Leahnaya/wut
1
0
Fork 0
mirror of https://github.com/devkitPro/wut.git synced 2026-09-14 06:06:07 -05:00
Code Issues Actions Packages Projects Releases Wiki Activity

avoid misaligned reads

Browse Source
This commit is contained in:
Dave Murphy
2022-02-26 19:58:41 +00:00
parent 0b196e8abc
commit f919d6b65b
1 changed files with 39 additions and 61 deletions
Download Patch File Download Diff File Expand all files Collapse all files

100
libraries/wutdevoptab/devoptab_fs_read.c
View File

@@ -1,16 +1,13 @@
#include "devoptab_fs.h"
ssize_t
__wut_fs_read(struct _reent *r,
void *fd,
char *ptr,
size_t len)
{
ssize_t __wut_fs_read(struct _reent *r, void *fd, char *ptr, size_t len) {
FSStatus status = 0;
FSCmdBlock cmd;
uint8_t *alignedReadBuffer;
uint32_t bytes, bytesRead;
__wut_fs_file_t *file;
size_t bytesRead = 0;
size_t partSize[3];
__wut_fs_file_t *file = (__wut_fs_file_t *) fd;
__attribute__((aligned(0x40))) uint8_t alignedBuffer[0x40];
if (!fd || !ptr) {
r->_errno = EINVAL;
@@ -18,8 +15,6 @@ __wut_fs_read(struct _reent *r,
}
FSInitCmdBlock(&cmd);
file = (__wut_fs_file_t *)fd;
bytesRead = 0;
// Check that the file was opened with read access
if ((file->flags & O_ACCMODE) == O_WRONLY) {
@@ -27,59 +22,42 @@ __wut_fs_read(struct _reent *r,
return -1;
}
if((((uintptr_t) ptr) & 0x3F) == 0){
status = FSReadFile(__wut_devoptab_fs_client, &cmd, (uint8_t *) ptr, 1,
len, file->fd, 0, FS_ERROR_FLAG_ALL);
if(status > 0){
bytesRead = (uint32_t) status;
file->offset += bytesRead;
partSize[0] = (0x40 - ((uintptr_t)ptr & 0x3f)) & 0x3f;
if (partSize[0] > len) partSize[0] = len;
partSize[1] = len - partSize[0];
partSize[2] = partSize[1] & 0x3f;
partSize[1] -= partSize[2];
if (partSize[0] + partSize[2] <= 0x40 && partSize[1] == 0) {
partSize[0] += partSize[2];
partSize[2] = 0;
}
uint8_t *tmp;
for (int part=0; part<3; part++) {
if (!partSize[0]) continue;
if (part == 1) {
tmp = (uint8_t *)ptr;
} else {
tmp = alignedBuffer;
}
} else {
// Copy to internal buffer due to alignment requirement and read in chunks.
// Using a buffer smaller than 128KiB takes a performance hit.
int buffer_size = len < 128*1024 ? len : 128*1024;
alignedReadBuffer = memalign(0x40, buffer_size);
if(!alignedReadBuffer){
r->_errno = ENOMEM;
status = FSReadFile(__wut_devoptab_fs_client, &cmd, tmp, 1, partSize[part], file->fd, 0, FS_ERROR_FLAG_ALL);
if (status < 0) {
r->_errno = __wut_fs_translate_error(status);
return -1;
}
while (len > 0) {
size_t toRead = len > buffer_size ? buffer_size : len;
if (part != 1) memcpy(ptr, alignedBuffer, status);
bytesRead += status;
ptr += status;
// Write the data
status = FSReadFile(__wut_devoptab_fs_client, &cmd, alignedReadBuffer, 1,
toRead, file->fd, 0, FS_ERROR_FLAG_ALL);
if (status <= 0) {
break;
}
// Copy to internal buffer
bytes = (uint32_t)status;
memcpy(ptr, alignedReadBuffer, bytes);
file->offset += bytes;
bytesRead += bytes;
ptr += bytes;
len -= bytes;
if (bytes < toRead) {
// If we did not read the full requested toRead bytes then we reached
// the end of the file.
break;
}
}
free(alignedReadBuffer);
if (status != partSize[part]) return bytesRead;
}
// Return partial read
if (bytesRead > 0) {
return bytesRead;
}
if (status < 0) {
r->_errno = __wut_fs_translate_error(status);
return -1;
}
return 0;
}
return bytesRead;
}