text: /******************************************************************************
   *
   *  Copyright (C) 2010-2014 Broadcom Corporation
   *
   *  Licensed under the Apache License, Version 2.0 (the "License");
   *  you may not use this file except in compliance with the License.
   *  You may obtain a copy of the License at:
   *
   *  http://www.apache.org/licenses/LICENSE-2.0
   *
   *  Unless required by applicable law or agreed to in writing, software
   *  distributed under the License is distributed on an "AS IS" BASIS,
   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   *  See the License for the specific language governing permissions and
   *  limitations under the License.
   *
   ******************************************************************************/
  
  
  /******************************************************************************
   *
   *  This file contains source code for some utility functions to help parse
   *  and build NFC Data Exchange Format (NDEF) messages
   *
   ******************************************************************************/
  #include <string.h>
  #include "ndef_utils.h"
  
  /*******************************************************************************
  **
  **              Static Local Functions
  **
  *******************************************************************************/
  
  
  /*******************************************************************************
  **
  ** Function         shiftdown
  **
  ** Description      shift memory down (to make space to insert a record)
  **
  *******************************************************************************/
  static void shiftdown (UINT8 *p_mem, UINT32 len, UINT32 shift_amount)
  {
      register UINT8 *ps = p_mem + len - 1;
      register UINT8 *pd = ps + shift_amount;
      register UINT32 xx;
  
      for (xx = 0; xx < len; xx++)
          *pd-- = *ps--;
  }
  
  /*******************************************************************************
  **
  ** Function         shiftup
  **
  ** Description      shift memory up (to delete a record)
  **
  *******************************************************************************/
  static void shiftup (UINT8 *p_dest, UINT8 *p_src, UINT32 len)
  {
      register UINT8 *ps = p_src;
      register UINT8 *pd = p_dest;
      register UINT32 xx;
  
      for (xx = 0; xx < len; xx++)
          *pd++ = *ps++;
  }
  
  /*******************************************************************************
  **
  ** Function         NDEF_MsgValidate
  **
  ** Description      This function validates an NDEF message.
  **
  ** Returns          TRUE if all OK, or FALSE if the message is invalid.
  **
  *******************************************************************************/
  tNDEF_STATUS NDEF_MsgValidate (UINT8 *p_msg, UINT32 msg_len, BOOLEAN b_allow_chunks)
  {
      UINT8   *p_rec = p_msg;
      UINT8   *p_end = p_msg + msg_len;
      UINT8   rec_hdr=0, type_len, id_len;
      int     count;
      UINT32  payload_len;
      BOOLEAN bInChunk = FALSE;
  
      if ( (p_msg == NULL) || (msg_len < 3) )
          return (NDEF_MSG_TOO_SHORT);
  
      /* The first record must have the MB bit set */
      if ((*p_msg & NDEF_MB_MASK) == 0)
          return (NDEF_MSG_NO_MSG_BEGIN);
  
      /* The first record cannot be a chunk */
      if ((*p_msg & NDEF_TNF_MASK) == NDEF_TNF_UNCHANGED)
          return (NDEF_MSG_UNEXPECTED_CHUNK);
  
      for (count = 0; p_rec < p_end; count++)
      {
          /* if less than short record header */
          if (p_rec + 3 > p_end)
              return (NDEF_MSG_TOO_SHORT);
  
          rec_hdr = *p_rec++;
  
          /* The second and all subsequent records must NOT have the MB bit set */
          if ( (count > 0) && (rec_hdr & NDEF_MB_MASK) )
              return (NDEF_MSG_EXTRA_MSG_BEGIN);
  
          /* Type field length */
          type_len = *p_rec++;
  
          /* Payload length - can be 1 or 4 bytes */
          if (rec_hdr & NDEF_SR_MASK)
              payload_len = *p_rec++;
          else
          {
              /* if less than 4 bytes payload length */
              if (p_rec + 4 > p_end)
                  return (NDEF_MSG_TOO_SHORT);
  
              BE_STREAM_TO_UINT32 (payload_len, p_rec);
          }
  
          /* ID field Length */
          if (rec_hdr & NDEF_IL_MASK)
          {
              /* if less than 1 byte ID field length */
              if (p_rec + 1 > p_end)
                  return (NDEF_MSG_TOO_SHORT);
  
              id_len = *p_rec++;
          }
          else
              id_len = 0;
  
          /* A chunk must have type "unchanged", and no type or ID fields */
          if (rec_hdr & NDEF_CF_MASK)
          {
              if (!b_allow_chunks)
                  return (NDEF_MSG_UNEXPECTED_CHUNK);
  
              /* Inside a chunk, the type must be unchanged and no type or ID field i sallowed */
              if (bInChunk)
              {
                  if ( (type_len != 0) || (id_len != 0) || ((rec_hdr & NDEF_TNF_MASK) != NDEF_TNF_UNCHANGED) )
                      return (NDEF_MSG_INVALID_CHUNK);
              }
              else
              {
                  /* First record of a chunk must NOT have type "unchanged" */
                  if ((rec_hdr & NDEF_TNF_MASK) == NDEF_TNF_UNCHANGED)
                      return (NDEF_MSG_INVALID_CHUNK);
  
                  bInChunk = TRUE;
              }
          }
          else
          {
              /* This may be the last guy in a chunk. */
              if (bInChunk)
              {
                  if ( (type_len != 0) || (id_len != 0) || ((rec_hdr & NDEF_TNF_MASK) != NDEF_TNF_UNCHANGED) )
                      return (NDEF_MSG_INVALID_CHUNK);
  
                  bInChunk = FALSE;
              }
              else
              {
                  /* If not in a chunk, the record must NOT have type "unchanged" */
                  if ((rec_hdr & NDEF_TNF_MASK) == NDEF_TNF_UNCHANGED)
                      return (NDEF_MSG_INVALID_CHUNK);
              }
          }
  
          /* An empty record must NOT have a type, ID or payload */
          if ((rec_hdr & NDEF_TNF_MASK) == NDEF_TNF_EMPTY)
          {
              if ( (type_len != 0) || (id_len != 0) || (payload_len != 0) )
                  return (NDEF_MSG_INVALID_EMPTY_REC);
          }
  
          if ((rec_hdr & NDEF_TNF_MASK) == NDEF_TNF_UNKNOWN)
          {
              if (type_len != 0)
                  return (NDEF_MSG_LENGTH_MISMATCH);
          }
  
