replace semver with home grown simplier alternative

src/core/EMSESP_Version.h

@@ -0,0 +1,124 @@
+/*
+ * EMS-ESP - https://github.com/emsesp/EMS-ESP
+ * Copyright 2020-2026  emsesp.org
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef EMSESP_Version_H
+#define EMSESP_Version_H
+
+#include <cstdio>
+#include <cstring>
+#include <string>
+
+// Drop-in lightweight replacement for the subset of the semver library actually used by EMS-ESP.
+// The previous semver library (lib/semver) builds a std::map + std::function-based state machine on
+// every parse, which fragments the internal heap on the ESP32. This replacement does no heap
+// allocation beyond the std::string member for the prerelease tag, and matches the API surface
+// we consume: construction from string, major()/minor()/patch()/prerelease(), and operator>/</==.
+//
+// Only strict numeric precedence (major.minor.patch) is used for comparison in EMS-ESP, so we
+// intentionally ignore prerelease tags during comparison rather than implement the full semver
+// ordering rules. This is consistent with how the old code was used (callers only check major/
+// minor/patch numerically; prerelease() is only read for logging).
+
+namespace version {
+
+class EMSESP_Version {
+  public:
+    EMSESP_Version() = default;
+
+    // Construct from a version string like "3.9.0-dev.14" or "3.9.0".
+    // Anything past a '-' or '+' is kept as the prerelease string and not interpreted.
+    explicit EMSESP_Version(const std::string & s) {
+        parse(s.c_str());
+    }
+
+    explicit EMSESP_Version(const char * s) {
+        parse(s ? s : "");
+    }
+
+    int major() const {
+        return major_;
+    }
+    int minor() const {
+        return minor_;
+    }
+    int patch() const {
+        return patch_;
+    }
+    const std::string & prerelease() const {
+        return prerelease_;
+    }
+
+    // Numeric-only comparison (major.minor.patch). Prerelease tags are ignored on purpose.
+    friend bool operator<(const EMSESP_Version & a, const EMSESP_Version & b) {
+        if (a.major_ != b.major_)
+            return a.major_ < b.major_;
+        if (a.minor_ != b.minor_)
+            return a.minor_ < b.minor_;
+        return a.patch_ < b.patch_;
+    }
+
+    friend bool operator>(const EMSESP_Version & a, const EMSESP_Version & b) {
+        return b < a;
+    }
+
+    friend bool operator==(const EMSESP_Version & a, const EMSESP_Version & b) {
+        return a.major_ == b.major_ && a.minor_ == b.minor_ && a.patch_ == b.patch_;
+    }
+
+    friend bool operator!=(const EMSESP_Version & a, const EMSESP_Version & b) {
+        return !(a == b);
+    }
+
+    friend bool operator>=(const EMSESP_Version & a, const EMSESP_Version & b) {
+        return !(a < b);
+    }
+
+    friend bool operator<=(const EMSESP_Version & a, const EMSESP_Version & b) {
+        return !(b < a);
+    }
+
+  private:
+    int         major_ = 0;
+    int         minor_ = 0;
+    int         patch_ = 0;
+    std::string prerelease_;
+
+    void parse(const char * s) {
+        major_ = minor_ = patch_ = 0;
+        prerelease_.clear();
+        if (s == nullptr || *s == '\0') {
+            return;
+        }
+        // parse numeric major.minor.patch; accept partial ("3", "3.9", "3.9.0")
+        sscanf(s, "%d.%d.%d", &major_, &minor_, &patch_);
+        // capture prerelease tag after '-' if present (stop at '+' which is build metadata)
+        const char * dash = strchr(s, '-');
+        if (dash != nullptr) {
+            const char * plus = strchr(dash, '+');
+            if (plus != nullptr) {
+                prerelease_.assign(dash + 1, plus - dash - 1);
+            } else {
+                prerelease_.assign(dash + 1);
+            }
+        }
+    }
+};
+
+} // namespace version
+
+#endif