags |= ZEROPAD;
					  goto repeat;
			}

		// get field width
		field_width = -1;
		if (is_digit(*format)) {
			field_width = skip_atoi(&format);
		} else if (*format == '*') {
			// it's the next argument
			field_width = va_arg(args, int);
			if (field_width < 0) {
				field_width = -field_width;
				flags |= LEFT;
			}
		}

		// get the precision
		precision = -1;
		if (*format == '.') {
			++format;
			if (is_digit(*format)) {
				precision = skip_atoi(&format);
			} else if (*format == '*') {
				// it's the next argument
				precision = va_arg(args, int);
			}

/*
** This vsnprintf() emulation does not implement the conversions:
**	%e, %E, %g, %G, %wc, %ws
** The %f implementation is limited.
*/
int vsnprintf(char *buf, size_t size, const char *fmt, va_list args)
{
  int len;
  unsigned long num;
  int i, base;
  char *str;
  const char *s;

  int flags;
  int dotflag;

  int field_width;
  int precision;

  int qualifier;

  size--;
  for(str = buf; *fmt && size; ++fmt) {
    if(*fmt != '%') {
      *str++ = *fmt;
      size--;
      continue;
    }

    flags = 0;
    dotflag = 0;
    repeat:
      ++fmt;
      switch(*fmt) {
        case '-': flags |= LEFT; goto repeat;
        case '+': flags |= PLUS; goto repeat;
        case ' ': flags |= SPACE; goto repeat;
        case '#': flags |= SPECIAL; goto repeat;
        case '0': flags |= ZEROPAD; goto repeat;
      }

      field_width = -1;
      if(isdigit(*fmt))
        field_width = skip_atoi(&fmt);
      else if(*fmt == '*') {
        ++fmt;
        field_width = va_arg(args,int);
        if(field_width < 0) {
          field_width = - field_width;
          flags |= LEFT;
        }
      }

      precision = -1;
      if(*fmt == '.') {
	dotflag++;
        ++fmt;
        if(isdigit(*fmt))
          precision = skip_atoi(&fmt);
        else if(*fmt == '*') {
          ++fmt;
          precision = va_arg(args,int);
        }

int vsprintf(char *buf, const char *fmt, va_list args) {
 int len;
 unsigned long num;
 int i, base;
 char *str;
 char *s;

 int flags;            // Flags to number()

 int field_width;      // Width of output field
 int precision;        // Min. # of digits for integers; max number of chars for from string
 int qualifier;        // 'l', or 'L' for integer fields

 for (str = buf; *fmt; fmt++) {
  if (*fmt != '%') {
   *str++ = *fmt;
   continue;
  }

  // Process flags
  flags = 0;
 repeat:
  fmt++; // This also skips first '%'
  switch (*fmt) {
  case '-': flags |= LEFT; goto repeat;
  case '+': flags |= PLUS; goto repeat;
  case ' ': flags |= SPACE; goto repeat;
  case '#': flags |= SPECIAL; goto repeat;
  case '0': flags |= ZEROPAD; goto repeat;
  }

  // Get field width
  field_width = -1;
  if (is_digit(*fmt)) {
   field_width = skip_atoi(&fmt);
  }
  else if (*fmt == '*') {
   fmt++;
   field_width = va_arg(args, int);
   if (field_width < 0) {
    field_width = -field_width;
    flags |= LEFT;
   }
  }

  // Get the precision
  precision = -1;
  if (*fmt == '.') {
   ++fmt;
   if (is_digit(*fmt)) {
    precision = skip_atoi(&fmt);
   }
   else if (*fmt == '*') {
    ++fmt;
    precision = va_arg(args, int);
   }

static int vsprintf(char *buff, const char *format, va_list args)
{
    int len;
    int i;
    char *str;
    char *s;
    int *ip;
    int flags;
    int field_width;
    int precision;
    
    for (str = buff; *format; ++format) {
        if (*format != '%') {
            *str ++ = *format;
            continue;
        }
        flags = 0;
        repeat:
            ++format;
            switch (*format) {
                case '-':   flags |= LEFT;
                            goto repeat;
                case '+':   flags |= PLUS;
                            goto repeat;
                case ' ':   flags |= SPACE;
                            goto repeat;
                case '#':   flags |= SPECIAL;
                            goto repeat;
                case '0':   flags |= ZEROPAD;
                            goto repeat;
            }
            
