BearSSL/tools/vector.c

67 lines
2.1 KiB
C

/*
* Copyright (c) 2016 Thomas Pornin <pornin@bolet.org>
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#include "brssl.h"
/*
* Prepare a vector buffer for adding 'extra' elements.
* buf current buffer
* esize size of a vector element
* ptr pointer to the 'ptr' vector field
* len pointer to the 'len' vector field
* extra number of elements to add
*
* If the buffer must be enlarged, then this function allocates the new
* buffer and releases the old one. The new buffer address is then returned.
* If the buffer needs not be enlarged, then the buffer address is returned.
*
* In case of enlargement, the 'len' field is adjusted accordingly. The
* 'ptr' field is not modified.
*/
void *
vector_expand(void *buf,
size_t esize, size_t *ptr, size_t *len, size_t extra)
{
size_t nlen;
void *nbuf;
if (*len - *ptr >= extra) {
return buf;
}
nlen = (*len << 1);
if (nlen - *ptr < extra) {
nlen = extra + *ptr;
if (nlen < 8) {
nlen = 8;
}
}
nbuf = xmalloc(nlen * esize);
if (buf != NULL) {
memcpy(nbuf, buf, *len * esize);
xfree(buf);
}
*len = nlen;
return nbuf;
}