| // Character Map Class |
| // |
| // Originally written by Daniel Dulitz |
| // Yanked out from url.cc on February 2003 by Wei-Hwa Huang |
| // |
| // Copyright (C) Google, 2001. |
| // |
| // A fast, bit-vector map for 8-bit unsigned characters. |
| // |
| // Internally stores 256 bits in an array of 8 uint32s. |
| // See changelist history for micro-optimization attempts. |
| // Does quick bit-flicking to lookup needed characters. |
| // |
| // This class is useful for non-character purposes as well. |
| |
| #ifndef UTIL_GTL_CHARMAP_H_ |
| #define UTIL_GTL_CHARMAP_H_ |
| |
| #include <string.h> |
| |
| #include "gutil/basictypes.h" |
| #include "gutil/integral_types.h" |
| #include "gutil/type_traits.h" |
| |
| class Charmap { |
| public: |
| // Initializes with given uint32 values. For instance, the first |
| // variable contains bits for values 0x1F (US) down to 0x00 (NUL). |
| Charmap(uint32 b0, uint32 b1, uint32 b2, uint32 b3, |
| uint32 b4, uint32 b5, uint32 b6, uint32 b7) { |
| m_[0] = b0; |
| m_[1] = b1; |
| m_[2] = b2; |
| m_[3] = b3; |
| m_[4] = b4; |
| m_[5] = b5; |
| m_[6] = b6; |
| m_[7] = b7; |
| } |
| |
| // Initializes with a given char*. Note that NUL is not treated as |
| // a terminator, but rather a char to be flicked. |
| Charmap(const char* str, int len) { |
| Init(str, len); |
| } |
| |
| // Initializes with a given char*. NUL is treated as a terminator |
| // and will not be in the charmap. |
| explicit Charmap(const char* str) { |
| Init(str, strlen(str)); |
| } |
| |
| bool contains(unsigned char c) const { |
| return (m_[c >> 5] >> (c & 0x1f)) & 0x1; |
| } |
| |
| // Returns true if and only if a character exists in both maps. |
| bool IntersectsWith(const Charmap & c) const { |
| for (int i = 0; i < 8; ++i) { |
| if ((m_[i] & c.m_[i]) != 0) |
| return true; |
| } |
| return false; |
| } |
| |
| bool IsZero() const { |
| for (uint32 c : m_) { |
| if (c != 0) |
| return false; |
| } |
| return true; |
| } |
| |
| protected: |
| uint32 m_[8]; |
| |
| void Init(const char* str, int len) { |
| memset(&m_, 0, sizeof m_); |
| for (int i = 0; i < len; ++i) { |
| unsigned char value = static_cast<unsigned char>(str[i]); |
| m_[value >> 5] |= 1UL << (value & 0x1f); |
| } |
| } |
| }; |
| DECLARE_POD(Charmap); |
| |
| #endif // UTIL_GTL_CHARMAP_H_ |