F32RFileHandle.cpp

00001 /* mbed Microcontroller Library
00002  * Copyright (c) 2006-2016 ARM Limited
00003  *
00004  * Permission is hereby granted, free of charge, to any person obtaining a copy
00005  * of this software and associated documentation files (the "Software"), to deal
00006  * in the Software without restriction, including without limitation the rights
00007  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
00008  * copies of the Software, and to permit persons to whom the Software is
00009  * furnished to do so, subject to the following conditions:
00010  *
00011  * The above copyright notice and this permission notice shall be included in
00012  * all copies or substantial portions of the Software.
00013  *
00014  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
00015  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
00016  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
00017  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
00018  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
00019  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
00020  * SOFTWARE.
00021  */
00022 #include <algorithm>
00023 #include "F32RFileHandle.h"
00024 #include "fsdebug.h"
00025 
00026 F32RFileHandle::F32RFileHandle(F32RFileSystem& fs_, uint32_t d):fs(fs_) {
00027     pos = 0;
00028     cluster = fs.storage_peek(d + 20, 2)<<16|fs.storage_peek(d + 26, 2);
00029     file_length = fs.storage_peek(d + 28, 4);
00030     FS_DBG("cluster=%d", cluster);
00031     FS_DBG("file_length=%d", file_length);
00032 }
00033 
00034 int F32RFileHandle::close() {
00035     delete this;
00036     return 0;
00037 }
00038 
00039 ssize_t F32RFileHandle::write(const void* buffer, size_t length) {
00040     return -1;
00041 }
00042 
00043 ssize_t F32RFileHandle::read(void* buffer, size_t length) {
00044     FS_DBG("length=%d", length);
00045     ssize_t n = 0;
00046     while(n < length && pos < file_length) {
00047         uint32_t chunk = std::min((filesize_t)length - n, file_length - pos);
00048         chunk = std::min(chunk, fs.cluster_tail(pos));
00049         FS_TEST_ASSERT(cluster >= 2 && cluster < 0x0ffffff8);
00050         fs.storage->Read(fs.base_data + (uint64_t)(cluster-2)*fs.cluster_size + fs.cluster_head(pos), (uint8_t*)buffer + n, chunk);
00051         pos += chunk;
00052         if (fs.cluster_head(pos) == 0) {
00053             cluster = fs.fat_read(cluster);
00054         }
00055         n += chunk;
00056     }
00057     return n;
00058 }
00059 
00060 int F32RFileHandle::isatty() {
00061     return 0;
00062 }
00063 
00064 off_t F32RFileHandle::lseek(off_t position, int whence) {
00065     FS_DBG("position=%d whence=%d", (uint32_t)position, whence);
00066     return -1;
00067 }
00068 
00069 int F32RFileHandle::fsync() {
00070     return 0;
00071 }
00072 
00073 off_t F32RFileHandle::flen() {
00074     FS_DBG("file_length=%d", file_length);
00075     return file_length;
00076 }