Moving certain aspects into their own static library

Problem:
	As our kernel grows we need more complex datastructures and functions these would come from
	the standard C/C++ library with normal programs.
	The kernel is a freestanding programme and has no access to standard libraries.

Solution:
	We build a mini version of the standard C/C++ library which will contain the
	datastructures and functions we want. This library can then be statically linked
	into our kernel binary.

	Making it a statically linked library also gives more structure to the project.
	Keeping these random functions and datastructures in the kernel just clutters the
	kernel source code with less relevant source code.

Makefile

@@ -1,11 +1,10 @@
-
 EMULATOR = qemu-system-i386
 AS = ${HOME}/opt/cross/bin/i686-elf-as
 CC = ${HOME}/opt/cross/bin/i686-elf-gcc
 CPP = ${HOME}/opt/cross/bin/i686-elf-g++ 
-CFLAGS =  -ffreestanding -Og -ggdb  -Wall -Wextra
+CFLAGS =  -ffreestanding -Og -ggdb  -Wall -Wextra  -I source/CoreLib/build/include
 
-OFILES =$(BUILD_DIR)/boot.o $(BUILD_DIR)/Path.o $(BUILD_DIR)/kterm.o $(BUILD_DIR)/kernel.o $(BUILD_DIR)/memory.o  $(BUILD_DIR)/paging.o	$(BUILD_DIR)/VFS.o $(BUILD_DIR)/pit.o 	$(BUILD_DIR)/time.o	$(BUILD_DIR)/keyboard.o	 $(BUILD_DIR)/io.o 	$(BUILD_DIR)/processor.o $(BUILD_DIR)/gdtc.o $(BUILD_DIR)/idt.o $(BUILD_DIR)/pic.o $(BUILD_DIR)/sv-terminal.o $(BUILD_DIR)/string.o  $(BUILD_DIR)/prekernel.o $(BUILD_DIR)/KHeap.o $(BUILD_DIR)/pci.o $(BUILD_DIR)/pcidevice.o $(BUILD_DIR)/atapiDevice.o $(BUILD_DIR)/ataDevice.o $(BUILD_DIR)/rsdp.o $(BUILD_DIR)/acpi.o
+OFILES =$(BUILD_DIR)/boot.o $(BUILD_DIR)/kterm.o $(BUILD_DIR)/kernel.o $(BUILD_DIR)/memory.o  $(BUILD_DIR)/paging.o	$(BUILD_DIR)/VFS.o $(BUILD_DIR)/pit.o 	$(BUILD_DIR)/time.o	$(BUILD_DIR)/keyboard.o	 $(BUILD_DIR)/io.o 	$(BUILD_DIR)/processor.o $(BUILD_DIR)/gdtc.o $(BUILD_DIR)/idt.o $(BUILD_DIR)/pic.o $(BUILD_DIR)/sv-terminal.o $(BUILD_DIR)/prekernel.o $(BUILD_DIR)/KHeap.o $(BUILD_DIR)/pci.o $(BUILD_DIR)/pcidevice.o $(BUILD_DIR)/atapiDevice.o $(BUILD_DIR)/ataDevice.o $(BUILD_DIR)/rsdp.o $(BUILD_DIR)/acpi.o
 
 SRC_DIR = source
 BUILD_DIR = build
@@ -53,8 +52,7 @@ test_disk: all
 
 
 build_kernel: $(OBJ_LINK_LIST)
-	$(CC) -T $(SRC_DIR)/kernel//linker.ld -o $(BUILD_DIR)/myos.bin \
-	 -ffreestanding -ggdb -Og -nostdlib $(OBJ_LINK_LIST) -lgcc
+	$(CPP) -T $(SRC_DIR)/kernel/linker.ld -o $(BUILD_DIR)/myos.bin -ffreestanding -ggdb -Og -nostdlib $(OBJ_LINK_LIST) -lgcc -L source/CoreLib/build -lCoreLib
 
 build_x86_64: 
 	$(AS) $(SRC_DIR)/cgc/x86_64/crti.s -o $(BUILD_DIR)/crti_64.o
@@ -71,7 +69,7 @@ $(BUILD_DIR)/kterm.o:
 	$(CPP) -c $(SRC_DIR)/kernel/terminal/kterm.cpp  -o $(BUILD_DIR)/kterm.o $(CFLAGS) -fno-exceptions -fno-rtti
 
