73 lines
1.9 KiB
C
73 lines
1.9 KiB
C
/*
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* Copyright (C) 2007 Michael Brown <mbrown@fensystems.co.uk>.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of the
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* License, or any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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/**
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* @file
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*
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* Automatically expanding buffers
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*
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*/
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#include <errno.h>
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#include <gpxe/buffer.h>
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#include <gpxe/umalloc.h>
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#include <gpxe/ebuffer.h>
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/**
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* Expand expandable buffer
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*
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* @v buffer Buffer descriptor
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* @v new_len Required new size
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* @ret rc Return status code
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*/
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static int ebuffer_expand ( struct buffer *buffer, size_t new_len ) {
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size_t actual_len = 1;
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userptr_t new_addr;
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/* Round new_len up to the nearest power of two, to reduce
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* total number of reallocations required.
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*/
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while ( actual_len < new_len )
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actual_len <<= 1;
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/* Reallocate buffer */
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new_addr = urealloc ( buffer->addr, actual_len );
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if ( ! new_addr )
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return -ENOMEM;
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buffer->addr = new_addr;
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buffer->len = actual_len;
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return 0;
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}
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/**
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* Allocate expandable buffer
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*
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* @v buffer Buffer descriptor
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* @v len Initial length (may be zero)
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* @ret rc Return status code
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*
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* Allocates space for the buffer and stores it in @c buffer->addr.
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* The space must eventually be freed by calling ufree(buffer->addr).
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*/
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int ebuffer_alloc ( struct buffer *buffer, size_t len ) {
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memset ( buffer, 0, sizeof ( *buffer ) );
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buffer->expand = ebuffer_expand;
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return ebuffer_expand ( buffer, len );
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}
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