[Issue #41] - Slimmed down FixedTFramedTransport class (#46)

* Removed fixedTTransport class

This may not be necessary, since we have upgraded Thrift to a version above 0.9.2.

See https://github.com/apache/thrift/blob/master/CHANGES.md\#092

* Re-adding TFrameTransport patch so  is supported.

Author: dopatraman

lib/util.ts

@@ -4,17 +4,11 @@ import fs, { WriteStream } from 'fs'
 import * as parquet_thrift from '../gen-nodejs/parquet_types'
 import { NewFileMetaData } from './types/types'
 
-/** We need to use a patched version of TFramedTransport where
-  * readString returns the original buffer instead of a string if the 
-  * buffer can not be safely encoded as utf8 (see http://bit.ly/2GXeZEF)
-  */
-
-
-type Enums = typeof parquet_thrift.Encoding | typeof parquet_thrift.FieldRepetitionType | typeof parquet_thrift.Type | typeof parquet_thrift.CompressionCodec | typeof parquet_thrift.PageType | typeof parquet_thrift.ConvertedType;
- 
-type ThriftObject = NewFileMetaData | parquet_thrift.PageHeader | parquet_thrift.BloomFilterHeader | parquet_thrift.OffsetIndex | parquet_thrift.ColumnIndex | NewFileMetaData;
-
-// May not be needed anymore, Issue at https://github.com/LibertyDSNP/parquetjs/issues/41
+/**
+ * We need to patch Thrift's TFramedTransport class bc the TS type definitions
+ * do not define a `readPos` field, even though the class implementation has
+ * one.
+ */
 class fixedTFramedTransport extends thrift.TFramedTransport {
   inBuf: Buffer
   readPos: number
@@ -23,19 +17,11 @@ class fixedTFramedTransport extends thrift.TFramedTransport {
     this.inBuf = inBuf
     this.readPos = 0
   }
-
-  readString(len = 0): string {
-    this.ensureAvailable(len);
-    var buffer = this.inBuf.slice(this.readPos, this.readPos + len);
-    var str = this.inBuf.toString('utf8', this.readPos, this.readPos + len);
-    this.readPos += len;
-    //@ts-ignore
-    return (Buffer.from(str).equals(buffer)) ? str : buffer;
-  }
 }
 
-
-/** Patch PageLocation to be three element array that has getters/setters
+type Enums = typeof parquet_thrift.Encoding | typeof parquet_thrift.FieldRepetitionType | typeof parquet_thrift.Type | typeof parquet_thrift.CompressionCodec | typeof parquet_thrift.PageType | typeof parquet_thrift.ConvertedType;
+ 
+type ThriftObject = NewFileMetaData | parquet_thrift.PageHeader | parquet_thrift.BloomFilterHeader | parquet_thrift.OffsetIndex | parquet_thrift.ColumnIndex | NewFileMetaData;/** Patch PageLocation to be three element array that has getters/setters
   * for each of the properties (offset, compressed_page_size, first_row_index)
   * This saves space considerably as we do not need to store the full variable
   * names for every PageLocation