Index: src/token.cc |
diff --git a/src/token.cc b/src/token.cc |
index bb42cead4b60a3c5bde23f2b9a0026bea45f9288..0a4ad4c1ad7fbf4e9045be14dff4bc9690c77a7d 100644 |
--- a/src/token.cc |
+++ b/src/token.cc |
@@ -55,109 +55,4 @@ int8_t Token::precedence_[NUM_TOKENS] = { |
#undef T |
-// A perfect (0 collision) hash table of keyword token values. |
- |
-// larger N will reduce the number of collisions (power of 2 for fast %) |
-const unsigned int N = 128; |
-// make this small since we have <= 256 tokens |
-static uint8_t Hashtable[N]; |
-static bool IsInitialized = false; |
- |
- |
-static unsigned int Hash(const char* s) { |
- // The following constants have been found using trial-and-error. If the |
- // keyword set changes, they may have to be recomputed (make them flags |
- // and play with the flag values). Increasing N is the simplest way to |
- // reduce the number of collisions. |
- |
- // we must use at least 4 or more chars ('const' and 'continue' share |
- // 'con') |
- const unsigned int L = 5; |
- // smaller S tend to reduce the number of collisions |
- const unsigned int S = 4; |
- // make this a prime, or at least an odd number |
- const unsigned int M = 3; |
- |
- unsigned int h = 0; |
- for (unsigned int i = 0; s[i] != '\0' && i < L; i++) { |
- h += (h << S) + s[i]; |
- } |
- // unsigned int % by a power of 2 (otherwise this will not be a bit mask) |
- return h * M % N; |
-} |
- |
- |
-Token::Value Token::Lookup(const char* str) { |
- ASSERT(IsInitialized); |
- Value k = static_cast<Value>(Hashtable[Hash(str)]); |
- const char* s = string_[k]; |
- ASSERT(s != NULL || k == IDENTIFIER); |
- if (s == NULL || strcmp(s, str) == 0) { |
- return k; |
- } |
- return IDENTIFIER; |
-} |
- |
- |
-#ifdef DEBUG |
-// We need this function because C++ doesn't allow the expression |
-// NULL == NULL, which is a result of macro expansion below. What |
-// the hell? |
-static bool IsNull(const char* s) { |
- return s == NULL; |
-} |
-#endif |
- |
- |
-void Token::Initialize() { |
- if (IsInitialized) return; |
- |
- // A list of all keywords, terminated by ILLEGAL. |
-#define T(name, string, precedence) name, |
- static Value keyword[] = { |
- TOKEN_LIST(IGNORE_TOKEN, T, IGNORE_TOKEN) |
- ILLEGAL |
- }; |
-#undef T |
- |
- // Assert that the keyword array contains the 25 keywords, 3 future |
- // reserved words (const, debugger, and native), and the 3 named literals |
- // defined by ECMA-262 standard. |
- ASSERT(ARRAY_SIZE(keyword) == 25 + 3 + 3 + 1); // +1 for ILLEGAL sentinel |
- |
- // Initialize Hashtable. |
- ASSERT(NUM_TOKENS <= 256); // Hashtable contains uint8_t elements |
- for (unsigned int i = 0; i < N; i++) { |
- Hashtable[i] = IDENTIFIER; |
- } |
- |
- // Insert all keywords into Hashtable. |
- int collisions = 0; |
- for (int i = 0; keyword[i] != ILLEGAL; i++) { |
- Value k = keyword[i]; |
- unsigned int h = Hash(string_[k]); |
- if (Hashtable[h] != IDENTIFIER) collisions++; |
- Hashtable[h] = k; |
- } |
- |
- if (collisions > 0) { |
- PrintF("%d collisions in keyword hashtable\n", collisions); |
- FATAL("Fix keyword lookup!"); |
- } |
- |
- IsInitialized = true; |
- |
- // Verify hash table. |
-#define T(name, string, precedence) \ |
- ASSERT(IsNull(string) || Lookup(string) == IDENTIFIER); |
- |
-#define K(name, string, precedence) \ |
- ASSERT(Lookup(string) == name); |
- |
- TOKEN_LIST(T, K, IGNORE_TOKEN) |
- |
-#undef K |
-#undef T |
-} |
- |
} } // namespace v8::internal |