From c709e9f3582989da778dabab0dc376bf30ab3eef Mon Sep 17 00:00:00 2001
From: mrbesen <y.g.2@gmx.de>
Date: Thu, 8 Oct 2020 10:34:12 +0200
Subject: [PATCH] readfile

---
 inc/files.h          |  3 +++
 src/files.cpp        | 30 ++++++++++++++++++++++++++++++
 tests/filestests.cpp | 32 ++++++++++++++++++++++++++++++++
 tests/main.cpp       |  3 ++-
 4 files changed, 67 insertions(+), 1 deletion(-)

diff --git a/inc/files.h b/inc/files.h
index 1931498..2a6a518 100644
--- a/inc/files.h
+++ b/inc/files.h
@@ -30,4 +30,7 @@ template<class Container>
 bool scan(const std::string& path, std::insert_iterator<Container> it, bool prefixdir = false, fileNameFilter fnf = fileNameFilter(nullptr));
 bool scan(const std::string& path, fileCallback clb, bool prefixdir = false, fileNameFilter fnf = fileNameFilter(nullptr));
 
+bool readFile(const std::string& name, std::ostream& output, unsigned int maxsize = 0); //reads file name and writes it line for line into output, it stops at maxsize (it might be a bit more, its not a hard limit - see it more as a hint), if maxsize is 0 it reads unlimited 
+bool readFile(int fd, std::ostream& output, unsigned int maxsize = 0);
+
 }
\ No newline at end of file
diff --git a/src/files.cpp b/src/files.cpp
index 2134f8a..ab2b02c 100644
--- a/src/files.cpp
+++ b/src/files.cpp
@@ -3,6 +3,11 @@
 #include <dirent.h>
 #include <list>
 #include <set>
+
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/types.h>
+
 #include "util.h"
 
 void mrbesen::files::parent(const std::string& child, std::string& out) {
@@ -78,3 +83,28 @@ bool mrbesen::files::scan(const std::string& path, fileCallback clb, bool prefix
 
 	return true;
 }
+
+bool mrbesen::files::readFile(const std::string& name, std::ostream& output, unsigned int maxsize) {
+	int fd = open(name.c_str(), O_RDONLY);
+	bool ret = readFile(fd, output, maxsize);
+	close(fd);
+	return ret;
+}
+
+bool mrbesen::files::readFile(int fd, std::ostream& output, unsigned int maxsize) {
+	if(fd < 0) return false;
+
+	const int BUFFERSIZE = 1024;
+	ssize_t readc;
+	uint32_t readbytes = 0;
+	do {
+		char b[BUFFERSIZE];
+		readc = read(fd, b, BUFFERSIZE);
+		if(readc == -1) return false; //error
+		output << std::string(b, readc);
+		readbytes += readc;
+	} while(readc == BUFFERSIZE && (readbytes < maxsize || maxsize == 0));
+
+	return true;
+}
+
diff --git a/tests/filestests.cpp b/tests/filestests.cpp
index 8f1ef19..377c5aa 100644
--- a/tests/filestests.cpp
+++ b/tests/filestests.cpp
@@ -5,6 +5,12 @@
 #include <list>
 #include <set>
 #include <string>
+#include <sstream>
+
+#include <cstring>
+
+#include <unistd.h>
+#include <fcntl.h>
 
 using namespace mrbesen;
 
@@ -121,3 +127,29 @@ int testFiles_scan() {
 	
 	return TESTGOOD;
 }
+
+int testFiles_readFile() {
+
+	std::ostringstream buf;
+
+	ASSERT(!files::readFile("tests/blabla.exe", buf), "this file should not be read"); //try to read non existing file
+
+	bool r = files::readFile(std::string("tests/filestests.cpp"), buf);
+	ASSERT(r, "failed to read");
+
+	//alternative read
+	int fd = open("tests/filestests.cpp", O_RDONLY);
+	const unsigned int size = 1024*1024; //1MB
+	char* buf2 = new char[size];
+	ssize_t rc = read(fd, buf2, size);
+	ASSERT(rc > 0, rc);
+	close(fd);
+
+	//compare
+	ASSERT(rc == buf.tellp(), "rc: " << rc << " buf.tellp(): " << buf.tellp());
+	ASSERT(std::memcmp(buf2, buf.str().c_str(), rc) == 0, "")
+
+	delete[] buf2;
+
+	return TESTGOOD;
+}
diff --git a/tests/main.cpp b/tests/main.cpp
index 79c311f..7384665 100644
--- a/tests/main.cpp
+++ b/tests/main.cpp
@@ -6,6 +6,7 @@ int testFiles_parent();
 int testFiles_file();
 int testFiles_extention();
 int testFiles_scan();
+int testFiles_readFile();
 
 int testUtil_Count();
 int testUtil_equalsIgnoreCase();
@@ -21,7 +22,7 @@ int testUtilSplit();
 
 int testGetDoy();
 
-test_t tests[] = {testFiles_parent, testFiles_file, testFiles_extention, testFiles_scan,
+test_t tests[] = {testFiles_parent, testFiles_file, testFiles_extention, testFiles_scan, testFiles_readFile,
 	testUtil_Count, testUtil_equalsIgnoreCase, testUtil_toLower, testUtil_start_endWith, testUtil_removeStart_End, testUtil_insertStart_End, testUtil_trim, testUtil_base,
 	testStringSpliterator, testUtilSplit,
 	testGetDoy,