text: /*
   * File     : stubs.c
   * Brief    : reimplement some basic functions of arm standard c library
   *
   * This file is part of RT-Thread RTOS
   * COPYRIGHT (C) 2006 - 2017, RT-Thread Development Team
   *
   *  This program is free software; you can redistribute it and/or modify
   *  it under the terms of the GNU General Public License as published by
   *  the Free Software Foundation; either version 2 of the License, or
   *  (at your option) any later version.
   *
   *  This program is distributed in the hope that it will be useful,
   *  but WITHOUT ANY WARRANTY; without even the implied warranty of
   *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   *  GNU General Public License for more details.
   *
   *  You should have received a copy of the GNU General Public License along
   *  with this program; if not, write to the Free Software Foundation, Inc.,
   *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * Change Logs:
   * Date           Author       Notes
   * 2012-11-23     Yihui        The first version
   * 2013-11-24     aozima       fixed _sys_read()/_sys_write() issues.
   * 2014-08-03     bernard      If using msh, use system() implementation
   *                             in msh.
   */
  
  #include <string.h>
  #include <rt_sys.h>
  
  #include "rtthread.h"
  #include "libc.h"
  
  #ifdef RT_USING_DFS
  	#include "dfs_posix.h"
  #endif
  
  #pragma import(__use_no_semihosting_swi)
  
  /* Standard IO device handles. */
  #define STDIN       0
  #define STDOUT      1
  #define STDERR      2
  
  /* Standard IO device name defines. */
  const char __stdin_name[]  = "STDIN";
  const char __stdout_name[] = "STDOUT";
  const char __stderr_name[] = "STDERR";
  
  /**
   * required by fopen() and freopen().
   *
   * @param name - file name with path.
   * @param openmode - a bitmap hose bits mostly correspond directly to
   *                     the ISO mode specification.
   * @return  -1 if an error occurs.
   */
  FILEHANDLE _sys_open(const char* name, int openmode)
  {
  #ifdef RT_USING_DFS
  	int fd;
  	int mode = O_RDONLY;
  #endif
  
  	/* Register standard Input Output devices. */
  	if(strcmp(name, __stdin_name) == 0)
  		return (STDIN);
  
  	if(strcmp(name, __stdout_name) == 0)
  		return (STDOUT);
  
  	if(strcmp(name, __stderr_name) == 0)
  		return (STDERR);
  
  #ifndef RT_USING_DFS
  	return -1;
  #else
  
  	/* Correct openmode from fopen to open */
  	if(openmode & OPEN_PLUS) {
  		if(openmode & OPEN_W) {
  			mode |= (O_RDWR | O_TRUNC | O_CREAT);
  		} else if(openmode & OPEN_A) {
  			mode |= (O_RDWR | O_APPEND | O_CREAT);
  		} else
  			mode |= O_RDWR;
  	} else {
  		if(openmode & OPEN_W) {
  			mode |= (O_WRONLY | O_TRUNC | O_CREAT);
  		} else if(openmode & OPEN_A) {
  			mode |= (O_WRONLY | O_APPEND | O_CREAT);
  		}
  	}
  
  	fd = open(name, mode, 0);
  
  	if(fd < 0)
  		return -1;
  	else
  		return fd;
  
  #endif
  }
  
  int _sys_close(FILEHANDLE fh)
  {
  #ifndef RT_USING_DFS
  	return 0;
  #else
  
  	if(fh <= STDERR) return 0;
  
  	return close(fh);
  #endif
  }
  
  /*
   * Read from a file. Can return:
   *  - zero if the read was completely successful
   *  - the number of bytes _not_ read, if the read was partially successful
   *  - the number of bytes not read, plus the top bit set (0x80000000), if
   *    the read was partially successful due to end of file
   *  - -1 if some error other than EOF occurred
   *
   * It is also legal to signal EOF by returning no data but
   * signalling no error (i.e. the top-bit-set mechanism need never
   * be used).
   *
   * So if (for example) the user is trying to read 8 bytes at a time
   * from a file in which only 5 remain, this routine can do three
   * equally valid things:
   *
   *  - it can return 0x80000003 (3 bytes not read due to EOF)
   *  - OR it can return 3 (3 bytes not read), and then return
   *    0x80000008 (8 bytes not read due to EOF) on the next attempt
   *  - OR it can return 3 (3 bytes not read), and then return
   *    8 (8 bytes not read, meaning 0 read, meaning EOF) on the next
   *    attempt
   *
   * `mode' exists for historical reasons and must be ignored.
   */
  int _sys_read(FILEHANDLE fh, unsigned char* buf, unsigned len, int mode)
  {
  #ifdef RT_USING_DFS
  	int size;
  #endif
  
