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VILLASnode/lib/web/buffer.c

161 lines
3.5 KiB
C

/** API buffer for sending and receiving data from libwebsockets.
*
* @author Steffen Vogel <stvogel@eonerc.rwth-aachen.de>
* @copyright 2017, Institute for Automation of Complex Power Systems, EONERC
* @license GNU General Public License (version 3)
*
* VILLASnode
*
* 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 3 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, see <http://www.gnu.org/licenses/>.
*********************************************************************************/
#include <jansson.h>
#include <string.h>
#include "compat.h"
#include "assert.h"
#include "utils.h"
#include "web/buffer.h"
int web_buffer_init(struct web_buffer *b, enum lws_write_protocol prot)
{
assert(b->state == STATE_DESTROYED);
b->protocol = prot;
b->size = 0;
b->len = 0;
b->buffer = NULL;
b->prefix = b->protocol == LWS_WRITE_TEXT || b->protocol == LWS_WRITE_BINARY ? LWS_PRE : 0;
b->state = STATE_INITIALIZED;
return 0;
}
int web_buffer_destroy(struct web_buffer *b)
{
if (b->state == STATE_DESTROYED)
return 0;
if (b->buffer)
free(b->buffer);
b->state = STATE_DESTROYED;
return 0;
}
int web_buffer_write(struct web_buffer *b, struct lws *w)
{
int ret, len, sent = 0;
unsigned char *chunk;
assert(b->state == STATE_INITIALIZED);
if (b->len <= 0)
return 0;
do {
chunk = (unsigned char *) b->buffer + b->prefix + sent;
len = strlen(b->buffer + b->prefix);
ret = lws_write(w, chunk, len, b->protocol);
if (ret < 0)
break;
sent += ret + 1;
} while (sent < b->len);
web_buffer_read(b, NULL, sent); /* drop sent bytes from the buffer*/
return sent;
}
int web_buffer_read(struct web_buffer *b, char *out, size_t len)
{
assert(b->state == STATE_INITIALIZED);
if (len > b->len)
len = b->len;
if (out)
memcpy(out, b->buffer + b->prefix, len);
memmove(b->buffer + b->prefix, b->buffer + b->prefix + len, b->len - len);
b->len -= len;
return 0;
}
int web_buffer_read_json(struct web_buffer *b, json_t **req)
{
json_error_t e;
assert(b->state == STATE_INITIALIZED);
if (b->len <= 0)
return -1;
*req = json_loadb(b->buffer + b->prefix, b->len, JSON_DISABLE_EOF_CHECK, &e);
if (!*req)
return -2;
web_buffer_read(b, NULL, e.position);
return 1;
}
int web_buffer_append(struct web_buffer *b, const char *in, size_t len)
{
assert(b->state == STATE_INITIALIZED);
/* We append a \0 to split messages */
len++;
if (b->size < b->len + len) {
b->buffer = realloc(b->buffer, b->prefix + b->len + len);
if (!b->buffer)
return -1;
b->size = b->len + len;
}
memcpy(b->buffer + b->prefix + b->len, in, len);
b->buffer[b->prefix + b->len + len - 1] = 0;
b->len += len;
return 0;
}
int web_buffer_append_json(struct web_buffer *b, json_t *res)
{
size_t len;
assert(b->state == STATE_INITIALIZED);
retry: len = json_dumpb(res, b->buffer + b->prefix + b->len, b->size - b->len, 0) + 1;
if (b->size < b->len + len) {
b->buffer = realloc(b->buffer, b->prefix + b->len + len);
if (!b->buffer)
return -1;
b->size = b->len + len;
goto retry;
}
b->buffer[b->prefix + b->len + len - 1] = 0;
b->len += len;
return 0;
}