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/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 2021 Free Software Foundation, Inc.
*
* GRUB 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 3 of the License, or
* (at your option) any later version.
*
* GRUB 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 GRUB. If not, see <http://www.gnu.org/licenses/>.
*/
#include <grub/buffer.h>
#include <grub/err.h>
#include <grub/misc.h>
#include <grub/mm.h>
#include <grub/safemath.h>
#include <grub/types.h>
grub_buffer_t
grub_buffer_new (grub_size_t sz)
{
struct grub_buffer *ret;
ret = (struct grub_buffer *) grub_malloc (sizeof (*ret));
if (ret == NULL)
return NULL;
ret->data = (grub_uint8_t *) grub_malloc (sz);
if (ret->data == NULL)
{
grub_free (ret);
return NULL;
}
ret->sz = sz;
ret->pos = 0;
ret->used = 0;
return ret;
}
void
grub_buffer_free (grub_buffer_t buf)
{
grub_free (buf->data);
grub_free (buf);
}
grub_err_t
grub_buffer_ensure_space (grub_buffer_t buf, grub_size_t req)
{
grub_uint8_t *d;
grub_size_t newsz = 1;
/* Is the current buffer size adequate? */
if (buf->sz >= req)
return GRUB_ERR_NONE;
/* Find the smallest power-of-2 size that satisfies the request. */
while (newsz < req)
{
if (newsz == 0)
return grub_error (GRUB_ERR_OUT_OF_RANGE,
N_("requested buffer size is too large"));
newsz <<= 1;
}
d = (grub_uint8_t *) grub_realloc (buf->data, newsz);
if (d == NULL)
return grub_errno;
buf->data = d;
buf->sz = newsz;
return GRUB_ERR_NONE;
}
void *
grub_buffer_take_data (grub_buffer_t buf)
{
void *data = buf->data;
buf->data = NULL;
buf->sz = buf->pos = buf->used = 0;
return data;
}
void
grub_buffer_reset (grub_buffer_t buf)
{
buf->pos = buf->used = 0;
}
grub_err_t
grub_buffer_advance_read_pos (grub_buffer_t buf, grub_size_t n)
{
grub_size_t newpos;
if (grub_add (buf->pos, n, &newpos))
return grub_error (GRUB_ERR_OUT_OF_RANGE, N_("overflow is detected"));
if (newpos > buf->used)
return grub_error (GRUB_ERR_OUT_OF_RANGE,
N_("new read is position beyond the end of the written data"));
buf->pos = newpos;
return GRUB_ERR_NONE;
}
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