ObjFW  Check-in [dc1093e2a5]

	if (fd == -1 || atEndOfStream || write(fd, buffer, length) < length)
		@throw [OFWriteFailedException exceptionWithClass: [self class]
							   stream: self
						  requestedLength: length];
}

- (void)lowlevelSeekToOffset: (off_t)offset

{
	if (lseek(fd, offset, SEEK_SET) == -1)
		@throw [OFSeekFailedException exceptionWithClass: [self class]
							  stream: self
							  offset: offset
							  whence: SEEK_SET];
}

- (off_t)lowlevelSeekForwardWithOffset: (off_t)offset
{
	off_t ret;

	if ((ret = lseek(fd, offset, SEEK_CUR)) == -1)
		@throw [OFSeekFailedException exceptionWithClass: [self class]
							  stream: self
							  offset: offset
							  whence: SEEK_CUR];

	return ret;
}

- (off_t)lowlevelSeekToOffsetRelativeToEnd: (off_t)offset
{
	off_t ret;

	if ((ret = lseek(fd, offset, SEEK_END)) == -1)
		@throw [OFSeekFailedException exceptionWithClass: [self class]
							  stream: self
							  offset: offset
							  whence: SEEK_END];

	return ret;
}

- (int)fileDescriptorForReading
{
	return fd;
}

{
	@throw [OFNotImplementedException exceptionWithClass: [self class]
						    selector: _cmd];
	[super dealloc];	/* Get rid of stupid warning */
}

- (void)lowlevelSeekToOffset: (off_t)offset
{
	@throw [OFNotImplementedException exceptionWithClass: [self class]
						    selector: _cmd];
}

- (off_t)lowlevelSeekForwardWithOffset: (off_t)offset
{
	@throw [OFNotImplementedException exceptionWithClass: [self class]
						    selector: _cmd];
}

- (off_t)lowlevelSeekToOffsetRelativeToEnd: (off_t)offset
{
	@throw [OFNotImplementedException exceptionWithClass: [self class]
						    selector: _cmd];
}
@end

#include <sys/types.h>

#import "OFStream.h"

/*!
 * @brief A stream that supports seeking.
 *
 * @note If you want to subclass this, override lowlevelSeekToOffset:,
 *	 lowlevelSeekForwardWithOffset: and lowlevelSeekToOffsetRelativeToEnd:,
 *	 but nothing else, as they do the actual work. OFSeekableStream uses
 *	 those and makes them work together with the caching of OFStream.
 *	 If you override these methods without the lowlevel prefix, you
 *	 <i>will</i> break caching, get broken results and seek to the wrong
 *	 position!
 */
@interface OFSeekableStream: OFStream
/*!
 * @brief Seeks to the specified absolute offset.
 *
 * @param offset The offset in bytes
 */
- (void)seekToOffset: (off_t)offset;

/*!
 * @brief Seeks to the specified offset, relative to the current location.
 *
 * @param offset The offset relative to the current location
 * @return The absolute offset

 */
- (off_t)seekForwardWithOffset: (off_t)offset;

/*!
 * @brief Seeks to the specified offset, relative to the end of the stream.
 *
 * @param offset The offset relative to the end of the stream
 * @return The absolute offset
 */
- (off_t)seekToOffsetRelativeToEnd: (off_t)offset;

/*!
 * @brief Seek the stream on the lowlevel.
 *
 * @warning Do not call this directly!
 *
 * Override this with this method with your actual seek implementation when
 * subclassing!
 *
 * @param offset The offset to seek to
 */
- (void)lowlevelSeekToOffset: (off_t)offset;

/*!
 * @brief Seek the stream on the lowlevel.
 *
 * @warning Do not call this directly!
 *
 * Override this with this method with your actual seek implementation when
 * subclassing!
 *
 * @param offset The offset to seek forward to
 */
- (off_t)lowlevelSeekForwardWithOffset: (off_t)offset;

/*!
 * @brief Seek the stream on the lowlevel.
 *
 * @warning Do not call this directly!
 *
 * Override this with this method with your actual seek implementation when
 * subclassing!
 *
 * @param offset The offset to seek to, relative to the end
 */
- (off_t)lowlevelSeekToOffsetRelativeToEnd: (off_t)offset;

@end

#import "OFSeekableStream.h"

#import "OFNotImplementedException.h"

@implementation OFSeekableStream
- (void)lowlevelSeekToOffset: (off_t)offset
{
	@throw [OFNotImplementedException exceptionWithClass: [self class]
						    selector: _cmd];
}

- (off_t)lowlevelSeekForwardWithOffset: (off_t)offset
{
	@throw [OFNotImplementedException exceptionWithClass: [self class]
						    selector: _cmd];
}

- (off_t)lowlevelSeekToOffsetRelativeToEnd: (off_t)offset
{
	@throw [OFNotImplementedException exceptionWithClass: [self class]
						    selector: _cmd];
}

- (void)seekToOffset: (off_t)offset

{
	[self lowlevelSeekToOffset: offset];

	[self freeMemory: cache];
	cache = NULL;
	cacheLength = 0;
}

- (off_t)seekForwardWithOffset: (off_t)offset
{
	off_t ret;

	ret = [self lowlevelSeekForwardWithOffset: offset - cacheLength];

	[self freeMemory: cache];
	cache = NULL;
	cacheLength = 0;

	return ret;
}

- (off_t)seekToOffsetRelativeToEnd: (off_t)offset
{
	off_t ret;

	ret = [self lowlevelSeekToOffsetRelativeToEnd: offset];

	[self freeMemory: cache];
	cache = NULL;
	cacheLength = 0;

	return ret;
}
@end