          /* Point to next record */
          p_rec += (payload_len + type_len + id_len);
  
          if (rec_hdr & NDEF_ME_MASK)
              break;
  
          rec_hdr = 0;
      }
  
      /* The last record should have the ME bit set */
      if ((rec_hdr & NDEF_ME_MASK) == 0)
          return (NDEF_MSG_NO_MSG_END);
  
      /* p_rec should equal p_end if all the length fields were correct */
      if (p_rec != p_end)
          return (NDEF_MSG_LENGTH_MISMATCH);
  
      return (NDEF_OK);
  }
  
  /*******************************************************************************
  **
  ** Function         NDEF_MsgGetNumRecs
  **
  ** Description      This function gets the number of records in the given NDEF
  **                  message.
  **
  ** Returns          The record count, or 0 if the message is invalid.
  **
  *******************************************************************************/
  INT32 NDEF_MsgGetNumRecs (UINT8 *p_msg)
  {
      UINT8   *p_rec = p_msg;
      UINT8   rec_hdr, type_len, id_len;
      int     count;
      UINT32  payload_len;
  
      for (count = 0; ; )
      {
          count++;
  
          rec_hdr = *p_rec++;
          if (rec_hdr & NDEF_ME_MASK)
              break;
  
          /* Type field length */
          type_len = *p_rec++;
  
          /* Payload length - can be 1 or 4 bytes */
          if (rec_hdr & NDEF_SR_MASK)
              payload_len = *p_rec++;
          else
              BE_STREAM_TO_UINT32 (payload_len, p_rec);
  
          /* ID field Length */
          if (rec_hdr & NDEF_IL_MASK)
              id_len = *p_rec++;
          else
              id_len = 0;
  
          /* Point to next record */
          p_rec += (payload_len + type_len + id_len);
      }
  
      /* Return the number of records found */
      return (count);
  }
  
  /*******************************************************************************
  **
  ** Function         NDEF_MsgGetRecLength
  **
  ** Description      This function returns length of the current record in the given
  **                  NDEF message.
  **
  ** Returns          Length of record
  **
  *******************************************************************************/
  UINT32 NDEF_MsgGetRecLength (UINT8 *p_cur_rec)
  {
      UINT8   rec_hdr, type_len, id_len;
      UINT32  rec_len = 0;
      UINT32  payload_len;
  
      /* Get the current record's header */
      rec_hdr = *p_cur_rec++;
      rec_len++;
  
      /* Type field length */
      type_len = *p_cur_rec++;
      rec_len++;
  
      /* Payload length - can be 1 or 4 bytes */
      if (rec_hdr & NDEF_SR_MASK)
      {
          payload_len = *p_cur_rec++;
          rec_len++;
      }
      else
      {
          BE_STREAM_TO_UINT32 (payload_len, p_cur_rec);
          rec_len += 4;
      }
  
      /* ID field Length */
      if (rec_hdr & NDEF_IL_MASK)
      {
          id_len = *p_cur_rec++;
          rec_len++;
      }
      else
          id_len = 0;
  
      /* Total length of record */
      rec_len += (payload_len + type_len + id_len);
  
      return (rec_len);
  }
  
  /*******************************************************************************
  **
  ** Function         NDEF_MsgGetNextRec
  **
  ** Description      This function gets a pointer to the next record in the given
  **                  NDEF message. If the current record pointer is NULL, a pointer
  **                  to the first record is returned.
  **
  ** Returns          Pointer to the start of the record, or NULL if no more
  **
  *******************************************************************************/
  UINT8 *NDEF_MsgGetNextRec (UINT8 *p_cur_rec)
  {
      UINT8   rec_hdr, type_len, id_len;
      UINT32  payload_len;
  
      /* Get the current record's header */
      rec_hdr = *p_cur_rec++;
  
      /* If this is the last record, return NULL */
      if (rec_hdr & NDEF_ME_MASK)
          return (NULL);
  
      /* Type field length */
      type_len = *p_cur_rec++;
  
      /* Payload length - can be 1 or 4 bytes */
      if (rec_hdr & NDEF_SR_MASK)
          payload_len = *p_cur_rec++;
      else
          BE_STREAM_TO_UINT32 (payload_len, p_cur_rec);
  
      /* ID field Length */
      if (rec_hdr & NDEF_IL_MASK)
          id_len = *p_cur_rec++;
      else
          id_len = 0;
  
      /* Point to next record */
      p_cur_rec += (payload_len + type_len + id_len);
  
      return (p_cur_rec);
  }
  
  /*******************************************************************************
  **
  ** Function         NDEF_MsgGetRecByIndex
  **
  ** Description      This function gets a pointer to the record with the given
  **                  index (0-based index) in the given NDEF message.
  **
  ** Returns          Pointer to the start of the record, or NULL
  **
  *******************************************************************************/
  UINT8 *NDEF_MsgGetRecByIndex (UINT8 *p_msg, INT32 index)
  {
      UINT8   *p_rec = p_msg;
      UINT8   rec_hdr, type_len, id_len;
      INT32   count;
      UINT32  payload_len;
  
      for (count = 0; ; count++)
      {
          if (count == index)
              return (p_rec);
  
          rec_hdr = *p_rec++;
  
          if (rec_hdr & NDEF_ME_MASK)
              return (NULL);
  
          /* Type field length */
          type_len = *p_rec++;
  
          /* Payload length - can be 1 or 4 bytes */
          if (rec_hdr & NDEF_SR_MASK)
              payload_len = *p_rec++;
          else
              BE_STREAM_TO_UINT32 (payload_len, p_rec);
  
          /* ID field Length */
          if (rec_hdr & NDEF_IL_MASK)
              id_len = *p_rec++;
          else
              id_len = 0;
  
          /* Point to next record */
          p_rec += (payload_len + type_len + id_len);
      }
  
