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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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} |