FAT12 read only file system
Fork of FATFileSystem by
F12RFileHandle.cpp
- Committer:
- va009039
- Date:
- 2015-11-11
- Revision:
- 7:f9f52d9c0c57
- Parent:
- 6:3c5b3606e019
- Child:
- 8:6c6acf81ff08
File content as of revision 7:f9f52d9c0c57:
/* mbed Microcontroller Library * Copyright (c) 2006-2016 ARM Limited * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE * SOFTWARE. */ #include <algorithm> #include "F12RFileHandle.h" #include "fsdebug.h" F12RFileHandle::F12RFileHandle(F12RFileSystem& fs_, uint32_t d):fs(fs_) { pos = 0; cluster = fs.storage_peek(d + 26, 2); file_length = fs.storage_peek(d + 28, 4); FS_DBG("cluster=%d", cluster); FS_DBG("file_length=%d", file_length); } int F12RFileHandle::close() { delete this; return 0; } ssize_t F12RFileHandle::write(const void* buffer, size_t length) { return -1; } ssize_t F12RFileHandle::read(void* buffer, size_t length) { FS_DBG("length=%d", length); ssize_t n = 0; while(n < length && pos < file_length) { uint32_t chunk = std::min(length - n, file_length - pos); chunk = std::min(chunk, fs.cluster_tail(pos)); FS_TEST_ASSERT(cluster >= 2 && cluster < 0xff8); fs.storage->storage_read((fs.base_data + cluster - 2)*512 + fs.cluster_head(pos), (uint8_t*)buffer + n, chunk); pos += chunk; if (fs.cluster_head(pos) == 0) { cluster = fs.fat_read(cluster); } n += chunk; } return n; } int F12RFileHandle::isatty() { return 0; } off_t F12RFileHandle::lseek(off_t position, int whence) { FS_DBG("position=%d whence=%d", (uint32_t)position, whence); return -1; } int F12RFileHandle::fsync() { return 0; } off_t F12RFileHandle::flen() { FS_DBG("file_length=%d", file_length); return file_length; }