hash_layout.cpp

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#include "logging/layouts/hash_layout.h"
 
#include <cstring>
#include <vector>
 
namespace CppLogging {
 
uint32_t HashLayout::Hash(std::string_view message)
{
    const uint32_t FNV_PRIME = 16777619u;
    const uint32_t OFFSET_BASIS = 2166136261u;
 
    uint32_t hash = OFFSET_BASIS;
    for (size_t i = 0; i < message.size(); ++i)
    {
        hash ^= message[i];
        hash *= FNV_PRIME;
    }
    return hash;
}
 
void HashLayout::LayoutRecord(Record& record)
{
    // Calculate logging record size
    uint32_t size = (uint32_t)(sizeof(uint64_t) + sizeof(uint64_t) + sizeof(Level) + sizeof(uint32_t) + sizeof(uint32_t) + sizeof(uint32_t) + record.buffer.size());
 
    // Resize the raw buffer to the required size
    record.raw.resize(sizeof(uint32_t) + size + 1);
 
    // Get the raw buffer start position
    uint8_t* buffer = record.raw.data();
 
    // Serialize the logging record
    std::memcpy(buffer, &size, sizeof(uint32_t));
    buffer += sizeof(uint32_t);
    std::memcpy(buffer, &record.timestamp, sizeof(uint64_t));
    buffer += sizeof(uint64_t);
    std::memcpy(buffer, &record.thread, sizeof(uint64_t));
    buffer += sizeof(uint64_t);
    std::memcpy(buffer, &record.level, sizeof(Level));
    buffer += sizeof(Level);
 
    // Serialize the logger name hash
    uint32_t logger_hash = Hash(record.logger);
    std::memcpy(buffer, &logger_hash, sizeof(uint32_t));
    buffer += sizeof(uint32_t);
 
    // Serialize the logging message hash
    uint32_t message_hash = Hash(record.message);
    std::memcpy(buffer, &message_hash, sizeof(uint32_t));
    buffer += sizeof(uint32_t);
 
    // Serialize the logging buffer
    uint32_t buffer_size = (uint32_t)record.buffer.size();
    std::memcpy(buffer, &buffer_size, sizeof(uint32_t));
    buffer += sizeof(uint32_t);
    std::memcpy(buffer, record.buffer.data(), record.buffer.size());
    buffer += record.buffer.size();
 
    // Write the last zero byte
    *buffer = 0;
}
 
} // namespace CppLogging