Decryptor/App/PostLAProtobufNativeTransforms.cpp

//
// Created by miti on 27/07/19.
//

#include "UntrustedInclude/PostLAProtobufNativeTransforms.h"
#include <string.h>

void PostLAProtobufNativeTransforms::get_lengths_for_protobuf_serialized_array(extension_to_decryptor_enclosed_msg &protobuf_ext_to_decryptor,
                                               uint32_t *op_ciphertext_length, uint32_t *op_number_of_ciphertext_fields)
{
    uint32_t number_of_ciphertext_fields, counter, total_length;
    // Didn't use bytesize() or bytesizelong() for getting the lengths of the public key or the ciphertext string
    // as that gives the *serialized* length of the message which should be an upper-bound.
    // Can switch to that if necessary for time performance reasons.
    total_length=protobuf_ext_to_decryptor.ciphertext_client_public_key().length();
    number_of_ciphertext_fields=protobuf_ext_to_decryptor.ciphertext_fields_size();
    for(counter=0; counter<number_of_ciphertext_fields; counter++)
        total_length+=protobuf_ext_to_decryptor.ciphertext_fields(counter).field().length();
    *op_ciphertext_length=total_length;
    *op_number_of_ciphertext_fields=number_of_ciphertext_fields;
}

void PostLAProtobufNativeTransforms::create_array_from_protobuf(extension_to_decryptor_enclosed_msg &protobuf_ext_to_decryptor,
                                unsigned char* double_ciphertext_client_data, uint32_t* sizes_array,
                                uint32_t* sizes_array_length)
{
    uint32_t counter, size_of_field, number_of_fields;
    unsigned char* ptr;

    // Set the size of the first element - the public key - and copy it to the output array.
    sizes_array[0] = protobuf_ext_to_decryptor.ciphertext_client_public_key().length();
    memcpy(double_ciphertext_client_data, protobuf_ext_to_decryptor.ciphertext_client_public_key().c_str(),
           sizes_array[0]);
    ptr=double_ciphertext_client_data + sizes_array[0];
    // Start copying past the length copied above, copy all ciphertext fields to the output string array
    // and set their lengths in the output integers array
    number_of_fields=protobuf_ext_to_decryptor.ciphertext_fields_size();
    for(counter=0;counter<number_of_fields;counter++)
    {
        // First element of the LHS array is the length of the client's public key.
        size_of_field = protobuf_ext_to_decryptor.ciphertext_fields(counter).field().length();
        memcpy(ptr, protobuf_ext_to_decryptor.ciphertext_fields(counter).field().c_str(), size_of_field);
        sizes_array[counter + 1] = size_of_field;
        ptr += sizes_array[counter + 1];
    }
    *sizes_array_length=number_of_fields+1;
}

void PostLAProtobufNativeTransforms::create_protobuf_from_array(   unsigned char* ciphertext_client_data, uint32_t* sizes_array, uint32_t sizes_array_length,
                                   extension_to_decryptor_enclosed_msg protobuf_extension_decryptor_msg)
{
    uint32_t counter;
    unsigned char* ptr;

    // Note that we don't care about setting the client public key as we don't include that in the outgoing message
    // to the extension.
    ptr=ciphertext_client_data;
    for(counter=0; counter<sizes_array_length; counter++)
    {
        protobuf_extension_decryptor_msg.mutable_ciphertext_fields(counter)->set_field(ptr, sizes_array[counter]);
        ptr+=sizes_array[counter];
    }
}