From 0db5c51ed9a3a0e210a8bd6603fa7e828bb6db58 Mon Sep 17 00:00:00 2001
From: heinrich5991 <heinrich5991@gmail.com>
Date: Mon, 22 Jun 2020 22:16:58 +0200
Subject: [PATCH] Add a simple CSV writer for Python's "excel" csv dialect

---
 CMakeLists.txt            |  3 +++
 src/engine/shared/csv.cpp | 40 ++++++++++++++++++++++++++++
 src/engine/shared/csv.h   |  8 ++++++
 src/test/csv.cpp          | 56 +++++++++++++++++++++++++++++++++++++++
 4 files changed, 107 insertions(+)
 create mode 100644 src/engine/shared/csv.cpp
 create mode 100644 src/engine/shared/csv.h
 create mode 100644 src/test/csv.cpp

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 395451b81..2def8e284 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -731,6 +731,8 @@ set_src(ENGINE_SHARED GLOB src/engine/shared
   config_variables.h
   console.cpp
   console.h
+  csv.cpp
+  csv.h
   datafile.cpp
   datafile.h
   demo.cpp
@@ -1336,6 +1338,7 @@ if(GTEST_FOUND OR DOWNLOAD_GTEST)
   set_src(TESTS GLOB src/test
     aio.cpp
     color.cpp
+    csv.cpp
     datafile.cpp
     fs.cpp
     git_revision.cpp
diff --git a/src/engine/shared/csv.cpp b/src/engine/shared/csv.cpp
new file mode 100644
index 000000000..0fc90a879
--- /dev/null
+++ b/src/engine/shared/csv.cpp
@@ -0,0 +1,40 @@
+#include "csv.h"
+
+void CsvWrite(IOHANDLE File, int NumColumns, const char *const *ppColumns)
+{
+	for(int i = 0; i < NumColumns; i++)
+	{
+		if(i != 0)
+		{
+			io_write(File, ",", 1);
+		}
+		const char *pColumn = ppColumns[i];
+		int ColumnLength = str_length(pColumn);
+		if(!str_find(pColumn, "\"") && !str_find(pColumn, ","))
+		{
+			io_write(File, pColumn, ColumnLength);
+			continue;
+		}
+
+		int Start = 0;
+		io_write(File, "\"", 1);
+		for(int j = 0; j < ColumnLength; j++)
+		{
+			if(pColumn[j] == '"')
+			{
+				if(Start != j)
+				{
+					io_write(File, pColumn + Start, j - Start);
+				}
+				Start = j + 1;
+				io_write(File, "\"\"", 2);
+			}
+		}
+		if(Start != ColumnLength)
+		{
+			io_write(File, pColumn + Start, ColumnLength - Start);
+		}
+		io_write(File, "\"", 1);
+	}
+	io_write_newline(File);
+}
diff --git a/src/engine/shared/csv.h b/src/engine/shared/csv.h
new file mode 100644
index 000000000..aa5273382
--- /dev/null
+++ b/src/engine/shared/csv.h
@@ -0,0 +1,8 @@
+#ifndef ENGINE_SHARED_CSV_H
+#define ENGINE_SHARED_CSV_H
+
+#include <base/system.h>
+
+void CsvWrite(IOHANDLE File, int NumColumns, const char *const *pColumns);
+
+#endif // ENGINE_SHARED_CSV_H
diff --git a/src/test/csv.cpp b/src/test/csv.cpp
new file mode 100644
index 000000000..bd2e6cf1f
--- /dev/null
+++ b/src/test/csv.cpp
@@ -0,0 +1,56 @@
+#include "test.h"
+#include <gtest/gtest.h>
+
+#include <engine/shared/csv.h>
+
+static void Expect(int NumColumns, const char *const *ppColumns, const char *pExpected)
+{
+	CTestInfo Info;
+
+	IOHANDLE File = io_open(Info.m_aFilename, IOFLAG_WRITE);
+	ASSERT_TRUE(File);
+	CsvWrite(File, NumColumns, ppColumns);
+	io_close(File);
+
+	char aBuf[1024];
+	File = io_open(Info.m_aFilename, IOFLAG_READ);
+	ASSERT_TRUE(File);
+	int Read = io_read(File, aBuf, sizeof(aBuf));
+	io_close(File);
+	fs_remove(Info.m_aFilename);
+
+	ASSERT_TRUE(Read >= 1);
+	Read -= 1;
+	ASSERT_EQ(aBuf[Read], '\n');
+	aBuf[Read] = 0;
+
+	#if defined(CONF_FAMILY_WINDOWS)
+	ASSERT_TRUE(Read >= 1);
+	Read -= 1;
+	ASSERT_EQ(aBuf[Read], '\r');
+	aBuf[Read] = 0;
+	#endif
+
+	for(int i = 0; i < Read; i++)
+	{
+		EXPECT_NE(aBuf[i], 0);
+	}
+	EXPECT_STREQ(aBuf, pExpected);
+}
+
+TEST(Csv, Simple)
+{
+	const char *apCols1[] = {"a", "b"};     Expect(2, apCols1, "a,b");
+	const char *apCols2[] = {"こんにちは"}; Expect(1, apCols2, "こんにちは");
+	const char *apCols3[] = {"я", "", "й"}; Expect(3, apCols3, "я,,й");
+	const char *apCols4[] = {""};           Expect(1, apCols4, "");
+	const char *apCols5[] = {0};            Expect(0, apCols5, "");
+}
+
+TEST(Csv, LetTheQuotingBegin)
+{
+	const char *apCols1[] = {"\""};             Expect(1, apCols1, "\"\"\"\"");
+	const char *apCols2[] = {","};              Expect(1, apCols2, "\",\"");
+	const char *apCols3[] = {",,", ",\"\"\""};  Expect(2, apCols3, "\",,\",\",\"\"\"\"\"\"\"");
+	const char *apCols4[] = {"\",", " "};       Expect(2, apCols4, "\"\"\",\", ");
+}