Implement relevant methods for DataIngestionLayer

GCryptCLI/src/DataIngestionLayer.cpp

@@ -2,6 +2,9 @@
 #include "CommandlineInterface.h"
 #include "Configuration.h"
 #include <iostream>
+#include <istream>
+#include <fstream>
+#include <sstream>
 #include <cstring>
 
 using namespace IO;
@@ -50,6 +53,9 @@ void DataIngestionLayer::Init() {
       break;
   }
 
+  initialized = true;
+  reachedEof = false;
+
   // Temporary
   std::size_t n_last_bytes_read = 0;
   char buf[64];
@@ -65,8 +71,62 @@ void DataIngestionLayer::Init() {
   return;
 }
 
+void DataIngestionLayer::ReadBlock() {
+  if (!initialized) {
+    throw std::runtime_error("Attempted to read on uninitialized DataIngestionLayer!");
+  }
+
+  if (!reachedEof) {
+    // Create buffer to read into
+    char buf[Block::BLOCK_SIZE];
+    memset(buf, 0, sizeof(buf));
+
+    // Read
+    in->read(buf, sizeof(buf));
+
+    // Fetch how much we've read
+    const std::size_t n_bytes_read = in->gcount();
+
+    // Is this fewer bytes than we requested?
+    if (n_bytes_read < sizeof(buf)) {
+      // Yes: EOF reached.
+      reachedEof = true;
+    }
+
+    // Construct a Block from this buf
+    Block block;
+    block.FromByteString(std::string(buf));
+
+    // Enqueue it
+    blocks.emplace(block);
+  }
+
+  return;
+}
+
+bool DataIngestionLayer::ReachedEOF() {
+  return reachedEof;
+}
+
+bool DataIngestionLayer::IsBlockReady() {
+  return blocks.size() > 0;
+}
+
+Block DataIngestionLayer::GetNextBlock() {
+  if (!IsBlockReady()) {
+    throw std::runtime_error("Attempted to get the next block, but there are none left!");
+  }
+
+  // Why... why not just return a T in pop()???
+  const Block popped = blocks.front();
+  blocks.pop();
+  return popped;
+}
 
 std::istream* DataIngestionLayer::in;
 std::ifstream DataIngestionLayer::ifs;
 std::istringstream DataIngestionLayer::iss;
+bool DataIngestionLayer::reachedEof = false;
+bool DataIngestionLayer::initialized = false;
+std::queue<Block> DataIngestionLayer::blocks;