(* csv.ml - comma separated values parser
*
- * $Id: csv.ml,v 1.4 2005-01-19 17:10:19 rich Exp $
+ * $Id: csv.ml,v 1.13 2006-11-24 09:43:15 rich Exp $
*)
(* The format of CSV files:
* 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
| x :: xs when f x -> dropwhile f xs
| xs -> xs
+(* from extlib: *)
+let rec drop n = function
+ | _ :: l when n > 0 -> drop (n-1) l
+ | l -> l
+
+let rec take n = function
+ | x :: xs when n > 0 -> x :: take (pred n) xs
+ | _ -> []
+
let lines = List.length
let columns csv =
if c != '\r' then ( (* Always ignore \r characters. *)
match !state with
StartField -> (* Expecting quote or other char. *)
- if c = '\"' then (
+ if c = '"' then (
state := InQuotedField;
field := []
) else if c = separator then (* Empty field. *)
) else
field := c :: !field
| InQuotedField -> (* Reading chars to end of field. *)
- if c = '\"' then
+ if c = '"' then
state := InQuotedFieldAfterQuote
else
field := c :: !field
| InQuotedFieldAfterQuote ->
- if c = '\"' then ( (* Doubled quote. *)
+ if c = '"' then ( (* Doubled quote. *)
field := c :: !field;
state := InQuotedField
) else if c = '0' then ( (* Quote-0 is ASCII NUL. *)
else if c = '\n' then ( (* End of field and end of row. *)
end_of_field ();
end_of_row ()
+ ) else ( (* Bad single quote in field. *)
+ field := c :: '"' :: !field;
+ state := InQuotedField
)
); (* end of match *)
loop ()
csv
+let square csv =
+ let columns = columns csv in
+ List.map (
+ fun row ->
+ let n = List.length row in
+ let row = List.rev row in
+ let rec loop acc = function
+ | 0 -> acc
+ | i -> "" :: loop acc (i-1)
+ in
+ let row = loop row (columns - n) in
+ List.rev row
+ ) csv
+
+let is_square csv =
+ let columns = columns csv in
+ List.for_all (fun row -> List.length row = columns) csv
+
+let rec set_columns cols = function
+ | [] -> []
+ | r :: rs ->
+ let rec loop i cells =
+ if i < cols then (
+ match cells with
+ | [] -> "" :: loop (succ i) []
+ | c :: cs -> c :: loop (succ i) cs
+ )
+ else []
+ in
+ loop 0 r :: set_columns cols rs
+
+let rec set_rows rows csv =
+ if rows > 0 then (
+ match csv with
+ | [] -> [] :: set_rows (pred rows) []
+ | r :: rs -> r :: set_rows (pred rows) rs
+ )
+ else []
+
+let set_size rows cols csv =
+ set_columns cols (set_rows rows csv)
+
+let sub r c rows cols csv =
+ let csv = drop r csv in
+ let csv = List.map (drop c) csv in
+ let csv = set_rows rows csv in
+ let csv = set_columns cols csv in
+ csv
+
+(* Compare two rows for semantic equality - ignoring any blank cells
+ * at the end of each row.
+ *)
+let rec compare_row (row1 : string list) row2 =
+ match row1, row2 with
+ | [], [] -> 0
+ | x :: xs, y :: ys ->
+ let c = compare x y in
+ if c <> 0 then c else compare_row xs ys
+ | "" :: xs , [] ->
+ compare_row xs []
+ | x :: xs, [] ->
+ 1
+ | [], "" :: ys ->
+ compare_row [] ys
+ | [], y :: ys ->
+ -1
+
+(* Semantic equality for CSV files. *)
+let rec compare (csv1 : t) csv2 =
+ match csv1, csv2 with
+ | [], [] -> 0
+ | x :: xs, y :: ys ->
+ let c = compare_row x y in
+ if c <> 0 then c else compare xs ys
+ | x :: xs, [] ->
+ let c = compare_row x [] in
+ if c <> 0 then c else compare xs []
+ | [], y :: ys ->
+ 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)
+
+let of_array csv =
+ List.map Array.to_list (Array.to_list csv)
+
let associate header data =
let nr_cols = List.length header in
let rec trunc = function
let chan = open_out file in
save_out ?separator chan csv;
close_out chan
+
+let save_out_readable chan csv =
+ (* Escape all the strings in the CSV file first. *)
+ (* XXX Why are we doing this? I commented it out anyway.
+ let csv = List.map (List.map String.escaped) csv in
+ *)
+
+ (* Find the width of each column. *)
+ let widths =
+ (* Don't consider rows with only a single element - typically
+ * long titles.
+ *)
+ let csv = List.filter (function [_] -> false | _ -> true) csv in
+
+ (* Square the CSV file - makes the next step simpler to implement. *)
+ let csv = square csv in
+
+ match csv with
+ | [] -> []
+ | 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 =
+ 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
+ List.fold_left max2rows lengths_row1 lengths_rest in
+
+ (* Print out each cell at the correct width. *)
+ let rec repeat f = function
+ | 0 -> ()
+ | i -> f (); repeat f (i-1)
+ in
+ List.iter (
+ function
+ | [cell] -> (* Single column. *)
+ output_string chan cell;
+ output_char chan '\n'
+ | row -> (* Other. *)
+ (* 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 (cell, width) ->
+ output_string chan cell;
+ let n = String.length cell in
+ repeat (fun () -> output_char chan ' ') (width - n + 1)
+ ) row;
+ output_char chan '\n'
+ ) csv
+
+let print_readable = save_out_readable stdout
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