mirror of
https://github.com/DragonOS-Community/DragonOS.git
synced 2025-06-11 09:06:47 +00:00
554 lines
14 KiB
C
554 lines
14 KiB
C
#include "printf.h"
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#include <libc/math.h>
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#include <libc/stdio.h>
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#include <libc/stdlib.h>
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#include <libc/string.h>
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#include <libsystem/syscall.h>
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static char *write_num(char *str, uint64_t num, int base, int field_width, int precision, int flags);
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static char *write_float_point_num(char *str, double num, int field_width, int precision, int flags);
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static int skip_and_atoi(const char **s)
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{
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/**
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* @brief 获取连续的一段字符对应整数的值
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* @param:**s 指向 指向字符串的指针 的指针
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*/
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int ans = 0;
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while (is_digit(**s))
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{
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ans = ans * 10 + (**s) - '0';
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++(*s);
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}
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return ans;
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}
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/**
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* @brief 往屏幕上输出字符串
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*
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* @param str 字符串指针
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* @param front_color 前景色
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* @param bg_color 背景色
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* @return int64_t
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*/
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int64_t put_string(char *str, uint64_t front_color, uint64_t bg_color)
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{
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return syscall_invoke(SYS_PUT_STRING, (uint64_t)str, front_color, bg_color, 0, 0, 0, 0, 0);
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}
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int printf(const char *fmt, ...)
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{
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char buf[4096];
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int count = 0;
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va_list args;
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va_start(args, fmt);
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count = vsprintf(buf, fmt, args);
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va_end(args);
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put_string(buf, COLOR_WHITE, COLOR_BLACK);
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return count;
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}
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int sprintf(char *buf, const char *fmt, ...)
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{
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int count = 0;
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va_list args;
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va_start(args, fmt);
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count = vsprintf(buf, fmt, args);
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va_end(args);
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return count;
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}
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/**
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* 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
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* @param buf 结果缓冲区
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* @param fmt 格式化字符串
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* @param args 内容
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* @return 最终字符串的长度
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*/
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int vsprintf(char *buf, const char *fmt, va_list args)
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{
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// 当需要输出的字符串的指针为空时，使用该字符填充目标字符串的指针
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static const char __end_zero_char = '\0';
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char *str = NULL, *s = NULL;
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str = buf;
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int flags; // 用来存储格式信息的bitmap
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int field_width; //区域宽度
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int precision; //精度
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int qualifier; //数据显示的类型
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int len;
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//开始解析字符串
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for (; *fmt; ++fmt)
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{
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//内容不涉及到格式化，直接输出
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if (*fmt != '%')
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{
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*str = *fmt;
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++str;
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continue;
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}
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//开始格式化字符串
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//清空标志位和field宽度
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field_width = flags = 0;
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bool flag_tmp = true;
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bool flag_break = false;
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++fmt;
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while (flag_tmp)
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{
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switch (*fmt)
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{
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case '\0':
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//结束解析
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flag_break = true;
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flag_tmp = false;
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break;
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case '-':
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// 左对齐
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flags |= LEFT;
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++fmt;
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break;
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case '+':
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//在正数前面显示加号
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flags |= PLUS;
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++fmt;
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break;
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case ' ':
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flags |= SPACE;
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++fmt;
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break;
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case '#':
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//在八进制数前面显示 '0o'，在十六进制数前面显示 '0x' 或 '0X'
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flags |= SPECIAL;
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++fmt;
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break;
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case '0':
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//显示的数字之前填充‘0’来取代空格
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flags |= PAD_ZERO;
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++fmt;
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break;
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default:
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flag_tmp = false;
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break;
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}
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}
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if (flag_break)
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break;
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//获取区域宽度
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field_width = -1;
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if (*fmt == '*')
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{
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field_width = va_arg(args, int);
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++fmt;
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}
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else if (is_digit(*fmt))
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{
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field_width = skip_and_atoi(&fmt);
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if (field_width < 0)
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{
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field_width = -field_width;
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flags |= LEFT;
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}
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}
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//获取小数精度
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precision = -1;
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if (*fmt == '.')
