Method Read

src/Storage/FileStore.cpp:383–432

Returns the number of bytes read or -1 if the read process failed

// Returns the number of bytes read or -1 if the read process failed
int FileStore::Read(char *_ecv_array extBuf, size_t nBytes) noexcept
{
	switch (usageMode)
	{
	case FileUseMode::free:
		REPORT_INTERNAL_ERROR;
		return -1;

	case FileUseMode::readOnly:
	case FileUseMode::readWrite:
#if HAS_SBC_INTERFACE
		if (reprap.UsingSbcInterface())
		{
			int bytesRead = reprap.GetSbcInterface().ReadFile(handle, extBuf, nBytes);
			if (bytesRead > 0)
			{
				offset += bytesRead;
			}
			return bytesRead;
		}
#endif
#if HAS_MASS_STORAGE
		{
			UINT bytes_read;
			const FRESULT readStatus = f_read(&file, extBuf, nBytes, &bytes_read);
			if (readStatus != FR_OK)
			{
				reprap.GetPlatform().MessageF(ErrorMessage, "Cannot read file, error code %d\n", (int)readStatus);
				return -1;
			}
			return (int)bytes_read;
		}
#elif HAS_EMBEDDED_FILES
		{
			const int ret = EmbeddedFiles::Read(fileIndex, offset, extBuf, nBytes);
			if (ret > 0)
			{
				offset += ret;
			}
			return ret;
		}
#else
		return -1;
#endif

	case FileUseMode::invalidated:
	default:
		return -1;
	}
}

// As Read but stop after '\n' or '\r\n' and null-terminate the string.
// If the next line is too long to fit in the buffer then the line will be split.