tor-browser

The Tor Browser
git clone https://git.dasho.dev/tor-browser.git
Log | Files | Refs | README | LICENSE

stringpiece.cpp (2617B)

      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 == nullptr) ? 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 != nullptr)
     49    length_ = static_cast<int32_t>(uprv_strlen(str));
     50  else
     51    length_ = 0;
     52 }
     53 
     54 int32_t StringPiece::find(StringPiece needle, int32_t offset) {
     55  if (length() == 0 && needle.length() == 0) {
     56    return 0;
     57  }
     58  // TODO: Improve to be better than O(N^2)?
     59  for (int32_t i = offset; i < length(); i++) {
     60    int32_t j = 0;
     61    for (; j < needle.length(); i++, j++) {
     62      if (data()[i] != needle.data()[j]) {
     63        i -= j;
     64        goto outer_end;
     65      }
     66    }
     67    return i - j;
     68    outer_end: void();
     69  }
     70  return -1;
     71 }
     72 
     73 int32_t StringPiece::compare(StringPiece other) {
     74  int32_t i = 0;
     75  for (; i < length(); i++) {
     76    if (i == other.length()) {
     77      // this is longer
     78      return 1;
     79    }
     80    char a = data()[i];
     81    char b = other.data()[i];
     82    if (a < b) {
     83      return -1;
     84    } else if (a > b) {
     85      return 1;
     86    }
     87  }
     88  if (i < other.length()) {
     89    // other is longer
     90    return -1;
     91  }
     92  return 0;
     93 }
     94 
     95 U_EXPORT UBool U_EXPORT2
     96 operator==(const StringPiece& x, const StringPiece& y) {
     97  int32_t len = x.size();
     98  if (len != y.size()) {
     99    return false;
    100  }
    101  if (len == 0) {
    102    return true;
    103  }
    104  const char* p = x.data();
    105  const char* p2 = y.data();
    106  // Test last byte in case strings share large common prefix
    107  --len;
    108  if (p[len] != p2[len]) return false;
    109  // At this point we can, but don't have to, ignore the last byte.
    110  return uprv_memcmp(p, p2, len) == 0;
    111 }
    112 
    113 
    114 const int32_t StringPiece::npos = 0x7fffffff;
    115 
    116 U_NAMESPACE_END