ulib.c

来自「类unix x86平台的简单操作系统」· C语言 代码 · 共 91 行

#include "types.h"
#include "stat.h"
#include "fcntl.h"
#include "user.h"

int
puts(char *s)
{
  return write(1, s, strlen(s));
}

char*
strcpy(char *s, char *t)
{
  char *os;

  os = s;
  while((*s++ = *t++) != 0)
    ;
  return os;
}

int
strcmp(const char *p, const char *q)
{
  while(*p && *p == *q)
    p++, q++;
  return (int) ((unsigned char) *p - (unsigned char) *q);
}

unsigned int
strlen(char *s)
{
  int n = 0;
  for(n = 0; s[n]; n++)
    ;
  return n;
}

void*
memset(void *dst, int c, unsigned int n)
{
  char *d = (char*) dst;

  while(n-- > 0)
    *d++ = c;

  return dst;
}

char*
strchr(const char *s, char c)
{
  for(; *s; s++)
    if(*s == c)
      return (char*) s;
  return 0;
}

char*
gets(char *buf, int max)
{
  int i = 0, cc;
  char c;

  while(i+1 < max){
    cc = read(0, &c, 1);
    if(cc < 1)
      break;
    if(c == '\n' || c == '\r')
      break;
    buf[i++] = c;
  }
  buf[i] = '\0';
  return buf;
}

int
stat(char *n, struct stat *st)
{
  int fd;
  int r;

  fd = open(n, O_RDONLY);
  if(fd < 0)
    return -1;
  r = fstat(fd, st);
  close(fd);
  return r;
}