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      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 (at) 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 NULL;
     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 NULL;
     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
     86