string_view conversions

neheb · neheb · commit 3b1a3ac8718f · 2025-02-21T15:04:13.000-08:00
Signed-off-by: Rosen Penev &lt;rosenp@gmail.com&gt;
diff --git a/src/canonmn_int.cpp b/src/canonmn_int.cpp
@@ -38,7 +38,7 @@ static std::ostream& printCsLensTypeByMetadata(std::ostream& os, const Value& va
 //! Special treatment pretty-print function for non-unique lens ids.
 static std::ostream& printCsLensFFFF(std::ostream& os, const Value& value, const ExifData* metadata);
 
-static float string_to_float(const std::string& str);
+static float string_to_float(std::string_view str);
 
 //! ModelId, tag 0x0010
 constexpr TagDetails canonModelId[] = {
@@ -2877,7 +2877,7 @@ std::ostream& printCsLensFFFF(std::ostream& os, const Value& value, const ExifDa
  * @param str string to convert
  * @return float value of string
  */
-float string_to_float(std::string const& str) {
+float string_to_float(std::string_view str) {
   float val{};
   std::stringstream ss;
   std::locale c_locale("C");
diff --git a/src/futils.cpp b/src/futils.cpp
@@ -207,8 +207,8 @@ size_t base64decode(const char* in, char* out, size_t out_size) {
 
 Protocol fileProtocol(const std::string& path) {
   Protocol result = pFile;
-  const struct {
-    std::string name;
+  constexpr struct {
+    std::string_view name;
     Protocol prot;
     bool isUrl;  // path.size() > name.size()
   } prots[] = {
diff --git a/src/makernote_int.cpp b/src/makernote_int.cpp
@@ -129,7 +129,7 @@ const TiffMnRegistry TiffMnCreator::registry_[] = {
     {"-", IfdId::casio2Id, nullptr, newCasio2Mn2},
 };
 
-bool TiffMnRegistry::operator==(const std::string& key) const {
+bool TiffMnRegistry::operator==(std::string_view key) const {
   if (!key.empty() && key.front() == '-')
     return false;
   return key.starts_with(make_);
@@ -139,7 +139,7 @@ bool TiffMnRegistry::operator==(IfdId key) const {
   return mnGroup_ == key;
 }
 
-std::unique_ptr<TiffComponent> TiffMnCreator::create(uint16_t tag, IfdId group, const std::string& make,
+std::unique_ptr<TiffComponent> TiffMnCreator::create(uint16_t tag, IfdId group, std::string_view make,
                                                      const byte* pData, size_t size, ByteOrder byteOrder) {
   if (auto tmr = Exiv2::find(registry_, make))
     return tmr->newMnFct_(tag, group, tmr->mnGroup_, pData, size, byteOrder);
diff --git a/src/makernote_int.hpp b/src/makernote_int.hpp
@@ -43,7 +43,7 @@ struct TiffMnRegistry {
            same size. E.g., registry = "OLYMPUS",
            key = "OLYMPUS OPTICAL CO.,LTD" (found in the image) match.
    */
-  bool operator==(const std::string& key) const;
+  bool operator==(std::string_view key) const;
 
   //! Compare a TiffMnRegistry structure with a makernote group
   bool operator==(IfdId key) const;
@@ -71,7 +71,7 @@ class TiffMnCreator {
            is used to indicate this transfer here in order to reduce
            file dependencies.
   */
-  static std::unique_ptr<TiffComponent> create(uint16_t tag, IfdId group, const std::string& make, const byte* pData,
+  static std::unique_ptr<TiffComponent> create(uint16_t tag, IfdId group, std::string_view make, const byte* pData,
                                                size_t size, ByteOrder byteOrder);
   /*!
     @brief Create the Makernote for a given group. This method is used
diff --git a/src/olympusmn_int.cpp b/src/olympusmn_int.cpp
@@ -1355,7 +1355,7 @@ std::ostream& OlympusMakerNote::print0x0201(std::ostream& os, const Value& value
 
   // 6 numbers: 0. Make, 1. Unknown, 2. Model, 3. Sub-model, 4-5. Unknown.
   // Only the Make, Model and Sub-model are used to determine the lens model
-  static const struct {
+  static constexpr struct {
     byte val[3];
     const char* label;
   } lensTypes[] = {
@@ -1509,7 +1509,7 @@ std::ostream& OlympusMakerNote::print0x0209(std::ostream& os, const Value& value
 std::ostream& OlympusMakerNote::printEq0x0301(std::ostream& os, const Value& value, const ExifData*) {
   // 6 numbers: 0. Make, 1. Unknown, 2. Model, 3. Sub-model, 4-5. Unknown.
   // Only the Make and Model are used to determine the extender model
-  static const struct {
+  static constexpr struct {
     byte val[2];
     const char* label;
   } extenderModels[] = {
diff --git a/src/pngchunk_int.cpp b/src/pngchunk_int.cpp
@@ -311,7 +311,7 @@ void PngChunk::parseChunkContent(Image* pImage, const byte* key, size_t keySize,
 
