Add copyStreamRange to StreamCopier (#4474)

* feat(Foundation): StreamCopier copyStreamRange #4413

* chore(ci): disable instalation of unused databases in odbc job

---------

Co-authored-by: Pavle <pavle@debian-gnu-linux-11.localdomain>
Co-authored-by: Alex Fabijanic <alex@pocoproject.org>

.github/workflows/ci.yml

@@ -660,27 +660,27 @@ jobs:
   linux-gcc-make-odbc:
     runs-on: ubuntu-22.04
     services:
-      mysql:
-        image: mysql:8.1.0
-        env:
-          MYSQL_ALLOW_EMPTY_PASSWORD: yes
-          MYSQL_USER: pocotest
-          MYSQL_PASSWORD: pocotest
-          MYSQL_DATABASE: pocotest
-        ports:
-          - 3306:3306
-      postgres:
-        image: postgres:16.0
-        env:
-          POSTGRES_PASSWORD: postgres
-        ports:
-          - 5432:5432
-      oracle:
-        image: container-registry.oracle.com/database/express:21.3.0-xe
-        env:
-          ORACLE_PWD: poco
-        ports:
-          - 1521:1521
+      #mysql:
+      #  image: mysql:8.1.0
+      #  env:
+      #    MYSQL_ALLOW_EMPTY_PASSWORD: yes
+      #    MYSQL_USER: pocotest
+      #    MYSQL_PASSWORD: pocotest
+      #    MYSQL_DATABASE: pocotest
+      #  ports:
+      #    - 3306:3306
+      #postgres:
+      #  image: postgres:16.0
+      #  env:
+      #    POSTGRES_PASSWORD: postgres
+      #  ports:
+      #    - 5432:5432
+      #oracle:
+      #  image: container-registry.oracle.com/database/express:21.3.0-xe
+      #  env:
+      #    ORACLE_PWD: poco
+      #  ports:
+      #    - 1521:1521
       sqlserver:
         image: mcr.microsoft.com/mssql/server:2022-latest
         env:
@@ -691,7 +691,7 @@ jobs:
           - 1433:1433
     steps:
       - uses: actions/checkout@v3
-      - run: sudo apt -y update && sudo apt -y install libssl-dev unixodbc-dev libmysqlclient-dev mysql-client alien libaio1 gnupg2 curl #odbc-postgresql
+      - run: sudo apt -y update && sudo apt -y install libssl-dev unixodbc-dev alien libaio1 gnupg2 curl # libmysqlclient-dev mysql-client odbc-postgresql
       - run: ./configure --everything --no-samples --omit=ActiveRecord,ApacheConnector,CppParser,Crypto,Data/MySQL,Data/PostgreSQL,Data/SQLite,Encodings,JSON,JWT,MongoDB,Net,NetSSL_OpenSSL,NetSSL_Win,PDF,PageCompiler,PocoDoc,ProGen,Prometheus,Redis,SevenZip,Util,XML,Zip && make all -s -j4 && sudo make install
       # - name: Setup MySQL ODBC connector
       #   run: |

Foundation/include/Poco/StreamCopier.h

@@ -19,6 +19,7 @@
 
 
 #include "Poco/Foundation.h"
+#include "Poco/Buffer.h"
 #include <istream>
 #include <ostream>
 #include <cstddef>
@@ -47,6 +48,21 @@ public:
 		/// integer is used to count the number of bytes copied.
 #endif
 
+	static std::streamsize copyStreamRange(std::istream& istr, std::ostream& ostr, std::streampos rangeStart, std::streamsize rangeLength, std::size_t bufferSize = 8192);
+		/// Writes range of bytes readable from istr to ostr, using an internal buffer.
+		///
+		/// Returns the number of bytes copied.
+
+#if defined(POCO_HAVE_INT64)
+	static Poco::UInt64 copyStreamRange64(std::istream& istr, std::ostream& ostr, std::streampos rangeStart, std::streamsize rangeLength, std::size_t bufferSize = 8192);
+		/// Writes range of bytes readable from istr to ostr, using an internal buffer.
+		///
+		/// Returns the number of bytes copied as a 64-bit unsigned integer.
+		///
+		/// Note: the only difference to copyStreamRange() is that a 64-bit unsigned
+		/// integer is used to count the number of bytes copied.
+#endif
+
 	static std::streamsize copyStreamUnbuffered(std::istream& istr, std::ostream& ostr);
 		/// Writes all bytes readable from istr to ostr.
 		///
@@ -62,6 +78,21 @@ public:
 		/// integer is used to count the number of bytes copied.
 #endif
 