 $(BUILD_DIR)/io.o:
-		$(CPP) -c $(SRC_DIR)/kernel/drivers/io/io.cpp  -o $(BUILD_DIR)/io.o $(CFLAGS) -fno-exceptions -fno-rtti
+	$(CPP) -c $(SRC_DIR)/kernel/drivers/io/io.cpp  -o $(BUILD_DIR)/io.o $(CFLAGS) -fno-exceptions -fno-rtti
 
 $(BUILD_DIR)/idt.o:
 	$(CPP) -c $(SRC_DIR)/kernel/interrupts/idt.cpp -o $(BUILD_DIR)/idt.o $(CFLAGS) -fno-exceptions -fno-rtti
@@ -82,9 +80,6 @@ $(BUILD_DIR)/gdtc.o:
 $(BUILD_DIR)/pic.o:
 	$(CPP) -c $(SRC_DIR)/kernel/drivers/pic/pic.cpp -o $(BUILD_DIR)/pic.o $(CFLAGS) -fno-exceptions -fno-rtti
 
-$(BUILD_DIR)/string.o:
-	$(CC) -c $(SRC_DIR)/lib/include/string.c  -o $(BUILD_DIR)/string.o $(CFLAGS) -std=gnu99
-
 $(BUILD_DIR)/PhysicalMemoryManager.o:
 	$(CPP) -c $(SRC_DIR)/kernel/memory/PhysicalMemoryManager.cpp  -o $(BUILD_DIR)/PhysicalMemoryManager.o $(CFLAGS) -fno-exceptions -fno-rtti
 
@@ -136,9 +131,6 @@ $(BUILD_DIR)/prekernel.o:
 $(BUILD_DIR)/processor.o:
 	$(CPP) -c $(SRC_DIR)/kernel/i386/processor.cpp -o $(BUILD_DIR)/processor.o $(CFLAGS) -fno-exceptions -fno-rtti
 
-$(BUILD_DIR)/Path.o:
-	$(CPP) -c $(SRC_DIR)/kernel/vfs/Path.cpp -o $(BUILD_DIR)/Path.o $(CFLAGS) -fno-exceptions -fno-rtti
-
 # Assembly -> Object files
 $(BUILD_DIR)/boot.o:
 	$(AS) $(SRC_DIR)/kernel/boot/boot.s -o $(BUILD_DIR)/boot.o

source/CoreLib/Makefile

@@ -0,0 +1,33 @@
+CPP = ${HOME}/opt/cross/bin/i686-elf-g++
+CFLAGS = -ffreestanding -Og -ggdb -Wall -Wextra
+
+SRC_DIR = .
+BUILD_DIR = build
+OBJ_FOLDER = bin
+OUTPUTFILE = $(BUILD_DIR)/libCoreLib.a
+
+OFILES = $(OBJ_FOLDER)/memory.o $(OBJ_FOLDER)/path.o $(OBJ_FOLDER)/stack.o $(OBJ_FOLDER)/string.o $(OBJ_FOLDER)/stringview.o
+
+
+.phony: all
+all: $(OUTPUTFILE)
+	cp *.h build/include/
+
+$(OUTPUTFILE): $(OFILES)
+	ar -rc $(OUTPUTFILE) $(OFILES)
+
+$(OBJ_FOLDER)/memory.o: Memory.cpp
+	$(CPP) -c Memory.cpp -o $(OBJ_FOLDER)/memory.o $(CFLAGS)
+
+$(OBJ_FOLDER)/path.o: Path.cpp
+	$(CPP) -c Path.cpp  -o $(OBJ_FOLDER)/path.o $(CFLAGS)
+
+$(OBJ_FOLDER)/stack.o: Stack.cpp
+	$(CPP) -c Stack.cpp  -o $(OBJ_FOLDER)/stack.o $(CFLAGS)
+
+$(OBJ_FOLDER)/string.o: String.cpp
+	$(CPP) -c String.cpp -o $(OBJ_FOLDER)/string.o $(CFLAGS)
+
+$(OBJ_FOLDER)/stringview.o: StringView.cpp
+	$(CPP) -c StringView.cpp  -o $(OBJ_FOLDER)/stringview.o $(CFLAGS)
+

