icuSources/common/stringpiece.cpp

   1 // Copyright (C) 2009-2013, International Business Machines
   2 // Corporation and others. All Rights Reserved.
   3 //
   4 // Copyright 2004 and onwards Google Inc.
   5 //
   6 // Author: wilsonh@google.com (Wilson Hsieh)
   7 //
   8
   9 #include "unicode/utypes.h"
  10 #include "unicode/stringpiece.h"
  11 #include "cstring.h"
  12 #include "cmemory.h"
  13
  14 U_NAMESPACE_BEGIN
  15
  16 StringPiece::StringPiece(const char* str)
  17     : ptr_(str), length_((str == NULL) ? 0 : static_cast<int32_t>(uprv_strlen(str))) { }
  18
  19 StringPiece::StringPiece(const StringPiece& x, int32_t pos) {
  20   if (pos < 0) {
  21     pos = 0;
  22   } else if (pos > x.length_) {
  23     pos = x.length_;
  24   }
  25   ptr_ = x.ptr_ + pos;
  26   length_ = x.length_ - pos;
  27 }
  28
  29 StringPiece::StringPiece(const StringPiece& x, int32_t pos, int32_t len) {
  30   if (pos < 0) {
  31     pos = 0;
  32   } else if (pos > x.length_) {
  33     pos = x.length_;
  34   }
  35   if (len < 0) {
  36     len = 0;
  37   } else if (len > x.length_ - pos) {
  38     len = x.length_ - pos;
  39   }
  40   ptr_ = x.ptr_ + pos;
  41   length_ = len;
  42 }
  43
  44 void StringPiece::set(const char* str) {
  45   ptr_ = str;
  46   if (str != NULL)
  47     length_ = static_cast<int32_t>(uprv_strlen(str));
  48   else
  49     length_ = 0;
  50 }
  51
  52 U_EXPORT UBool U_EXPORT2
  53 operator==(const StringPiece& x, const StringPiece& y) {
  54   int32_t len = x.size();
  55   if (len != y.size()) {
  56     return false;
  57   }
  58   if (len == 0) {
  59     return true;
  60   }
  61   const char* p = x.data();
  62   const char* p2 = y.data();
  63   // Test last byte in case strings share large common prefix
  64   --len;
  65   if (p[len] != p2[len]) return false;
  66   // At this point we can, but don't have to, ignore the last byte.
  67   return uprv_memcmp(p, p2, len) == 0;
  68 }
  69
  70
  71 const int32_t StringPiece::npos = 0x7fffffff;
  72
  73 U_NAMESPACE_END