GMDataBackedFileDelegate.m

//
//  GMDataBackedFileDelegate.m
//  OSXFUSE
//

//  OSXFUSE.framework is based on MacFUSE.framework. MacFUSE.framework is
//  covered under the following BSD-style license:
//
//  Copyright (c) 2007 Google Inc.
//  All rights reserved.
//
//  Redistribution  and  use  in  source  and  binary  forms,  with  or  without
//  modification, are permitted provided that the following conditions are met:
//
//  1. Redistributions of source code must retain the  above  copyright  notice,
//     this list of conditions and the following disclaimer.
//  2. Redistributions in binary form must reproduce the above copyright notice,
//     this list of conditions and the following disclaimer in the documentation
//     and/or other materials provided with the distribution.
//  3. Neither the name of Google Inc. nor the names of its contributors may  be
//     used to endorse or promote products derived from  this  software  without
//     specific prior written permission.
//
//  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS  IS"
//  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT  LIMITED  TO,  THE
//  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A  PARTICULAR  PURPOSE
//  ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT  OWNER  OR  CONTRIBUTORS  BE
//  LIABLE  FOR  ANY  DIRECT,  INDIRECT,  INCIDENTAL,  SPECIAL,  EXEMPLARY,   OR
//  CONSEQUENTIAL  DAMAGES  (INCLUDING,  BUT  NOT  LIMITED  TO,  PROCUREMENT  OF
//  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,  OR  PROFITS;  OR  BUSINESS
//  INTERRUPTION) HOWEVER CAUSED AND ON ANY  THEORY  OF  LIABILITY,  WHETHER  IN
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#import "GMDataBackedFileDelegate.h"

@implementation GMDataBackedFileDelegate

+ (GMDataBackedFileDelegate *)fileDelegateWithData:(NSData *)data {
  return [[[self alloc] initWithData:data] autorelease];
}

- (id)initWithData:(NSData *)data {
  self = [super init];
  if (self) {
    data_ = [data retain];
  }
  return self;
}

- (void)dealloc {
  [data_ release];
  [super dealloc];
}

- (NSData *)data {
  return data_;
}

- (int)readToBuffer:(char *)buffer 
               size:(size_t)size 
             offset:(off_t)offset 
              error:(NSError **)error {
  size_t len = [data_ length];
  if (offset > len) {
    return 0;  // No data to read.
  }
  if (offset + size > len) {
    size = len - offset;
  }
  NSRange range = NSMakeRange(offset, size);
  [data_ getBytes:buffer range:range];
  return size;
}

@end

@implementation GMMutableDataBackedFileDelegate

+ (GMMutableDataBackedFileDelegate *)fileDelegateWithData:(NSMutableData *)data {
  return [[[self alloc] initWithMutableData:data] autorelease];
}

- (id)initWithMutableData:(NSMutableData *)data {
  self = [super initWithData:data];
  return self;
}

- (int)writeFromBuffer:(const char *)buffer 
                  size:(size_t)size 
                offset:(off_t)offset
                 error:(NSError **)error {
  // Take the lazy way out.  We just extend the NSData to be as large as needed
  // and then replace whatever bytes they want to write.
  NSMutableData* data = (NSMutableData*)[self data];
  if ([data length] < (offset + size)) {
    int bytesBeyond = (offset + size) - [data length];
    [(NSMutableData *)data increaseLengthBy:bytesBeyond];
  }
  NSRange range = NSMakeRange(offset, size);
  [data replaceBytesInRange:range withBytes:buffer];
  return size;
}

- (BOOL)truncateToOffset:(off_t)offset 
                   error:(NSError **)error {
  NSMutableData* data = (NSMutableData*)[self data];
  [data setLength:offset];
  return YES;
}

@end