+static std::streamsize copyStreamRangeUnbuffered(std::istream& istr, std::ostream& ostr, std::streampos rangeStart, std::streamsize rangeLength);
+		/// Writes range of bytes readable from istr to ostr.
+		///
+		/// Returns the number of bytes copied.
+
+#if defined(POCO_HAVE_INT64)
+	static Poco::UInt64 copyStreamRangeUnbuffered64(std::istream& istr, std::ostream& ostr, std::streampos rangeStart, std::streamsize rangeLength);
+		/// Writes range of bytes readable from istr to ostr.
+		///
+		/// Returns the number of bytes copied as a 64-bit unsigned integer.
+		///
+		/// Note: the only difference to copyStreamRangeUnbuffered() is that a 64-bit unsigned
+		/// integer is used to count the number of bytes copied.
+#endif
+
 	static std::streamsize copyToString(std::istream& istr, std::string& str, std::size_t bufferSize = 8192);
 		/// Appends all bytes readable from istr to the given string, using an internal buffer.
 		///
@@ -76,6 +107,119 @@ public:
 		/// Note: the only difference to copyToString() is that a 64-bit unsigned
 		/// integer is used to count the number of bytes copied.
 #endif
+
+private:
+	template <typename T>
+	static T copyStreamImpl(std::istream& istr, std::ostream& ostr, std::size_t bufferSize)
+	{
+		poco_assert (bufferSize > 0);
+
+		Buffer<char> buffer(bufferSize);
+		T len = 0;
+		istr.read(buffer.begin(), bufferSize);
+		std::streamsize n = istr.gcount();
+		while (n > 0)
+		{
+			len += n;
+			ostr.write(buffer.begin(), n);
+			if (istr && ostr)
+			{
+				istr.read(buffer.begin(), bufferSize);
+				n = istr.gcount();
+			}
+			else n = 0;
+		}
+		return len;
+	}
+
+	template <typename T>
+	static T copyStreamRangeImpl(std::istream& istr, std::ostream& ostr, std::streampos rangeStart, std::streamsize rangeLength, std::size_t bufferSize)
+	{
+		poco_assert (bufferSize > 0);
+
+		if (bufferSize > rangeLength)
+			bufferSize = rangeLength;
+
+		Buffer<char> buffer(bufferSize);
+		T len = 0;
+		if (istr)
+		{
+			istr.seekg(rangeStart);
+			istr.read(buffer.begin(), bufferSize);
+			std::streamsize n = istr.gcount();
+			while (n > 0)
+			{
+				len += n;
+				ostr.write(buffer.begin(), n);
+				if ((len < rangeLength) && istr && ostr)
+				{
+					if (bufferSize > (rangeLength - len))
+						bufferSize = rangeLength - len;
+					istr.read(buffer.begin(), bufferSize);
+					n = istr.gcount();
+				}
+				else n = 0;
+			}
+		}
+		return len;
+	}
+
+	template <typename T>
+	static T copyToStringImpl(std::istream& istr, std::string& str, std::size_t bufferSize)
+	{
+		poco_assert (bufferSize > 0);
+
+		Buffer<char> buffer(bufferSize);
+		T len = 0;
+		istr.read(buffer.begin(), bufferSize);
+		std::streamsize n = istr.gcount();
+		while (n > 0)
+		{
+			len += n;
+			str.append(buffer.begin(), static_cast<std::string::size_type>(n));
+			if (istr)
+			{
+				istr.read(buffer.begin(), bufferSize);
+				n = istr.gcount();
+			}
+			else n = 0;
+		}
+		return len;
+	}
+
+	template <typename T>
+	static T copyStreamUnbufferedImpl(std::istream& istr, std::ostream& ostr)
+	{
+		char c = 0;
+		T len = 0;
+		istr.get(c);
+		while (istr && ostr)
+		{
+			++len;
+			ostr.put(c);
+			istr.get(c);
+		}
+		return len;
+	}
+
+	template <typename T>
+	static T copyStreamRangeUnbufferedImpl(std::istream& istr, std::ostream& ostr, std::streampos rangeStart, std::streamsize rangeLength)
+	{
+		T len = 0;
+		char c = 0;
+		if (istr)
+		{
+			istr.seekg(rangeStart);
+			istr.get(c);
+			while (istr && ostr && (len < rangeLength))
+			{
+				ostr.put(c);
+				++len;
+				istr.get(c);
+			}
+		}
+		return len;
+	}
 };
 
 