      /* If here, there is no record of that index */
      return (NULL);
  }
  
  
  /*******************************************************************************
  **
  ** Function         NDEF_MsgGetLastRecInMsg
  **
  ** Description      This function gets a pointer to the last record in the
  **                  given NDEF message.
  **
  ** Returns          Pointer to the start of the last record, or NULL if some problem
  **
  *******************************************************************************/
  UINT8 *NDEF_MsgGetLastRecInMsg (UINT8 *p_msg)
  {
      UINT8   *p_rec = p_msg;
      UINT8   *pRecStart;
      UINT8   rec_hdr, type_len, id_len;
      UINT32  payload_len;
  
      for ( ; ; )
      {
          pRecStart = p_rec;
          rec_hdr = *p_rec++;
  
          if (rec_hdr & NDEF_ME_MASK)
              break;
  
          /* Type field length */
          type_len = *p_rec++;
  
          /* Payload length - can be 1 or 4 bytes */
          if (rec_hdr & NDEF_SR_MASK)
              payload_len = *p_rec++;
          else
              BE_STREAM_TO_UINT32 (payload_len, p_rec);
  
          /* ID field Length */
          if (rec_hdr & NDEF_IL_MASK)
              id_len = *p_rec++;
          else
              id_len = 0;
  
          /* Point to next record */
          p_rec += (payload_len + type_len + id_len);
      }
  
      return (pRecStart);
  }
  
  
  /*******************************************************************************
  **
  ** Function         NDEF_MsgGetFirstRecByType
  **
  ** Description      This function gets a pointer to the first record with the given
  **                  record type in the given NDEF message.
  **
  ** Returns          Pointer to the start of the record, or NULL
  **
  *******************************************************************************/
  UINT8 *NDEF_MsgGetFirstRecByType (UINT8 *p_msg, UINT8 tnf, UINT8 *p_type, UINT8 tlen)
  {
      UINT8   *p_rec = p_msg;
      UINT8   *pRecStart;
      UINT8   rec_hdr, type_len, id_len;
      UINT32  payload_len;
  
      for ( ; ; )
      {
          pRecStart = p_rec;
  
          rec_hdr = *p_rec++;
  
          /* Type field length */
          type_len = *p_rec++;
  
          /* Payload length - can be 1 or 4 bytes */
          if (rec_hdr & NDEF_SR_MASK)
              payload_len = *p_rec++;
          else
              BE_STREAM_TO_UINT32 (payload_len, p_rec);
  
          /* ID field Length */
          if (rec_hdr & NDEF_IL_MASK)
              id_len = *p_rec++;
          else
              id_len = 0;
  
          /* At this point, p_rec points to the start of the type field. We need to */
          /* compare the type of the type, the length of the type and the data     */
          if ( ((rec_hdr & NDEF_TNF_MASK) == tnf)
           &&  (type_len == tlen)
           &&  (!memcmp (p_rec, p_type, tlen)) )
               return (pRecStart);
  
          /* If this was the last record, return NULL */
          if (rec_hdr & NDEF_ME_MASK)
              return (NULL);
  
          /* Point to next record */
          p_rec += (payload_len + type_len + id_len);
      }
  
      /* If here, there is no record of that type */
      return (NULL);
  }
  
  /*******************************************************************************
  **
  ** Function         NDEF_MsgGetNextRecByType
  **
  ** Description      This function gets a pointer to the next record with the given
  **                  record type in the given NDEF message.
  **
  ** Returns          Pointer to the start of the record, or NULL
  **
  *******************************************************************************/
  UINT8 *NDEF_MsgGetNextRecByType (UINT8 *p_cur_rec, UINT8 tnf, UINT8 *p_type, UINT8 tlen)
  {
      UINT8   *p_rec;
      UINT8   *pRecStart;
      UINT8   rec_hdr, type_len, id_len;
      UINT32  payload_len;
  
      /* If this is the last record in the message, return NULL */
      if ((p_rec = NDEF_MsgGetNextRec (p_cur_rec)) == NULL)
          return (NULL);
  
      for ( ; ; )
      {
          pRecStart = p_rec;
  
          rec_hdr = *p_rec++;
  
          /* Type field length */
          type_len = *p_rec++;
  
          /* Payload length - can be 1 or 4 bytes */
          if (rec_hdr & NDEF_SR_MASK)
              payload_len = *p_rec++;
          else
              BE_STREAM_TO_UINT32 (payload_len, p_rec);
  
          /* ID field Length */
          if (rec_hdr & NDEF_IL_MASK)
              id_len = *p_rec++;
          else
              id_len = 0;
  
          /* At this point, p_rec points to the start of the type field. We need to */
          /* compare the type of the type, the length of the type and the data     */
          if ( ((rec_hdr & NDEF_TNF_MASK) == tnf)
           &&  (type_len == tlen)
           &&  (!memcmp (p_rec, p_type, tlen)) )
               return (pRecStart);
  
          /* If this was the last record, return NULL */
          if (rec_hdr & NDEF_ME_MASK)
              break;
  
          /* Point to next record */
          p_rec += (payload_len + type_len + id_len);
      }
  
      /* If here, there is no record of that type */
      return (NULL);
  }
  
  
  /*******************************************************************************
  **
  ** Function         NDEF_MsgGetFirstRecById
  **
  ** Description      This function gets a pointer to the first record with the given
  **                  record id in the given NDEF message.
  **
  ** Returns          Pointer to the start of the record, or NULL
  **
  *******************************************************************************/
  UINT8 *NDEF_MsgGetFirstRecById (UINT8 *p_msg, UINT8 *p_id, UINT8 ilen)
  {
      UINT8   *p_rec = p_msg;
      UINT8   *pRecStart;
      UINT8   rec_hdr, type_len, id_len;
      UINT32  payload_len;
  
      for ( ; ; )
      {
          pRecStart = p_rec;
  
          rec_hdr = *p_rec++;
  
          /* Type field length */
          type_len = *p_rec++;
  
          /* Payload length - can be 1 or 4 bytes */
          if (rec_hdr & NDEF_SR_MASK)
              payload_len = *p_rec++;
          else
              BE_STREAM_TO_UINT32 (payload_len, p_rec);
  
          /* ID field Length */
          if (rec_hdr & NDEF_IL_MASK)
              id_len = *p_rec++;
          else
              id_len = 0;
  
          /* At this point, p_rec points to the start of the type field. Skip it */
          p_rec += type_len;
  
          /* At this point, p_rec points to the start of the ID field. Compare length and data */
          if ( (id_len == ilen) && (!memcmp (p_rec, p_id, ilen)) )
               return (pRecStart);
  
