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/*
* section and descriptor parser
*
* Copyright (C) 2005 Andrew de Quincey (adq_dvb@lidskialf.net)
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
*/
#include <errno.h>
#include <string.h>
#include "section_buf.h"
#define SECTION_HDR_SIZE 3
#define SECTION_PAD 0xff
int section_buf_init(struct section_buf *section, int max)
{
if (max < SECTION_HDR_SIZE)
return -EINVAL;
memset(section, 0, sizeof(struct section_buf));
section->max = max; /* max size of data */
section->len = SECTION_HDR_SIZE;
section->wait_pdu = 1;
return 0;
}
int section_buf_add(struct section_buf *section, uint8_t* frag, int len, int *section_status)
{
int copy;
int used = 0;
uint8_t *data;
uint8_t *pos = (uint8_t*) section + sizeof(struct section_buf) + section->count;
/* have we finished? */
if (section->header && (section->len == section->count)) {
*section_status = 1;
return 0;
}
/* skip over section padding bytes */
*section_status = 0;
if (section->count == 0) {
while(len && (*frag == SECTION_PAD)) {
frag++;
len--;
used++;
}
if (len == 0)
return used;
}
/* grab the header to get the section length */
if (!section->header) {
/* copy the header frag */
copy = SECTION_HDR_SIZE - section->count;
if (copy > len)
copy = len;
memcpy(pos, frag, copy);
section->count += copy;
pos += copy;
frag += copy;
used += copy;
len -= copy;
/* we need 3 bytes for the section header */
if (section->count != SECTION_HDR_SIZE)
return used;
/* work out the length & check it isn't too big */
data = (uint8_t*) section + sizeof(struct section_buf);
section->len = SECTION_HDR_SIZE + (((data[1] & 0x0f) << 8) | data[2]);
if (section->len > section->max) {
*section_status = -ERANGE;
return len + used;
}
/* update fields */
section->header = 1;
}
/* accumulate frag */
copy = section->len - section->count;
if (copy > len)
copy = len;
memcpy(pos, frag, copy);
section->count += copy;
used += copy;
/* have we finished? */
if (section->header && (section->len == section->count))
*section_status = 1;
/* return number of bytes used */
return used;
}
int section_buf_add_transport_payload(struct section_buf *section,
uint8_t* payload, int len,
int pdu_start, int *section_status)
{
int used = 0;
int tmp;
/* have we finished? */
if (section->header && (section->len == section->count)) {
*section_status = 1;
return 0;
}
/* don't bother if we're waiting for a PDU */
*section_status = 0;
if (section->wait_pdu && (!pdu_start))
return len;
/* if we're at a PDU start, we need extra handling for the extra first
* byte giving the offset to the start of the next section. */
if (pdu_start) {
/* we have received a pdu */
section->wait_pdu = 0;
/* work out the offset to the _next_ payload */
int offset = payload[0];
if ((offset+1) > len) {
section->wait_pdu = 1;
*section_status = -EINVAL;
return len;
}
/* accumulate the end if we need to */
if (section->count != 0) {
/* add the final fragment. */
tmp = section_buf_add(section, payload + 1, offset, section_status);
/* the stream said this was the final fragment
* (PDU START bit) - check that it really was! */
if ((tmp != offset) || section_buf_remaining(section) || (*section_status != 1)) {
*section_status = -ERANGE;
section->wait_pdu = 1;
return 1 + tmp;
}
/* it is complete - return the number of bytes we used */
return 1 + tmp;
}
/* otherwise, we skip the end of the previous section, and
* start accumulating the new data. */
used = 1 + offset;
}
/* ok, just accumulate the data as normal */
tmp = section_buf_add(section, payload+used, len - used, section_status);
if (*section_status < 0) {
section->wait_pdu = 1;
}
return used + tmp;
}
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