mirror of
https://github.com/DragonOS-Community/DragonOS.git
synced 2025-06-09 15:26:47 +00:00
381 lines
9.2 KiB
C
381 lines
9.2 KiB
C
//
|
||
// Created by longjin on 2022/1/22.
|
||
//
|
||
#include "printk.h"
|
||
#include <math.h>
|
||
|
||
int skip_and_atoi(const char **s)
|
||
{
|
||
/**
|
||
* @brief 获取连续的一段字符对应整数的值
|
||
* @param:**s 指向 指向字符串的指针 的指针
|
||
*/
|
||
int ans = 0;
|
||
while (is_digit(**s))
|
||
{
|
||
ans = ans * 10 + (**s) - '0';
|
||
++(*s);
|
||
}
|
||
return ans;
|
||
}
|
||
static int vsprintf(char *buf, const char *fmt, va_list args)
|
||
{
|
||
/**
|
||
* 将字符串按照fmt和args中的内容进行格式化，然后保存到buf中
|
||
* @param buf 结果缓冲区
|
||
* @param fmt 格式化字符串
|
||
* @param args 内容
|
||
* @return 最终字符串的长度
|
||
*/
|
||
|
||
char *str, *s;
|
||
|
||
str = buf;
|
||
|
||
int flags; // 用来存储格式信息的bitmap
|
||
int field_width; //区域宽度
|
||
int precision; //精度
|
||
int qualifier; //数据显示的类型
|
||
int len;
|
||
|
||
//开始解析字符串
|
||
for (; *fmt; ++fmt)
|
||
{
|
||
//内容不涉及到格式化，直接输出
|
||
if (*fmt != '%')
|
||
{
|
||
*str = *fmt;
|
||
++str;
|
||
continue;
|
||
}
|
||
|
||
//开始格式化字符串
|
||
|
||
//清空标志位和field宽度
|
||
field_width = flags = 0;
|
||
++fmt;
|
||
|
||
bool flag_tmp = true;
|
||
bool flag_break = false;
|
||
|
||
while (flag_tmp)
|
||
{
|
||
switch (*fmt)
|
||
{
|
||
case '\0':
|
||
//结束解析
|
||
flag_break = true;
|
||
flag_tmp = false;
|
||
break;
|
||
case '%':
|
||
//输出 %
|
||
*str = '%';
|
||
++str;
|
||
++fmt;
|
||
flag_break = true;
|
||
break;
|
||
case '-':
|
||
// 左对齐
|
||
flags |= LEFT;
|
||
++fmt;
|
||
break;
|
||
case '+':
|
||
//在正数前面显示加号
|
||
flags |= PLUS;
|
||
++fmt;
|
||
break;
|
||
case ' ':
|
||
flags |= SPACE;
|
||
++fmt;
|
||
break;
|
||
case '#':
|
||
//在八进制数前面显示 '0o'，在十六进制数前面显示 '0x' 或 '0X'
|
||
flags |= SPECIAL;
|
||
++fmt;
|
||
break;
|
||
case '0':
|
||
//显示的数字之前填充‘0’来取代空格
|
||
flags |= PAD_ZERO;
|
||
++fmt;
|
||
break;
|
||
default:
|
||
flag_tmp = false;
|
||
break;
|
||
}
|
||
}
|
||
if (flag_break)
|
||
break;
|
||
|
||
//获取区域宽度
|
||
if (*fmt == '*')
|
||
{
|
||
field_width = va_arg(args, int);
|
||
++fmt;
|
||
}
|
||
else if (is_digit(*fmt))
|
||
field_width = skip_and_atoi(&fmt);
|
||
|
||
//获取小数精度
|
||
precision = -1;
|
||
if (*fmt == '.')
|
||
{
|
||
++fmt;
|
||
if (*fmt == '*')
|
||
{
|
||
precision = va_arg(args, int);
|
||
++fmt;
|
||
}
|
||
else if is_digit (*fmt)
|
||
{
|
||
precision = skip_and_atoi(&fmt);
|
||
}
|
||
}
|
||
|
||
//获取要显示的数据的类型
|
||
if (*fmt == 'h' || *fmt == 'l' || *fmt == 'L' || *fmt == 'Z')
|
||
{
|
||
qualifier = *fmt;
|
||
++fmt;
|
||
}
|
||
|
||
//转化成字符串
|
||
|
||
switch (*fmt)
|
||
{
|
||
// 显示一个字符
|
||
case 'c':
|
||
//靠右对齐
|
||
if (!(flags & LEFT))
|
||
{
|
||
while (--field_width)
|
||
{
|
||
*str = ' ';
|
||
++str;
|
||
}
|
||
}
|
||
else //靠左对齐
|
||
{
|
||
*str = (char)va_arg(args, int);
|
||
++str;
|
||
--field_width;
|
||
}
|
||
while (--field_width)
|
||
{
|
||
*str = ' ';
|
||
++str;
|
||
}
|
||
|
||
break;
|
||
|
||
//显示一个字符串
|
||
case 's':
|
||
s = va_arg(args, char *);
|
||
if (!s)
|
||
s = '\0';
|
||
len = strlen(s);
|
||
if (precision < 0)
|
||
{
|
||
//未指定精度
|
||
precision = len;
|
||
}
|
||
|
||
else if (len > precision)
|
||
{
|
||
len = precision;
|
||
}
|
||
|
||
//靠右对齐
|
||
if (!(flags & LEFT))
|
||
while (len < field_width--)
|
||
{
|
||
*str = ' ';
|
||
++str;
|
||
}
|
||
|
||
for (int i = 0; i < len; i++)
|
||
{
|
||
*str = *s;
|
||
++s;
|
||
++str;
|
||
}
|
||
|
||
while (len < field_width--)
|
||
{
|
||
*str = ' ';
|
||
++str;
|
||
}
|
||
|
||
break;
|
||
//以八进制显示字符串
|
||
case 'o':
|
||
if (qualifier == 'l')
|
||
write_num(str, va_arg(args, long long), 8, field_width, precision, flags);
