icuSources/common/stringpiece.cpp

   1 // © 2016 and later: Unicode, Inc. and others.
   2 // License & terms of use: http://www.unicode.org/copyright.html
   3 // Copyright (C) 2009-2013, International Business Machines
   4 // Corporation and others. All Rights Reserved.
   5 //
   6 // Copyright 2004 and onwards Google Inc.
   7 //
   8 // Author: wilsonh@google.com (Wilson Hsieh)
   9 //
  10
  11 #include "unicode/utypes.h"
  12 #include "unicode/stringpiece.h"
  13 #include "cstring.h"
  14 #include "cmemory.h"
  15
  16 U_NAMESPACE_BEGIN
  17
  18 StringPiece::StringPiece(const char* str)
  19     : ptr_(str), length_((str == NULL) ? 0 : static_cast<int32_t>(uprv_strlen(str))) { }
  20
  21 StringPiece::StringPiece(const StringPiece& x, int32_t pos) {
  22   if (pos < 0) {
  23     pos = 0;
  24   } else if (pos > x.length_) {
  25     pos = x.length_;
  26   }
  27   ptr_ = x.ptr_ + pos;
  28   length_ = x.length_ - pos;
  29 }
  30
  31 StringPiece::StringPiece(const StringPiece& x, int32_t pos, int32_t len) {
  32   if (pos < 0) {
  33     pos = 0;
  34   } else if (pos > x.length_) {
  35     pos = x.length_;
  36   }
  37   if (len < 0) {
  38     len = 0;
  39   } else if (len > x.length_ - pos) {
  40     len = x.length_ - pos;
  41   }
  42   ptr_ = x.ptr_ + pos;
  43   length_ = len;
  44 }
  45
  46 void StringPiece::set(const char* str) {
  47   ptr_ = str;
  48   if (str != NULL)
  49     length_ = static_cast<int32_t>(uprv_strlen(str));
  50   else
  51     length_ = 0;
  52 }
  53
  54 U_EXPORT UBool U_EXPORT2
  55 operator==(const StringPiece& x, const StringPiece& y) {
  56   int32_t len = x.size();
  57   if (len != y.size()) {
  58     return false;
  59   }
  60   if (len == 0) {
  61     return true;
  62   }
  63   const char* p = x.data();
  64   const char* p2 = y.data();
  65   // Test last byte in case strings share large common prefix
  66   --len;
  67   if (p[len] != p2[len]) return false;
  68   // At this point we can, but don't have to, ignore the last byte.
  69   return uprv_memcmp(p, p2, len) == 0;
  70 }
  71
  72
  73 const int32_t StringPiece::npos = 0x7fffffff;
  74
  75 U_NAMESPACE_END