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/*
* @file circbuffer.h Buffer Utility Functions
* @ingroup core
*/
/* Purple is the legal property of its developers, whose names are too numerous
* to list here. Please refer to the COPYRIGHT file distributed with this
* source distribution.
*
* 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
* (at your option) 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., 51 Franklin Street, Fifth Floor, Boston, MA 02111-1301 USA
*/
#include "internal.h"
#include "circbuffer.h"
#define DEFAULT_BUF_SIZE 256
PurpleCircBuffer *
purple_circ_buffer_new(gsize growsize) {
PurpleCircBuffer *buf = g_new0(PurpleCircBuffer, 1);
buf->growsize = growsize ? growsize : DEFAULT_BUF_SIZE;
return buf;
}
void purple_circ_buffer_destroy(PurpleCircBuffer *buf) {
g_return_if_fail(buf != NULL);
g_free(buf->buffer);
g_free(buf);
}
static void grow_circ_buffer(PurpleCircBuffer *buf, gsize len) {
gsize in_offset = 0, out_offset = 0;
gsize start_buflen;
g_return_if_fail(buf != NULL);
start_buflen = buf->buflen;
while ((buf->buflen - buf->bufused) < len)
buf->buflen += buf->growsize;
if (buf->inptr != NULL) {
in_offset = buf->inptr - buf->buffer;
out_offset = buf->outptr - buf->buffer;
}
buf->buffer = g_realloc(buf->buffer, buf->buflen);
/* adjust the fill and remove pointer locations */
if (buf->inptr == NULL) {
buf->inptr = buf->outptr = buf->buffer;
} else {
buf->inptr = buf->buffer + in_offset;
buf->outptr = buf->buffer + out_offset;
}
/* If the fill pointer is wrapped to before the remove
* pointer, we need to shift the data */
if (in_offset < out_offset
|| (in_offset == out_offset && buf->bufused > 0)) {
gsize shift_n = MIN(buf->buflen - start_buflen, in_offset);
memcpy(buf->buffer + start_buflen, buf->buffer, shift_n);
/* If we couldn't fit the wrapped read buffer
* at the end */
if (shift_n < in_offset) {
memmove(buf->buffer,
buf->buffer + shift_n,
in_offset - shift_n);
buf->inptr = buf->buffer +
(in_offset - shift_n);
} else {
buf->inptr = buf->buffer +
start_buflen + in_offset;
}
}
}
void purple_circ_buffer_append(PurpleCircBuffer *buf, gconstpointer src, gsize len) {
gsize len_stored;
g_return_if_fail(buf != NULL);
/* Grow the buffer, if necessary */
if ((buf->buflen - buf->bufused) < len)
grow_circ_buffer(buf, len);
/* If there is not enough room to copy all of src before hitting
* the end of the buffer then we will need to do two copies.
* One copy from inptr to the end of the buffer, and the
* second copy from the start of the buffer to the end of src. */
if (buf->inptr >= buf->outptr)
len_stored = MIN(len, buf->buflen - (buf->inptr - buf->buffer));
else
len_stored = len;
if (len_stored > 0)
memcpy(buf->inptr, src, len_stored);
if (len_stored < len) {
memcpy(buf->buffer, (char*)src + len_stored, len - len_stored);
buf->inptr = buf->buffer + (len - len_stored);
} else {
buf->inptr += len_stored;
}
buf->bufused += len;
}
gsize purple_circ_buffer_get_max_read(const PurpleCircBuffer *buf) {
gsize max_read;
g_return_val_if_fail(buf != NULL, 0);
if (buf->bufused == 0)
max_read = 0;
else if ((buf->outptr - buf->inptr) >= 0)
max_read = buf->buflen - (buf->outptr - buf->buffer);
else
max_read = buf->inptr - buf->outptr;
return max_read;
}
gboolean purple_circ_buffer_mark_read(PurpleCircBuffer *buf, gsize len) {
g_return_val_if_fail(buf != NULL, FALSE);
g_return_val_if_fail(purple_circ_buffer_get_max_read(buf) >= len, FALSE);
buf->outptr += len;
buf->bufused -= len;
/* wrap to the start if we're at the end */
if ((gsize)(buf->outptr - buf->buffer) == buf->buflen)
buf->outptr = buf->buffer;
return TRUE;
}
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