 }  // PngChunk::parseChunkContent
 
-std::string PngChunk::makeMetadataChunk(const std::string& metadata, MetadataId type) {
+std::string PngChunk::makeMetadataChunk(std::string_view metadata, MetadataId type) {
   std::string rawProfile;
 
   switch (type) {
@@ -362,7 +362,7 @@ void PngChunk::zlibUncompress(const byte* compressedText, unsigned int compresse
   }
 }  // PngChunk::zlibUncompress
 
-std::string PngChunk::zlibCompress(const std::string& text) {
+std::string PngChunk::zlibCompress(std::string_view text) {
   auto compressedLen = static_cast<uLongf>(text.size() * 2);  // just a starting point
   int zlibResult = Z_BUF_ERROR;
 
@@ -396,7 +396,7 @@ std::string PngChunk::zlibCompress(const std::string& text) {
 
 }  // PngChunk::zlibCompress
 
-std::string PngChunk::makeAsciiTxtChunk(const std::string& keyword, const std::string& text, bool compress) {
+std::string PngChunk::makeAsciiTxtChunk(std::string_view keyword, std::string_view text, bool compress) {
   // Chunk structure: length (4 bytes) + chunk type + chunk data + CRC (4 bytes)
   // Length is the size of the chunk data
   // CRC is calculated on chunk type + chunk data
@@ -408,7 +408,7 @@ std::string PngChunk::makeAsciiTxtChunk(const std::string& keyword, const std::s
   // Chunk data format : keyword + 0x00 + text
 
   // Build chunk data, determine chunk type
-  std::string chunkData = keyword + '\0';
+  auto chunkData = std::string(keyword) + '\0';
   std::string chunkType;
   if (compress) {
     chunkData += '\0' + zlibCompress(text);
@@ -432,7 +432,7 @@ std::string PngChunk::makeAsciiTxtChunk(const std::string& keyword, const std::s
 
 }  // PngChunk::makeAsciiTxtChunk
 
-std::string PngChunk::makeUtf8TxtChunk(const std::string& keyword, const std::string& text, bool compress) {
+std::string PngChunk::makeUtf8TxtChunk(std::string_view keyword, std::string_view text, bool compress) {
   // Chunk structure: length (4 bytes) + chunk type + chunk data + CRC (4 bytes)
   // Length is the size of the chunk data
   // CRC is calculated on chunk type + chunk data
@@ -442,13 +442,13 @@ std::string PngChunk::makeUtf8TxtChunk(const std::string& keyword, const std::st
   //                     + translated keyword (null) + 0x00 + text (compressed or not)
 
   // Build chunk data, determine chunk type
-  std::string chunkData = keyword;
+  auto chunkData = std::string(keyword);
   if (compress) {
     static const char flags[] = {0x00, 0x01, 0x00, 0x00, 0x00};
     chunkData += std::string(flags, 5) + zlibCompress(text);
   } else {
     static const char flags[] = {0x00, 0x00, 0x00, 0x00, 0x00};
-    chunkData += std::string(flags, 5) + text;
+    chunkData += std::string(flags, 5) + text.data();
   }
   // Determine length of the chunk data
   byte length[4];
@@ -574,7 +574,7 @@ DataBuf PngChunk::readRawProfile(const DataBuf& text, bool iTXt) {
 
 }  // PngChunk::readRawProfile
 
-std::string PngChunk::writeRawProfile(const std::string& profileData, const char* profileType) {
+std::string PngChunk::writeRawProfile(std::string_view profileData, const char* profileType) {
   static const byte hex[16] = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};
 
   auto ss = stringFormat("\n{}\n{:08}", profileType, profileData.size());
diff --git a/src/pngchunk_int.hpp b/src/pngchunk_int.hpp
@@ -70,7 +70,7 @@ class PngChunk {
     @param metadata    metadata buffer.
     @param type        metadata type.
   */
-  static std::string makeMetadataChunk(const std::string& metadata, MetadataId type);
+  static std::string makeMetadataChunk(std::string_view metadata, MetadataId type);
 
  private:
   /*!
@@ -100,7 +100,7 @@ class PngChunk {
 
     @return String containing the PNG chunk
   */
-  static std::string makeAsciiTxtChunk(const std::string& keyword, const std::string& text, bool compress);
+  static std::string makeAsciiTxtChunk(std::string_view keyword, std::string_view text, bool compress);
 