        // get field width
        field_width = -1;
        if (is_digit(*format)) {
            field_width = skip_atoi(&format);
        } else if (*format == '*') {
            // it's the next arguments
            field_width = va_arg(args, int);
            if (field_width < 0) {
                field_width = -field_width;
                flags |= LEFT;
            }
        }
        
        // get the precision
        precision = -1;
        if (*format == '.') {
            ++ format;
            if (is_digit(*format)) {
                precision = skip_atoi(&format);
            } else if (*format == '*') {
                // it's the next arguments
                precision = va_arg(args, int);
            }

int sprintf(char *buf, const char *fmt, va_list args)
{
	char *str;	// for keeping track of output location in buf
	int flags;	// for keeping track of formatting flags
	int field_width;// width of output field
	int precision;	// min number of digits for integers; for strings,
			// max number of chars
	int qualifier;	// 'h', 'l' or 'L' for integers
	char *s;	// if there's a string argument, this is it
	int len;	// this is its length
	int i;		// index variable
	int *ip;	// ptr for 'n' format

	for (str = buf; *fmt; ++fmt) { // loop til end of format string
		if (*fmt != '%') { // detect speshul placeholders
			*str++ = *fmt; // twas a regular char so stick it in
			continue;
		}

		flags = 0;
repeat: // an elegant use of goto if I've ever seen one
		++fmt;		// look at next char, or skip first '%'
		switch(*fmt) {	// look at it!
			case '-': flags |= LEFT; goto repeat;
			case '+': flags |= PLUS; goto repeat;
			case ' ': flags |= SPACE; goto repeat;
			case '#': flags |= SPECIAL; goto repeat;
			case '0': flags |= ZEROPAD; goto repeat;
		}

		// flags done, now field width
		field_width = -1;
		if (is_digit(*fmt)) {
			field_width = skip_atoi(&fmt);
		} else if (*fmt == '*') { // width in next arg
			field_width = va_arg(args, int);
			if (field_width < 0) {
				// negative width means left-align
				field_width = -field_width;
				flags |= LEFT;
			}
		}

		// width done, get precision
		precision = -1;
		if (*fmt == '.') { // precision coming up
			++fmt;
			if (is_digit(*fmt)) {
				precision = skip_atoi(&fmt);
			} else if (*fmt == '*') {
				// precision is next argument
				precision = va_arg(args, int);
			}

static int vsprintf(char *buf, const char *fmt, va_list args)
{

	int len;
	unsigned long num;
	int i, base;
	char * str;
	const char *s;

	int flags;		/* flags to number() */

	int field_width;	/* width of output field */
	int precision;		/* min. # of digits for integers; max
				   number of chars for from string */
	int qualifier;		/* 'h', 'l', or 'L' for integer fields */

    for (str = buf; *fmt; ++fmt) {
        if (*fmt != '%') {
            *str++ = *fmt;
            continue;
        }
        flags = 0;
repeat:
        ++fmt;
        switch (*fmt) {
        case '-': flags |= LEFT; goto repeat;
        case '+': flags |= PLUS; goto repeat;
        case ' ': flags |= SPACE;goto repeat;
        case '#': flags |= SPECIAL;goto repeat;
        case '0': flags |= ZEROPAD;goto repeat;
        }
        field_width = -1;
        if (is_digit(*fmt))
            field_width = skip_atoi(&fmt);
        else if (*fmt == '*') {
            ++ fmt;
            field_width = va_arg(args, int);
            if (field_width < 0) {
                field_width = -field_width;
                flags |= LEFT;
            }
        }

        precision = -1;
        if (*fmt == '.') {
            ++fmt;
            if (is_digit(*fmt))
                precision = skip_atoi(&fmt);
            else if (*fmt == '*') {
                ++fmt;
                precision = va_arg(args, int);
            }

