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    /*	$OpenBSD: abuf.c,v 1.4 2016/01/08 16:17:31 ratchov Exp $	*/  | 
    
    
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    /*  | 
    
    
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     * Copyright (c) 2008-2012 Alexandre Ratchov <alex@caoua.org>  | 
    
    
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     *  | 
    
    
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     * Permission to use, copy, modify, and distribute this software for any  | 
    
    
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     * purpose with or without fee is hereby granted, provided that the above  | 
    
    
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     * copyright notice and this permission notice appear in all copies.  | 
    
    
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     *  | 
    
    
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     * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES  | 
    
    
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     * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF  | 
    
    
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     * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  | 
    
    
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     * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES  | 
    
    
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     * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN  | 
    
    
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     * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  | 
    
    
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     * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.  | 
    
    
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     */  | 
    
    
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    /*  | 
    
    
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     * Simple byte fifo.  | 
    
    
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     *  | 
    
    
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     * The abuf data is split in two parts: (1) valid data available to the reader  | 
    
    
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     * (2) space available to the writer, which is not necessarily unused. It works  | 
    
    
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     * as follows: the write starts filling at offset (start + used), once the data  | 
    
    
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     * is ready, the writer adds to used the count of bytes available.  | 
    
    
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     */  | 
    
    
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    #include <stdio.h>  | 
    
    
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    #include <stdlib.h>  | 
    
    
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    #include <string.h>  | 
    
    
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    #include "abuf.h"  | 
    
    
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    #include "utils.h"  | 
    
    
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    #ifdef DEBUG  | 
    
    
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    void  | 
    
    
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    abuf_log(struct abuf *buf)  | 
    
    
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    { | 
    
    
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    	log_putu(buf->start);  | 
    
    
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    	log_puts("+"); | 
    
    
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    	log_putu(buf->used);  | 
    
    
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    	log_puts("/"); | 
    
    
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    	log_putu(buf->len);  | 
    
    
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    }  | 
    
    
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    #endif  | 
    
    
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    void  | 
    
    
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    abuf_init(struct abuf *buf, unsigned int len)  | 
    
    
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    { | 
    
    
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    	buf->data = xmalloc(len);  | 
    
    
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    	buf->len = len;  | 
    
    
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    	buf->used = 0;  | 
    
    
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    	buf->start = 0;  | 
    
    
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    }  | 
    
    
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    void  | 
    
    
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    abuf_done(struct abuf *buf)  | 
    
    
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    { | 
    
    
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    #ifdef DEBUG  | 
    
    
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    	if (buf->used > 0) { | 
    
    
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    		if (log_level >= 3) { | 
    
    
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    			log_puts("deleting non-empty buffer, used = "); | 
    
    
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    			log_putu(buf->used);  | 
    
    
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    			log_puts("\n"); | 
    
    
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    		}  | 
    
    
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    	}  | 
    
    
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    #endif  | 
    
    
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    	xfree(buf->data);  | 
    
    
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    	buf->data = (void *)0xdeadbeef;  | 
    
    
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    }  | 
    
    
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    /*  | 
    
    
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     * return the reader pointer and the number of bytes available  | 
    
    
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     */  | 
    
    
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    unsigned char *  | 
    
    
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    abuf_rgetblk(struct abuf *buf, int *rsize)  | 
    
    
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    { | 
    
    
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    	int count;  | 
    
    
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    	count = buf->len - buf->start;  | 
    
    
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    	if (count > buf->used)  | 
    
    
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    		count = buf->used;  | 
    
    
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    	*rsize = count;  | 
    
    
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    	return buf->data + buf->start;  | 
    
    
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    }  | 
    
    
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    /*  | 
    
    
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     * discard "count" bytes at the start postion.  | 
    
    
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     */  | 
    
    
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    void  | 
    
    
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    abuf_rdiscard(struct abuf *buf, int count)  | 
    
    
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    { | 
    
    
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    #ifdef DEBUG  | 
    
    
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    	if (count < 0 || count > buf->used) { | 
    
    
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    		log_puts("abuf_rdiscard: bad count = "); | 
    
    
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    		log_putu(count);  | 
    
    
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    		log_puts("\n"); | 
    
    
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    		panic();  | 
    
    
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    	}  | 
    
    
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    #endif  | 
    
    
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    	buf->used -= count;  | 
    
    
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    	buf->start += count;  | 
    
    
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    	if (buf->start >= buf->len)  | 
    
    
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    		buf->start -= buf->len;  | 
    
    
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    }  | 
    
    
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    /*  | 
    
    
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     * advance the writer pointer by "count" bytes  | 
    
    
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     */  | 
    
    
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    void  | 
    
    
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    abuf_wcommit(struct abuf *buf, int count)  | 
    
    
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    { | 
    
    
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    #ifdef DEBUG  | 
    
    
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    	if (count < 0 || count > (buf->len - buf->used)) { | 
    
    
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    		log_puts("abuf_wcommit: bad count = "); | 
    
    
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    		log_putu(count);  | 
    
    
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    		log_puts("\n"); | 
    
    
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    		panic();  | 
    
    
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    	}  | 
    
    
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    #endif  | 
    
    
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    	buf->used += count;  | 
    
    
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    }  | 
    
    
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    /*  | 
    
    
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     * get writer pointer and the number of bytes writable  | 
    
    
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     */  | 
    
    
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    unsigned char *  | 
    
    
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    abuf_wgetblk(struct abuf *buf, int *rsize)  | 
    
    
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    { | 
    
    
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    	int end, avail, count;  | 
    
    
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    	end = buf->start + buf->used;  | 
    
    
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    	if (end >= buf->len)  | 
    
    
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    		end -= buf->len;  | 
    
    
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    	avail = buf->len - buf->used;  | 
    
    
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    	count = buf->len - end;  | 
    
    
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    	if (count > avail)  | 
    
    
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    		count = avail;  | 
    
    
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    	*rsize = count;  | 
    
    
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    	return buf->data + end;  | 
    
    
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    }  |