| /* |
| * camutils.c - |
| * Copyright (C) 2007 Alessandro Decina |
| * |
| * Authors: |
| * Alessandro Decina <alessandro@nnva.org> |
| * |
| * This library is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU Library General Public |
| * License as published by the Free Software Foundation; either |
| * version 2 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 |
| * Library General Public License for more details. |
| * |
| * You should have received a copy of the GNU Library General Public |
| * License along with this library; if not, write to the |
| * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, |
| * Boston, MA 02110-1301, USA. |
| */ |
| |
| #include <gst/gst.h> |
| #include <string.h> |
| |
| #include "cam.h" |
| #include "camutils.h" |
| |
| #define GST_CAT_DEFAULT cam_debug_cat |
| |
| /* From the spec: |
| * length_field() { |
| * size_indicator |
| * if (size_indicator == 0) |
| * length_value |
| * else if (size_indicator == 1) { |
| * length_field_size |
| * for (i=0; i<length_field_size; i++) { |
| * length_value_byte |
| * } |
| * } |
| * } |
| */ |
| |
| guint8 |
| cam_calc_length_field_size (guint length) |
| { |
| guint field_len; |
| |
| if (length < G_MAXUINT8) |
| field_len = 1; |
| else if (length <= G_MAXUINT16) |
| field_len = 3; |
| else if (length <= (1 << 24) - 1) |
| field_len = 4; |
| else |
| field_len = 5; |
| |
| return field_len; |
| } |
| |
| /* write a length_field */ |
| guint8 |
| cam_write_length_field (guint8 * buff, guint length) |
| { |
| guint8 field_len = cam_calc_length_field_size (length); |
| |
| if (buff) { |
| switch (field_len) { |
| case 1: |
| buff[0] = length; |
| break; |
| case 2: |
| g_return_val_if_reached (0); |
| break; |
| case 3: |
| buff[0] = TPDU_HEADER_SIZE_INDICATOR | (field_len - 1); |
| buff[1] = length >> 8; |
| buff[2] = length & 0xFF; |
| break; |
| case 4: |
| buff[0] = TPDU_HEADER_SIZE_INDICATOR | (field_len - 1); |
| buff[1] = length >> 16; |
| buff[2] = (length >> 8) & 0xFF; |
| buff[3] = length & 0xFF; |
| break; |
| case 5: |
| buff[0] = TPDU_HEADER_SIZE_INDICATOR | (field_len - 1); |
| buff[1] = length >> 24; |
| buff[2] = (length >> 16) & 0xFF; |
| buff[3] = (length >> 8) & 0xFF; |
| buff[4] = length & 0xFF; |
| break; |
| default: |
| g_return_val_if_reached (0); |
| } |
| } |
| |
| return field_len; |
| } |
| |
| /* read a length_field */ |
| guint8 |
| cam_read_length_field (guint8 * buff, guint * length) |
| { |
| guint i; |
| guint field_len; |
| guint8 len; |
| |
| if (buff[0] <= G_MAXINT8) { |
| field_len = 1; |
| len = buff[0]; |
| } else { |
| field_len = buff[0] & ~TPDU_HEADER_SIZE_INDICATOR; |
| if (field_len > 4) { |
| GST_ERROR ("length_field length exceeds 4 bytes: %d", field_len); |
| field_len = 0; |
| len = 0; |
| } else { |
| len = 0; |
| for (i = 0; i < field_len; ++i) |
| len = (len << 8) | *++buff; |
| |
| /* count the size indicator byte */ |
| field_len += 1; |
| } |
| } |
| |
| if (length) |
| *length = len; |
| |
| return field_len; |
| } |
| |
| /* |
| * ca_pmt () { |
| * ca_pmt_tag 24 uimsbf |
| * length_field() |
| * ca_pmt_list_management 8 uimsbf |
| * program_number 16 uimsbf |
| * reserved 2 bslbf |
| * version_number 5 uimsbf |
| * current_next_indicator 1 bslbf |
| * reserved 4 bslbf |
| * program_info_length 12 uimsbf |
| * if (program_info_length != 0) { |
| * ca_pmt_cmd_id at program level 8 uimsbf |
| * for (i=0; i<n; i++) { |
