# See the License for the specific language governing permissions and
# limitations under the License.
-# CSV output facilities
+# CSV document handling.
module csv
-# A CSV document representation
-class CSVDocument
- super Streamable
+redef class Text
+ # Escape the content of `self` for inclusion in a CSV document
+ private fun escape_to_csv(sep_char, delim_char: Char, eol: String): String do
+ var add_sp = chars_to_escape_csv(sep_char, delim_char, eol)
+ if add_sp == 0 then return to_s
+ var bf = new Buffer.with_cap(add_sp + byte_length)
+ bf.add '"'
+ for i in [0 .. length[ do
+ var c = self[i]
+ if c == delim_char then
+ bf.add c
+ end
+ bf.add c
+ end
+ bf.add '"'
+ return bf.to_s
+ end
- var header: Array[String] = new Array[String] is writable
- var lines: Array[Array[String]] = new Array[Array[String]]
+ # How many more bytes should be allocated for CSV escaping ?
+ private fun chars_to_escape_csv(sep_char, delim_char: Char, eol: String): Int do
+ var more_ln = 0
+ var ln = length
+ var need_esc = false
+ var fst_eol = eol.first
+ var i = 0
+ while i < ln do
+ var c = self[i]
+ if c == delim_char then more_ln += 1
+ if c == fst_eol then
+ need_esc = true
+ for j in [1 .. eol.length[ do
+ i += 1
+ c = self[i]
+ if c != eol[j] then
+ i -= j
+ need_esc = false
+ break
+ end
+ end
+ end
+ if c == sep_char then need_esc = true
+ i += 1
+ end
+ var more = more_ln * delim_char.u8char_len
+ if need_esc then more += 2
+ return more
+ end
- fun set_header(values: Object...) do
- header.clear
- for value in values do
- header.add(value.to_s)
+ # Unescape the content of `self` from CSV format to Nit String
+ private fun unescape_csv(delim_char: Char): String do
+ var to_un = chars_to_unescape_csv(delim_char)
+ if to_un == 0 then return to_s
+ var buf = new Buffer.with_cap(byte_length - to_un)
+ var pos = 0
+ var ln = length
+ while pos < ln do
+ var c = self[pos]
+ if c == delim_char then pos += 1
+ buf.add c
+ pos += 1
end
+ return buf.to_s
end
- fun add_line(values: Object...) do
- if values.length != header.length then
- print "CSV error: header declares {header.length} columns, line contains {values.length} values"
- abort
+ # How many bytes should be removed for CSV unescaping ?
+ private fun chars_to_unescape_csv(delim_char: Char): Int do
+ var pos = 0
+ var to_un = 0
+ var ln = length
+ while pos < ln do
+ var c = self[pos]
+ if c == delim_char then
+ pos += 1
+ to_un += 1
+ end
+ pos += 1
end
- var line = new Array[String]
- for value in values do
- line.add(value.to_s)
+ return to_un
+ end
+end
+
+# Shared properties by all CSV-related classes
+#
+# This class is basically only here for implementation purposes and should not be used
+# by clients for typing.
+abstract class CsvStream
+ # The character that delimits escaped value.
+ #
+ # The delimiter is escaped by doubling it.
+ var delimiter = '"' is writable
+
+ # The character that split each cell in a record.
+ var separator = ',' is writable
+
+ # The character that ends a record (end of line).
+ var eol = "\n" is writable
+end
+
+# A CSV document representation.
+class CsvDocument
+ super Writable
+ super CsvStream
+
+ # The header.
+ #
+ # Contains the name of all fields in this table.
+ var header = new Array[String] is writable, optional
+
+ # The list of the records.
+ #
+ # All records must have the same length than `header`.
+ var records = new Array[Array[String]] is writable, optional
+
+ # Adds a new record to document containing the values in `objs`
+ fun add_record(objs: Object...) do
+ var ln = new Array[String].with_capacity(objs.length)
+ for i in objs do ln.add(i.to_s)
+ records.add ln
+ end
+
+ redef fun write_to(stream) do
+ var s = new CsvWriter(stream)
+ s.separator = separator
+ s.eol = eol
+ s.delimiter = delimiter
+ if not header.is_empty then
+ s.write_line header
end
- lines.add(line)
+ s.write_lines(records)
end
- private fun write_line_to(line: Collection[String], stream: OStream)
- do
- var i = line.iterator
- if i.is_ok then
- stream.write(i.item)
- i.next
- while i.is_ok do
- stream.write(";")
- stream.write(i.item)
- i.next
- end
+ # Load from the specified stream.
+ #
+ # Parameters:
+ #
+ # * `stream`: Input stream.
+ # * `has_header`: Is the first record the header? - defaults to true
+ # * `skip_empty`: Do we skip the empty lines? - defaults to true
+ fun load_from(stream: Reader, has_header: nullable Bool, skip_empty: nullable Bool) do
+ if has_header == null then has_header = true
+ if skip_empty == null then skip_empty = true
+ var reader = new CsvReader(stream)
+ reader.separator = separator
+ reader.eol = eol
+ reader.delimiter = delimiter
+ reader.skip_empty = skip_empty
+ end
+end
+
+# Appends CSV records to a file.
+#
+# By default, uses the format recommended by RFC 4180 (see `rfc4180`).
