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diff --git a/files/data_io/dataset_loader.py b/files/data_io/dataset_loader.py
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+from typing import Optional
+import yaml
+import torch
+from torch.utils.data import Dataset, DataLoader
+import os
+import h5py
+import numpy as np
+from .encoders import poisson_encoder, latency_encoder, rank_order_encoder
+from .transforms import normalization, spike_augmentation
+# from .utils import file_utils  # 目前未使用可先注释
+
+
+
+# -----
+# Base synthetic dataset placeholder
+# -----
+class BaseDataset(Dataset):
+    """
+    Abstract base class for datasets.
+    Each subclass must implement __getitem__ and __len__.
+
+    This base implementation uses synthetic placeholders for quick smoke tests.
+    """
+
+    def __init__(self, data_dir, encoder, transforms=None):
+        self.data_dir = data_dir
+        self.encoder = encoder
+        self.transforms = transforms or []
+        self.samples = list(range(200))  # placeholder synthetic samples
+
+    def __getitem__(self, idx):
+        # synthetic static input -> encode to (T, D) via encoder
+        raw_data = torch.rand(128)  # 128-dim intensity
+        label = torch.randint(0, 10, (1,)).item()
+        encoded = self.encoder.encode(raw_data.numpy()) if self.encoder is not None else raw_data
+        x = torch.as_tensor(encoded)
+        for t in self.transforms:
+            x = t(x)
+        return x, label
+
+    def __len__(self):
+        return len(self.samples)
+
+
+# -----
+# SHD dataset: true event data, read H5 per-sample; fixed global T; adaptive D
+# -----
+import h5py  # noqa: E402
+
+
+class SHDDataset(Dataset):
+    """
+    SHD Dataset Loader (.h5) with time-adaptive binning and fixed global T.
+
+    H5 structure (Zenke Lab convention):
+      - f["labels"][i]            -> scalar label for sample i
+      - f["spikes"]["times"][i]   -> 1D array of spike times (ms) for sample i
+      - f["spikes"]["units"][i]   -> 1D array of channel ids for sample i
+
+    We:
+      (1) scan once to determine global T = ceil(max_time / dt_ms)
+      (2) decide D from max unit id (fallback to default_D=700)
+      (3) in __getitem__, open H5, read ragged arrays for that sample, and bin to (T, D)
+    """
+
+    def __init__(
+        self,
+        data_dir: str,
+        encoder=None,                 # ignored for SHD (already spiking events)
+        transforms=None,
+        split: str = "train",
+        dt_ms: float = 1.0,
+        seed: Optional[int] = None,
+        default_D: int = 700
+    ):
+        super().__init__()
+        self.data_dir = data_dir
+        self.transforms = transforms or []
+        self.dt_ms = float(dt_ms)
+        self.seed = 42 if seed is None else int(seed)
+        self.encoder = None  # IMPORTANT: do not apply intensity encoders to event data
+        self.default_D = int(default_D)
+
+        fname = f"shd_{split}.h5"
+        self.path = os.path.join(self.data_dir, fname)
+        if not os.path.exists(self.path):
+            raise FileNotFoundError(f"SHD file not found: {self.path}")
+
+        with h5py.File(self.path, "r") as f:
+            # labels is dense array
+            self.labels = np.array(f["labels"], dtype=np.int64)
+            self.N = int(self.labels.shape[0])
+
+            # ragged datasets for events
+            times_ds = f["spikes"]["times"]
+            units_ds = f["spikes"]["units"]
+
+            # scan once to compute global T and adaptive D
+            t_max_global = 0.0
+            max_unit = -1
+            for i in range(self.N):
+                ti = times_ds[i]
+                ui = units_ds[i]
+                if ti.size > 0:
+                    last_t = float(ti[-1])  # ms
+                    if last_t > t_max_global:
+                        t_max_global = last_t
+                if ui.size > 0:
+                    uimax = int(ui.max())
+                    if uimax > max_unit:
+                        max_unit = uimax
+
+            # decide D
+            if max_unit >= 0:
+                self.D = max(max_unit + 1, self.default_D)
+            else:
+                self.D = self.default_D
+
+            # decide T from global max time
+            self.T = int(np.ceil(t_max_global / self.dt_ms)) if t_max_global > 0 else 1
+
+        # rng in case transforms need it
+        self._rng = np.random.default_rng(self.seed)
+
+    def __len__(self):
+        return self.N
+
+    def __getitem__(self, idx: int):
+        # open file per-sample for worker safety
+        with h5py.File(self.path, "r") as f:
+            ti = f["spikes"]["times"][idx][:]
+            ui = f["spikes"]["units"][idx][:]
+            y = int(f["labels"][idx])
+
+        # bin events to (T, D)
+        spikes = np.zeros((self.T, self.D), dtype=np.float32)
+        if ti.size > 0:
+            bins = (ti / self.dt_ms).astype(np.int64)
+            bins = np.clip(bins, 0, self.T - 1)
+            ui = np.clip(ui.astype(np.int64), 0, self.D - 1)
+            spikes[bins, ui] = 1.0  # presence; if you prefer counts: +=1 then clip to 1
+
+        x = torch.from_numpy(spikes)
+
+        # apply transforms (on torch tensor)
+        for tr in self.transforms:
+            x = tr(x)
+
+        return x, y
+
+
+# -----
+# SSC / DVS placeholders (still synthetic; implement real readers later)
+# -----
+class SSCDataset(BaseDataset):
+    """Placeholder SSC dataset (synthetic)."""
