GMDataBackedFileDelegate.m

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//
//  GMDataBackedFileDelegate.m
//  Fuse4X
//
//  Created by ted on 1/5/08.
//
#import "GMDataBackedFileDelegate.h"

@implementation GMDataBackedFileDelegate

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

- (id)initWithData:(NSData *)data {
  if ((self = [super init])) {
    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 {
  if ((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