implement '--range' with Python ranges

gallery_dl/util.py

@@ -714,29 +714,33 @@ def chain_predicates(predicates, url, kwdict):
 
 
 class RangePredicate():
-    """Predicate; True if the current index is in the given range"""
+    """Predicate; True if the current index is in the given range(s)"""
+
     def __init__(self, rangespec):
-        self.ranges = self.optimize_range(self.parse_range(rangespec))
+        self.ranges = ranges = self._parse(rangespec)
         self.index = 0
 
-        if self.ranges:
-            self.lower, self.upper = self.ranges[0][0], self.ranges[-1][1]
+        if ranges:
+            # technically wrong, but good enough for now
+            # and evaluating min/max for a öarge range is slow
+            self.lower = min(r.start for r in ranges)
+            self.upper = max(r.stop for r in ranges) - 1
         else:
-            self.lower, self.upper = 0, 0
+            self.lower = self.upper = 0
 
-    def __call__(self, url, _):
-        self.index += 1
+    def __call__(self, _url, _kwdict):
+        self.index = index = self.index + 1
 
-        if self.index > self.upper:
+        if index > self.upper:
             raise exception.StopExtraction()
 
-        for lower, upper in self.ranges:
-            if lower <= self.index <= upper:
+        for range in self.ranges:
+            if index in range:
                 return True
         return False
 
     @staticmethod
-    def parse_range(rangespec):
+    def _parse(rangespec):
         """Parse an integer range string and return the resulting ranges
 
         Examples:
@@ -744,22 +748,29 @@ class RangePredicate():
             parse_range(" - 3 , 4-  4, 2-6") -> [(1,3), (4,4), (2,6)]
         """
         ranges = []
+        append = ranges.append
 
-        for group in rangespec.split(","):
+        if isinstance(rangespec, str):
+            rangespec = rangespec.split(",")
+
+        for group in rangespec:
             if not group:
                 continue
+
             first, sep, last = group.partition("-")
-            if not sep:
-                beg = end = int(first)
+            if sep:
+                append(range(
+                    int(first) if first.strip() else 1,
+                    int(last) + 1 if last.strip() else sys.maxsize,
+                ))
             else:
-                beg = int(first) if first.strip() else 1
-                end = int(last) if last.strip() else sys.maxsize
-            ranges.append((beg, end) if beg <= end else (end, beg))
+                v = int(first)
+                append(range(v, v+1))
 
         return ranges
 
     @staticmethod
-    def optimize_range(ranges):
+    def _optimize(ranges):
         """Simplify/Combine a parsed list of ranges
 
         Examples: