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Window Function FFI for JIT

External C functions for SQL-style window functions called from JIT-compiled code. Window functions require partition and ordering context, so these FFI functions operate on pre-computed partition data passed from the query executor.

Functions

jit_window_avg

AVG() over window frame Args: running_sum, count

jit_window_count

COUNT() over window frame Args: count (pre-computed count over frame)

jit_window_dense_rank

DENSE_RANK() - Returns rank without gaps for ties Args: current_idx, partition_size Note: Simplified - assumes ORDER BY already applied and no ties

jit_window_first_value

FIRST_VALUE(expr) - Returns first value in the window frame

jit_window_frame_end

Calculate frame end index Args: current_idx, following (n following or -1 for unbounded), partition_size

jit_window_frame_start

Calculate frame start index Args: current_idx, preceding (n preceding or -1 for unbounded)

jit_window_lag

LAG(value, offset) - Returns value from offset rows before current Args: current_value, offset, default_value, is_valid (1 if in bounds, 0 if out)

jit_window_last_value

LAST_VALUE(expr) - Returns last value in the window frame

jit_window_lead

LEAD(value, offset) - Returns value from offset rows after current Args: current_value, offset, default_value, is_valid (1 if in bounds, 0 if out)

jit_window_max

MAX() over window frame Args: running_max (pre-computed max over frame)

jit_window_min

MIN() over window frame Args: running_min (pre-computed min over frame)

jit_window_nth_value

NTH_VALUE(expr, n) - Returns nth value in the window frame Args: nth_value, is_valid (1 if nth exists, 0 if not)

jit_window_ntile

NTILE(n) - Distributes rows into n buckets Args: current_idx, partition_size, num_buckets

jit_window_rank

RANK() - Returns rank with gaps for ties Args: current_idx, partition_size Note: Simplified - assumes ORDER BY already applied and no ties

jit_window_row_number

ROW_NUMBER() - Returns sequential row number within partition Args: current_idx (0-based position in partition)

jit_window_sum

SUM() over window frame Args: running_sum (pre-computed sum over frame)