   /*!
     @brief Return a compressed or uncompressed (iTXt) PNG international text chunk
@@ -110,7 +110,7 @@ class PngChunk {
     @param text     Text to be recorded in the PNG chunk.
     @param compress Flag indicating whether to compress the PNG chunk data.
   */
-  static std::string makeUtf8TxtChunk(const std::string& keyword, const std::string& text, bool compress);
+  static std::string makeUtf8TxtChunk(std::string_view keyword, std::string_view text, bool compress);
 
   /*!
     @brief Wrapper around zlib to uncompress a PNG chunk content.
@@ -120,7 +120,7 @@ class PngChunk {
   /*!
     @brief Wrapper around zlib to compress a PNG chunk content.
    */
-  static std::string zlibCompress(const std::string& text);
+  static std::string zlibCompress(std::string_view text);
 
   /*!
     @brief Decode from ImageMagick raw text profile which host encoded Exif/Iptc/Xmp metadata byte array.
@@ -131,7 +131,7 @@ class PngChunk {
     @brief Encode to ImageMagick raw text profile, which host encoded
            Exif/IPTC/XMP metadata byte arrays.
    */
-  static std::string writeRawProfile(const std::string& profileData, const char* profileType);
+  static std::string writeRawProfile(std::string_view profileData, const char* profileType);
 
   friend class Exiv2::PngImage;
 
diff --git a/src/tags.cpp b/src/tags.cpp
@@ -45,7 +45,7 @@ constexpr SectionInfo sectionInfo[] = {
 }  // namespace Exiv2
 
 namespace Exiv2::Internal {
-bool TagVocabulary::operator==(const std::string& key) const {
+bool TagVocabulary::operator==(std::string_view key) const {
   return key.ends_with(voc_);
 }
 
diff --git a/src/tags_int.cpp b/src/tags_int.cpp
@@ -28,7 +28,7 @@
 // local declarations
 namespace {
 // Print version string from an intermediate string
-std::ostream& printVersion(std::ostream& os, const std::string& str) {
+std::ostream& printVersion(std::ostream& os, std::string_view str) {
   if (str.size() != 4) {
     return os << "(" << str << ")";
   }
diff --git a/src/tags_int.hpp b/src/tags_int.hpp
@@ -45,8 +45,8 @@ struct StringTagDetails {
   const char* label_;  //!< Translation of the tag value
 
   //! Comparison operator for use with the find template
-  bool operator==(const std::string& key) const {
-    return (key == val_);
+  bool operator==(std::string_view key) const {
+    return key == val_;
   }
 };  // struct TagDetails
 
@@ -80,7 +80,7 @@ struct TagVocabulary {
     "http://ns.useplus.org/ldf/vocab/PR-NON" and return true if the vocabulary
     string matches the end of the key.
    */
-  bool operator==(const std::string& key) const;
+  bool operator==(std::string_view key) const;
 };  // struct TagDetails
 
 /*!
diff --git a/src/tiffcomposite_int.hpp b/src/tiffcomposite_int.hpp
@@ -366,9 +366,9 @@ struct TiffMappingInfo {
 
 //! Search key for TIFF mapping structures.
 struct TiffMappingInfo::Key {
-  std::string m_;  //!< Camera make
-  uint32_t e_;     //!< Extended tag
-  IfdId g_;        //!< %Group
+  std::string_view m_;  //!< Camera make
+  uint32_t e_;          //!< Extended tag
+  IfdId g_;             //!< %Group
 };
 
 /*!
diff --git a/src/tifffwd_int.hpp b/src/tifffwd_int.hpp
@@ -61,11 +61,11 @@ using EncoderFct = void (TiffEncoder::*)(TiffEntryBase*, const Exifdatum*);
 /*!
   @brief Type for a function pointer for a function to decode a TIFF component.
  */
-using FindDecoderFct = DecoderFct (*)(const std::string& make, uint32_t extendedTag, IfdId group);
+using FindDecoderFct = DecoderFct (*)(std::string_view make, uint32_t extendedTag, IfdId group);
 /*!
   @brief Type for a function pointer for a function to encode a TIFF component.
  */
-using FindEncoderFct = EncoderFct (*)(const std::string& make, uint32_t extendedTag, IfdId group);
+using FindEncoderFct = EncoderFct (*)(std::string_view make, uint32_t extendedTag, IfdId group);
 /*!
   @brief Type for a function pointer for a function to create a TIFF component.
          Use TiffComponent::UniquePtr, it is not used in this declaration only
diff --git a/src/tiffimage_int.cpp b/src/tiffimage_int.cpp
@@ -1975,7 +1975,7 @@ const TiffMappingInfo TiffMapping::tiffMappingInfo_[] = {
     {"*", 0x0026, IfdId::canonId, &TiffDecoder::decodeCanonAFInfo, nullptr /* Exiv2.Canon.AFInfo is read-only */},
 };
 
