added better garabge collection

mathstream/README.md

@@ -23,6 +23,7 @@ from mathstream import (
     pow,
     is_even,
     is_odd,
+    collect_garbage,
 )
 
 a = StreamNumber("instance/log/huge.txt")
@@ -37,6 +38,9 @@ print("modulo =", "".join(mod(a, b).stream()))
 print("power =", "".join(pow(a, e).stream()))
 print("a is even?", is_even(a))
 print("b is odd?", is_odd(b))
+
+# reclaim space for files whose age outweighs their use
+collect_garbage(0.5)
 ```
 
 Each arithmetic call writes its result back into `instance/log` (configurable via `mathstream.number.LOG_DIR`) so you can stream the digits later or reuse them in further operations.
@@ -49,6 +53,9 @@ Each arithmetic call writes its result back into `instance/log` (configurable vi
 - **Sign-aware** – Addition, subtraction, multiplication, division (`//` behavior), modulo, and exponentiation (non-negative exponents) all respect operand sign. Division/modulo follow Python’s floor-division rules.
 - **Utilities** – `clear_logs()` wipes prior staged results so you can start fresh.
 - **Parity helpers** – `is_even` and `is_odd` inspect the streamed digits without materializing the integer.
+- **Garbage collection** – `collect_garbage(score_threshold)` computes a score from file age, access count, and reference count (tracked in `instance/mathstream_logs.sqlite`, freshly truncated each run). Files whose score meets or exceeds the threshold are deleted, letting you tune how aggressively to reclaim space. Both staged results and literal caches participate.
+
+Divide-by-zero scenarios raise the custom `DivideByZeroError` so callers can distinguish mathstream issues from Python’s native exceptions.
 
 ## Example Script
 

mathstream/__init__.py

@@ -1,11 +1,20 @@
 from .engine import clear_logs, add, sub, mul, div, mod, pow, is_even, is_odd
+from .exceptions import MathStreamError, DivideByZeroError
 from .number import StreamNumber
+from .utils import collect_garbage
 
 __all__ = [
     "clear_logs",
-    "add", "sub",
-    "mul", "div", "mod",
+    "collect_garbage",
+    "add",
+    "sub",
+    "mul",
+    "div",
+    "mod",
     "pow",
-    "is_even", "is_odd",
+    "is_even",
+    "is_odd",
     "StreamNumber",
+    "MathStreamError",
+    "DivideByZeroError",
 ]

mathstream/engine.py

@@ -2,7 +2,9 @@ from __future__ import annotations
 
 from typing import Iterable, Tuple
 
+from .exceptions import DivideByZeroError
 from .number import StreamNumber, LOG_DIR
+from .utils import register_log_file, wipe_log_records
 
 
 def _ensure_log_dir() -> None:
@@ -123,7 +125,7 @@ def _multiply_digit(num: str, digit: int) -> str:
 
 def _divide_abs(dividend: str, divisor: str) -> Tuple[str, str]:
     if divisor == "0":
-        raise ZeroDivisionError("division by zero")
+        raise DivideByZeroError("division by zero")
     if dividend == "0":
         return "0", "0"
 
@@ -171,6 +173,7 @@ def _write_result(operation: str, operands: Iterable[StreamNumber], digits: str)
     out_file = LOG_DIR / f"{operation}_{operand_hash}.bin"
     with open(out_file, "w", encoding="utf-8") as out:
         out.write(digits)
+    register_log_file(out_file)
     return StreamNumber(out_file)
 
 
@@ -179,6 +182,7 @@ def clear_logs():
         for p in LOG_DIR.glob("*"):
             p.unlink()
     _ensure_log_dir()
+    wipe_log_records()
 
 
 def add(num_a: StreamNumber, num_b: StreamNumber) -> StreamNumber:
@@ -266,6 +270,9 @@ def mod(num_a: StreamNumber, num_b: StreamNumber) -> StreamNumber:
     sign_a, a_digits = _normalize_stream(num_a)
     sign_b, b_digits = _normalize_stream(num_b)
 
+    if b_digits == "0":
+        raise DivideByZeroError("modulo by zero")
+
     _, remainder = _divide_abs(a_digits, b_digits)
 
     if remainder == "0":

mathstream/exceptions.py

@@ -0,0 +1,6 @@
+class MathStreamError(Exception):
+    """Base class for mathstream-specific errors."""
+
+
+class DivideByZeroError(MathStreamError):
+    """Raised when division or modulo operations encounter a zero divisor."""

