text: /**
   * \file asn1write.h
   *
   * \brief ASN.1 buffer writing functionality
   */
  /*
   *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
   *  SPDX-License-Identifier: Apache-2.0
   *
   *  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 is part of mbed TLS (https://tls.mbed.org)
   */
  #ifndef MBEDTLS_ASN1_WRITE_H
  #define MBEDTLS_ASN1_WRITE_H
  
  #include "asn1.h"
  
  #define MBEDTLS_ASN1_CHK_ADD(g, f)                      \
      do {                                                \
          if( ( ret = f ) < 0 )                           \
              return( ret );                              \
          else                                            \
              g += ret;                                   \
      } while( 0 )
  
  #ifdef __cplusplus
  extern "C" {
  #endif
  
  /**
   * \brief           Write a length field in ASN.1 format.
   *
   * \note            This function works backwards in data buffer.
   *
   * \param p         The reference to the current position pointer.
   * \param start     The start of the buffer, for bounds-checking.
   * \param len       The length value to write.
   *
   * \return          The number of bytes written to \p p on success.
   * \return          A negative \c MBEDTLS_ERR_ASN1_XXX error code on failure.
   */
  int mbedtls_asn1_write_len( unsigned char **p, unsigned char *start,
                              size_t len );
  /**
   * \brief           Write an ASN.1 tag in ASN.1 format.
   *
   * \note            This function works backwards in data buffer.
   *
   * \param p         The reference to the current position pointer.
   * \param start     The start of the buffer, for bounds-checking.
   * \param tag       The tag to write.
   *
   * \return          The number of bytes written to \p p on success.
   * \return          A negative \c MBEDTLS_ERR_ASN1_XXX error code on failure.
   */
  int mbedtls_asn1_write_tag( unsigned char **p, unsigned char *start,
                              unsigned char tag );
  
  /**
   * \brief           Write raw buffer data.
   *
   * \note            This function works backwards in data buffer.
   *
   * \param p         The reference to the current position pointer.
   * \param start     The start of the buffer, for bounds-checking.
   * \param buf       The data buffer to write.
   * \param size      The length of the data buffer.
   *
   * \return          The number of bytes written to \p p on success.
   * \return          A negative \c MBEDTLS_ERR_ASN1_XXX error code on failure.
   */
  int mbedtls_asn1_write_raw_buffer( unsigned char **p, unsigned char *start,
                                     const unsigned char *buf, size_t size );
  
  #if defined(MBEDTLS_BIGNUM_C)
  /**
   * \brief           Write a arbitrary-precision number (#MBEDTLS_ASN1_INTEGER)
   *                  in ASN.1 format.
   *
   * \note            This function works backwards in data buffer.
   *
   * \param p         The reference to the current position pointer.
   * \param start     The start of the buffer, for bounds-checking.
   * \param X         The MPI to write.
   *
   * \return          The number of bytes written to \p p on success.
   * \return          A negative \c MBEDTLS_ERR_ASN1_XXX error code on failure.
   */
  int mbedtls_asn1_write_mpi( unsigned char **p, unsigned char *start,
                              const mbedtls_mpi *X );
  #endif /* MBEDTLS_BIGNUM_C */
  
  /**
   * \brief           Write a NULL tag (#MBEDTLS_ASN1_NULL) with zero data
   *                  in ASN.1 format.
   *
   * \note            This function works backwards in data buffer.
   *
   * \param p         The reference to the current position pointer.
   * \param start     The start of the buffer, for bounds-checking.
   *
   * \return          The number of bytes written to \p p on success.
   * \return          A negative \c MBEDTLS_ERR_ASN1_XXX error code on failure.
   */
  int mbedtls_asn1_write_null( unsigned char **p, unsigned char *start );
  
