chore: call common djb2 implementations in game hashing funcs

2026-06-09 18:22:33 +00:00 · 2026-02-21 10:52:36 +00:00
parent 9502ebfc26
commit f7e0cb3c45
10 changed files with 318 additions and 164 deletions
@@ -0,0 +1,100 @@
+#pragma once
+
+#include <cctype>
+#include <cstdint>
+
+// This header contains multiple varying implementations of the DJB2 algorithm:
+// http://www.cse.yorku.ca/~oz/hash.html
+
+constexpr uint32_t DJB2_STARTING_VALUE = 5381;
+
+static constexpr uint32_t djb2(const char* str, uint32_t hash)
+{
+    for (char c = *str; c; c = *++str)
+    {
+        // hash * 33 + c
+        hash = ((hash << 5) + hash) + c;
+    }
+
+    return hash;
+}
+
+static constexpr uint32_t djb2(const char* str)
+{
+    return djb2(str, DJB2_STARTING_VALUE);
+}
+
+static constexpr uint32_t djb2_nocase(const char* str, uint32_t hash)
+{
+    for (char c = *str; c; c = *++str)
+    {
+        // Or with 0x20 makes the string case-insensitive
+        // but also messes up non-letters
+        hash = ((hash << 5) + hash) + (c | 0x20);
+    }
+
+    return hash;
+}
+
+static constexpr uint32_t djb2_nocase(const char* str)
+{
+    return djb2_nocase(str, DJB2_STARTING_VALUE);
+}
+
+static constexpr uint32_t djb2_lower(const char* str, uint32_t hash)
+{
+    for (char c = *str; c; c = *++str)
+        hash = ((hash << 5) + hash) + std::tolower(c);
+
+    return hash;
+}
+
+static constexpr uint32_t djb2_lower(const char* str)
+{
+    return djb2_lower(str, DJB2_STARTING_VALUE);
+}
+
+static constexpr uint32_t djb2_xor(const char* str, uint32_t hash)
+{
+    for (char c = *str; c; c = *++str)
+    {
+        hash = ((hash << 5) + hash) ^ c;
+    }
+
+    return hash;
+}
+
+static constexpr uint32_t djb2_xor(const char* str)
+{
+    return djb2_xor(str, DJB2_STARTING_VALUE);
+}
+
+static constexpr uint32_t djb2_xor_nocase(const char* str, uint32_t hash)
+{
+    for (char c = *str; c; c = *++str)
+    {
+        // Or with 0x20 makes the string case-insensitive
+        // but also messes up non-letters
+        hash = ((hash << 5) + hash) ^ (c | 0x20);
+    }
+
+    return hash;
+}
+
+static constexpr uint32_t djb2_xor_nocase(const char* str)
+{
+    return djb2_xor_nocase(str, DJB2_STARTING_VALUE);
+}
+
+static constexpr uint32_t djb2_xor_lower(const char* str, uint32_t hash)
+{
+    for (char c = *str; c; c = *++str)
+        hash = ((hash << 5) + hash) ^ std::tolower(c);
+
+    return hash;
+}
+
+static constexpr uint32_t djb2_xor_lower(const char* str)
+{
+    return djb2_xor_lower(str, DJB2_STARTING_VALUE);
+}