1 files changed, 45 insertions, 0 deletions
diff --git a/sqlglot/time.py b/sqlglot/time.py
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+++ b/sqlglot/time.py
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+# the generic time format is based on python time.strftime
+# https://docs.python.org/3/library/time.html#time.strftime
+from sqlglot.trie import in_trie, new_trie
+
+
+def format_time(string, mapping, trie=None):
+    """
+    Converts a time string given a mapping.
+
+    Examples:
+        >>> format_time("%Y", {"%Y": "YYYY"})
+        'YYYY'
+
+    mapping: Dictionary of time format to target time format
+    trie: Optional trie, can be passed in for performance
+    """
+    start = 0
+    end = 1
+    size = len(string)
+    trie = trie or new_trie(mapping)
+    current = trie
+    chunks = []
+    sym = None
+
+    while end <= size:
+        chars = string[start:end]
+        result, current = in_trie(current, chars[-1])
+
+        if result == 0:
+            if sym:
+                end -= 1
+                chars = sym
+                sym = None
+            start += len(chars)
+            chunks.append(chars)
+            current = trie
+        elif result == 2:
+            sym = chars
+
+        end += 1
+
+        if result and end > size:
+            chunks.append(chars)
+
+    return "".join(mapping.get(chars, chars) for chars in chunks)