/**
 * parse_printf_fmt() - Parse printf/printk conversion spec.
 * fmt points to the '%' in a printk conversion specification.  Advance
 * fmt past any flags, width and/or precision specifiers, and qualifiers
 * such as 'l' and 'L'.  Return a pointer to the conversion character.
 * Stores the qualifier character (or -1, if there is none) at *pqualifier.
 * *wp is set to flags indicating whether the width and/or precision are '*'.
 * For example, given
 *      %*.2lx
 * *pqualifier is set to 'l', *wp is set to 0x1, and a pointer to the 'x'
 * is returned.
 *
 * Note: This function is derived from vsnprintf() (see * lib/vsprintf.c),
 * and should be kept in sync with that function.
 *
 * @fmt - points to '%' in conversion spec
 * @pqualifier - *pqualifier is set to conversion spec's qualifier, or -1.
 * @wp - Bits in *wp are set if the width or/and precision are '*'.
 */
const char *
parse_printf_fmt(const char *fmt, int *pqualifier, int *wp)
{
	int qualifier = -1;
	*wp = 0;

	/* process flags */
	repeat:
		++fmt;          /* this also skips first '%' */
		switch (*fmt) {
			case '-':
			case '+':
			case ' ':
			case '#':
			case '0':
				goto repeat;
		}

	/* get field width */
	if (isdigit(*fmt))
		skip_atoi(&fmt);
	else if (*fmt == '*') {
		++fmt;
		/* it's the next argument */
		*wp |= 0x1;
	}

	/* get the precision */
	if (*fmt == '.') {
		++fmt;
		if (isdigit(*fmt))
			skip_atoi(&fmt);
		else if (*fmt == '*') {
			++fmt;
			/* it's the next argument */
			*wp |= 0x2;
		}
	}

	/* get the conversion qualifier */
	if (*fmt == 'h' || *fmt == 'l' || *fmt == 'L' || *fmt =='Z') {
		qualifier = *fmt;
		++fmt;
		if (qualifier == 'l' && *fmt == 'l') {
			qualifier = 'L';
			++fmt;
		}
	}

	*pqualifier = qualifier;
	return fmt;
}

static int  do_gpio(int argc, const char* argv[])
{
	char *tmp = argv[2];
	int gpio = skip_atoi(&tmp);
	
	if (strcmp(argv[1], "in") == 0) {
		GPIO_DIS_OUTPUT(gpio);
		console_printf("GP%d==%d\n", gpio, GPIO_INPUT_GET(gpio));
	} else 	if (strcmp(argv[1], "out") == 0) {
		if (argc < 4)
			return;
		tmp = argv[3];
		int v = skip_atoi(&tmp);
		GPIO_OUTPUT_SET(gpio, v);
	}
	
}

static int   do_listen(int argc, const char* argv[])
{
	int port = skip_atoi(&argv[1]);
	console_printf("Listening (TCP) on port %d\n", port);
	esp_conn.type = ESPCONN_TCP;
	esp_conn.state = ESPCONN_NONE;
	esp_conn.proto.tcp = &esptcp;
	esp_conn.proto.tcp->local_port = port;
	espconn_regist_connectcb(&esp_conn, webserver_listen);
	espconn_accept(&esp_conn);
	linebuffer = os_malloc(LINEBUFFER_SIZE);
	lineptr = 0;
	console_lock(1);
}

/**
 * bvsnprintf - BIRD's vsnprintf()
 * @buf: destination buffer
 * @size: size of the buffer
 * @fmt: format string
 * @args: a list of arguments to be formatted
 *
 * This functions acts like ordinary sprintf() except that it checks
 * available space to avoid buffer overflows and it allows some more
 * format specifiers: |%I| for formatting of IP addresses (any non-zero
 * width is automatically replaced by standard IP address width which
 * depends on whether we use IPv4 or IPv6; |%#I| gives hexadecimal format),
 * |%R| for Router / Network ID (u32 value printed as IPv4 address)
 * and |%m| resp. |%M| for error messages (uses strerror() to translate @errno code to
 * message text). On the other hand, it doesn't support floating
 * point numbers.
 *
 * Result: number of characters of the output string or -1 if
 * the buffer space was insufficient.
 */
int bvsnprintf(char *buf, int size, const char *fmt, va_list args)
{
	int len;
	unsigned long num;
	int i, base;
	u32 x;
	char *str, *start;
	const char *s;
	char ipbuf[STD_ADDRESS_P_LENGTH+1];
	struct iface *iface;

	int flags;		/* flags to number() */

	int field_width;	/* width of output field */
	int precision;		/* min. # of digits for integers; max
				   number of chars for from string */
	int qualifier;		/* 'h', 'l', or 'L' for integer fields */

	for (start=str=buf ; *fmt ; ++fmt, size-=(str-start), start=str) {
		if (*fmt != '%') {
			if (!size)
				return -1;
			*str++ = *fmt;
			continue;
		}
			