+#
+# Note: If a record contains only an empty cell, its representation is
+# undistinguishable from an empty line. This is because the empty values are
+# always written unescaped in order to avoid them to be interpreted as escaped
+# delimiters by some parsers.
+#
+# ~~~nit
+# var out = new StringWriter
+# var writer = new CsvWriter(out)
+# writer.write_elements(1, 2.0, "foo\nbar")
+# writer.write_line([""])
+# assert out.to_s == """1,2.0,"foo\nbar"\n\n"""
+# ~~~
+class CsvWriter
+ super CsvStream
+
+ # The output stream.
+ var ostream: Writer
+
+ # Write several lines to a stream
+ fun write_lines(lines: Array[Array[Object]]) do for i in lines do write_line i
+
+ # Append the elements in `els` as a record.
+ #
+ # The representation of each cell is determined by `to_s`.
+ fun write_elements(els: Object...) do
+ var os = ostream
+ var esc = delimiter
+ var sep = separator
+ var eol = eol
+ for i in [0 .. els.length - 1[ do
+ os.write(els[i].to_s.escape_to_csv(sep, esc, eol))
+ os.write_char(sep)
end
- stream.write("\n")
+ os.write(els.last.to_s.escape_to_csv(sep, esc, eol))
+ os.write(eol)
end
- redef fun write_to(stream)
- do
- write_line_to(header, stream)
- for line in lines do write_line_to(line, stream)
+ # Append the specified record.
+ #
+ # The representation of each cell is determined by `to_s`.
+ fun write_line(line: Array[Object]) do
+ var os = ostream
+ var esc = delimiter
+ var sep = separator
+ var eol = eol
+ for i in [0 .. line.length - 1[ do
+ os.write(line[i].to_s.escape_to_csv(sep, esc, eol))
+ os.write_char(sep)
+ end
+ os.write(line.last.to_s.escape_to_csv(sep, esc, eol))
+ os.write(eol)
end
+end
+
+# Reads records from a CSV file.
+#
+# By default, the format recognizes EOLs as `\n`
+#
+# ~~~nit
+# var example = """
+# foo,bar
+# "Hello, word!",1234.5 + 42
+# "Something
+# ""else""\", baz
+# """
+# var reader = new CsvReader.from_string(example)
+# var table = reader.read_all
+#
+# assert table.header == ["foo","bar"]
+# assert table.records == [["Hello, word!","1234.5 + 42"],
+# ["Something\n\"else\""," baz"]]
+# ~~~
+class CsvReader
+ super CsvStream
+
+ # The input stream.
+ var istream: Reader
+
+ # Do we skip the empty lines?
+ #
+ # Note: Even if this attribute is `false`, the presence of an line ending at
+ # end of the last record does not change the number of returned record.
+ # This is because the line endings are processed as terminators, not as
+ # separators. Therefore, when there is more than one line ending at the end
+ # of the file, the additional lines are interpreted as empty records that
+ # are skipped only if `skip_empty` is set to `true`.
+ #
+ # `false` by default.
+ var skip_empty: Bool = false is writable
+
+ # Creates a new CSVReader from a `string` data
+ init from_string(s: String) do init(new StringReader(s))
- # deprecated alias for `write_to_file`
- fun save(file: String) do write_to_file(file)
+ # Reads the content of the Stream and interprets it as a CSV Document
+ #
+ # Optional parameter `has_header` determines whether the first line
+ # of the CSV Document is header data.
+ # Defaults to true
+ fun read_all(has_header: nullable Bool): CsvDocument do
+ var header: nullable Array[String] = null
+ if has_header == null then has_header = true
+ var iss = istream
+ var res_data = new Array[Array[String]]
+ var eol_st = eol.first
+ var line = new Array[String]
+ var esc = delimiter
+ var sep = separator
+ var eol = eol
+ var is_eol = false
+ var eol_buf = new Buffer.with_cap(eol.length)
+ var c = iss.read_char
+ var el = new Buffer
+ while not iss.eof do
+ if c == null then continue
+ loop
+ if c == esc then
+ c = iss.read_char
+ loop
+ if c == esc then
+ c = iss.read_char
+ if c != esc then break
+ end
+ if c == null then break
+ el.add c
+ c = iss.read_char
+ end
+ end
+ if c == sep then break
+ if c == eol_st then
+ eol_buf.add c.as(not null)
+ is_eol = true
+ for i in [1 .. eol.length[ do
+ c = iss.read_char
+ if c == null or c != eol[i] then
+ is_eol = false
+ el.append(eol_buf)
+ eol_buf.clear
+ break
+ end
+ eol_buf.add c
+ end
+ if not is_eol then continue
+ eol_buf.clear
+ break
+ end
+ if c == sep then break
+ el.add c.as(not null)
+ c = iss.read_char
+ if c == null then break
+ end
+ line.add el.to_s
+ el.clear
+ if is_eol or iss.eof then
+ c = iss.read_char
+ is_eol = false
+ if skip_empty and line.is_empty then
+ continue
+ end
+ if has_header and header == null then
+ header = line
+ else res_data.add line
+ line = new Array[String]
+ end
+ if c == sep then c = iss.read_char
+ end
+ if header == null then header = new Array[String]
+ var doc = new CsvDocument
+ doc.header = header
+ doc.records = res_data
+ return doc
+ end
end
nitlanguage / nit.git / blobdiff