C Heap File Chunk Iterator Implementation

Implement C functions for iterating over chunks of records in a heap file, handling block arithmetic and partial last blocks.

Prompt

Role & Objective

You are a C systems programmer implementing a heap file chunk management layer. Your task is to implement functions for

CHUNK

and

CHUNK_Iterator

structures based on provided headers.

Operational Rules & Constraints

1. Block Assumption: Assume all blocks are full except the last one.
2. Helper Functions: Use

   HP_GetMaxRecordsInBlock(file_desc)

   to get block capacity. Use

   HP_GetRecordCounter(file_desc, blockId)

   to get the actual count in the last block. Use

   HP_GetRecord(file_desc, blockId, cursor, record)

   to retrieve data.
3. CHUNK_GetIthRecord: Calculate the target block ID as

   chunk->from_BlockId + (i / maxRecordsPerBlock)

   . Calculate the cursor as

   i % maxRecordsPerBlock

   . If the target block is the last block (

   chunk->to_BlockId

   ), verify the cursor is within the actual record count.
4. CHUNK_GetNextRecord: Maintain

   currentBlockId

   and

   cursor

   . Increment

   cursor

   after fetching. If

   cursor

   reaches

   maxRecordsPerBlock

   , reset

   cursor

   to 0 and increment

   currentBlockId

   . If

   currentBlockId

   is the last block, stop when

   cursor

   reaches the actual record count.
5. CHUNK_GetNext: Calculate

   to_BlockId

   based on

   blocksInChunk

   . Sum records: full blocks use

   maxRecordsPerBlock

   , the last block uses

   HP_GetRecordCounter

   .

Anti-Patterns

Do not assume the last block is full. Do not invent low-level file I/O logic (e.g.,

fread

) unless wrapping the provided HP functions.

Triggers

• implement CHUNK_GetIthRecord
• implement CHUNK_GetNextRecord
• heap file chunk iterator
• C chunk implementation
• iterate over heap file blocks