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{
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++fmt;
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if (*fmt == '*')
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{
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precision = va_arg(args, int);
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++fmt;
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}
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else if is_digit (*fmt)
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{
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precision = skip_and_atoi(&fmt);
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}
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}
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//获取要显示的数据的类型
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if (*fmt == 'h' || *fmt == 'l' || *fmt == 'L' || *fmt == 'Z')
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{
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qualifier = *fmt;
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++fmt;
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}
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//为了支持lld
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if (qualifier == 'l' && *fmt == 'l', *(fmt + 1) == 'd')
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++fmt;
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//转化成字符串
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long long *ip;
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switch (*fmt)
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{
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//输出 %
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case '%':
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*str++ = '%';
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break;
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// 显示一个字符
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case 'c':
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//靠右对齐
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if (!(flags & LEFT))
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{
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while (--field_width > 0)
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{
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*str = ' ';
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++str;
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}
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}
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*str++ = (unsigned char)va_arg(args, int);
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while (--field_width > 0)
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{
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*str = ' ';
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++str;
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}
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break;
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//显示一个字符串
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case 's':
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s = va_arg(args, char *);
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if (!s)
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s = &__end_zero_char;
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len = strlen(s);
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if (precision < 0)
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{
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//未指定精度
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precision = len;
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}
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else if (len > precision)
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{
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len = precision;
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}
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//靠右对齐
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if (!(flags & LEFT))
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while (len < field_width--)
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{
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*str = ' ';
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++str;
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}
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for (int i = 0; i < len; i++)
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{
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*str = *s;
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++s;
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++str;
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}
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while (len < field_width--)
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{
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*str = ' ';
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++str;
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}
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break;
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//以八进制显示字符串
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case 'o':
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flags |= SMALL;
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case 'O':
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flags |= SPECIAL;
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if (qualifier == 'l')
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str = write_num(str, va_arg(args, long long), 8, field_width, precision, flags);
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else
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str = write_num(str, va_arg(args, int), 8, field_width, precision, flags);
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break;
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//打印指针指向的地址
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case 'p':
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if (field_width == 0)
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{
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field_width = 2 * sizeof(void *);
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flags |= PAD_ZERO;
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}
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str = write_num(str, (unsigned long)va_arg(args, void *), 16, field_width, precision, flags);
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break;
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//打印十六进制
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case 'x':
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flags |= SMALL;
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case 'X':
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// flags |= SPECIAL;
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if (qualifier == 'l')
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str = write_num(str, va_arg(args, int64_t), 16, field_width, precision, flags);
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else
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str = write_num(str, va_arg(args, int), 16, field_width, precision, flags);
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break;
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//打印十进制有符号整数
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case 'i':
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case 'd':
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flags |= SIGN;
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if (qualifier == 'l')
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str = write_num(str, va_arg(args, long long), 10, field_width, precision, flags);
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else
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str = write_num(str, va_arg(args, int), 10, field_width, precision, flags);
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break;
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//打印十进制无符号整数
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case 'u':
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if (qualifier == 'l')
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str = write_num(str, va_arg(args, unsigned long long), 10, field_width, precision, flags);
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else
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str = write_num(str, va_arg(args, unsigned int), 10, field_width, precision, flags);
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break;
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//输出有效字符数量到*ip对应的变量
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case 'n':
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if (qualifier == 'l')
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ip = va_arg(args, long long *);
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else
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ip = (int64_t *)va_arg(args, int *);
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*ip = str - buf;
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break;
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case 'f':
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// 默认精度为3
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if (precision < 0)
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precision = 3;
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str = write_float_point_num(str, va_arg(args, double), field_width, precision, flags);
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break;
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//对于不识别的控制符，直接输出
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default:
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*str++ = '%';
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if (*fmt)
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*str++ = *fmt;
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else
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--fmt;
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break;
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}
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}
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*str = '\0';
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//返回缓冲区已有字符串的长度。
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return str - buf;
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}
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static char *write_num(char *str, uint64_t num, int base, int field_width, int precision, int flags)
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{
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/**
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* @brief 将数字按照指定的要求转换成对应的字符串
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*
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* @param str 要返回的字符串
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* @param num 要打印的数值
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* @param base 基数
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* @param field_width 区域宽度
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* @param precision 精度
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* @param flags 标志位
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*/