+    pass
+
+
+class DVSDataset(BaseDataset):
+    """Placeholder DVS dataset (synthetic)."""
+    pass
+
+
+# -----
+# Helpers: encoders / transforms / cfg path resolution
+# -----
+def build_encoder(cfg):
+    """
+    Build encoder from config dict.
+
+    Expected schema:
+    encoder:
+      type: poisson | latency | rank_order
+      # Poisson-only optional fields:
+      max_rate: 50
+      T: 64
+      dt_ms: 1.0
+      seed: 123
+    """
+    etype = cfg["type"].lower()
+    if etype == "poisson":
+        return poisson_encoder.PoissonEncoder(
+            max_rate=cfg.get("max_rate", cfg.get("rate", 20)),
+            T=cfg.get("T", 50),
+            dt_ms=cfg.get("dt_ms", 1.0),
+            seed=cfg.get("seed", None),
+        )
+    elif etype == "latency":
+        return latency_encoder.LatencyEncoder()
+    elif etype == "rank_order":
+        return rank_order_encoder.RankOrderEncoder()
+    else:
+        raise ValueError(f"Unknown encoder type: {etype}")
+
+
+def build_transforms(cfg):
+    tlist = []
+    if cfg.get("normalize", False):
+        tlist.append(normalization.Normalize())
+    if cfg.get("spike_jitter", None) is not None:
+        tlist.append(spike_augmentation.SpikeJitter(std=cfg["spike_jitter"]))
+    return tlist
+
+
+def _resolve_cfg_path(cfg_path: str) -> str:
+    """
+    Resolve cfg_path against:
+      1) as-is (absolute or CWD-relative)
+      2) relative to this package directory
+      3) <pkg_dir>/configs/<basename>
+    """
+    if os.path.isabs(cfg_path) and os.path.exists(cfg_path):
+        return cfg_path
+    if os.path.exists(cfg_path):
+        return cfg_path
+    pkg_dir = os.path.dirname(__file__)
+    cand2 = os.path.normpath(os.path.join(pkg_dir, cfg_path))
+    if os.path.exists(cand2):
+        return cand2
+    cand3 = os.path.join(pkg_dir, "configs", os.path.basename(cfg_path))
+    if os.path.exists(cand3):
+        return cand3
+    raise FileNotFoundError(f"Config file not found. Tried: {cfg_path}, {cand2}, {cand3}")
+
+
+# -----
+# Entry: get_dataloader
+# -----
+def get_dataloader(cfg_path):
+    """
+    Create train/val DataLoader from YAML config.
+    Handles SHD as true event dataset (encoder=None), others as synthetic placeholders.
+    """
+    cfg_path_resolved = _resolve_cfg_path(cfg_path)
+    with open(cfg_path_resolved, "r") as f:
+        cfg = yaml.safe_load(f)
+
+    dataset_name = cfg["dataset"].lower()
+    data_dir = cfg["data_dir"]
+    transforms = build_transforms(cfg.get("transforms", {}))
+
+    if dataset_name == "shd":
+        # event dataset: do NOT use intensity encoders here
+        dt_ms = cfg.get("encoder", {}).get("dt_ms", 1.0)
+        seed = cfg.get("encoder", {}).get("seed", 42)
+        ds_train = SHDDataset(
+            data_dir, encoder=None, transforms=transforms, split="train",
+            dt_ms=dt_ms, seed=seed
+        )
+        ds_val = SHDDataset(
+            data_dir, encoder=None, transforms=transforms, split="test",
+            dt_ms=dt_ms, seed=seed
+        )
+    elif dataset_name == "ssc":
+        # placeholder path; later implement true SSC reader
+        encoder = build_encoder(cfg["encoder"])
+        ds_train = SSCDataset(data_dir, encoder, transforms)
+        ds_val = SSCDataset(data_dir, encoder, transforms)
+    elif dataset_name == "dvs":
+        encoder = build_encoder(cfg["encoder"])
+        ds_train = DVSDataset(data_dir, encoder, transforms)
+        ds_val = DVSDataset(data_dir, encoder, transforms)
+    else:
+        raise ValueError(f"Unknown dataset: {dataset_name}")
+
+    train_loader = DataLoader(
+        ds_train,
+        batch_size=cfg.get("batch_size", 16),
+        shuffle=cfg.get("shuffle", True),
+        num_workers=cfg.get("num_workers", 0),
+        pin_memory=cfg.get("pin_memory", False),
+    )
+    val_loader = DataLoader(
+        ds_val,
+        batch_size=cfg.get("batch_size", 16),
+        shuffle=False,
+        num_workers=cfg.get("num_workers", 0),
+        pin_memory=cfg.get("pin_memory", False),
+    )
+    return train_loader, val_loader
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