util/buffer.c

   1 /*
   2  * QEMU generic buffers
   3  *
   4  * Copyright (c) 2015 Red Hat, Inc.
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
  18  *
  19  */
  20
  21 #include "qemu/buffer.h"
  22
  23 void buffer_reserve(Buffer *buffer, size_t len)
  24 {
  25     if ((buffer->capacity - buffer->offset) < len) {
  26         buffer->capacity += (len + 1024);
  27         buffer->buffer = g_realloc(buffer->buffer, buffer->capacity);
  28     }
  29 }
  30
  31 gboolean buffer_empty(Buffer *buffer)
  32 {
  33     return buffer->offset == 0;
  34 }
  35
  36 uint8_t *buffer_end(Buffer *buffer)
  37 {
  38     return buffer->buffer + buffer->offset;
  39 }
  40
  41 void buffer_reset(Buffer *buffer)
  42 {
  43     buffer->offset = 0;
  44 }
  45
  46 void buffer_free(Buffer *buffer)
  47 {
  48     g_free(buffer->buffer);
  49     buffer->offset = 0;
  50     buffer->capacity = 0;
  51     buffer->buffer = NULL;
  52 }
  53
  54 void buffer_append(Buffer *buffer, const void *data, size_t len)
  55 {
  56     memcpy(buffer->buffer + buffer->offset, data, len);
  57     buffer->offset += len;
  58 }
  59
  60 void buffer_advance(Buffer *buffer, size_t len)
  61 {
  62     memmove(buffer->buffer, buffer->buffer + len,
  63             (buffer->offset - len));
  64     buffer->offset -= len;
  65 }