-DecoderFct TiffMapping::findDecoder(const std::string& make, uint32_t extendedTag, IfdId group) {
+DecoderFct TiffMapping::findDecoder(std::string_view make, uint32_t extendedTag, IfdId group) {
   DecoderFct decoderFct = &TiffDecoder::decodeStdTiffEntry;
   if (auto td = Exiv2::find(tiffMappingInfo_, TiffMappingInfo::Key{make, extendedTag, group})) {
     // This may set decoderFct to 0, meaning that the tag should not be decoded
@@ -1984,7 +1984,7 @@ DecoderFct TiffMapping::findDecoder(const std::string& make, uint32_t extendedTa
   return decoderFct;
 }
 
-EncoderFct TiffMapping::findEncoder(const std::string& make, uint32_t extendedTag, IfdId group) {
+EncoderFct TiffMapping::findEncoder(std::string_view make, uint32_t extendedTag, IfdId group) {
   EncoderFct encoderFct = nullptr;
   if (auto td = Exiv2::find(tiffMappingInfo_, TiffMappingInfo::Key{make, extendedTag, group})) {
     // Returns 0 if no special encoder function is found
@@ -2185,7 +2185,7 @@ DataBuf TiffHeaderBase::write() const {
   return buf;
 }
 
-void TiffHeaderBase::print(std::ostream& os, const std::string& prefix) const {
+void TiffHeaderBase::print(std::ostream& os, std::string_view prefix) const {
   std::ios::fmtflags f(os.flags());
   os << prefix << _("TIFF header, offset") << " = 0x" << std::setw(8) << std::setfill('0') << std::hex << std::right
      << offset_;
diff --git a/src/tiffimage_int.hpp b/src/tiffimage_int.hpp
@@ -71,7 +71,7 @@ class TiffHeaderBase {
     @param os Output stream to write to.
     @param prefix Prefix to be written before each line of output.
    */
-  virtual void print(std::ostream& os, const std::string& prefix = "") const;
+  virtual void print(std::ostream& os, std::string_view prefix = "") const;
   //! Return the byte order (little or big endian).
   [[nodiscard]] virtual ByteOrder byteOrder() const;
   //! Return the offset to the start of the root directory.
@@ -267,7 +267,7 @@ class TiffMapping {
 
     @return Pointer to the decoder function
    */
-  static DecoderFct findDecoder(const std::string& make, uint32_t extendedTag, IfdId group);
+  static DecoderFct findDecoder(std::string_view make, uint32_t extendedTag, IfdId group);
   /*!
     @brief Find special encoder function for a key.
 
@@ -281,7 +281,7 @@ class TiffMapping {
 
     @return Pointer to the encoder function
    */
-  static EncoderFct findEncoder(const std::string& make, uint32_t extendedTag, IfdId group);
+  static EncoderFct findEncoder(std::string_view make, uint32_t extendedTag, IfdId group);
 
  private:
   static const TiffMappingInfo tiffMappingInfo_[];  //!< TIFF mapping table
diff --git a/src/tiffvisitor_int.cpp b/src/tiffvisitor_int.cpp
@@ -36,7 +36,7 @@ class FindExifdatum2 {
 
 };  // class FindExifdatum2
 
-Exiv2::ByteOrder stringToByteOrder(const std::string& val) {
+Exiv2::ByteOrder stringToByteOrder(std::string_view val) {
   if (val == "II")
     return Exiv2::littleEndian;
   if (val == "MM")

Original file line number	Diff line number	Diff line change
`@@ -45,7 +45,7 @@ constexpr SectionInfo sectionInfo[] = {`
`45`	`45`	`} // namespace Exiv2`
`46`	`46`
`47`	`47`	`namespace Exiv2::Internal {`
`48`		`-bool TagVocabulary::operator==(const std::string& key) const {`
	`48`	`+bool TagVocabulary::operator==(std::string_view key) const {`
`49`	`49`	`return key.ends_with(voc_);`
`50`	`50`	`}`
`51`	`51`
Original file line number	Diff line number	Diff line change
`@@ -28,7 +28,7 @@`
`28`	`28`	`// local declarations`
`29`	`29`	`namespace {`
`30`	`30`	`// Print version string from an intermediate string`
`31`		`-std::ostream& printVersion(std::ostream& os, const std::string& str) {`
	`31`	`+std::ostream& printVersion(std::ostream& os, std::string_view str) {`
`32`	`32`	`if (str.size() != 4) {`
`33`	`33`	`return os << "(" << str << ")";`
`34`	`34`	`}`