  	if(fh == STDIN) {
  #ifdef RT_USING_POSIX
  		size = libc_stdio_read(buf, len);
  		return len - size;
  #else
  		/* no stdin */
  		return -1;
  #endif
  	}
  
  	if((fh == STDOUT) || (fh == STDERR))
  		return -1;
  
  #ifndef RT_USING_DFS
  	return 0;
  #else
  	size = read(fh, buf, len);
  
  	if(size >= 0)
  		return len - size;
  	else
  		return -1;
  
  #endif
  }
  
  /*
   * Write to a file. Returns 0 on success, negative on error, and
   * the number of characters _not_ written on partial success.
   * `mode' exists for historical reasons and must be ignored.
   */
  int _sys_write(FILEHANDLE fh, const unsigned char* buf, unsigned len, int mode)
  {
  #ifdef RT_USING_DFS
  	int size;
  #endif
  
  	if((fh == STDOUT) || (fh == STDERR)) {
  #ifndef RT_USING_CONSOLE
  		return 0;
  #else
  #ifdef RT_USING_POSIX
  		size = libc_stdio_write(buf, len);
  		return len - size;
  #else
  
  		if(rt_console_get_device()) {
  			rt_device_write(rt_console_get_device(), -1, buf, len);
  			return 0;
  		}
  
  		return -1;
  #endif
  #endif
  	}
  
  	if(fh == STDIN) return -1;
  
  #ifndef RT_USING_DFS
  	return 0;
  #else
  	size = write(fh, buf, len);
  
  	if(size >= 0)
  		return len - size;
  	else
  		return -1;
  
  #endif
  }
  
  /*
   * Move the file position to a given offset from the file start.
   * Returns >=0 on success, <0 on failure.
   */
  int _sys_seek(FILEHANDLE fh, long pos)
  {
  	if(fh < STDERR)
  		return -1;
  
  #ifndef RT_USING_DFS
  	return -1;
  #else
  
  	/* position is relative to the start of file fh */
  	return lseek(fh, pos, 0);
  #endif
  }
  
  /**
   * used by tmpnam() or tmpfile()
   */
  int _sys_tmpnam(char* name, int fileno, unsigned maxlength)
  {
  	return -1;
  }
  
  char* _sys_command_string(char* cmd, int len)
  {
  	/* no support */
  	return cmd;
  }
  
  /* This function writes a character to the console. */
  void _ttywrch(int ch)
  {
  #ifdef RT_USING_CONSOLE
  	char c;
  
  	c = (char)ch;
  	rt_kprintf(&c);
  #endif
  }
  
  void _sys_exit(int return_code)
  {
  	/* TODO: perhaps exit the thread which is invoking this function */
  	while(1);
  }
  
  /**
   * return current length of file.
   *
   * @param fh - file handle
   * @return file length, or -1 on failed
   */
  long _sys_flen(FILEHANDLE fh)
  {
  	return -1;
  }
  
  int _sys_istty(FILEHANDLE fh)
  {
  	return 0;
  }
  
  int remove(const char* filename)
  {
  #ifndef RT_USING_DFS
  	return -1;
  #else
  	return unlink(filename);
  #endif
  }
  
  #if defined(RT_USING_FINSH) && defined(FINSH_USING_MSH) && defined(RT_USING_MODULE) && defined(RT_USING_DFS)
  /* use system(const char *string) implementation in the msh */
  #else
  int system(const char* string)
  {
  	RT_ASSERT(0);
  
  	for(;;);
  }
  #endif
  
  #ifdef __MICROLIB
  #include <stdio.h>
  
  int fputc(int c, FILE* f)
  {
  	char ch = c;
  
  	rt_kprintf(&ch);
  	return 1;
  }
  
  int fgetc(FILE* f)
  {
  	char ch;
  
  #ifdef RT_USING_POSIX
  
  	if(libc_stdio_read(&ch, 1) == 1)
  		return ch;
  
  #endif
  
  	return -1;
  }
  #endif
  