/*
 Itay Marom
 Cisco Systems, Inc.
*/

/*
Copyright (c) 2015-2015 Cisco Systems, Inc.

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.
*/

#include <trex_vm_splitter.h>
#include <trex_stateless.h>

/**
 * split a specific stream's VM to multiple cores
 * number of cores is implied by the size of the vector
 * 
 */
void
TrexVmSplitter::split(TrexStream *stream, std::vector<TrexStream *> core_streams) {

    /* nothing to do if no VM */
    if (stream->m_vm.is_vm_empty()) {
        return;
    }

    /* prepare some vars */
    m_dp_core_count = core_streams.size();
    m_core_streams  = &core_streams;
    m_stream        = stream;

    uint16_t cache_size=m_stream->m_cache_size;
    /* split the cache_size  */
    if (cache_size>0) {

        /* TBD need to check if we need to it is not too big from pool */
        if (cache_size > 10000) {
            throw TrexException("Cache is too big try to reduce it ");
        }

        /* split like variable splitters with leftovers */
        uint16_t cache_per_core = cache_size/m_dp_core_count;
        uint16_t leftover   = cache_size % m_dp_core_count;

        if (cache_per_core<1) {
            cache_per_core=1;
            leftover=0;
        }

        for (TrexStream *core_stream : *m_core_streams) {
            core_stream->m_cache_size = cache_per_core;
            if (leftover) {
                core_stream->m_cache_size+=1; 
                leftover-=1;
            }
        }
    }


    /* if we cannot split - compile the main and duplicate */
    bool rc = split_internal();
    if (!rc) {

        /* compile the stream and simply clone it to all streams */
        m_stream->vm_compile();

        /* for every core - simply clone the DP object */
        for (TrexStream *core_stream : *m_core_streams) {
            core_stream->m_vm_dp = m_stream->m_vm_dp->clone();
        }

        /* no need for the reference stream DP object */
        delete m_stream->m_vm_dp;
        m_stream->m_vm_dp = NULL;
    }
}

bool
TrexVmSplitter::split_internal() {

    const StreamVmInstructionVar *split_instr = m_stream->m_vm.get_split_instruction();

    /* if no split instruction was specified - fall back*/
    if (split_instr == NULL) {
        return false;
    }

    if (split_instr->get_instruction_type() == StreamVmInstruction::itFLOW_MAN) {
        return split_by_flow_var( (const StreamVmInstructionFlowMan *)split_instr );

    } else if (split_instr->get_instruction_type() == StreamVmInstruction::itFLOW_CLIENT) {
        return split_by_flow_client_var( (const StreamVmInstructionFlowClient *)split_instr );

    } else {
        throw TrexException("VM splitter : cannot split by instruction which is not flow var or flow client var");
    }

}

/**
 * split VM by flow var 
 * 
 * @author imarom (20-Dec-15)
 * 
 * @param instr 
 * 
 * @return bool 
 */
bool
TrexVmSplitter::split_by_flow_var(const StreamVmInstructionFlowMan *instr) {
    /* no point in splitting random */
    if (instr->m_op == StreamVmInstructionFlowMan::FLOW_VAR_OP_RANDOM) {
        return false;
    }

    /* if the range is too small - it is unsplitable  */
    if (instr->get_splitable_range() < m_dp_core_count) {
        return false;
    }

    /* split only step of 1 */
    if (!instr->is_valid_for_split() ){
        return false;
    }

    /* we need to split - duplicate VM now */
    duplicate_vm();

    /* calculate range splitting */
    uint64_t range = instr->get_splitable_range();

    uint64_t range_part = range / m_dp_core_count;
    uint64_t leftover   = range % m_dp_core_count;

    /* first core handles a bit more */
    uint64_t start   = instr->m_min_value;
    uint64_t end     = start + range_part + leftover - 1;


    /* do work */
    for (TrexStream *core_stream : *m_core_streams) {

        /* get the per-core instruction to split */
        StreamVmInstructionFlowMan *per_core_instr = (StreamVmInstructionFlowMan *)core_stream->m_vm.get_split_instruction();

        per_core_instr->m_min_value  = start;
        per_core_instr->m_max_value  = end; 

        /* after split this has no meaning - choose it as we see fit */
        per_core_instr->m_init_value = (per_core_instr->m_op == StreamVmInstructionFlowMan::FLOW_VAR_OP_DEC ? end : start);

        core_stream->vm_compile();

        start = end + 1;
        end   = start + range_part - 1;
    }

    return true;
}


bool
TrexVmSplitter::split_by_flow_client_var(const StreamVmInstructionFlowClient *instr) {

    /* if the range is too small - it is unsplitable  */
    if (instr->get_ip_range() < m_dp_core_count) {
        return false;
    }

    /* we need to split - duplicate VM now */
    duplicate_vm();

    /* calculate range splitting */
    uint64_t range = instr->get_ip_range();

    uint64_t range_part = range / m_dp_core_count;
    uint64_t leftover   = range % m_dp_core_count;

    /* first core handles a bit more */
    uint64_t start   = instr->m_client_min;
    uint64_t end     = start + range_part + leftover - 1;


    /* do work */
    for (TrexStream *core_stream : *m_core_streams) {

        /* get the per-core instruction to split */
        StreamVmInstructionFlowClient *per_core_instr = (StreamVmInstructionFlowClient *)core_stream->m_vm.get_split_instruction();

        per_core_instr->m_client_min  = start;
        per_core_instr->m_client_max  = end; 

        core_stream->vm_compile();

        start = end + 1;
        end   = start + range_part - 1;
    }

    return true;
}

/**
 * duplicate the VM instructions
 * to all the cores
 */
void
TrexVmSplitter::duplicate_vm() {
    /* for each core - duplicate the instructions */
    for (TrexStream *core_stream : *m_core_streams) {
        m_stream->m_vm.clone(core_stream->m_vm);
    }
}