          /* If this was the last record, return NULL */
          if (rec_hdr & NDEF_ME_MASK)
              return (NULL);
  
          /* Point to next record */
          p_rec += (id_len + payload_len);
      }
  
      /* If here, there is no record of that ID */
      return (NULL);
  }
  
  /*******************************************************************************
  **
  ** Function         NDEF_MsgGetNextRecById
  **
  ** Description      This function gets a pointer to the next record with the given
  **                  record id in the given NDEF message.
  **
  ** Returns          Pointer to the start of the record, or NULL
  **
  *******************************************************************************/
  UINT8 *NDEF_MsgGetNextRecById (UINT8 *p_cur_rec, UINT8 *p_id, UINT8 ilen)
  {
      UINT8   *p_rec;
      UINT8   *pRecStart;
      UINT8   rec_hdr, type_len, id_len;
      UINT32  payload_len;
  
      /* If this is the last record in the message, return NULL */
      if ((p_rec = NDEF_MsgGetNextRec (p_cur_rec)) == NULL)
          return (NULL);
  
      for ( ; ; )
      {
          pRecStart = p_rec;
  
          rec_hdr = *p_rec++;
  
          /* Type field length */
          type_len = *p_rec++;
  
          /* Payload length - can be 1 or 4 bytes */
          if (rec_hdr & NDEF_SR_MASK)
              payload_len = *p_rec++;
          else
              BE_STREAM_TO_UINT32 (payload_len, p_rec);
  
          /* ID field Length */
          if (rec_hdr & NDEF_IL_MASK)
              id_len = *p_rec++;
          else
              id_len = 0;
  
          /* At this point, p_rec points to the start of the type field. Skip it */
          p_rec += type_len;
  
          /* At this point, p_rec points to the start of the ID field. Compare length and data */
          if ( (id_len == ilen) && (!memcmp (p_rec, p_id, ilen)) )
               return (pRecStart);
  
          /* If this was the last record, return NULL */
          if (rec_hdr & NDEF_ME_MASK)
              break;
  
          /* Point to next record */
          p_rec += (id_len + payload_len);
      }
  
      /* If here, there is no record of that ID */
      return (NULL);
  }
  
  /*******************************************************************************
  **
  ** Function         NDEF_RecGetType
  **
  ** Description      This function gets a pointer to the record type for the given NDEF record.
  **
  ** Returns          Pointer to Type (NULL if none). TNF and len are filled in.
  **
  *******************************************************************************/
  UINT8 *NDEF_RecGetType (UINT8 *p_rec, UINT8 *p_tnf, UINT8 *p_type_len)
  {
      UINT8   rec_hdr, type_len;
  
      /* First byte is the record header */
      rec_hdr = *p_rec++;
  
      /* Next byte is the type field length */
      type_len = *p_rec++;
  
      /* Skip the payload length */
      if (rec_hdr & NDEF_SR_MASK)
          p_rec += 1;
      else
          p_rec += 4;
  
      /* Skip ID field Length, if present */
      if (rec_hdr & NDEF_IL_MASK)
          p_rec++;
  
      /* At this point, p_rec points to the start of the type field.  */
      *p_type_len = type_len;
      *p_tnf      = rec_hdr & NDEF_TNF_MASK;
  
      if (type_len == 0)
          return (NULL);
      else
          return (p_rec);
  }
  
  /*******************************************************************************
  **
  ** Function         NDEF_RecGetId
  **
  ** Description      This function gets a pointer to the record id for the given NDEF record.
  **
  ** Returns          Pointer to Id (NULL if none). ID Len is filled in.
  **
  *******************************************************************************/
  UINT8 *NDEF_RecGetId (UINT8 *p_rec, UINT8 *p_id_len)
  {
      UINT8   rec_hdr, type_len;
  
      /* First byte is the record header */
      rec_hdr = *p_rec++;
  
      /* Next byte is the type field length */
      type_len = *p_rec++;
  
      /* Skip the payload length */
      if (rec_hdr & NDEF_SR_MASK)
          p_rec++;
      else
          p_rec += 4;
  
      /* ID field Length */
      if (rec_hdr & NDEF_IL_MASK)
          *p_id_len = *p_rec++;
      else
          *p_id_len = 0;
  
      /* p_rec now points to the start of the type field. The ID field follows it */
      if (*p_id_len == 0)
          return (NULL);
      else
          return (p_rec + type_len);
  }
  
  
  /*******************************************************************************
  **
  ** Function         NDEF_RecGetPayload
  **
  ** Description      This function gets a pointer to the payload for the given NDEF record.
  **
  ** Returns          a pointer to the payload (or NULL none). Payload len filled in.
  **
  *******************************************************************************/
  UINT8 *NDEF_RecGetPayload (UINT8 *p_rec, UINT32 *p_payload_len)
  {
      UINT8   rec_hdr, type_len, id_len;
      UINT32  payload_len;
  
      /* First byte is the record header */
      rec_hdr = *p_rec++;
  
      /* Next byte is the type field length */
      type_len = *p_rec++;
  
      /* Next is the payload length (1 or 4 bytes) */
      if (rec_hdr & NDEF_SR_MASK)
          payload_len = *p_rec++;
      else
          BE_STREAM_TO_UINT32 (payload_len, p_rec);
  
      *p_payload_len = payload_len;
  
      /* ID field Length */
      if (rec_hdr & NDEF_IL_MASK)
          id_len = *p_rec++;
      else
          id_len = 0;
  
      /* p_rec now points to the start of the type field. The ID field follows it, then the payload */
      if (payload_len == 0)
          return (NULL);
      else
          return (p_rec + type_len + id_len);
  }
  
  
  /*******************************************************************************
  **
  ** Function         NDEF_MsgInit
  **
  ** Description      This function initializes an NDEF message.
  **
  ** Returns          void
  **                  *p_cur_size is initialized to 0
  **
  *******************************************************************************/
  void NDEF_MsgInit (UINT8 *p_msg, UINT32 max_size, UINT32 *p_cur_size)
  {
      *p_cur_size = 0;
      memset (p_msg, 0, max_size);
  }
  