Foundation/src/StreamCopier.cpp

@@ -13,7 +13,6 @@
 
 
 #include "Poco/StreamCopier.h"
-#include "Poco/Buffer.h"
 
 
 namespace Poco {
@@ -21,128 +20,69 @@ namespace Poco {
 
 std::streamsize StreamCopier::copyStream(std::istream& istr, std::ostream& ostr, std::size_t bufferSize)
 {
-	poco_assert (bufferSize > 0);
-
-	Buffer<char> buffer(bufferSize);
-	std::streamsize len = 0;
-	istr.read(buffer.begin(), bufferSize);
-	std::streamsize n = istr.gcount();
-	while (n > 0)
-	{
-		len += n;
-		ostr.write(buffer.begin(), n);
-		if (istr && ostr)
-		{
-			istr.read(buffer.begin(), bufferSize);
-			n = istr.gcount();
-		}
-		else n = 0;
-	}
-	return len;
+	return copyStreamImpl<std::streamsize>(istr, ostr, bufferSize);
 }
 
 
 #if defined(POCO_HAVE_INT64)
 Poco::UInt64 StreamCopier::copyStream64(std::istream& istr, std::ostream& ostr, std::size_t bufferSize)
 {
-	poco_assert (bufferSize > 0);
+	return copyStreamImpl<Poco::UInt64>(istr, ostr, bufferSize);
+}
+#endif
 
-	Buffer<char> buffer(bufferSize);
-	Poco::UInt64 len = 0;
-	istr.read(buffer.begin(), bufferSize);
-	std::streamsize n = istr.gcount();
-	while (n > 0)
-	{
-		len += n;
-		ostr.write(buffer.begin(), n);
-		if (istr && ostr)
-		{
-			istr.read(buffer.begin(), bufferSize);
-			n = istr.gcount();
-		}
-		else n = 0;
-	}
-	return len;
+
+std::streamsize StreamCopier::copyStreamRange(std::istream& istr, std::ostream& ostr, std::streampos rangeStart, std::streamsize rangeLength, std::size_t bufferSize)
+{
+	return copyStreamRangeImpl<std::streamsize>(istr, ostr, rangeStart, rangeLength, bufferSize);
+}
+
+
+#if defined(POCO_HAVE_INT64)
+Poco::UInt64 StreamCopier::copyStreamRange64(std::istream& istr, std::ostream& ostr, std::streampos rangeStart, std::streamsize rangeLength, std::size_t bufferSize)
+{
+	return copyStreamRangeImpl<Poco::UInt64>(istr, ostr, rangeStart, rangeLength, bufferSize);
 }
 #endif
 
 
 std::streamsize StreamCopier::copyToString(std::istream& istr, std::string& str, std::size_t bufferSize)
 {
-	poco_assert (bufferSize > 0);
-
-	Buffer<char> buffer(bufferSize);
-	std::streamsize len = 0;
-	istr.read(buffer.begin(), bufferSize);
-	std::streamsize n = istr.gcount();
-	while (n > 0)
-	{
-		len += n;
-		str.append(buffer.begin(), static_cast<std::string::size_type>(n));
-		if (istr)
-		{
-			istr.read(buffer.begin(), bufferSize);
-			n = istr.gcount();
-		}
-		else n = 0;
-	}
-	return len;
+	return copyToStringImpl<std::streamsize>(istr, str, bufferSize);
 }
 
 
 #if defined(POCO_HAVE_INT64)
 Poco::UInt64 StreamCopier::copyToString64(std::istream& istr, std::string& str, std::size_t bufferSize)
 {
-	poco_assert (bufferSize > 0);
-
-	Buffer<char> buffer(bufferSize);
-	Poco::UInt64 len = 0;
-	istr.read(buffer.begin(), bufferSize);
-	std::streamsize n = istr.gcount();
-	while (n > 0)
-	{
-		len += n;
-		str.append(buffer.begin(), static_cast<std::string::size_type>(n));
-		if (istr)
-		{
-			istr.read(buffer.begin(), bufferSize);
-			n = istr.gcount();
-		}
-		else n = 0;
-	}
-	return len;
+	return copyToStringImpl<Poco::UInt64>(istr, str, bufferSize);
 }
 #endif
 
 
 std::streamsize StreamCopier::copyStreamUnbuffered(std::istream& istr, std::ostream& ostr)
 {
-	char c = 0;
-	std::streamsize len = 0;
-	istr.get(c);
-	while (istr && ostr)
-	{
-		++len;
-		ostr.put(c);
-		istr.get(c);
-	}
-	return len;
+	return copyStreamUnbufferedImpl<std::streamsize>(istr, ostr);
 }
 
