csv skipping rows and documentation

csv.documentation

@@ -6,11 +6,14 @@ fio,pathjoin,string
 csv,load,table
 none,",comma in field", and ""quote""
 
-Commas in fields must be in quotes
-If there are quotes in a field, it must be double-quotes.
+Commas an linebreaks in fields must be in quotes
+Quotes in fields is repeated two times quote character.
 You can set delimiter and quote character:
     csv.delimiter = ','
     csv.quote = '"'
+Input/output works through readable/writable objects, for example files or sockets.
+Readable object has method read(N), which returns N or less bytes as string.
+Writable object has method write(string), which sends string to output.
 
 csv.iterate = function(readable[, csv_chunk_size])
 --@brief parse csv string by string
@@ -29,12 +32,32 @@ Output:
     csv     load    table
     none    ,comma in field and "quote"
 
-csv.load = function(readable, csv_chunk_size)
+csv.load = function(readable[, skip_lines, csv_chunk_size])
 --@brief parse csv and make table
+--@param skip_lines is number of lines to skip.
 --@return table
+If csv file has a header, it may be skipped.
 
-
-csv.dump = function(t, writable)
+csv.dump = function(t[, writable])
 --@brief dumps tuple or table as csv
+--@param t is table or tuple. Fields may be of any type, but it will be converted to string by method tostring(field).
 --@param writable must be object with method write(string) like file or socket
---@return there is no writable it returns csv as string
\ No newline at end of file
+--@return there is no writable it returns csv as string
+
+Example:
+    f = require("fio").open("dump.csv", { "O_WRONLY", "O_TRUNC" , "O_CREAT"}, 0x1FF)
+    multiline_header = {{'csv example'}, {'3 numbers per string:'}}
+    csv.dump(multiline_header, f)
+    for i=0,14,3 do 
+    t = {i, i + 1, i + 2} 
+    s = csv.dump(t, f) 
+    end
+dump.csv:
+    csv example
+    3 numbers per string:
+    0,1,2
+    3,4,5
+    6,7,8
+    9,10,11
+    12,13,14
+

src/lua/csv.lua

@@ -69,6 +69,7 @@ local iter = function(csvstate)
             log.warn("CSV file has errors")
             break
         elseif st == ffi.C.CSV_IT_EOF then
+            ffi.C.csv_destroy(csv)
             break
         end
         st = ffi.C.csv_next(it)
@@ -129,12 +130,19 @@ module.iterate = function(readable, csv_chunk_size)
 end
 
 --@brief parse csv and make table
+--@param skip_lines is number of lines to skip.
 --@return table
-module.load = function(readable, csv_chunk_size)
+module.load = function(readable, skip_lines, csv_chunk_size)
+    skip_lines = skip_lines or 0
     csv_chunk_size = csv_chunk_size or 4096
     result = {}
+    i = 0
     for tup in module.iterate(readable, csv_chunk_size) do
-        table.insert(result, tup)
+        if i < skip_lines then 
+            i = i + 1
+        else
+            table.insert(result, tup)
+        end
     end
 
     return result
@@ -177,6 +185,7 @@ module.dump = function(t, writable)
         end
         writable:write('\n')
     end
+    ffi.C.csv_destroy(csv)
     csv[0].csv_realloc(buf, 0)
     if writable.returnstring then
         return writable.returnstring

test/app/csv.result

@@ -20,7 +20,6 @@ fio test1:
 |ok|	
 
 fio test2:
-fio test3:
 |1|	
 |23|	|456|	|abcac|	|'multiword field 4'|	
 |none|	|none|	|0|	
@@ -30,8 +29,7 @@ fio test3:
 |iflag = bit.bor(iflag|	|fio.c.flag[ flag ])|	
 ||	||	||	
 
-fio test4:
-|1|	
+fio test3:
 |23|	|456|	|abcac|	|'multiword field 4'|	
 |none|	|none|	|0|	
 ||	||	||	

test/app/csv.test.lua

@@ -29,12 +29,12 @@ print(table2str(csv.load(readable)))
 print("obj test2:")
 readable.v = ", ,\n , \n\n"
 readable.i = 0
-print(table2str(csv.load(readable, 1)))
+print(table2str(csv.load(readable, 0, 1)))
 
 print("obj test3:")
 readable.v = ", \r\nkp\"\"v"
 readable.i = 0
-print(table2str(csv.load(readable, 3)))
+print(table2str(csv.load(readable, 0, 3)))
 
 tmpdir = fio.tempdir()
 file1 = fio.pathjoin(tmpdir, 'file.1')
@@ -47,7 +47,7 @@ f:write("123 , 5  ,       92    , 0, 0\n" ..
         "1, 12  34, 56, \"quote , \", 66\nok")
 f:close()
 f = fio.open(file1, {'O_RDONLY'}) 
-print(table2str(csv.load(f,10)))
+print(table2str(csv.load(f,0,10)))
 f:close()
 
 
@@ -62,15 +62,13 @@ f:write("1\n23,456,abcac,\'multiword field 4\'\n" ..
         ",,"
 )
 f:close()
-
-print("fio test3:")
 f = fio.open(file2, {'O_RDONLY'}) 
-print(table2str(csv.load(f, 1))) --symbol by symbol reading
+print(table2str(csv.load(f, 0, 1))) --symbol by symbol reading
 f:close()
 
-print("fio test4:")
+print("fio test3:")
 f = fio.open(file2, {'O_RDONLY'}) 
-print(table2str(csv.load(f, 7))) --7 symbols per chunk
+print(table2str(csv.load(f, 1, 7))) --7 symbols per chunk
 f:close()
 
 
@@ -87,7 +85,7 @@ f = require("fio").open(file3, { "O_WRONLY", "O_TRUNC" , "O_CREAT"}, 0x1FF)
 csv.dump(t, f)
 f:close()
 f = fio.open(file3, {'O_RDONLY'}) 
-t2 = csv.load(f, 5)
+t2 = csv.load(f, 0, 5)
 f:close()
 
 print("test roundtrip: ")