Added utilty functions to read an entire file.

source/mijin/io/stream.cpp

@@ -63,6 +63,60 @@ StreamError Stream::writeString(std::string_view str)
     return writeSpan(str.begin(), str.end());
 }
 
+StreamError Stream::getTotalLength(std::size_t& outLength)
+{
+    const StreamFeatures features = getFeatures();
+    if (!features.tell || !features.seek) {
+        return StreamError::NOT_SUPPORTED;
+    }
+    const std::size_t origPos = tell();
+    if (StreamError error = seek(0, SeekMode::RELATIVE_TO_END); error != StreamError::SUCCESS)
+    {
+        return error;
+    }
+    outLength = tell();
+    if (StreamError error = seek(static_cast<std::intptr_t>(origPos)); error != StreamError::SUCCESS)
+    {
+        return error;
+    }
+    return StreamError::SUCCESS;
+}
+
+StreamError Stream::readRest(TypelessBuffer& outBuffer)
+{
+    // first try to allocate everything at once
+    std::size_t length = 0;
+    if (StreamError lengthError = getTotalLength(length); lengthError == StreamError::SUCCESS)
+    {
+        MIJIN_ASSERT(getFeatures().tell, "How did you find the length if you cannot tell()?");
+        length -= tell();
+        outBuffer.resize(length);
+        if (StreamError error = readRaw(outBuffer.data(), length); error != StreamError::SUCCESS)
+        {
+            return error;
+        }
+        return StreamError::SUCCESS;
+    }
+
+    // could not determine the size, read chunk-wise
+    static constexpr std::size_t CHUNK_SIZE = 4096;
+    std::array<std::byte, CHUNK_SIZE> chunk = {};
+
+    while (!isAtEnd())
+    {
+        std::size_t bytesRead = 0;
+        if (StreamError error = readRaw(chunk, true, &bytesRead); error != StreamError::SUCCESS)
+        {
+            return error;
+        }
+
+        outBuffer.resize(outBuffer.byteSize() + bytesRead);
+        std::span<std::byte> bufferBytes = outBuffer.makeSpan<std::byte>();
+        std::copy_n(chunk.begin(), bytesRead, bufferBytes.end() - static_cast<long>(bytesRead));
+    }
+    return StreamError::SUCCESS;
+}
+
 FileStream::~FileStream()
 {
     if (handle) {