		/* process flags */
		flags = 0;
		repeat:
			++fmt;		/* this also skips first '%' */
			switch (*fmt) {
				case '-': flags |= LEFT; goto repeat;
				case '+': flags |= PLUS; goto repeat;
				case ' ': flags |= SPACE; goto repeat;
				case '#': flags |= SPECIAL; goto repeat;
				case '0': flags |= ZEROPAD; goto repeat;
				}
		
		/* get field width */
		field_width = -1;
		if (is_digit(*fmt))
			field_width = skip_atoi(&fmt);
		else if (*fmt == '*') {
			++fmt;
			/* it's the next argument */
			field_width = va_arg(args, int);
			if (field_width < 0) {
				field_width = -field_width;
				flags |= LEFT;
			}
		}

		/* get the precision */
		precision = -1;
		if (*fmt == '.') {
			++fmt;	
			if (is_digit(*fmt))
				precision = skip_atoi(&fmt);
			else if (*fmt == '*') {
				++fmt;
				/* it's the next argument */
				precision = va_arg(args, int);
			}

int
vsnprintf(char *buffer, size_t bufferSize, const char *format, va_list args)
{
	uint64 num;
	int base;
	int flags;			/* flags to number() */
	int fieldWidth;	/* width of output field */
	int precision;
		/* min. # of digits for integers; max number of chars for from string */
	int qualifier;		/* 'h', 'l', or 'L' for integer fields */

	Buffer outBuffer(buffer, bufferSize);

	for (; format[0]; format++) {
		if (format[0] != '%') {
			outBuffer.PutCharacter(format[0]);
			continue;
		}

		/* process flags */

		flags = 0;

	repeat:
		format++;
			/* this also skips first '%' */
		switch (format[0]) {
			case '-': flags |= LEFT; goto repeat;
			case '+': flags |= PLUS; goto repeat;
			case ' ': flags |= SPACE; goto repeat;
			case '#': flags |= SPECIAL; goto repeat;
			case '0': flags |= ZEROPAD; goto repeat;

			case '%':
				outBuffer.PutCharacter(format[0]);
				continue;
		}

		/* get field width */

		fieldWidth = -1;
		if (isdigit(*format))
			fieldWidth = skip_atoi(&format);
		else if (format[0] == '*') {
			format++;
			/* it's the next argument */
			fieldWidth = va_arg(args, int);
			if (fieldWidth < 0) {
				fieldWidth = -fieldWidth;
				flags |= LEFT;
			}
		}

		/* get the precision */

		precision = -1;
		if (format[0] == '.') {
			format++;
			if (isdigit(*format))
				precision = skip_atoi(&format);
			else if (format[0] == '*') {
				format++;
				/* it's the next argument */
				precision = va_arg(args, int);
			}

rt_int32_t rt_vsnprintf(char       *buf,
                        rt_size_t   size,
                        const char *fmt,
                        va_list     args)
{
#ifdef RT_PRINTF_LONGLONG
    unsigned long long num;
#else
    rt_uint32_t num;
#endif
    int i, len;
    char *str, *end, c;
    const char *s;

    rt_uint8_t base;            /* the base of number */
    rt_uint8_t flags;           /* flags to print number */
    rt_uint8_t qualifier;       /* 'h', 'l', or 'L' for integer fields */
    rt_int32_t field_width;     /* width of output field */

#ifdef RT_PRINTF_PRECISION
    int precision;      /* min. # of digits for integers and max for a string */
#endif

    str = buf;
    end = buf + size - 1;

    /* Make sure end is always >= buf */
    if (end < buf)
    {
        end  = ((char *)-1);
        size = end - buf;
    }

    for (; *fmt ; ++fmt)
    {
        if (*fmt != '%')
        {
            if (str <= end)
                *str = *fmt;
            ++ str;
            continue;
        }

        /* process flags */
        flags = 0;

        while (1)
        {
            /* skips the first '%' also */
            ++ fmt;
            if (*fmt == '-') flags |= LEFT;
            else if (*fmt == '+') flags |= PLUS;
            else if (*fmt == ' ') flags |= SPACE;
            else if (*fmt == '#') flags |= SPECIAL;
            else if (*fmt == '0') flags |= ZEROPAD;
            else break;
        }

