strintmap.hpp

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#ifndef UPnPdsk_STRINTMAP_HPP
#define UPnPdsk_STRINTMAP_HPP
// Copyright (C) 2024+ GPL 3 and higher by Ingo Höft, <Ingo@Hoeft-online.de>
// Redistribution only with this Copyright remark. Last modified: 2025-04-07
 
#include <UPnPsdk/synclog.hpp>
#include <UPnPsdk/port.hpp>
#include <cstddef> // for size_t
#include <cstring>
#include <climits>
 
 
namespace UPnPsdk {
 
struct str_int_entry {
    const char* name; 
    int id; 
};
 
// Don't export class symbol; only used library intern.
template <typename T> //
class CStrIntMap {
  public:
    static constexpr size_t npos = size_t(-1);
 
    CStrIntMap(T& a_table) : m_table(a_table) {}
 
    size_t index_of(
        const char* a_name,
        bool a_case_sensitive = false);
 
    size_t index_of(
        const int a_id);
 
  private:
    T& m_table;
};
 
template <typename T>
size_t CStrIntMap<T>::index_of(const char* a_name, bool a_case_sensitive) {
    TRACE("Executing index_of(const char*)");
    if (a_name == nullptr || a_name[0] == '\0')
        return this->npos;
 
    // Select library compare function outside the loop with a function pointer
    // so we do not have to check on every loop for nothing.
    int (*str_cmp)(const char*, const char*);
    str_cmp = a_case_sensitive ? strcmp : strcasecmp;
 
    size_t top, mid, bot, idxmax;
    int cmp;
 
    top = 0;
    bot = m_table.size() - 1;
    idxmax = bot;
 
    while (top <= bot) {
        mid = (top + bot) / 2;
        if (mid > idxmax) // unsigned index outer low bound
            break;
        cmp = str_cmp(a_name, m_table[mid].name);
        if (cmp > 0) {
            top = mid + 1; /* look below mid */
        } else if (cmp < 0) {
            bot = mid - 1; /* look above mid */
        } else if (mid > INT_MAX) { // guard for the following type cast
            UPnPsdk_LOGCRIT("MSG1026") "Index mid="
                << mid
                << "exceeds integer limit. This program error MUST be fixed! "
                   "Program is stable but may have ignored runtime "
                   "conditions.\n";
            return this->npos;
        } else {
            return mid; /* match, return table index. */
        }
    }
    return this->npos;
}
 
template <typename T> //
size_t CStrIntMap<T>::index_of(int a_id) {
    TRACE("Executing index_of(int)");
    for (size_t i{0}; i < m_table.size(); i++) {
        if (m_table[i].id == a_id) {
            return i;
        }
    }
    return this->npos;
}
 
} // namespace UPnPsdk
 
#endif /* UPnPdsk_STRINTMAP_HPP */