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