read.c

来自「mips架构的bootloader,99左右的版本 但源代码现在没人更新了」· C语言 代码 · 共 30 行

/*************************************************************
 * File: lib/read.c
 * Purpose: Part of C runtime library
 * Author: Phil Bunce ([e-mail])
 * Revision History:
 *	970304	Start of revision history
 */

#include <termio.h>

/** read(fd,buf,n) read n bytes into buf from fd */
read(fd,buf,n)
int fd,n;
char *buf;
{
Ramfile *p;

if (fd < FILEOFFSET) return(_read(fd,buf,n));

fd -= FILEOFFSET;
if (_mfile[fd].open != 1) return(0);

p = &_mfile[fd];
if (p->posn + n >  p->size) n =  p->size - p->posn;
memcpy(buf,(char *)(p->base+p->posn),n);
p->posn += n;
return(n);
}