mathstream/number.py

@@ -2,6 +2,8 @@ import hashlib
 from pathlib import Path
 from typing import Optional, Union
 
+from .utils import register_log_file, register_reference, touch_log_file
+
 LOG_DIR = Path("./instance/log")
 
 
@@ -29,6 +31,14 @@ def _canonicalize_literal(value: str) -> str:
     return f"{sign}{digits}"
 
 
+def _is_in_log_dir(path: Path) -> bool:
+    try:
+        path.resolve().relative_to(LOG_DIR.resolve())
+        return True
+    except ValueError:
+        return False
+
+
 class StreamNumber:
     def __init__(
         self,
@@ -50,6 +60,10 @@ class StreamNumber:
             if not self.path.exists():
                 raise FileNotFoundError(self.path)
 
+        if _is_in_log_dir(self.path):
+            register_log_file(self.path)
+            register_reference(self.path)
+
         self.hash = hashlib.sha1(str(self.path).encode()).hexdigest()[:10]
 
     def __repr__(self):
@@ -57,6 +71,8 @@ class StreamNumber:
 
     def stream(self, chunk_size=4096):
         """Yield chunks of digits as strings."""
+        if _is_in_log_dir(self.path):
+            touch_log_file(self.path)
         with open(self.path, "r", encoding="utf-8") as f:
             while chunk := f.read(chunk_size):
                 yield chunk.strip().replace(",", ".")
@@ -67,4 +83,5 @@ class StreamNumber:
         stage_file = LOG_DIR / f"{self.hash}_stage_{stage}.bin"
         with open(stage_file, "wb") as f:
             f.write(data.encode())
+        register_log_file(stage_file)
         return stage_file

mathstream/utils.py

@@ -0,0 +1,180 @@
+import sqlite3
+from datetime import datetime, timezone
+from pathlib import Path
+from typing import Iterable, List
+
+LOG_DB_PATH = Path("./instance/mathstream_logs.sqlite")
+
+
+def _normalize_paths(paths: Iterable[Path]) -> List[str]:
+    return [str(Path(p).resolve()) for p in paths]
+
+
+def _ensure_db(reset: bool = False) -> None:
+    LOG_DB_PATH.parent.mkdir(parents=True, exist_ok=True)
+    with sqlite3.connect(LOG_DB_PATH) as conn:
+        conn.execute(
+            """
+            CREATE TABLE IF NOT EXISTS logs (
+                path TEXT PRIMARY KEY,
+                created_at REAL,
+                last_access REAL,
+                access_count INTEGER DEFAULT 0
+            )
+            """
+        )
+        conn.execute(
+            """
+            CREATE TABLE IF NOT EXISTS refs (
+                path TEXT PRIMARY KEY,
+                ref_count INTEGER DEFAULT 0
+            )
+            """
+        )
+        if reset:
+            conn.execute("DELETE FROM logs")
+            conn.execute("DELETE FROM refs")
+        conn.commit()
+
+
+_ensure_db(reset=True)
+
+
+def register_log_file(path: Path) -> None:
+    """Ensure the log database is aware of a file's existence."""
+    normalized = _normalize_paths([path])[0]
+    _ensure_db()
+    timestamp = datetime.now(timezone.utc).timestamp()
+    with sqlite3.connect(LOG_DB_PATH) as conn:
+        conn.execute(
+            """
+            INSERT INTO logs (path, created_at, last_access, access_count)
+            VALUES (?, ?, ?, 0)
+            ON CONFLICT(path)
+            DO NOTHING
+            """,
+            (normalized, timestamp, timestamp),
+        )
+        conn.execute(
+            """
+            INSERT INTO refs (path, ref_count)
+            VALUES (?, 0)
+            ON CONFLICT(path)
+            DO NOTHING
+            """,
+            (normalized,),
+        )
+        conn.commit()
+
+
+def register_reference(path: Path) -> None:
+    """Increment reference count similarly to Python's ref counter."""
+    normalized = _normalize_paths([path])[0]
+    _ensure_db()
+    timestamp = datetime.now(timezone.utc).timestamp()
+    with sqlite3.connect(LOG_DB_PATH) as conn:
+        conn.execute(
+            """
+            INSERT INTO logs (path, created_at, last_access, access_count)
+            VALUES (?, ?, ?, 1)
+            ON CONFLICT(path)
+            DO NOTHING
+            """,
+            (normalized, timestamp, timestamp),
+        )
+        conn.execute(
+            """
+            INSERT INTO refs (path, ref_count)
+            VALUES (?, 1)
+            ON CONFLICT(path)
+            DO UPDATE SET ref_count = ref_count + 1
+            """,
+            (normalized,),
+        )
+        conn.execute(
+            """
+            UPDATE logs
+            SET last_access = ?, access_count = access_count + 1
+            WHERE path = ?
