programs/ramdisk/file.c

   1 /*
   2  * Copyright (c) 2008 The LOST Project. All rights reserved.
   3  *
   4  * This code is derived from software contributed to the LOST Project
   5  * by Alexander Siol and Janosch Graef.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. All advertising materials mentioning features or use of this software
  16  *    must display the following acknowledgement:
  17  *     This product includes software developed by the LOST Project
  18  *     and its contributors.
  19  * 4. Neither the name of the LOST Project nor the names of its
  20  *    contributors may be used to endorse or promote products derived
  21  *    from this software without specific prior written permission.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  24  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  25  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  26  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR
  27  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  28  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  29  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
  30  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  31  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
  32  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
  33  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  34  */
  35
  36 #include "ramdisk_cdi.h"
  37
  38 size_t ramdisk_fs_file_read(struct cdi_fs_stream* stream, uint64_t start,
  39     size_t size, void* data)
  40 {
  41     struct ramdisk_fs_res* res = (struct ramdisk_fs_res*) stream->res;
  42
  43     // maximal bis Ende lesen.
  44     if ((res->size - start) < size) {
  45         size = res->size - start;
  46     }
  47
  48     memcpy(data, res->buffer + start, size);
  49     return size;
  50 }
  51
  52 size_t ramdisk_fs_file_write(struct cdi_fs_stream* stream, uint64_t start,
  53     size_t size, const void* data)
  54 {
  55     struct ramdisk_fs_res* res = (struct ramdisk_fs_res*) stream->res;
  56
  57     // Es soll mehr geschrieben werden als Platz ist. Buffer vergroessern!.
  58     if ((res->size - start) < size) {
  59         void* new_buffer;
  60         size_t new_size;
  61         new_size = start + size;
  62         if (!(new_buffer = realloc(res->buffer,new_size))) {
  63             stream->error = CDI_FS_ERROR_INTERNAL;
  64             return 0;
  65         }
  66         memset(new_buffer + res->size, 0, new_size - res->size);
  67         res->buffer = new_buffer;
  68         res->size = new_size;
  69     }
  70
  71     memcpy(res->buffer + start, data, size);
  72     return size;
  73 }
  74
  75 int ramdisk_fs_file_truncate(struct cdi_fs_stream* stream, uint64_t size)
  76 {
  77     struct ramdisk_fs_res* res = (struct ramdisk_fs_res*) stream->res;
  78
  79     // Nichts zu tun
  80     if (size == res->size) {
  81         return 1;
  82     }
  83
  84     void* new_buffer;
  85     if (!(new_buffer = realloc(res->buffer,size))) {
  86         stream->error = CDI_FS_ERROR_INTERNAL;
  87     }
  88     if (res->size < size) {
  89         memset(new_buffer + res->size,0,size - res->size);
  90     }
  91
  92     res->buffer = new_buffer;
  93     res->size = size;
  94     return 1;
  95 }