Fix sign conversion warnings

cppformat/format.cc

@@ -362,6 +362,21 @@ class CharConverter : public fmt::internal::ArgVisitor<CharConverter, void> {
     arg_.int_value = static_cast<char>(value);
   }
 };
+
+// Write the content of w to os.
+void write(std::ostream &os, fmt::MemoryWriter &w) {
+  const char *data = w.data();
+  std::size_t size = w.size();
+  typedef internal::MakeUnsigned<std::streamsize>::Type UnsignedStreamSize;
+  UnsignedStreamSize max_size =
+      internal::to_unsigned((std::numeric_limits<std::streamsize>::max)());
+  do {
+    UnsignedStreamSize n = size <= max_size ? size : max_size;
+    os.write(data, static_cast<std::streamsize>(n));
+    data += n;
+    size -= n;
+  } while (size != 0);
+}
 }  // namespace
 
 namespace internal {
@@ -884,10 +899,11 @@ FMT_FUNC void fmt::print(CStringRef format_str, ArgList args) {
   print(stdout, format_str, args);
 }
 
-FMT_FUNC void fmt::print(std::ostream &os, CStringRef format_str, ArgList args) {
+FMT_FUNC void fmt::print(std::ostream &os, CStringRef format_str,
+                         ArgList args) {
   MemoryWriter w;
   w.write(format_str, args);
-  os.write(w.data(), w.size());
+  write(os, w);
 }
 
 FMT_FUNC void fmt::print_colored(Color c, CStringRef format, ArgList args) {
@@ -908,7 +924,7 @@ FMT_FUNC int fmt::fprintf(std::FILE *f, CStringRef format, ArgList args) {
 FMT_FUNC int fmt::fprintf(std::ostream &os, CStringRef format, ArgList args) {
   MemoryWriter w;
   printf(w, format, args);
-  os.write(w.data(), w.size());
+  write(os, w);
   return static_cast<int>(w.size());
 }
 

cppformat/format.h

@@ -2021,7 +2021,7 @@ class FormatBuf : public std::basic_streambuf<Char> {
 
   int_type overflow(int_type ch = traits_type::eof()) {
     if (!traits_type::eq_int_type(ch, traits_type::eof())) {
-      size_t size = this->pptr() - start_;
+      size_t size = this->size();
       buffer_.resize(size);
       buffer_.reserve(size * 2);
 
@@ -2033,7 +2033,7 @@ class FormatBuf : public std::basic_streambuf<Char> {
   }
 
   size_t size() const {
-    return this->pptr() - start_;
+    return to_unsigned(this->pptr() - start_);
   }
 };
 }  // namespace internal

cppformat/posix.cc

@@ -173,7 +173,7 @@ std::size_t fmt::File::read(void *buffer, std::size_t count) {
   FMT_RETRY(result, FMT_POSIX_CALL(read(fd_, buffer, convert_rwcount(count))));
   if (result < 0)
     throw SystemError(errno, "cannot read from file");
-  return result;
+  return internal::to_unsigned(result);
 }
 
 std::size_t fmt::File::write(const void *buffer, std::size_t count) {
@@ -181,7 +181,7 @@ std::size_t fmt::File::write(const void *buffer, std::size_t count) {
   FMT_RETRY(result, FMT_POSIX_CALL(write(fd_, buffer, convert_rwcount(count))));
   if (result < 0)
     throw SystemError(errno, "cannot write to file");
-  return result;
+  return internal::to_unsigned(result);
 }
 
 fmt::File fmt::File::dup(int fd) {

cppformat/posix.h

@@ -305,7 +305,8 @@ class File {
   // Closes the file.
   void close();
 
-  // Returns the file size.
+  // Returns the file size. The size has signed type for consistency with
+  // stat::st_size.
   LongLong size() const;
 
   // Attempts to read count bytes from the file into the specified buffer.