        /* get field width */
        field_width = -1;
        if (isdigit(*fmt)) field_width = skip_atoi(&fmt);
        else if (*fmt == '*')
        {
            ++ fmt;
            /* it's the next argument */
            field_width = va_arg(args, int);
            if (field_width < 0)
            {
                field_width = -field_width;
                flags |= LEFT;
            }
        }

#ifdef RT_PRINTF_PRECISION
        /* get the precision */
        precision = -1;
        if (*fmt == '.')
        {
            ++ fmt;
            if (isdigit(*fmt)) precision = skip_atoi(&fmt);
            else if (*fmt == '*')
            {
                ++ fmt;
                /* it's the next argument */
                precision = va_arg(args, int);
            }

// 下面函数是送格式化输出到字符串中。
// 为了能在内核中使用格式化的输出，Linus 在内核实现了该C 标准函数。
// 其中参数fmt 是格式字符串；args 是个数变化的值；buf 是输出字符串缓冲区。
// 请参见本代码列表后的有关格式转换字符的介绍。
int
vsprintf (char *buf, const char *fmt, va_list args)
{
  int len;
  int i;
  char *str;			// 用于存放转换过程中的字符串。
  char *s;
  int *ip;

  int flags;			/* flags to number() */
/* number()函数使用的标志 */
  int field_width;		/* width of output field */
/* 输出字段宽度*/
  int precision;		/* min. # of digits for integers; max
				   number of chars for from string */
/* min. 整数数字个数；max. 字符串中字符个数 */
  int qualifier;		/* 'h', 'l', or 'L' for integer fields */
/* 'h', 'l',或'L'用于整数字段 */
// 首先将字符指针指向buf，然后扫描格式字符串，对各个格式转换指示进行相应的处理。
  for (str = buf; *fmt; ++fmt)
    {
// 格式转换指示字符串均以'%'开始，这里从fmt 格式字符串中扫描'%'，寻找格式转换字符串的开始。
// 不是格式指示的一般字符均被依次存入str。
      if (*fmt != '%')
	{
	  *str++ = *fmt;
	  continue;
	}

// 下面取得格式指示字符串中的标志域，并将标志常量放入flags 变量中。
/* process flags */
      flags = 0;
    repeat:
      ++fmt;			/* this also skips first '%' */
      switch (*fmt)
	{
	case '-':
	  flags |= LEFT;
	  goto repeat;		// 左靠齐调整。
	case '+':
	  flags |= PLUS;
	  goto repeat;		// 放加号。
	case ' ':
	  flags |= SPACE;
	  goto repeat;		// 放空格。
	case '#':
	  flags |= SPECIAL;
	  goto repeat;		// 是特殊转换。
	case '0':
	  flags |= ZEROPAD;
	  goto repeat;		// 要填零(即'0')。
	}

// 取当前参数字段宽度域值，放入field_width 变量中。如果宽度域中是数值则直接取其为宽度值。
// 如果宽度域中是字符'*'，表示下一个参数指定宽度。因此调用va_arg 取宽度值。若此时宽度值
// 小于0，则该负数表示其带有标志域'-'标志（左靠齐），因此还需在标志变量中添入该标志，并
// 将字段宽度值取为其绝对值。
/* get field width */
      field_width = -1;
      if (is_digit (*fmt))
	field_width = skip_atoi (&fmt);
      else if (*fmt == '*')
	{
/* it's the next argument */
	  field_width = va_arg (args, int);
	  if (field_width < 0)
	    {
	      field_width = -field_width;
	      flags |= LEFT;
	    }
	}

// 下面这段代码，取格式转换串的精度域，并放入precision 变量中。精度域开始的标志是'.'。
// 其处理过程与上面宽度域的类似。如果精度域中是数值则直接取其为精度值。如果精度域中是
// 字符'*'，表示下一个参数指定精度。因此调用va_arg 取精度值。若此时宽度值小于0，则
// 将字段精度值取为其绝对值。
/* get the precision */
      precision = -1;
      if (*fmt == '.')
	{
	  ++fmt;
	  if (is_digit (*fmt))
	    precision = skip_atoi (&fmt);
	  else if (*fmt == '*')
	    {
/* it's the next argument */
	      precision = va_arg (args, int);
	    }