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// 首先判断是否支持该进制
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if (base < 2 || base > 36)
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return 0;
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char pad, sign, tmp_num[100];
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const char *digits = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
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// 显示小写字母
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if (flags & SMALL)
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digits = "0123456789abcdefghijklmnopqrstuvwxyz";
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if (flags & LEFT)
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flags &= ~PAD_ZERO;
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// 设置填充元素
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pad = (flags & PAD_ZERO) ? '0' : ' ';
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sign = 0;
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if (flags & SIGN)
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{
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int64_t signed_num = (int64_t)num;
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if (signed_num < 0)
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{
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sign = '-';
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num = -signed_num;
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}
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else
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num = signed_num;
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}
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else
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{
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// 设置符号
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sign = (flags & PLUS) ? '+' : ((flags & SPACE) ? ' ' : 0);
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}
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// sign占用了一个宽度
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if (sign)
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--field_width;
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if (flags & SPECIAL)
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if (base == 16) // 0x占用2个位置
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field_width -= 2;
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else if (base == 8) // O占用一个位置
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--field_width;
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int js_num = 0; // 临时数字字符串tmp_num的长度
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if (num == 0)
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tmp_num[js_num++] = '0';
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else
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{
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num = llabs(num);
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//进制转换
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while (num > 0)
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{
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tmp_num[js_num++] = digits[num % base]; // 注意这里，输出的数字，是小端对齐的。低位存低位
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num /= base;
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}
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}
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if (js_num > precision)
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precision = js_num;
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field_width -= precision;
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// 靠右对齐
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if (!(flags & (LEFT + PAD_ZERO)))
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while (field_width-- > 0)
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*str++ = ' ';
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if (sign)
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*str++ = sign;
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if (flags & SPECIAL)
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if (base == 16)
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{
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*str++ = '0';
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*str++ = digits[33];
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}
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else if (base == 8)
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*str++ = digits[24]; //注意这里是英文字母O或者o
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if (!(flags & LEFT))
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while (field_width-- > 0)
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*str++ = pad;
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while (js_num < precision)
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{
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--precision;
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*str++ = '0';
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}
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while (js_num-- > 0)
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*str++ = tmp_num[js_num];
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while (field_width-- > 0)
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*str++ = ' ';
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return str;
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}
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static char *write_float_point_num(char *str, double num, int field_width, int precision, int flags)
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{
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/**
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* @brief 将浮点数按照指定的要求转换成对应的字符串
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*
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* @param str 要返回的字符串
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* @param num 要打印的数值
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* @param field_width 区域宽度
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* @param precision 精度
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* @param flags 标志位
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*/
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char pad, sign, tmp_num_z[100], tmp_num_d[350];
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const char *digits = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
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// 显示小写字母
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if (flags & SMALL)
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digits = "0123456789abcdefghijklmnopqrstuvwxyz";
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// 设置填充元素
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pad = (flags & PAD_ZERO) ? '0' : ' ';
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sign = 0;
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if (flags & SIGN && num < 0)
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{
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sign = '-';
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num = -num;
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}
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else
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{
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// 设置符号
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sign = (flags & PLUS) ? '+' : ((flags & SPACE) ? ' ' : 0);
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}
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// sign占用了一个宽度
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if (sign)
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--field_width;
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int js_num_z = 0, js_num_d = 0; // 临时数字字符串tmp_num_z tmp_num_d的长度
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uint64_t num_z = (uint64_t)(num); // 获取整数部分
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uint64_t num_decimal = (uint64_t)(round(1.0 * (num - num_z) * pow(10, precision))); // 获取小数部分
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if (num == 0 || num_z == 0)
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tmp_num_z[js_num_z++] = '0';
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else
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{
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//存储整数部分
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while (num_z > 0)
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{
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tmp_num_z[js_num_z++] = digits[num_z % 10]; // 注意这里，输出的数字，是小端对齐的。低位存低位
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num_z /= 10;
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}
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}
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while (num_decimal > 0)
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{
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tmp_num_d[js_num_d++] = digits[num_decimal % 10];
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num_decimal /= 10;
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}
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field_width -= (precision + 1 + js_num_z);
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// 靠右对齐
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if (!(flags & LEFT))
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while (field_width-- > 0)
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*str++ = pad;
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if (sign)
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*str++ = sign;
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// 输出整数部分
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// while (js_num_z-- > 0)
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// *str++ = tmp_num_z[js_num_z];
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while (js_num_z > 0)
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{
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*str++ = tmp_num_z[js_num_z - 1];
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--js_num_z;
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}
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*str++ = '.';
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// 输出小数部分
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int total_dec_count = js_num_d;
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for (int i = 0; i < precision && js_num_d-- > 0; ++i)
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*str++ = tmp_num_d[js_num_d];
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while (total_dec_count < precision)
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{
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++total_dec_count;
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*str++ = '0';
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}
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while (field_width-- > 0)
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*str++ = ' ';
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return str;
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} |