source/CoreLib/Memory.cpp

@@ -0,0 +1,58 @@
+//
+// Created by nigel on 19/02/23.
+//
+#include "Memory.h"
+
+void* memset (void* ptr, int value, size_t num)
+{
+    for( int i = 0; i < num; i++ )
+    {
+        unsigned char* data  = (unsigned char*)ptr+ i;
+        *data = (unsigned char)value;
+    }
+    return ptr;
+}
+
+
+int memcmp( const void* ptr1, const void* ptr2, size_t num)
+{
+    const unsigned char * cs = (const unsigned char*) ptr1;
+    const unsigned char * ct = (const unsigned char*) ptr2;
+
+
+    for (int i = 0 ; i < num ; i++, cs++, ct++ ){
+        if( *cs < *ct){
+            return -1;
+        } else if( *cs > *ct){
+            return 1;
+        }
+    }
+
+    return 0;
+
+}
+
+size_t strlen(const char* str) {
+    size_t len = 0;
+    while(str[len]){
+        len++;
+    }
+    return len;
+}
+
+int strncmp ( const char* str1, const char* str2, size_t num ){
+    for( int i = 0; i < num ; i++){
+
+        if( str1[i] < str2[i]){
+            return -1;
+        }
+
+        if( str1[i] > str2[i] ){
+            return 1;
+        }
+
+
+    }
+
+    return 0;
+}

source/CoreLib/Memory.h

@@ -0,0 +1,12 @@
+#pragma once
+
+#include <stddef.h>
+#include <stdint.h>
+
+void* memset (void* ptr, int value, size_t num);
+
+int memcmp( const void* ptr1, const void* ptr2, size_t num);
+
+size_t strlen(const char* str);
+
+int strncmp ( const char* str1, const char* str2, size_t num );

source/CoreLib/Path.cpp

@@ -0,0 +1,24 @@
+//
+// Created by nigel on 19/02/23.
+//
+#include "Path.h"
+
+Path::Path(String path)
+: path(path)
+{
+
+}
+
+StringView Path::getbasename()
+{
+    unsigned int path_length = path.length();
+    int i = path_length;
+    while (path[i] != '/')
+        i--;
+
+    return {path,static_cast<unsigned int>(i +1), path_length};
+}
+
+char* Path::str() {
+    return path.str();
+}

source/CoreLib/Path.h

@@ -0,0 +1,22 @@
+//
+// Created by nigel on 19/02/23.
+//
+#pragma once
+#include <stddef.h>
+#include "StringView.h"
+
+
+class Path{
+public:
+    explicit Path(String path);
+
+    StringView getbasename();
+
+    char* str();
+
+private:
+    String path;
+
+};
+
+

source/CoreLib/Stack.cpp

@@ -0,0 +1,3 @@
+//
+// Created by nigel on 19/02/23.
+//

source/CoreLib/Stack.h

@@ -1,5 +1,5 @@
 #pragma once
-#include "../../kernel/memory/KernelHeap.h"
+#include "../kernel/memory/KernelHeap.h"
 #include <stdint.h>
 
 template <typename T>

source/CoreLib/String.cpp

@@ -0,0 +1,39 @@
+#include "String.h"
+#include <stdint.h>
+#include <stddef.h>
+
+
+String::String(char* characters)
+: chars(characters)
+        {
+
+        }
+
+char* String::str(){
+    return chars;
+}
+
+unsigned int String::length ()
+{
+    int i = 0;
+
+    while (  chars[i] != '\0'){
+        i++;
+    }
+
+    return i;
+}
+
+// Returns a null character if size exceeds limits
+char String::operator[] (size_t idx)
+{
+    if( idx  > this->length())
+        return '\0';
+
+    return chars[idx];
+}
+
+const char String::operator[](size_t idx) const {
+return (const char) chars[idx];
+}
+

source/CoreLib/String.h

@@ -0,0 +1,18 @@
+#pragma once
+#include <stddef.h>
+
+class  String {
+public:
+    String(char* characters);
+    String(String&) = default;
+    unsigned int length();
+
+    char* str ();
+    char operator[](size_t index) ;
+    const char operator[](size_t idx) const;
+
+protected:
+    char* chars;
+
+
+};

source/CoreLib/StringView.cpp

@@ -0,0 +1,14 @@
+//
+// Created by nigel on 19/02/23.
+//
+#include "StringView.h"
+
+StringView::StringView(String string, unsigned int start, unsigned int end)
+        : String(string), begin(start), end(end)
+{
+
+}
+
+char* StringView::str(){
+   //TODO: Not implemented
+}