 
 #if defined(POCO_HAVE_INT64)
 Poco::UInt64 StreamCopier::copyStreamUnbuffered64(std::istream& istr, std::ostream& ostr)
 {
-	char c = 0;
-	Poco::UInt64 len = 0;
-	istr.get(c);
-	while (istr && ostr)
-	{
-		++len;
-		ostr.put(c);
-		istr.get(c);
-	}
-	return len;
+	return copyStreamUnbufferedImpl<Poco::UInt64>(istr, ostr);
+}
+#endif
+
+std::streamsize StreamCopier::copyStreamRangeUnbuffered(std::istream& istr, std::ostream& ostr, std::streampos rangeStart, std::streamsize rangeLength)
+{
+	return copyStreamRangeUnbufferedImpl<std::streamsize>(istr, ostr, rangeStart, rangeLength);
+}
+
+
+#if defined(POCO_HAVE_INT64)
+Poco::UInt64 StreamCopier::copyStreamRangeUnbuffered64(std::istream& istr, std::ostream& ostr, std::streampos rangeStart, std::streamsize rangeLength)
+{
+	return copyStreamRangeUnbufferedImpl<Poco::UInt64>(istr, ostr, rangeStart, rangeLength);
 }
 #endif
 

Foundation/testsuite/src/StreamCopierTest.cpp

@@ -93,6 +93,74 @@ void StreamCopierTest::testCopyToString()
 }
 
 
+void StreamCopierTest::testBufferedCopyRange()
+{
+	{
+		std::string src;
+		for (int i = 0; i < 512; ++i) src += char(i % 256);
+		std::istringstream istr(src);
+		std::ostringstream ostr;
+		std::streampos rangeStart = 100;
+		std::streamsize rangeLength = 20;
+		std::string subSrc = src.substr(100, 20);
+		std::streamsize n = StreamCopier::copyStreamRange(istr, ostr, rangeStart, rangeLength);
+		assertTrue (ostr.str() == subSrc);
+		assertTrue (n == subSrc.size());
+	}
+	{
+		std::string src;
+		for (int i = 0; i < 512; ++i) src += char(i % 256);
+		std::istringstream istr(src);
+		std::ostringstream ostr;
+		std::streampos rangeStart = 100;
+		std::streamsize rangeLength = 20;
+		std::string subSrc = src.substr(100, 20);
+		std::streamsize n = StreamCopier::copyStreamRange(istr, ostr, rangeStart, rangeLength, 100);
+		assertTrue (ostr.str() == subSrc);
+		assertTrue (n == subSrc.size());
+	}
+	{
+		std::string src;
+		for (int i = 0; i < 512; ++i) src += char(i % 256);
+		std::istringstream istr(src);
+		std::ostringstream ostr;
+		std::streampos rangeStart = 100;
+		std::streamsize rangeLength = 150;
+		std::string subSrc = src.substr(100, 150);
+		std::streamsize n = StreamCopier::copyStreamRange(istr, ostr, rangeStart, rangeLength, 100);
+		assertTrue (ostr.str() == subSrc);
+		assertTrue (n == subSrc.size());
+	}
+	{
+		std::string src;
+		for (int i = 0; i < 512; ++i) src += char(i % 256);
+		std::istringstream istr(src);
+		std::ostringstream ostr;
+		std::streampos rangeStart = 100;
+		std::streamsize rangeLength = 128;
+		std::string subSrc = src.substr(100, 128);
+		std::streamsize n = StreamCopier::copyStreamRange(istr, ostr, rangeStart, rangeLength, 128);
+		assertTrue (ostr.str() == subSrc);
+		assertTrue (n == subSrc.size());
+	}
+}
+
+
+void StreamCopierTest::testUnbufferedCopyRange()
+{
+	std::string src;
+	for (int i = 0; i < 255; ++i) src += char(i);
+	std::istringstream istr(src);
+	std::ostringstream ostr;
+	std::streampos rangeStart = 100;
+	std::streamsize rangeLength = 20;
+	std::string subSrc = src.substr(100, 20);
+	std::streamsize n = StreamCopier::copyStreamRangeUnbuffered(istr, ostr, rangeStart, rangeLength);
+	assertTrue (ostr.str() == subSrc);
+	assertTrue (n == subSrc.size());
+}
+
+
 #if defined(POCO_HAVE_INT64)
 void StreamCopierTest::testBufferedCopy64()
 {
@@ -157,6 +225,74 @@ void StreamCopierTest::testCopyToString64()
 	assertTrue (src == dest);
 	assertTrue (n == src.size());
 }
+
+
+void StreamCopierTest::testBufferedCopyRange64()
+{
+	{
+		std::string src;
+		for (int i = 0; i < 512; ++i) src += char(i % 256);
+		std::istringstream istr(src);
+		std::ostringstream ostr;
+		std::streampos rangeStart = 100;
+		std::streamsize rangeLength = 20;
+		std::string subSrc = src.substr(100, 20);
+		Poco::UInt64 n = StreamCopier::copyStreamRange64(istr, ostr, rangeStart, rangeLength);
+		assertTrue (ostr.str() == subSrc);
+		assertTrue (n == subSrc.size());
+	}
+	{
+		std::string src;
+		for (int i = 0; i < 512; ++i) src += char(i % 256);
+		std::istringstream istr(src);
+		std::ostringstream ostr;
+		std::streampos rangeStart = 100;
+		std::streamsize rangeLength = 20;
+		std::string subSrc = src.substr(100, 20);
+		Poco::UInt64 n = StreamCopier::copyStreamRange64(istr, ostr, rangeStart, rangeLength, 100);
+		assertTrue (ostr.str() == subSrc);
+		assertTrue (n == subSrc.size());
+	}
+	{
+		std::string src;
+		for (int i = 0; i < 512; ++i) src += char(i % 256);
+		std::istringstream istr(src);
+		std::ostringstream ostr;
+		std::streampos rangeStart = 100;
+		std::streamsize rangeLength = 150;
+		std::string subSrc = src.substr(100, 150);
+		Poco::UInt64 n = StreamCopier::copyStreamRange64(istr, ostr, rangeStart, rangeLength, 100);
+		assertTrue (ostr.str() == subSrc);
+		assertTrue (n == subSrc.size());
+	}
+	{
+		std::string src;
+		for (int i = 0; i < 512; ++i) src += char(i % 256);
+		std::istringstream istr(src);
+		std::ostringstream ostr;
+		std::streampos rangeStart = 100;
+		std::streamsize rangeLength = 128;
+		std::string subSrc = src.substr(100, 128);
+		Poco::UInt64 n = StreamCopier::copyStreamRange64(istr, ostr, rangeStart, rangeLength, 128);
+		assertTrue (ostr.str() == subSrc);
+		assertTrue (n == subSrc.size());
+	}
+}
+
+
+void StreamCopierTest::testUnbufferedCopyRange64()
+{
+	std::string src;
+	for (int i = 0; i < 255; ++i) src += char(i);
+	std::istringstream istr(src);
+	std::ostringstream ostr;
+	std::streampos rangeStart = 100;
+	std::streamsize rangeLength = 20;
+	std::string subSrc = src.substr(100, 20);
+	Poco::UInt64 n = StreamCopier::copyStreamRangeUnbuffered64(istr, ostr, rangeStart, rangeLength);
+	assertTrue (ostr.str() == subSrc);
+	assertTrue (n == subSrc.size());
+}
 #endif
 
