tor-browser

The Tor Browser
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bytestream.cpp (2465B)

      1 // © 2016 and later: Unicode, Inc. and others.
      2 // License & terms of use: http://www.unicode.org/copyright.html
      3 // Copyright (C) 2009-2011, International Business Machines
      4 // Corporation and others. All Rights Reserved.
      5 //
      6 // Copyright 2007 Google Inc. All Rights Reserved.
      7 // Author: sanjay@google.com (Sanjay Ghemawat)
      8 
      9 #include "unicode/utypes.h"
     10 #include "unicode/bytestream.h"
     11 #include "cmemory.h"
     12 
     13 U_NAMESPACE_BEGIN
     14 
     15 ByteSink::~ByteSink() {}
     16 
     17 char* ByteSink::GetAppendBuffer(int32_t min_capacity,
     18                                int32_t /*desired_capacity_hint*/,
     19                                char* scratch, int32_t scratch_capacity,
     20                                int32_t* result_capacity) {
     21  if (min_capacity < 1 || scratch_capacity < min_capacity) {
     22    *result_capacity = 0;
     23    return nullptr;
     24  }
     25  *result_capacity = scratch_capacity;
     26  return scratch;
     27 }
     28 
     29 void ByteSink::Flush() {}
     30 
     31 CheckedArrayByteSink::CheckedArrayByteSink(char* outbuf, int32_t capacity)
     32    : outbuf_(outbuf), capacity_(capacity < 0 ? 0 : capacity),
     33      size_(0), appended_(0), overflowed_(false) {
     34 }
     35 
     36 CheckedArrayByteSink::~CheckedArrayByteSink() {}
     37 
     38 CheckedArrayByteSink& CheckedArrayByteSink::Reset() {
     39  size_ = appended_ = 0;
     40  overflowed_ = false;
     41  return *this;
     42 }
     43 
     44 void CheckedArrayByteSink::Append(const char* bytes, int32_t n) {
     45  if (n <= 0) {
     46    return;
     47  }
     48  if (n > (INT32_MAX - appended_)) {
     49    // TODO: Report as integer overflow, not merely buffer overflow.
     50    appended_ = INT32_MAX;
     51    overflowed_ = true;
     52    return;
     53  }
     54  appended_ += n;
     55  int32_t available = capacity_ - size_;
     56  if (n > available) {
     57    n = available;
     58    overflowed_ = true;
     59  }
     60  if (n > 0 && bytes != (outbuf_ + size_)) {
     61    uprv_memcpy(outbuf_ + size_, bytes, n);
     62  }
     63  size_ += n;
     64 }
     65 
     66 char* CheckedArrayByteSink::GetAppendBuffer(int32_t min_capacity,
     67                                            int32_t /*desired_capacity_hint*/,
     68                                            char* scratch,
     69                                            int32_t scratch_capacity,
     70                                            int32_t* result_capacity) {
     71  if (min_capacity < 1 || scratch_capacity < min_capacity) {
     72    *result_capacity = 0;
     73    return nullptr;
     74  }
     75  int32_t available = capacity_ - size_;
     76  if (available >= min_capacity) {
     77    *result_capacity = available;
     78    return outbuf_ + size_;
     79  } else {
     80    *result_capacity = scratch_capacity;
     81    return scratch;
     82  }
     83 }
     84 
     85 U_NAMESPACE_END