source/CoreLib/StringView.h

@@ -0,0 +1,14 @@
+//
+// Created by nigel on 19/02/23.
+//
+#pragma once
+#include "String.h"
+
+class StringView : String {
+public:
+    StringView(String string, unsigned int start, unsigned  int end );
+    char* str ();
+private:
+    unsigned int begin;
+    unsigned int end;
+};

source/kernel/drivers/acpi/rsdp.h

@@ -1,7 +1,8 @@
 #pragma once
 #include <stdint.h>
 #include "./../../terminal/kterm.h"
-#include "../../../lib/include/mem.h"
+#include <CoreLib/Memory.h>
+
 struct RSDPTR {
     char signature[8];
     uint8_t Checksum ;

source/kernel/drivers/ata/ataDevice.cpp

@@ -12,7 +12,6 @@ void ATA_DEVICE::Soft_Reset(uint8_t DEVICE_CHANNEL,DEVICE_DRIVE drive){
 
 }
 
-
 void ATA_DEVICE::Identify(uint16_t DEVICE_CHANNEL,DEVICE_DRIVE drive ){
     // lets ignore which port we actually want to check for now !
 

source/kernel/kernel.cpp

@@ -1,10 +1,6 @@
 /*
     Copyright © Nigel Barink 2023
 */
-extern "C"{
-#include "../lib/include/string.h"
-}
-
 #include "memory/memory.h"
 #include "memory/KernelHeap.h"
 #include "memory/gdt/gdtc.h"

source/kernel/memory/PhysicalMemoryManager.h

@@ -1,8 +1,9 @@
 #pragma once
 #include <stddef.h>
+#include <CoreLib/Memory.h>
+
 #include "../prekernel/bootstructure.h"
 #include "../terminal/kterm.h"
-#include "../../lib/include/mem.h"
 #include "../bitmap.h"
 
 #define BLOCK_SIZE 4092 

source/kernel/memory/TaskStateSegment.h

@@ -1,6 +1,6 @@
 #pragma once
 #include "gdt/gdtc.h"
-#include "../../lib/include/string.h"
+#include <CoreLib/Memory.h>
 
 struct TaskStateSegment {
     uint32_t prev_tss;

source/kernel/memory/memory.h

@@ -5,7 +5,8 @@
 #include "memoryinfo.h"
 #include "../prekernel/multiboot.h"
 #include "../terminal/kterm.h"
-#include "../../lib/include/mem.h"
+#include <CoreLib/Memory.h>
+
 #include "../bitmap.h"
 
 #define BLOCK_SIZE 4092

source/kernel/supervisorterminal/superVisorTerminal.h

@@ -4,8 +4,6 @@
 #include "../drivers/pit/pit.h"
 #include "../drivers/ps-2/keyboard.h"
 #include "../memory/PhysicalMemoryManager.h"
-extern "C" {
-    #include "../../lib/include/string.h"
-}
+#include <CoreLib/Memory.h>
 
 extern "C" void startSuperVisorTerminal();

source/kernel/terminal/kterm.h

@@ -5,10 +5,7 @@
 
 #include "../drivers/vga/colors.h"
 #include "../drivers/io/io.h"
-extern "C" {
-#include "../../lib/include/string.h"
-}
-
+#include "CoreLib/Memory.h"
 
 void kterm_init();
 

source/kernel/vfs/Path.cpp

@@ -1,83 +0,0 @@
-//
-// Created by nigel on 19/02/23.
-//
-#include "Path.h"
-#include "../memory/KernelHeap.h"
-String::String(char* characters)
-: chars(characters)
-{
-
-}
-
-char* String::str(){
-    return chars;
-}
-
-unsigned int String::length ()
-{
-    int i = 0;
-
-    while (  chars[i] != '\0'){
-        i++;
-    }
-
-    return i;
-}
-
-// Returns a null character if size exceeds limits
-char String::operator[] (size_t idx)
-{
-    if( idx  > this->length())
-        return '\0';
-
-    return chars[idx];
-}
-
-const char String::operator[](size_t idx) const {
-    return (const char) chars[idx];
-}
-
-StringView::StringView(String &string, unsigned int start, unsigned int end)
-: String(string), begin(start), end(end)
-{
-
-}
-
-char* StringView::str(){
-    char* str = (char*) malloc((this->length() * sizeof(char))+1);
-
-    int index = 0;
-    for ( int i = begin; i < end ; i++){
-        str[index] = chars[i];
-        index++;
-    }
-    chars[index+1] ='\0';
-    return str;
-}
-
-
-Path::Path(char *path)
-: path(String(path))
-{
-
-}
-
-Path::Path(String &path)
-: path(path)
-{
-
-}
-
-StringView Path::getbasename()
-{
-    unsigned int path_length = path.length();
-    int i = path_length;
-    while (path[i] != '/')
-        i--;
-
-    return StringView(path,i +1, path_length);
-}
-
-char* Path::str() {
-    return path.str();
-}

