buffer changes

buffer.hpp

@@ -1,145 +1,65 @@
 #pragma once
+
 #include "record.hpp"
-#include <algorithm>
-#include <iostream>
+#include <stdexcept>
 #include <vector>
 
-// Main buffer pool - owns all memory
-class BufferPool {
+class Buffer;
+
+class SubBuffer {
 private:
-    std::vector<Record> storage;
-    int buffer_capacity;
-    int num_buffers;
+    Record* data_;
+    size_t size_;
+
+    friend class Buffer;
+
+    SubBuffer(Record* data, size_t size)
+        : data_(data)
+        , size_(size)
+    {
+    }
 
 public:
-    BufferPool(int num_buffers, int buffer_capacity)
-        : storage(num_buffers * buffer_capacity)
-        , buffer_capacity(buffer_capacity)
-        , num_buffers(num_buffers)
+    // for std::sort support
+    using iterator = Record*;
+    iterator begin() { return data_; }
+    iterator end() { return data_ + size_; }
+
+    Record& operator[](size_t index)
     {
+        return data_[index];
     }
 
-    Record* get_buffer_ptr(int index)
-    {
-        return storage.data() + (index * buffer_capacity);
-    }
-
-    int get_buffer_capacity() const { return buffer_capacity; }
-    int get_num_buffers() const { return num_buffers; }
-    int total_capacity() const { return storage.size(); }
-
-    // Sort entire pool (for stage 1 - creating runs)
-    void sort_all(int count)
-    {
-        std::sort(storage.begin(), storage.begin() + count);
-    }
+    size_t size() const { return size_; }
 };
 
-// View into a section of the buffer pool
-class BufferView {
+class Buffer {
 private:
-    Record* data;
-    int capacity;
-    int length;
+    std::vector<Record> storage_;
 
 public:
-    BufferView(Record* ptr, int cap)
-        : data(ptr)
-        , capacity(cap)
-        , length(0)
+    explicit Buffer(size_t total_size)
+        : storage_(total_size)
     {
     }
 
-    // Read up to capacity records from stream
-    int read_from(std::istream& in)
+    std::vector<SubBuffer> divide(size_t n)
     {
-        length = 0;
-        for (int i = 0; i < capacity; i++) {
-            if (!(in >> data[i])) {
-                break;
-            }
-            length++;
-        }
-        return length;
+        if (n == 0) {
+            throw std::invalid_argument("Cannot divide buffer into 0 pieces");
         }
 
-    // Write all current records to stream
-    bool write_to(std::ostream& out) const
-    {
-        for (int i = 0; i < length; i++) {
-            out << data[i] << '\n';
-            if (!out)
-                return false;
-        }
-        return true;
+        size_t total_size = storage_.size();
+        if (total_size % n != 0) {
+            throw std::invalid_argument("Size not divisible by n");
         }
 
-    // For stage 2: peek at front record without consuming
-    const Record& front() const { return data[0]; }
-
-    // For stage 2: consume the front record
-    void pop_front()
-    {
-        if (length > 0) {
-            for (int i = 0; i < length - 1; i++) {
-                data[i] = data[i + 1];
-            }
-            length--;
-        }
+        std::vector<SubBuffer> result(n);
+        size_t piece_size = total_size / n;
+        for (size_t i = 0; i < n; ++i) {
+            result[i] = SubBuffer(storage_.data() + i * piece_size, piece_size);
         }
 
-    // Refill from stream when buffer becomes empty during merge
-    bool refill_from(std::istream& in)
-    {
-        return read_from(in) > 0;
+        return result;
     }
-
-    int size() const { return length; }
-    int get_capacity() const { return capacity; }
-    bool empty() const { return length == 0; }
-    bool full() const { return length == capacity; }
-
-    Record& operator[](int i) { return data[i]; }
-    const Record& operator[](int i) const { return data[i]; }
-};
-
-// For output buffer during merge
-class OutputBuffer {
-private:
-    Record* data;
-    int capacity;
-    int length;
-
-public:
-    OutputBuffer(Record* ptr, int cap)
-        : data(ptr)
-        , capacity(cap)
-        , length(0)
-    {
-    }
-
-    // Add record to output buffer
-    bool add(const Record& rec)
-    {
-        if (length >= capacity) {
-            return false; // Buffer full
-        }
-        data[length++] = rec;
-        return true;
-    }
-
-    // Flush buffer to stream and reset
-    bool flush_to(std::ostream& out)
-    {
-        for (int i = 0; i < length; i++) {
-            out << data[i] << '\n';
-            if (!out)
-                return false;
-        }
-        length = 0;
-        return true;
-    }
-
-    bool full() const { return length >= capacity; }
-    int size() const { return length; }
 };