|
||
else
|
||
write_num(str, va_arg(args, int), 8, field_width, precision, flags);
|
||
break;
|
||
|
||
//打印指针指向的地址
|
||
case 'p':
|
||
if (field_width == 0)
|
||
{
|
||
field_width = 2 * sizeof(void *);
|
||
flags |= PAD_ZERO;
|
||
}
|
||
|
||
write_num(str, (unsigned long)va_arg(args, void *), 16, field_width, precision, flags);
|
||
|
||
break;
|
||
|
||
//打印十六进制
|
||
case 'x':
|
||
flags |= SMALL;
|
||
case 'X':
|
||
if (qualifier == 'l')
|
||
write_num(str, va_arg(args, long long), 16, field_width, precision, flags);
|
||
else
|
||
write_num(str, va_arg(args, int), 16, field_width, precision, flags);
|
||
break;
|
||
|
||
//打印十进制有符号整数
|
||
case 'i':
|
||
case 'd':
|
||
case 'ld':
|
||
flags |= SIGN;
|
||
if (qualifier == 'l')
|
||
write_num(str, va_arg(args, long long), 10, field_width, precision, flags);
|
||
else
|
||
write_num(str, va_arg(args, int), 10, field_width, precision, flags);
|
||
break;
|
||
|
||
//打印十进制无符号整数
|
||
case 'u':
|
||
if (qualifier == 'l')
|
||
write_num(str, va_arg(args, unsigned long long), 10, field_width, precision, flags);
|
||
else
|
||
write_num(str, va_arg(args, unsigned int), 10, field_width, precision, flags);
|
||
break;
|
||
|
||
//输出有效字符数量到*ip对应的变量
|
||
case 'n':
|
||
long long *ip;
|
||
if (qualifier == 'l')
|
||
ip = va_arg(args, long long *);
|
||
else
|
||
ip = va_arg(args, int *);
|
||
|
||
*ip = str - buf;
|
||
break;
|
||
|
||
//对于不识别的控制符，直接输出
|
||
default:
|
||
*str++ = '%';
|
||
if(*fmt)
|
||
*str++ = *fmt;
|
||
else --fmt;
|
||
break;
|
||
}
|
||
}
|
||
*str = '\0';
|
||
//返回缓冲区已有字符串的长度。
|
||
return str-buf;
|
||
}
|
||
|
||
static void write_num(char *str, long long num, int base, int field_width, int precision, int flags)
|
||
{
|
||
/**
|
||
* @brief 将数字按照指定的要求转换成对应的字符串
|
||
*
|
||
* @param str 要返回的字符串
|
||
* @param num 要打印的数值
|
||
* @param base 基数
|
||
* @param field_width 区域宽度
|
||
* @param precision 精度
|
||
* @param flags 标志位
|
||
*/
|
||
|
||
// 首先判断是否支持该进制
|
||
if (base < 2 || base > 36)
|
||
return 0;
|
||
|
||
char pad, sign, tmp_num[100];
|
||
|
||
const char *digits = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
|
||
// 显示小写字母
|
||
if (flags & SMALL)
|
||
digits = "0123456789abcdefghijklmnopqrstuvwxyz";
|
||
|
||
// 设置填充元素
|
||
pad = (flags & PAD_ZERO) ? '0' : ' ';
|
||
|
||
sign = 0;
|
||
if (flags & SIGN && num < 0)
|
||
{
|
||
sign = '-';
|
||
num = -num;
|
||
}
|
||
else
|
||
{
|
||
// 设置符号
|
||
sign = (flags & PLUS) ? '+' : ((flags & SPACE) ? ' ' : 0);
|
||
}
|
||
|
||
// sign占用了一个宽度
|
||
if (sign)
|
||
--field_width;
|
||
|
||
if (flags & SPECIAL)
|
||
if (base == 16) // 0x占用2个位置
|
||
field_width -= 2;
|
||
else if (base == 8) // O占用一个位置
|
||
--field_width;
|
||
|
||
int js_num = 0; // 临时数字字符串tmp_num的长度
|
||
|
||
if (num == 0)
|
||
tmp_num[js_num++] = '0';
|
||
else
|
||
{
|
||
num = abs(num);
|
||
//进制转换
|
||
while (num)
|
||
{
|
||
tmp_num[js_num++] = num % base; // 注意这里，输出的数字，是小端对齐的。低位存低位
|
||
num /= base;
|
||
}
|
||
}
|
||
|
||
if (js_num > precision)
|
||
precision = js_num;
|
||
|
||
field_width -= precision;
|
||
|
||
// 靠右对齐
|
||
if (!(flags & LEFT))
|
||
while (field_width--)
|
||
*str++ = pad;
|
||
|
||
if (sign)
|
||
*str++ = sign;
|
||
if (flags & SPECIAL)
|
||
if (base == 16)
|
||
{
|
||
*str++ = '0';
|
||
*str++ = digits[33];
|
||
}
|
||
else if (base == 8)
|
||
*str++ = digits[24]; //注意这里是英文字母O或者o
|
||
|
||
while (js_num < precision)
|
||
{
|
||
--precision;
|
||
*str++ = '0';
|
||
}
|
||
|
||
while (js_num--)
|
||
*str++ = tmp_num[js_num];
|
||
|
||
while (field_width--)
|
||
*str++ = ' ';
|
||
|
||
return str;
|
||
} |