 
@@ -177,11 +313,15 @@ CppUnit::Test* StreamCopierTest::suite()
 	CppUnit_addTest(pSuite, StreamCopierTest, testBufferedCopy);
 	CppUnit_addTest(pSuite, StreamCopierTest, testUnbufferedCopy);
 	CppUnit_addTest(pSuite, StreamCopierTest, testCopyToString);
+	CppUnit_addTest(pSuite, StreamCopierTest, testBufferedCopyRange);
+	CppUnit_addTest(pSuite, StreamCopierTest, testUnbufferedCopyRange);
 
 #if defined(POCO_HAVE_INT64)
 	CppUnit_addTest(pSuite, StreamCopierTest, testBufferedCopy64);
 	CppUnit_addTest(pSuite, StreamCopierTest, testUnbufferedCopy64);
 	CppUnit_addTest(pSuite, StreamCopierTest, testCopyToString64);
+	CppUnit_addTest(pSuite, StreamCopierTest, testBufferedCopyRange64);
+	CppUnit_addTest(pSuite, StreamCopierTest, testUnbufferedCopyRange64);
 #endif
 
 	return pSuite;

Foundation/testsuite/src/StreamCopierTest.h

@@ -27,10 +27,14 @@ public:
 	void testBufferedCopy();
 	void testUnbufferedCopy();
 	void testCopyToString();
+	void testBufferedCopyRange();
+	void testUnbufferedCopyRange();
 #if defined(POCO_HAVE_INT64)
 	void testBufferedCopy64();
 	void testUnbufferedCopy64();
 	void testCopyToString64();
+	void testBufferedCopyRange64();
+	void testUnbufferedCopyRange64();
 #endif
 
 	void setUp();