1 // Copyright 2022 The PDFium Authors 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com 6 7 #include "core/fxcrt/cfx_read_only_span_stream.h" 8 9 #include "core/fxcrt/fx_safe_types.h" 10 #include "core/fxcrt/span_util.h" 11 #include "third_party/base/numerics/safe_conversions.h" 12 CFX_ReadOnlySpanStream(pdfium::span<const uint8_t> span)13CFX_ReadOnlySpanStream::CFX_ReadOnlySpanStream(pdfium::span<const uint8_t> span) 14 : span_(span) {} 15 16 CFX_ReadOnlySpanStream::~CFX_ReadOnlySpanStream() = default; 17 GetSize()18FX_FILESIZE CFX_ReadOnlySpanStream::GetSize() { 19 return pdfium::base::checked_cast<FX_FILESIZE>(span_.size()); 20 } 21 ReadBlockAtOffset(pdfium::span<uint8_t> buffer,FX_FILESIZE offset)22bool CFX_ReadOnlySpanStream::ReadBlockAtOffset(pdfium::span<uint8_t> buffer, 23 FX_FILESIZE offset) { 24 if (buffer.empty() || offset < 0) 25 return false; 26 27 FX_SAFE_SIZE_T pos = buffer.size(); 28 pos += offset; 29 if (!pos.IsValid() || pos.ValueOrDie() > span_.size()) 30 return false; 31 32 fxcrt::spancpy( 33 buffer, 34 span_.subspan(pdfium::base::checked_cast<size_t>(offset), buffer.size())); 35 return true; 36 } 37