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78 lines
2.0 KiB
C
78 lines
2.0 KiB
C
#pragma once
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#include "glib.h"
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/**
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* @brief 拷贝整个字符串
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*
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* @param dst 目标地址
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* @param src 源地址
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* @return char* 目标字符串
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*/
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char *strcpy(char *dst, const char *src);
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//计算字符串的长度（经过测试，该版本比采用repne/scasb汇编的运行速度快16.8%左右）
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static inline int strlen(const char *s)
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{
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if (s == NULL)
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return 0;
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register int __res = 0;
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while (s[__res] != '\0')
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{
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++__res;
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}
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return __res;
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}
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/**
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* @brief 测量字符串的长度
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*
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* @param src 字符串
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* @param maxlen 最大长度
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* @return long
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*/
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long strnlen(const char *src, unsigned long maxlen);
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/*
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比较字符串 FirstPart and SecondPart
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FirstPart = SecondPart => 0
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FirstPart > SecondPart => 1
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FirstPart < SecondPart => -1
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*/
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int strcmp(const char *FirstPart, const char *SecondPart);
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char *strncpy(char *dst, const char *src, long count);
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long strncpy_from_user(char *dst, const char *src, unsigned long size);
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/**
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* @brief 测量来自用户空间的字符串的长度，会检验地址空间是否属于用户空间
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* @param src
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* @param maxlen
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* @return long
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*/
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long strnlen_user(const char *src, unsigned long maxlen);
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/**
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* @brief 逐字节比较指定内存区域的值，并返回s1、s2的第一个不相等的字节i处的差值（s1[i]-s2[i])。
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* 若两块内存区域的内容相同，则返回0
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*
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* @param s1 内存区域1
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* @param s2 内存区域2
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* @param len 要比较的内存区域长度
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* @return int s1、s2的第一个不相等的字节i处的差值（s1[i]-s2[i])。若两块内存区域的内容相同，则返回0
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*/
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static inline int memcmp(const void *s1, const void *s2, size_t len)
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{
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int diff;
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asm("cld \n\t" // 复位DF，确保s1、s2指针是自增的
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"repz; cmpsb\n\t" CC_SET(nz)
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: CC_OUT(nz)(diff), "+D"(s1), "+S"(s2)
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: "c"(len)
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: "memory");
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if (diff)
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diff = *(const unsigned char *)(s1 - 1) - *(const unsigned char *)(s2 - 1);
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return diff;
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} |