+            """,
+            (timestamp, normalized),
+        )
+        conn.commit()
+
+
+def touch_log_file(path: Path) -> None:
+    """Refresh access metadata when a file is streamed."""
+    normalized = _normalize_paths([path])[0]
+    _ensure_db()
+    timestamp = datetime.now(timezone.utc).timestamp()
+    with sqlite3.connect(LOG_DB_PATH) as conn:
+        conn.execute(
+            """
+            INSERT INTO logs (path, created_at, last_access, access_count)
+            VALUES (?, ?, ?, 1)
+            ON CONFLICT(path)
+            DO UPDATE SET
+                last_access = excluded.last_access,
+                access_count = logs.access_count + 1
+            """,
+            (normalized, timestamp, timestamp),
+        )
+        conn.commit()
+
+
+def wipe_log_records() -> None:
+    """Drop all bookkeeping (used after manual log purges)."""
+    _ensure_db()
+    with sqlite3.connect(LOG_DB_PATH) as conn:
+        conn.execute("DELETE FROM logs")
+        conn.execute("DELETE FROM refs")
+        conn.commit()
+
+
+def _delete_records(paths: List[Path]) -> None:
+    if not paths:
+        return
+    normalized = [(str(p.resolve()),) for p in paths]
+    with sqlite3.connect(LOG_DB_PATH) as conn:
+        conn.executemany("DELETE FROM logs WHERE path = ?", normalized)
+        conn.executemany("DELETE FROM refs WHERE path = ?", normalized)
+        conn.commit()
+
+
+def collect_garbage(score_threshold: float) -> list[Path]:
+    """Remove seldom-used staged files based on an age/refcount score."""
+    if score_threshold < 0:
+        raise ValueError("score_threshold must be non-negative")
+    _ensure_db()
+    now = datetime.now(timezone.utc).timestamp()
+    with sqlite3.connect(LOG_DB_PATH) as conn:
+        rows = conn.execute(
+            """
+            SELECT
+                l.path,
+                COALESCE(l.created_at, ?),
+                COALESCE(l.last_access, l.created_at, ?),
+                COALESCE(l.access_count, 0),
+            COALESCE(r.ref_count, 0)
+            FROM logs l
+            LEFT JOIN refs r ON l.path = r.path
+            """,
+            (now, now),
+        ).fetchall()
+
+    removed: list[Path] = []
+    for path_str, created_at, last_access, access_count, ref_count in rows:
+        path = Path(path_str)
+        age = now - (last_access or created_at or now)
+        score = age / ((ref_count + 1) * (access_count + 1))
+        if score < score_threshold:
+            continue
+        if path.exists():
+            try:
+                path.unlink()
+            except OSError:
+                continue
+        removed.append(path)
+
+    _delete_records(removed)
+    return removed

test.py

@@ -13,6 +13,8 @@ from mathstream import (
     is_even,
     is_odd,
     clear_logs,
+    collect_garbage,
+    DivideByZeroError,
 )
 
 NUMBERS_DIR = Path(__file__).parent / "tests"
@@ -54,6 +56,7 @@ def main() -> None:
     negative_divisor = write_number("neg_divisor", "-34567")
     literal_even = StreamNumber(literal="2000")
     literal_odd = StreamNumber(literal="-3")
+    zero_literal = StreamNumber(literal="0")
 
     # Showcase the core operations.
     total = add(big, small)
@@ -85,6 +88,27 @@ def main() -> None:
     check_bool("is_even(literal_even)", is_even(literal_even), True)
     check_bool("is_odd(literal_odd)", is_odd(literal_odd), True)
 
+    # Custom exception coverage
+    try:
+        div(literal_even, zero_literal)
+    except DivideByZeroError:
+        print("div(literal_even, zero_literal) raised DivideByZeroError as expected")
+    else:
+        raise AssertionError("div by zero did not raise DivideByZeroError")
+
+    try:
+        mod(literal_even, zero_literal)
+    except DivideByZeroError:
+        print("mod(literal_even, zero_literal) raised DivideByZeroError as expected")
+    else:
+        raise AssertionError("mod by zero did not raise DivideByZeroError")
+
+    removed = collect_garbage(0)
+    print(f"collect_garbage removed {len(removed)} files")
+    check_bool("total exists post GC", total.path.exists(), False)
+    check_bool("literal_even exists post GC", literal_even.path.exists(), False)
+    check_bool("huge operand persists", big.path.exists(), True)
+
 
 if __name__ == "__main__":
     main()