  /*******************************************************************************
  **
  ** Function         NDEF_MsgAddRec
  **
  ** Description      This function adds an NDEF record to the end of an NDEF message.
  **
  ** Returns          OK, or error if the record did not fit
  **                  *p_cur_size is updated
  **
  *******************************************************************************/
  extern tNDEF_STATUS  NDEF_MsgAddRec (UINT8 *p_msg, UINT32 max_size, UINT32 *p_cur_size,
                                       UINT8 tnf, UINT8 *p_type, UINT8 type_len,
                                       UINT8 *p_id, UINT8  id_len,
                                       UINT8 *p_payload, UINT32 payload_len)
  {
      UINT8   *p_rec = p_msg + *p_cur_size;
      UINT32  recSize;
      int     plen = (payload_len < 256) ? 1 : 4;
      int     ilen = (id_len == 0) ? 0 : 1;
  
      if (tnf > NDEF_TNF_RESERVED)
      {
          tnf = NDEF_TNF_UNKNOWN;
          type_len  = 0;
      }
  
      /* First, make sure the record will fit. we need at least 2 bytes for header and type length */
      recSize = payload_len + 2 + type_len + plen + ilen + id_len;
  
      if ((*p_cur_size + recSize) > max_size)
          return (NDEF_MSG_INSUFFICIENT_MEM);
  
      /* Construct the record header. For the first record, set both begin and end bits */
      if (*p_cur_size == 0)
          *p_rec = tnf | NDEF_MB_MASK | NDEF_ME_MASK;
      else
      {
          /* Find the previous last and clear his 'Message End' bit */
          UINT8  *pLast = NDEF_MsgGetLastRecInMsg (p_msg);
  
          if (!pLast)
              return (NDEF_MSG_NO_MSG_END);
  
          *pLast &= ~NDEF_ME_MASK;
          *p_rec   = tnf | NDEF_ME_MASK;
      }
  
      if (plen == 1)
          *p_rec |= NDEF_SR_MASK;
  
      if (ilen != 0)
          *p_rec |= NDEF_IL_MASK;
  
      p_rec++;
  
      /* The next byte is the type field length */
      *p_rec++ = type_len;
  
      /* Payload length - can be 1 or 4 bytes */
      if (plen == 1)
          *p_rec++ = (UINT8)payload_len;
      else
           UINT32_TO_BE_STREAM (p_rec, payload_len);
  
      /* ID field Length (optional) */
      if (ilen > 0)
          *p_rec++ = id_len;
  
      /* Next comes the type */
      if (type_len)
      {
          if (p_type)
              memcpy (p_rec, p_type, type_len);
  
          p_rec += type_len;
      }
  
      /* Next comes the ID */
      if (id_len)
      {
          if (p_id)
              memcpy (p_rec, p_id, id_len);
  
          p_rec += id_len;
      }
  
      /* And lastly the payload. If NULL, the app just wants to reserve memory */
      if (p_payload)
          memcpy (p_rec, p_payload, payload_len);
  
      *p_cur_size += recSize;
  
      return (NDEF_OK);
  }
  
  /*******************************************************************************
  **
  ** Function         NDEF_MsgInsertRec
  **
  ** Description      This function inserts a record at a specific index into the
  **                  given NDEF message
  **
  ** Returns          OK, or error if the record did not fit
  **                  *p_cur_size is updated
  **
  *******************************************************************************/
  extern tNDEF_STATUS NDEF_MsgInsertRec (UINT8 *p_msg, UINT32 max_size, UINT32 *p_cur_size, INT32 index,
                                         UINT8 tnf, UINT8 *p_type, UINT8 type_len,
                                         UINT8 *p_id, UINT8  id_len,
                                         UINT8 *p_payload, UINT32 payload_len)
  {
      UINT8   *p_rec;
      UINT32  recSize;
      INT32   plen = (payload_len < 256) ? 1 : 4;
      INT32   ilen = (id_len == 0) ? 0 : 1;
  
      /* First, make sure the record will fit. we need at least 2 bytes for header and type length */
      recSize = payload_len + 2 + type_len + plen + ilen + id_len;
  
      if ((*p_cur_size + recSize) > max_size)
          return (NDEF_MSG_INSUFFICIENT_MEM);
  
      /* See where the new record goes. If at the end, call the 'AddRec' function */
      if ( (index >= NDEF_MsgGetNumRecs (p_msg))
        || ((p_rec = NDEF_MsgGetRecByIndex(p_msg, index)) == NULL) )
      {
          return NDEF_MsgAddRec (p_msg, max_size, p_cur_size, tnf, p_type, type_len,
                                 p_id, id_len, p_payload, payload_len);
      }
  
      /* If we are inserting at the beginning, remove the MB bit from the current first */
      if (index == 0)
          *p_msg &= ~NDEF_MB_MASK;
  
      /* Make space for the new record */
      shiftdown (p_rec, (UINT32)(*p_cur_size - (p_rec - p_msg)), recSize);
  
      /* If adding at the beginning, set begin bit */
      if (index == 0)
          *p_rec = tnf | NDEF_MB_MASK;
      else
          *p_rec = tnf;
  
      if (plen == 1)
          *p_rec |= NDEF_SR_MASK;
  
      if (ilen != 0)
          *p_rec |= NDEF_IL_MASK;
  
      p_rec++;
  
      /* The next byte is the type field length */
      *p_rec++ = type_len;
  
      /* Payload length - can be 1 or 4 bytes */
      if (plen == 1)
          *p_rec++ = (UINT8)payload_len;
      else
           UINT32_TO_BE_STREAM (p_rec, payload_len);
  
      /* ID field Length (optional) */
      if (ilen != 0)
          *p_rec++ = id_len;
  
      /* Next comes the type */
      if (type_len)
      {
          if (p_type)
              memcpy (p_rec, p_type, type_len);
  
          p_rec += type_len;
      }
  
      /* Next comes the ID */
      if (ilen != 0)
      {
          if (p_id)
              memcpy (p_rec, p_id, id_len);
  
          p_rec += id_len;
      }
  
      /* And lastly the payload. If NULL, the app just wants to reserve memory */
      if (p_payload)
          memcpy (p_rec, p_payload, payload_len);
  
      *p_cur_size += recSize;
  
      return (NDEF_OK);
  }
  
  /*******************************************************************************
  **
  ** Function         NDEF_MsgAppendRec
  **
  ** Description      This function adds NDEF records to the end of an NDEF message.
  **
  ** Returns          OK, or error if the record did not fit
  **                  *p_cur_size is updated
  **
  *******************************************************************************/
  extern tNDEF_STATUS  NDEF_MsgAppendRec (UINT8 *p_msg, UINT32 max_size, UINT32 *p_cur_size,
                                          UINT8 *p_new_rec, UINT32 new_rec_len)
  {
      UINT8   *p_rec;
      tNDEF_STATUS    status;
  