  /**
   * \brief           Write an OID tag (#MBEDTLS_ASN1_OID) and data
   *                  in ASN.1 format.
   *
   * \note            This function works backwards in data buffer.
   *
   * \param p         The reference to the current position pointer.
   * \param start     The start of the buffer, for bounds-checking.
   * \param oid       The OID to write.
   * \param oid_len   The length of the OID.
   *
   * \return          The number of bytes written to \p p on success.
   * \return          A negative \c MBEDTLS_ERR_ASN1_XXX error code on failure.
   */
  int mbedtls_asn1_write_oid( unsigned char **p, unsigned char *start,
                              const char *oid, size_t oid_len );
  
  /**
   * \brief           Write an AlgorithmIdentifier sequence in ASN.1 format.
   *
   * \note            This function works backwards in data buffer.
   *
   * \param p         The reference to the current position pointer.
   * \param start     The start of the buffer, for bounds-checking.
   * \param oid       The OID of the algorithm to write.
   * \param oid_len   The length of the algorithm's OID.
   * \param par_len   The length of the parameters, which must be already written.
   *                  If 0, NULL parameters are added
   *
   * \return          The number of bytes written to \p p on success.
   * \return          A negative \c MBEDTLS_ERR_ASN1_XXX error code on failure.
   */
  int mbedtls_asn1_write_algorithm_identifier( unsigned char **p,
                                               unsigned char *start,
                                               const char *oid, size_t oid_len,
                                               size_t par_len );
  
  /**
   * \brief           Write a boolean tag (#MBEDTLS_ASN1_BOOLEAN) and value
   *                  in ASN.1 format.
   *
   * \note            This function works backwards in data buffer.
   *
   * \param p         The reference to the current position pointer.
   * \param start     The start of the buffer, for bounds-checking.
   * \param boolean   The boolean value to write, either \c 0 or \c 1.
   *
   * \return          The number of bytes written to \p p on success.
   * \return          A negative \c MBEDTLS_ERR_ASN1_XXX error code on failure.
   */
  int mbedtls_asn1_write_bool( unsigned char **p, unsigned char *start,
                               int boolean );
  
  /**
   * \brief           Write an int tag (#MBEDTLS_ASN1_INTEGER) and value
   *                  in ASN.1 format.
   *
   * \note            This function works backwards in data buffer.
   *
   * \param p         The reference to the current position pointer.
   * \param start     The start of the buffer, for bounds-checking.
   * \param val       The integer value to write.
   *
   * \return          The number of bytes written to \p p on success.
   * \return          A negative \c MBEDTLS_ERR_ASN1_XXX error code on failure.
   */
  int mbedtls_asn1_write_int( unsigned char **p, unsigned char *start, int val );
  
  /**
   * \brief           Write a string in ASN.1 format using a specific
   *                  string encoding tag.
  
   * \note            This function works backwards in data buffer.
   *
   * \param p         The reference to the current position pointer.
   * \param start     The start of the buffer, for bounds-checking.
   * \param tag       The string encoding tag to write, e.g.
   *                  #MBEDTLS_ASN1_UTF8_STRING.
   * \param text      The string to write.
   * \param text_len  The length of \p text in bytes (which might
   *                  be strictly larger than the number of characters).
   *
   * \return          The number of bytes written to \p p on success.
   * \return          A negative error code on failure.
   */
  int mbedtls_asn1_write_tagged_string( unsigned char **p, unsigned char *start,
                                        int tag, const char *text,
                                        size_t text_len );
  
  /**
   * \brief           Write a string in ASN.1 format using the PrintableString
   *                  string encoding tag (#MBEDTLS_ASN1_PRINTABLE_STRING).
   *
   * \note            This function works backwards in data buffer.
   *
   * \param p         The reference to the current position pointer.
   * \param start     The start of the buffer, for bounds-checking.
   * \param text      The string to write.
   * \param text_len  The length of \p text in bytes (which might
   *                  be strictly larger than the number of characters).
   *
   * \return          The number of bytes written to \p p on success.
   * \return          A negative error code on failure.
   */
  int mbedtls_asn1_write_printable_string( unsigned char **p,
                                           unsigned char *start,
                                           const char *text, size_t text_len );
  
