sergiotarxz/nuttx
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

libc:Optimize the behavior of fwrite

Browse Source 
Signed-off-by: anjiahao <anjiahao@xiaomi.com>
This commit is contained in:
anjiahao 2022-06-02 23:53:14 +08:00 committed by Xiang Xiao
parent af87921eda
commit e0c3bf64a0
1 changed files with 27 additions and 20 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

47
libs/libc/stdio/lib_libfwrite.c
View File

@ -49,7 +49,7 @@ ssize_t lib_fwrite(FAR const void *ptr, size_t count, FAR FILE *stream)
FAR const unsigned char *start = ptr; FAR const unsigned char *start = ptr;
FAR const unsigned char *src = ptr; FAR const unsigned char *src = ptr;
ssize_t ret = ERROR; ssize_t ret = ERROR;
unsigned char *dest; size_t gulp_size;
/* Make sure that writing to this stream is allowed */ /* Make sure that writing to this stream is allowed */
@ -72,13 +72,11 @@ ssize_t lib_fwrite(FAR const void *ptr, size_t count, FAR FILE *stream)
if (stream->fs_bufstart == NULL) if (stream->fs_bufstart == NULL)
{ {
ret = _NX_WRITE(stream->fs_fd, ptr, count); ret = _NX_WRITE(stream->fs_fd, ptr, count);
#if defined(CONFIG_BUILD_FLAT) || defined(__KERNEL__)
if (ret < 0) if (ret < 0)
{ {
_NX_SETERRNO(ret); _NX_SETERRNO(ret);
ret = ERROR; ret = ERROR;
} }
#endif
goto errout; goto errout;
} }
@ -97,18 +95,11 @@ ssize_t lib_fwrite(FAR const void *ptr, size_t count, FAR FILE *stream)
goto errout_with_semaphore; goto errout_with_semaphore;
} }
/* Loop until all of the bytes have been buffered */ /* Determine the number of bytes left in the buffer */
while (count > 0) gulp_size = stream->fs_bufend - stream->fs_bufpos;
if (gulp_size != CONFIG_STDIO_BUFFER_SIZE || count < gulp_size)
{ {
/* Determine the number of bytes left in the buffer */
size_t gulp_size = stream->fs_bufend - stream->fs_bufpos;
/* Will the user data fit into the amount of buffer space
* that we have left?
*/
if (gulp_size > count) if (gulp_size > count)
{ {
/* Yes, clip the gulp to the size of the user data */ /* Yes, clip the gulp to the size of the user data */
@ -124,16 +115,13 @@ ssize_t lib_fwrite(FAR const void *ptr, size_t count, FAR FILE *stream)
/* Transfer the data into the buffer */ /* Transfer the data into the buffer */
for (dest = stream->fs_bufpos; gulp_size > 0; gulp_size--) memcpy(stream->fs_bufpos, src, gulp_size);
{ stream->fs_bufpos += gulp_size;
*dest++ = *src++; src += gulp_size;
}
stream->fs_bufpos = dest;
/* Is the buffer full? */ /* Is the buffer full? */
if (dest >= stream->fs_bufend) if (stream->fs_bufpos >= stream->fs_bufend)
{ {
/* Flush the buffered data to the IO stream */ /* Flush the buffered data to the IO stream */
@ -145,6 +133,25 @@ ssize_t lib_fwrite(FAR const void *ptr, size_t count, FAR FILE *stream)
} }
} }
if (count >= CONFIG_STDIO_BUFFER_SIZE)
{
ret = _NX_WRITE(stream->fs_fd, src, count);
if (ret < 0)
{
_NX_SETERRNO(ret);
ret = ERROR;
goto errout_with_semaphore;
}
src += ret;
}
else if (count > 0)
{
memcpy(stream->fs_bufpos, src, count);
stream->fs_bufpos += count;
src += count;
}
/* Return the number of bytes written */ /* Return the number of bytes written */
ret = (uintptr_t)src - (uintptr_t)start; ret = (uintptr_t)src - (uintptr_t)start;