      /* First, validate new records */
      if ((status = NDEF_MsgValidate(p_new_rec, new_rec_len, FALSE)) != NDEF_OK)
          return (status);
  
      /* First, make sure the record will fit */
      if ((*p_cur_size + new_rec_len) > max_size)
          return (NDEF_MSG_INSUFFICIENT_MEM);
  
      /* Find where to copy new record */
      if (*p_cur_size == 0)
          p_rec = p_msg;
      else
      {
          /* Find the previous last and clear his 'Message End' bit */
          UINT8  *pLast = NDEF_MsgGetLastRecInMsg (p_msg);
  
          if (!pLast)
              return (NDEF_MSG_NO_MSG_END);
  
          *pLast &= ~NDEF_ME_MASK;
          p_rec   = p_msg + *p_cur_size;
  
          /* clear 'Message Begin' bit of new record */
          *p_new_rec &= ~NDEF_MB_MASK;
      }
  
      /* append new records */
      memcpy (p_rec, p_new_rec, new_rec_len);
  
      *p_cur_size += new_rec_len;
  
      return (NDEF_OK);
  }
  
  /*******************************************************************************
  **
  ** Function         NDEF_MsgAppendPayload
  **
  ** Description      This function appends extra payload to a specific record in the
  **                  given NDEF message
  **
  ** Returns          OK, or error if the extra payload did not fit
  **                  *p_cur_size is updated
  **
  *******************************************************************************/
  tNDEF_STATUS NDEF_MsgAppendPayload (UINT8 *p_msg, UINT32 max_size, UINT32 *p_cur_size,
                                      UINT8 *p_rec, UINT8 *p_add_pl, UINT32 add_pl_len)
  {
      UINT32      prev_paylen, new_paylen;
      UINT8       *p_prev_pl, *pp;
      UINT8       incr_lenfld = 0;
      UINT8       type_len, id_len;
  
      /* Skip header */
      pp = p_rec + 1;
  
      /* Next byte is the type field length */
      type_len = *pp++;
  
      /* Next is the payload length (1 or 4 bytes) */
      if (*p_rec & NDEF_SR_MASK)
          prev_paylen = *pp++;
      else
          BE_STREAM_TO_UINT32 (prev_paylen, pp);
  
      /* ID field Length */
      if (*p_rec & NDEF_IL_MASK)
          id_len = *pp++;
      else
          id_len = 0;
  
      p_prev_pl = pp + type_len + id_len;
  
      new_paylen = prev_paylen + add_pl_len;
  
      /* Previous payload may be < 256, and this addition may make it larger than 256 */
      /* If that were to happen, the payload length field goes from 1 byte to 4 bytes */
      if ( (prev_paylen < 256) && (new_paylen > 255) )
          incr_lenfld = 3;
  
      /* Check that it all fits */
      if ((*p_cur_size + add_pl_len + incr_lenfld) > max_size)
          return (NDEF_MSG_INSUFFICIENT_MEM);
  
      /* Point to payload length field */
      pp = p_rec + 2;
  
      /* If we need to increase the length field from 1 to 4 bytes, do it first */
      if (incr_lenfld)
      {
          shiftdown (pp + 1, (UINT32)(*p_cur_size - (pp - p_msg) - 1), 3);
          p_prev_pl += 3;
      }
  
      /* Store in the new length */
      if (new_paylen > 255)
      {
          *p_rec &= ~NDEF_SR_MASK;
          UINT32_TO_BE_STREAM (pp, new_paylen);
      }
      else
          *pp = (UINT8)new_paylen;
  
      /* Point to the end of the previous payload */
      pp = p_prev_pl + prev_paylen;
  
      /* If we are not the last record, make space for the extra payload */
      if ((*p_rec & NDEF_ME_MASK) == 0)
          shiftdown (pp, (UINT32)(*p_cur_size - (pp - p_msg)), add_pl_len);
  
      /* Now copy in the additional payload data */
      memcpy (pp, p_add_pl, add_pl_len);
  
      *p_cur_size += add_pl_len + incr_lenfld;
  
      return (NDEF_OK);
  }
  
  /*******************************************************************************
  **
  ** Function         NDEF_MsgReplacePayload
  **
  ** Description      This function replaces the payload of a specific record in the
  **                  given NDEF message
  **
  ** Returns          OK, or error if the new payload did not fit
  **                  *p_cur_size is updated
  **
  *******************************************************************************/
  tNDEF_STATUS NDEF_MsgReplacePayload (UINT8 *p_msg, UINT32 max_size, UINT32 *p_cur_size,
                                       UINT8 *p_rec, UINT8 *p_new_pl, UINT32 new_pl_len)
  {
      UINT32      prev_paylen;
      UINT8       *p_prev_pl, *pp;
      UINT32      paylen_delta;
      UINT8       type_len, id_len;
  
      /* Skip header */
      pp = p_rec + 1;
  
      /* Next byte is the type field length */
      type_len = *pp++;
  
      /* Next is the payload length (1 or 4 bytes) */
      if (*p_rec & NDEF_SR_MASK)
          prev_paylen = *pp++;
      else
          BE_STREAM_TO_UINT32 (prev_paylen, pp);
  
      /* ID field Length */
      if (*p_rec & NDEF_IL_MASK)
          id_len = *pp++;
      else
          id_len = 0;
  
      p_prev_pl = pp + type_len + id_len;
  
      /* Point to payload length field again */
      pp = p_rec + 2;
  
      if (new_pl_len > prev_paylen)
      {
          /* New payload is larger than the previous */
          paylen_delta = new_pl_len - prev_paylen;
  
          /* If the previous payload length was < 256, and new is > 255 */
          /* the payload length field goes from 1 byte to 4 bytes       */
          if ( (prev_paylen < 256) && (new_pl_len > 255) )
          {
              if ((*p_cur_size + paylen_delta + 3) > max_size)
                  return (NDEF_MSG_INSUFFICIENT_MEM);
  
              shiftdown (pp + 1, (UINT32)(*p_cur_size - (pp - p_msg) - 1), 3);
              p_prev_pl   += 3;
              *p_cur_size += 3;
              *p_rec      &= ~NDEF_SR_MASK;
          }
          else if ((*p_cur_size + paylen_delta) > max_size)
              return (NDEF_MSG_INSUFFICIENT_MEM);
  