  /**
   * \brief           Write a UTF8 string in ASN.1 format using the UTF8String
   *                  string encoding tag (#MBEDTLS_ASN1_PRINTABLE_STRING).
   *
   * \note            This function works backwards in data buffer.
   *
   * \param p         The reference to the current position pointer.
   * \param start     The start of the buffer, for bounds-checking.
   * \param text      The string to write.
   * \param text_len  The length of \p text in bytes (which might
   *                  be strictly larger than the number of characters).
   *
   * \return          The number of bytes written to \p p on success.
   * \return          A negative error code on failure.
   */
  int mbedtls_asn1_write_utf8_string( unsigned char **p, unsigned char *start,
                                      const char *text, size_t text_len );
  
  /**
   * \brief           Write a string in ASN.1 format using the IA5String
   *                  string encoding tag (#MBEDTLS_ASN1_IA5_STRING).
   *
   * \note            This function works backwards in data buffer.
   *
   * \param p         The reference to the current position pointer.
   * \param start     The start of the buffer, for bounds-checking.
   * \param text      The string to write.
   * \param text_len  The length of \p text in bytes (which might
   *                  be strictly larger than the number of characters).
   *
   * \return          The number of bytes written to \p p on success.
   * \return          A negative error code on failure.
   */
  int mbedtls_asn1_write_ia5_string( unsigned char **p, unsigned char *start,
                                     const char *text, size_t text_len );
  
  /**
   * \brief           Write a bitstring tag (#MBEDTLS_ASN1_BIT_STRING) and
   *                  value in ASN.1 format.
   *
   * \note            This function works backwards in data buffer.
   *
   * \param p         The reference to the current position pointer.
   * \param start     The start of the buffer, for bounds-checking.
   * \param buf       The bitstring to write.
   * \param bits      The total number of bits in the bitstring.
   *
   * \return          The number of bytes written to \p p on success.
   * \return          A negative error code on failure.
   */
  int mbedtls_asn1_write_bitstring( unsigned char **p, unsigned char *start,
                                    const unsigned char *buf, size_t bits );
  
  /**
   * \brief           Write an octet string tag (#MBEDTLS_ASN1_OCTET_STRING)
   *                  and value in ASN.1 format.
   *
   * \note            This function works backwards in data buffer.
   *
   * \param p         The reference to the current position pointer.
   * \param start     The start of the buffer, for bounds-checking.
   * \param buf       The buffer holding the data to write.
   * \param size      The length of the data buffer \p buf.
   *
   * \return          The number of bytes written to \p p on success.
   * \return          A negative error code on failure.
   */
  int mbedtls_asn1_write_octet_string( unsigned char **p, unsigned char *start,
                                       const unsigned char *buf, size_t size );
  
  /**
   * \brief           Create or find a specific named_data entry for writing in a
   *                  sequence or list based on the OID. If not already in there,
   *                  a new entry is added to the head of the list.
   *                  Warning: Destructive behaviour for the val data!
   *
   * \param list      The pointer to the location of the head of the list to seek
   *                  through (will be updated in case of a new entry).
   * \param oid       The OID to look for.
   * \param oid_len   The size of the OID.
   * \param val       The data to store (can be \c NULL if you want to fill
   *                  it by hand).
   * \param val_len   The minimum length of the data buffer needed.
   *
   * \return          A pointer to the new / existing entry on success.
   * \return          \c NULL if if there was a memory allocation error.
   */
  mbedtls_asn1_named_data *mbedtls_asn1_store_named_data( mbedtls_asn1_named_data **list,
                                          const char *oid, size_t oid_len,
                                          const unsigned char *val,
                                          size_t val_len );
  
  #ifdef __cplusplus
  }
  #endif
  
  #endif /* MBEDTLS_ASN1_WRITE_H */
  