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Diffstat (limited to 'V8Binding/v8/src/token.cc')
| -rw-r--r-- | V8Binding/v8/src/token.cc | 163 |
1 files changed, 0 insertions, 163 deletions
diff --git a/V8Binding/v8/src/token.cc b/V8Binding/v8/src/token.cc deleted file mode 100644 index bb42cea..0000000 --- a/V8Binding/v8/src/token.cc +++ /dev/null @@ -1,163 +0,0 @@ -// Copyright 2006-2008 the V8 project authors. All rights reserved. -// Redistribution and use in source and binary forms, with or without -// modification, are permitted provided that the following conditions are -// met: -// -// * Redistributions of source code must retain the above copyright -// notice, this list of conditions and the following disclaimer. -// * Redistributions in binary form must reproduce the above -// copyright notice, this list of conditions and the following -// disclaimer in the documentation and/or other materials provided -// with the distribution. -// * Neither the name of Google Inc. nor the names of its -// contributors may be used to endorse or promote products derived -// from this software without specific prior written permission. -// -// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS -// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT -// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR -// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT -// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, -// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT -// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, -// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY -// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT -// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE -// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. - -#include "v8.h" - -#include "token.h" - -namespace v8 { -namespace internal { - -#ifdef DEBUG -#define T(name, string, precedence) #name, -const char* Token::name_[NUM_TOKENS] = { - TOKEN_LIST(T, T, IGNORE_TOKEN) -}; -#undef T -#endif - - -#define T(name, string, precedence) string, -const char* Token::string_[NUM_TOKENS] = { - TOKEN_LIST(T, T, IGNORE_TOKEN) -}; -#undef T - - -#define T(name, string, precedence) precedence, -int8_t Token::precedence_[NUM_TOKENS] = { - TOKEN_LIST(T, T, IGNORE_TOKEN) -}; -#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 |