          /* Store in the new length */
          if (new_pl_len > 255)
          {
              UINT32_TO_BE_STREAM (pp, new_pl_len);
          }
          else
              *pp = (UINT8)new_pl_len;
  
          /* Point to the end of the previous payload */
          pp = p_prev_pl + prev_paylen;
  
          /* If we are not the last record, make space for the extra payload */
          if ((*p_rec & NDEF_ME_MASK) == 0)
              shiftdown (pp, (UINT32)(*p_cur_size - (pp - p_msg)), paylen_delta);
  
          *p_cur_size += paylen_delta;
      }
      else if (new_pl_len < prev_paylen)
      {
          /* New payload is smaller than the previous */
          paylen_delta = prev_paylen - new_pl_len;
  
          /* If the previous payload was > 256, and new is less than 256 */
          /* the payload length field goes from 4 bytes to 1 byte        */
          if ( (prev_paylen > 255) && (new_pl_len < 256) )
          {
              shiftup (pp + 1, pp + 4, (UINT32)(*p_cur_size - (pp - p_msg) - 3));
              p_prev_pl   -= 3;
              *p_cur_size -= 3;
              *p_rec      |= NDEF_SR_MASK;
          }
  
          /* Store in the new length */
          if (new_pl_len > 255)
          {
              UINT32_TO_BE_STREAM (pp, new_pl_len);
          }
          else
              *pp = (UINT8)new_pl_len;
  
          /* Point to the end of the previous payload */
          pp = p_prev_pl + prev_paylen;
  
          /* If we are not the last record, remove the extra space from the previous payload */
          if ((*p_rec & NDEF_ME_MASK) == 0)
              shiftup (pp - paylen_delta, pp, (UINT32)(*p_cur_size - (pp - p_msg)));
  
          *p_cur_size -= paylen_delta;
      }
  
      /* Now copy in the new payload data */
      if (p_new_pl)
          memcpy (p_prev_pl, p_new_pl, new_pl_len);
  
      return (NDEF_OK);
  }
  
  /*******************************************************************************
  **
  ** Function         NDEF_MsgReplaceType
  **
  ** Description      This function replaces the type field of a specific record in the
  **                  given NDEF message
  **
  ** Returns          OK, or error if the new type field did not fit
  **                  *p_cur_size is updated
  **
  *******************************************************************************/
  tNDEF_STATUS NDEF_MsgReplaceType (UINT8 *p_msg, UINT32 max_size, UINT32 *p_cur_size,
                                    UINT8 *p_rec, UINT8 *p_new_type, UINT8 new_type_len)
  {
      UINT8       typelen_delta;
      UINT8       *p_prev_type, prev_type_len;
      UINT8       *pp;
  
      /* Skip header */
      pp = p_rec + 1;
  
      /* Next byte is the type field length */
      prev_type_len = *pp++;
  
      /* Skip the payload length */
      if (*p_rec & NDEF_SR_MASK)
          pp += 1;
      else
          pp += 4;
  
      if (*p_rec & NDEF_IL_MASK)
          pp++;
  
      /* Save pointer to the start of the type field */
      p_prev_type = pp;
  
      if (new_type_len > prev_type_len)
      {
          /* New type is larger than the previous */
          typelen_delta = new_type_len - prev_type_len;
  
          if ((*p_cur_size + typelen_delta) > max_size)
              return (NDEF_MSG_INSUFFICIENT_MEM);
  
          /* Point to the end of the previous type, and make space for the extra data */
          pp = p_prev_type + prev_type_len;
          shiftdown (pp, (UINT32)(*p_cur_size - (pp - p_msg)), typelen_delta);
  
          *p_cur_size += typelen_delta;
      }
      else if (new_type_len < prev_type_len)
      {
          /* New type field is smaller than the previous */
          typelen_delta = prev_type_len - new_type_len;
  
          /* Point to the end of the previous type, and shift up to fill the the unused space */
          pp = p_prev_type + prev_type_len;
          shiftup (pp - typelen_delta, pp, (UINT32)(*p_cur_size - (pp - p_msg)));
  
          *p_cur_size -= typelen_delta;
      }
  
      /* Save in new type length */
      p_rec[1] = new_type_len;
  
      /* Now copy in the new type field data */
      if (p_new_type)
          memcpy (p_prev_type, p_new_type, new_type_len);
  
      return (NDEF_OK);
  }
  
  /*******************************************************************************
  **
  ** Function         NDEF_MsgReplaceId
  **
  ** Description      This function replaces the ID field of a specific record in the
  **                  given NDEF message
  **
  ** Returns          OK, or error if the new ID field did not fit
  **                  *p_cur_size is updated
  **
  *******************************************************************************/
  tNDEF_STATUS NDEF_MsgReplaceId (UINT8 *p_msg, UINT32 max_size, UINT32 *p_cur_size,
                                  UINT8 *p_rec, UINT8 *p_new_id, UINT8 new_id_len)
  {
      UINT8       idlen_delta;
      UINT8       *p_prev_id, *p_idlen_field;
      UINT8       prev_id_len, type_len;
      UINT8       *pp;
  
      /* Skip header */
      pp = p_rec + 1;
  
      /* Next byte is the type field length */
      type_len = *pp++;
  
      /* Skip the payload length */
      if (*p_rec & NDEF_SR_MASK)
          pp += 1;
      else
          pp += 4;
  
      p_idlen_field = pp;
  
      if (*p_rec & NDEF_IL_MASK)
          prev_id_len = *pp++;
      else
          prev_id_len = 0;
  
      /* Save pointer to the start of the ID field (right after the type field) */
      p_prev_id = pp + type_len;
  
      if (new_id_len > prev_id_len)
      {
          /* New ID field is larger than the previous */
          idlen_delta = new_id_len - prev_id_len;
  
