Use findlib.

[ocaml-csv.git] / csv.ml

diff --git a/csv.ml b/csv.ml
index efb1bc0..ee0623e 100644 (file)
--- a/csv.ml
+++ b/csv.ml
@@ -1,6 +1,6 @@
 (* csv.ml - comma separated values parser
  *
- * $Id: csv.ml,v 1.9 2006-02-23 15:24:25 rich Exp $
+ * $Id: csv.ml,v 1.13 2006-11-24 09:43:15 rich Exp $
  *)
 
 (* The format of CSV files:
@@ -40,6 +40,13 @@
  * subset of it into a matrix.
  *)
 
+open Printf
+
+(* Uncomment the next line to enable Extlib's List function.  These
+ * avoid stack overflows on really huge CSV files.
+ *)
+(*open ExtList*)
+
 type t = string list list
 
 exception Bad_CSV_file of string
@@ -297,6 +304,27 @@ let rec compare (csv1 : t) csv2 =
       let c = compare_row [] y in
       if c <> 0 then c else compare [] ys
 
+(* Concatenate - arrange left to right. *)
+let rec concat = function
+  | [] -> []
+  | [csv] -> csv
+  | left_csv :: csvs ->
+      (* Concatenate the remaining CSV files. *)
+      let right_csv = concat csvs in
+
+      (* Set the height of the left and right CSVs to the same. *)
+      let nr_rows = max (lines left_csv) (lines right_csv) in
+      let left_csv = set_rows nr_rows left_csv in
+      let right_csv = set_rows nr_rows right_csv in
+
+      (* Square off the left CSV. *)
+      let left_csv = square left_csv in
+
+      (* Prepend the right CSV rows with the left CSV rows. *)
+      List.map (
+       fun (left_row, right_row) -> List.append left_row right_row
+      ) (List.combine left_csv right_csv)
+
 let to_array csv =
   Array.of_list (List.map Array.of_list csv)
 
@@ -369,18 +397,18 @@ let save_out_readable chan csv =
 
     match csv with
       | [] -> []
-      | r :: _ ->
-         let n = List.length r in
-         let lengths = List.map (List.map String.length) csv in
+      | row1 :: rest ->
+         let lengths_row1 = List.map String.length row1 in
+         let lengths_rest = List.map (List.map String.length) rest in
          let max2rows r1 r2 =
-           let rp = List.combine r1 r2 in
+           let rp =
+             try List.combine r1 r2
+             with
+               Invalid_argument "List.combine" ->
+                 failwith (sprintf "Csv.save_out_readable: internal error: length r1 = %d, length r2 = %d" (List.length r1) (List.length r2)) in
            List.map (fun ((a : int), (b : int)) -> max a b) rp
          in
-         let rec repeat x = function
-           | 0 -> []
-           | i -> x :: repeat x (i-1)
-         in
-         List.fold_left max2rows (repeat 0 n) lengths in
+         List.fold_left max2rows lengths_row1 lengths_rest in
 
   (* Print out each cell at the correct width. *)
   let rec repeat f = function
@@ -393,9 +421,17 @@ let save_out_readable chan csv =
        output_string chan cell;
        output_char chan '\n'
     | row ->                           (* Other. *)
-       let row = List.combine widths row in
+       (* Pair up each cell with its max width. *)
+       let row =
+         let rec loop = function
+           | ([], _) -> []
+           | (_, []) -> failwith "Csv.save_out_readable: internal error"
+           | (cell :: cells, width :: widths) ->
+               (cell, width) :: loop (cells, widths)
+         in
+         loop (row, widths) in
        List.iter (
-         fun (width, cell) ->
+         fun (cell, width) ->
            output_string chan cell;
            let n = String.length cell in
            repeat (fun () -> output_char chan ' ') (width - n + 1)