| * CA_descriptor() programme level |
| * } |
| * } |
| * for (i=0; i<n; i++) { |
| * stream_type 8 uimsbf |
| * reserved 3 bslbf |
| * elementary_PID elementary stream PID 13 uimsbf |
| * reserved 4 bslbf |
| * ES_info_length 12 uimsbf |
| * if (ES_info_length != 0) { |
| * ca_pmt_cmd_id at ES level 8 uimsbf |
| * for (i=0; i<n; i++) { |
| * CA_descriptor() elementary stream level |
| * } |
| * } |
| * } |
| * } |
| */ |
| |
| static guint |
| get_ca_descriptors_length (GPtrArray * descriptors) |
| { |
| guint i; |
| guint nb_desc = descriptors->len; |
| guint len = 0; |
| |
| for (i = 0; i < nb_desc; i++) { |
| GstMpegtsDescriptor *desc = g_ptr_array_index (descriptors, i); |
| if (desc->tag == 0x09) |
| len += desc->length; |
| } |
| |
| return len; |
| } |
| |
| static guint8 * |
| write_ca_descriptors (guint8 * body, GPtrArray * descriptors) |
| { |
| guint i, nb_desc; |
| |
| nb_desc = descriptors->len; |
| for (i = 0; i < nb_desc; i++) { |
| GstMpegtsDescriptor *desc = g_ptr_array_index (descriptors, i); |
| if (desc->tag == 0x09) { |
| memcpy (body, desc->data, desc->length); |
| body += desc->length; |
| } |
| } |
| |
| return body; |
| } |
| |
| guint8 * |
| cam_build_ca_pmt (GstMpegtsPMT * pmt, guint8 list_management, guint8 cmd_id, |
| guint * size) |
| { |
| GstMpegtsSection *section = (GstMpegtsSection *) pmt; |
| guint body_size = 0; |
| guint8 *buffer; |
| guint8 *body; |
| GList *lengths = NULL; |
| guint len = 0; |
| guint i; |
| |
| /* get the length of program level CA_descriptor()s */ |
| len = get_ca_descriptors_length (pmt->descriptors); |
| if (len > 0) |
| /* add one byte for the program level cmd_id */ |
| len += 1; |
| |
| lengths = g_list_append (lengths, GINT_TO_POINTER (len)); |
| body_size += 6 + len; |
| |
| for (i = 0; i < pmt->streams->len; i++) { |
| GstMpegtsPMTStream *pmtstream = g_ptr_array_index (pmt->streams, i); |
| |
| len = get_ca_descriptors_length (pmtstream->descriptors); |
| if (len > 0) |
| /* one byte for the stream level cmd_id */ |
| len += 1; |
| |
| lengths = g_list_append (lengths, GINT_TO_POINTER (len)); |
| body_size += 5 + len; |
| } |
| |
| GST_DEBUG ("Body Size %d", body_size); |
| |
| buffer = g_malloc0 (body_size); |
| body = buffer; |
| |
| /* ca_pmt_list_management 8 uimsbf */ |
| *body++ = list_management; |
| |
| /* program_number 16 uimsbf */ |
| GST_WRITE_UINT16_BE (body, section->subtable_extension); |
| body += 2; |
| |
| /* reserved 2 |
| * version_number 5 |
| * current_next_indicator 1 |
| */ |
| *body++ = (section->version_number << 1) | 0x01; |
| |
| /* Reserved 4 |
| * program_info_length 12 |
| */ |
| len = GPOINTER_TO_INT (lengths->data); |
| lengths = g_list_delete_link (lengths, lengths); |
| GST_WRITE_UINT16_BE (body, len); |
| body += 2; |
| |
| if (len != 0) { |
| *body++ = cmd_id; |
| |
| body = write_ca_descriptors (body, pmt->descriptors); |
| } |
| |
| for (i = 0; i < pmt->streams->len; i++) { |
| GstMpegtsPMTStream *pmtstream = g_ptr_array_index (pmt->streams, i); |
| |
| *body++ = pmtstream->stream_type; |
| GST_WRITE_UINT16_BE (body, pmtstream->pid); |
| body += 2; |
| len = GPOINTER_TO_INT (lengths->data); |
| lengths = g_list_delete_link (lengths, lengths); |
| GST_WRITE_UINT16_BE (body, len); |
| body += 2; |
| |
| if (len != 0) { |
| *body++ = cmd_id; |
| body = write_ca_descriptors (body, pmtstream->descriptors); |
| } |
| } |
| |
| *size = body_size; |
| return buffer; |
| } |
