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/* Implementation of TLBufferedMutableStream class.
This file is part of TL, Tiggr's Library.
Written by Tiggr <tiggr@es.ele.tue.nl>
Copyright (C) 1995, 1996 Pieter J. Schoenmakers
TL is distributed WITHOUT ANY WARRANTY.
See the file LICENSE in the TL distribution for details.
$Id: TLBufferedMutableStream.m,v 1.1 1998/01/08 16:11:30 tiggr Exp $ */
#define TLBUFFEREDMUTABLESTREAM_DECLARE_PRIVATE_METHODS
#import "tl/support.h"
#import "tl/TLBufferedMutableStream.h"
#import "tl/TLString.h"
#import <string.h>
@implementation TLBufferedMutableStream
-(int) copyBytes: (int) n fromBuffer: (const char *) b
{
int i;
if ([stream _seek: off from: TLSEEK_ABSOLUTE] != off)
return -1;
i = [super copyBytes: n fromBuffer: b];
if (i > 0)
off += i;
return i;
} /* -copyBytes:fromBuffer: */
-(int) copyBytes: (int) n intoBuffer: (char *) b
{
int i;
if ([stream _seek: off from: TLSEEK_ABSOLUTE] != off)
return -1;
i = [super copyBytes: n intoBuffer: b];
if (i > 0)
off += i;
return i;
} /* -copyBytes:intoBuffer: */
-(void) emptyBuffer
{
off += num;
[super emptyBuffer];
} /* -emptyBuffer */
-(int) readBytes: (int) n toOffset: (int) buf_off
{
if ([stream _seek: off + buf_off from: TLSEEK_ABSOLUTE] != off + buf_off)
return -1;
return [stream readBytes: n intoBuffer: buf + buf_off];
} /* -readBytes:toOffset: */
-(long) _seek: (long) new_offset from: (int) pos
{
switch (pos)
{
case TLSEEK_ABSOLUTE:
break;
case TLSEEK_FROM_END:
new_offset = [stream _seek: new_offset from: pos];
break;
case TLSEEK_RELATIVE:
new_offset = off + new_offset;
if (new_offset >= 0)
break;
/* Fall through. */
default:
[self error: "bad TLSEEK %d (to %d)", pos, new_offset];
return -1;
}
if (new_offset >= off && new_offset < off + num)
next = new_offset - off;
else
{
[self emptyBuffer];
off = new_offset;
}
return off + next;
} /* -_seek:from: */
-(long) _tell
{
return off + next;
} /* _tell */
-(int) unreadBytes: (int) n fromBuffer: (const char *) b
{
int r, prev_num;
if (buf_write_p)
[self flushOutput];
prev_num = num;
r = [super unreadBytes: n fromBuffer: b];
off -= num - prev_num;
return r;
} /* -unreadBytes:fromBuffer: */
-(int) _writeRange: (id <TLRange>) r toStream: (id <TLOutputStream>) s
{
int start = [r _start];
int n;
/* Iff the buffered data does not overlap with what is to be written,
flush it. */
if (start < off || start >= off + num)
[self emptyBuffer];
/* Now the buffer is empty, we might as well use a straight write.
XXX If the STREAM understands that... */
if (!num && [stream respondsTo: @selector (_writeRange:toStream:)])
{
n = [stream _writeRange: r toStream: s];
if (n > 0)
off += n;
}
else
{
int to_be_read, length = [r length];
/* Fill the buffer, resizing iff needed. */
to_be_read = start + length - (off + num);
if (num + to_be_read > cap)
{
cap = num + to_be_read;
buf = xrealloc (buf, cap);
}
n = [self readBytes: to_be_read toOffset: num];
if (n > 0)
num += n;
next = start - off;
length = num - next;
n = [s writeBytes: length fromBuffer: buf + next];
if (n > 0)
next += n;
}
return n;
} /* _writeRange:toStream: */
@end
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