          /* If the previous ID length was 0, we need to add a 1-byte ID length */
          if (prev_id_len == 0)
          {
              if ((*p_cur_size + idlen_delta + 1) > max_size)
                  return (NDEF_MSG_INSUFFICIENT_MEM);
  
              shiftdown (p_idlen_field, (UINT32)(*p_cur_size - (p_idlen_field - p_msg)), 1);
              p_prev_id   += 1;
              *p_cur_size += 1;
              *p_rec      |= NDEF_IL_MASK;
          }
          else if ((*p_cur_size + idlen_delta) > max_size)
              return (NDEF_MSG_INSUFFICIENT_MEM);
  
          /* Point to the end of the previous ID field, and make space for the extra data */
          pp = p_prev_id + prev_id_len;
          shiftdown (pp, (UINT32)(*p_cur_size - (pp - p_msg)), idlen_delta);
  
          *p_cur_size += idlen_delta;
      }
      else if (new_id_len < prev_id_len)
      {
          /* New ID field is smaller than the previous */
          idlen_delta = prev_id_len - new_id_len;
  
          /* Point to the end of the previous ID, and shift up to fill the the unused space */
          pp = p_prev_id + prev_id_len;
          shiftup (pp - idlen_delta, pp, (UINT32)(*p_cur_size - (pp - p_msg)));
  
          *p_cur_size -= idlen_delta;
  
          /* If removing the ID, make sure that length field is also removed */
          if (new_id_len == 0)
          {
              shiftup (p_idlen_field, p_idlen_field + 1, (UINT32)(*p_cur_size - (p_idlen_field - p_msg - (UINT32)1)));
              *p_rec      &= ~NDEF_IL_MASK;
              *p_cur_size -= 1;
          }
      }
  
      /* Save in new ID length and data */
      if (new_id_len)
      {
          *p_idlen_field = new_id_len;
  
          if (p_new_id)
              memcpy (p_prev_id, p_new_id, new_id_len);
      }
  
      return (NDEF_OK);
  }
  
  /*******************************************************************************
  **
  ** Function         NDEF_MsgRemoveRec
  **
  ** Description      This function removes the record at the given
  **                  index in the given NDEF message.
  **
  ** Returns          TRUE if OK, FALSE if the index was invalid
  **                  *p_cur_size is updated
  **
  *******************************************************************************/
  tNDEF_STATUS NDEF_MsgRemoveRec (UINT8 *p_msg, UINT32 *p_cur_size, INT32 index)
  {
      UINT8   *p_rec = NDEF_MsgGetRecByIndex (p_msg, index);
      UINT8   *pNext, *pPrev;
  
      if (!p_rec)
          return (NDEF_REC_NOT_FOUND);
  
      /* If this is the first record in the message... */
      if (*p_rec & NDEF_MB_MASK)
      {
          /* Find the second record (if any) and set his 'Message Begin' bit */
          if ((pNext = NDEF_MsgGetRecByIndex(p_msg, 1)) != NULL)
          {
              *pNext |= NDEF_MB_MASK;
  
              *p_cur_size -= (UINT32)(pNext - p_msg);
  
              shiftup (p_msg, pNext, *p_cur_size);
          }
          else
              *p_cur_size = 0;              /* No more records, lenght must be zero */
  
          return (NDEF_OK);
      }
  
      /* If this is the last record in the message... */
      if (*p_rec & NDEF_ME_MASK)
      {
          if (index > 0)
          {
              /* Find the previous record and set his 'Message End' bit */
              if ((pPrev = NDEF_MsgGetRecByIndex(p_msg, index - 1)) == NULL)
                  return (FALSE);
  
              *pPrev |= NDEF_ME_MASK;
          }
          *p_cur_size = (UINT32)(p_rec - p_msg);
  
          return (NDEF_OK);
      }
  
      /* Not the first or the last... get the address of the next record */
      if ((pNext = NDEF_MsgGetNextRec (p_rec)) == NULL)
          return (FALSE);
  
      /* We are removing p_rec, so shift from pNext to the end */
      shiftup (p_rec, pNext, (UINT32)(*p_cur_size - (pNext - p_msg)));
  
      *p_cur_size -= (UINT32)(pNext - p_rec);
  
      return (NDEF_OK);
  }
  
  
  /*******************************************************************************
  **
  ** Function         NDEF_MsgCopyAndDechunk
  **
  ** Description      This function copies and de-chunks an NDEF message.
  **                  It is assumed that the destination is at least as large
  **                  as the source, since the source may not actually contain
  **                  any chunks.
  **
  ** Returns          The output byte count
  **
  *******************************************************************************/
  tNDEF_STATUS NDEF_MsgCopyAndDechunk (UINT8 *p_src, UINT32 src_len, UINT8 *p_dest, UINT32 *p_out_len)
  {
      UINT32          out_len, max_out_len;
      UINT8           *p_rec;
      UINT8           *p_prev_rec = p_dest;
      UINT8           *p_type, *p_id, *p_pay;
      UINT8           type_len, id_len, tnf;
      UINT32          pay_len;
      tNDEF_STATUS    status;
  
      /* First, validate the source */
      if ((status = NDEF_MsgValidate(p_src, src_len, TRUE)) != NDEF_OK)
          return (status);
  
      /* The output buffer must be at least as large as the input buffer */
      max_out_len = src_len;
  
      /* Initialize output */
      NDEF_MsgInit (p_dest, max_out_len, &out_len);
  
      p_rec = p_src;
  
      /* Now, copy record by record */
      while ((p_rec != NULL) && (status == NDEF_OK))
      {
          p_type = NDEF_RecGetType (p_rec, &tnf, &type_len);
          p_id   = NDEF_RecGetId (p_rec, &id_len);
          p_pay  = NDEF_RecGetPayload (p_rec, &pay_len);
  
          /* If this is the continuation of a chunk, append the payload to the previous */
          if (tnf == NDEF_TNF_UNCHANGED)
          {
              if (p_pay)
              {
                  status = NDEF_MsgAppendPayload (p_dest, max_out_len, &out_len, p_prev_rec, p_pay, pay_len);
              }
          }
          else
          {
              p_prev_rec = p_dest + out_len;
  
              status = NDEF_MsgAddRec (p_dest, max_out_len, &out_len, tnf, p_type, type_len,
                              p_id, id_len, p_pay, pay_len);
          }
  
          p_rec = NDEF_MsgGetNextRec (p_rec);
      }
  
      *p_out_len = out_len;
  
      return (status);
  }
  