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libc:Optimize the behavior of fwrite

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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
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47
libs/libc/stdio/lib_libfwrite.c
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@ -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 *src = ptr;
ssize_t ret = ERROR;
unsigned char *dest;
size_t gulp_size;
/* 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)
{
ret = _NX_WRITE(stream->fs_fd, ptr, count);
#if defined(CONFIG_BUILD_FLAT) || defined(__KERNEL__)
if (ret < 0)
{
_NX_SETERRNO(ret);
ret = ERROR;
}
#endif
goto errout;
}
@ -97,18 +95,11 @@ ssize_t lib_fwrite(FAR const void *ptr, size_t count, FAR FILE *stream)
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)
{
/* 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 */
for (dest = stream->fs_bufpos; gulp_size > 0; gulp_size--)
{
*dest++ = *src++;
}
stream->fs_bufpos = dest;
memcpy(stream->fs_bufpos, src, gulp_size);
stream->fs_bufpos += gulp_size;
src += gulp_size;
/* Is the buffer full? */
if (dest >= stream->fs_bufend)
if (stream->fs_bufpos >= stream->fs_bufend)
{
/* 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 */
ret = (uintptr_t)src - (uintptr_t)start;