source/kernel/vfs/Path.h

@@ -1,46 +0,0 @@
-//
-// Created by nigel on 19/02/23.
-//
-#pragma once
-#include <stddef.h>
-
-class  String {
-public:
-    String(char* characters);
-    String(String&) = default;
-    unsigned int length();
-
-    char* str ();
-    char operator[](size_t index) ;
-    const char operator[](size_t idx) const;
-
-protected:
-    char* chars;
-
-
-};
-
-class StringView : String {
-public:
-    StringView(String& string, unsigned int start, unsigned  int end );
-    char* str ();
-private:
-    unsigned int begin;
-    unsigned int end;
-};
-
-class Path{
-public:
-    Path(String& path);
-    Path(char* path);
-
-    StringView getbasename();
-
-    char* str();
-
-private:
-    String path;
-
-};
-
-

source/kernel/vfs/VFS.cpp

@@ -4,7 +4,7 @@
 #include "../drivers/ata/ataDevice.h"
 #include "../partitiontable/mbr/MasterBootRecord.h"
 #include "../memory/KernelHeap.h"
-#include "Path.h"
+#include "../../CoreLib/Memory.h"
 #include "../filesystem/FAT/DirectoryEntry.h"
 
 MOUNT_INFO mountInfo;
@@ -389,6 +389,8 @@ char* FindNextEntryName (char* path )
 
 void FileSystem::ResolvePath(Path &path)
 {
+    // See reference material (1) https://man7.org/linux/man-pages/man7/path_resolution.7.html
+
     char* string_path  = path.str();
     void* cpy = string_path;
 
@@ -410,9 +412,6 @@ void FileSystem::ResolvePath(Path &path)
     skip = strlen(entry_name);
     free(entry_name);
 
-
-
-
     free(cpy);
 
 }

source/kernel/vfs/VFS.h

@@ -1,6 +1,6 @@
 #pragma once
 #include <stdint.h>
-#include "Path.h"
+#include "../../CoreLib/Path.h"
 
 #define FS_FILE 0
 #define FS_DIRECTORY 1

source/lib/include/mem.h

@@ -1,31 +0,0 @@
-#pragma once
-// NOTE: These should not be inline 
-inline void* memset (void* ptr, int value, size_t num)
-{
-    for( int i = 0; i < num; i++ )
-    {
-        unsigned char* data  = (unsigned char*)ptr+ i;
-        *data = (unsigned char)value;
-    }
-    return ptr;
-}
-
-
-
-inline int memcmp( const void* ptr1, const void* ptr2, size_t num)
-{
-    const unsigned char * cs = (const unsigned char*) ptr1;
-    const unsigned char * ct = (const unsigned char*) ptr2;
-
-
-    for (int i = 0 ; i < num ; i++, cs++, ct++ ){
-       if( *cs < *ct){
-           return -1;
-       } else if( *cs > *ct){
-           return 1;
-       }
-    }
-
-    return 0;
-
-}

source/lib/include/string.c

@@ -1,26 +0,0 @@
-#include "string.h"
-
-size_t strlen(const char* str) {
-    size_t len = 0;
-    while(str[len]){
-        len++;
-    }
-    return len;
-}
-
-int strncmp ( const char* str1, const char* str2, size_t num ){
-    for( int i = 0; i < num ; i++){
-        
-        if( str1[i] < str2[i]){
-            return -1;
-        } 
-
-        if( str1[i] > str2[i] ){
-            return 1;
-        }
-
-
-    }
-
-    return 0;
-}

source/lib/include/string.h

@@ -1,4 +0,0 @@
-#pragma once
-#include <stddef.h>
-size_t strlen(const char* str);
-int strncmp ( const char* str1, const char* str2, size_t num );