[CPP] Add std::string

Author: scopeInfinity

src/usr/include/iostream.h

@@ -1,5 +1,6 @@
 #pragma once
 
+#include <string.h>
 
 namespace std {
 
@@ -9,8 +10,9 @@ extern const char endl;
 class ostream {
 public:
     ostream& operator<<(const char c);
-    ostream& operator<<(const char* str);
     ostream& operator<<(const int num);
+    ostream& operator<<(const std::string &str);
+    ostream& operator<<(const char* str);
 };
 
 class istream {

src/usr/include/string.h

@@ -7,9 +7,9 @@ extern "C" {
 namespace std {
 #endif
 
-int strcmp(char *l, char *r);
-int strcmpi(char *l, char *r);
-int strlen(char *str);
+int strcmp(const char *l, const char *r);
+int strcmpi(const char *l, const char *r);
+int strlen(const char *str);
 char *strcpy(char *dest, const char *src);
 char *strncpy(char *dest, const char *src, size_t n);
 void *memcpy(void *dest, const void *src, unsigned int n);
@@ -22,3 +22,34 @@ char *strtok(char *str, const char *delim);
 }  // namespace std end
 }  // extern C end
 #endif
+
+
+#ifdef __cplusplus
+#include <vector.h>
+
+namespace std {
+
+template<typename CharT>
+class basic_string {
+    std::vector<CharT> _data;
+
+public:
+    basic_string();
+    basic_string(std::size_t n, CharT c);
+    basic_string(const CharT* str);
+    basic_string(const CharT* str, std::size_t n);
+
+    CharT& back();
+    CharT& front();
+    CharT& at(std::size_t pos);
+    CharT& operator[](std::size_t pos);
+    const CharT *c_str() const;
+};
+
+using string = basic_string<char>;
+
+}  // namespace std end
+
+#include <string.tcc>
+
+#endif

src/usr/include/string.tcc

@@ -0,0 +1,58 @@
+#pragma once
+
+// This is internal headerfile to be included by string.h only
+
+#include <string.h>
+
+namespace std {
+
+template <typename CharT>
+basic_string<CharT>::basic_string() : _data(1, '\0') {}
+
+template <typename CharT>
+basic_string<CharT>::basic_string(std::size_t n, CharT c) : _data(n+1, c) {
+    this->_data[n] = '\0';
+}
+
+template <typename CharT>
+basic_string<CharT>::basic_string(const CharT* str) : _data(std::strlen(str)+1, '\0') {
+    for (std::size_t i = 0; i < this->_data.size(); i++) {
+        this->_data[i] = str[i];
+    }
+}
+
+template <typename CharT>
+basic_string<CharT>::basic_string(const CharT* str, std::size_t n) {
+    int str_n = std::strlen(str);
+    this->_data(n+1, '\0');
+    for (std::size_t i = 0; i < n && i < str_n; i++) {
+        this->_data[i] = str[i];
+    }
+}
+
+template <typename CharT>
+CharT& basic_string<CharT>::back() {
+    return this->_data.at(this->_data.size()-2);
+}
+
+template <typename CharT>
+CharT& basic_string<CharT>::front() {
+    return this->_data.at(0);
+}
+
+template <typename CharT>
+CharT& basic_string<CharT>::at(std::size_t pos) {
+    return this->_data.at(pos);
+}
+
+template <typename CharT>
+CharT& basic_string<CharT>::operator[](std::size_t pos) {
+    return this->_data[pos];
+}
+
+template <typename CharT>
+const CharT *basic_string<CharT>::c_str() const {
+    return this->_data.raw_data();
+}
+
+} // namespace std end

src/usr/include/vector.h

@@ -14,6 +14,7 @@ class vector {
     vector<T>();
     vector<T>(std::size_t size, const T &_default);
 
+    T *raw_data() const;
     bool empty();
     std::size_t size();
     void push_back(const T &val);

src/usr/include/vector.tcc

@@ -44,6 +44,11 @@ void vector<T>::resize_capacity(std::size_t capacity) {
     this->_data = _new_data;
 }
 
+template <typename T>
+T *vector<T>::raw_data() const {
+    return this->_data;
+}
+
 template <typename T>
 bool vector<T>::empty() {
     return this->_size == 0;
@@ -74,6 +79,7 @@ template <typename T>
 T &vector<T>::back() {
     return this->_data[this->_size-1];
 }
+
 template <typename T>
 T &vector<T>::front() {
     return this->_data[0];

src/usr/lib/iostream.cpp

@@ -9,8 +9,9 @@ ostream cout;
 istream cin;
 
 ostream& ostream::operator<<(const char c) { putchar(c); return *this; }
-ostream& ostream::operator<<(const char *str) { puts(str); return *this; }
 ostream& ostream::operator<<(const int num) { printf("%d", num); return *this; }
+ostream& ostream::operator<<(const char *str) { puts(str); return *this; }
+ostream& ostream::operator<<(const std::string &str) { puts(str.c_str()); return *this; }
 
 istream& istream::operator>>(char &c) { c = getch(); putchar(c); return *this; }
 istream& istream::operator>>(char *str) { gets(str); return *this; }

src/usr/lib/string.c

@@ -2,8 +2,8 @@
 #include <stddef.h>
 #include <ctype.h>
 
-int strcmp(char *l, char *r) {
-    int i=0,j=0;
+int strcmp(const char *l, const char *r) {
+    int i=0, j=0;
     while(l[i]!='\0' && r[j]!='\0') {
         if(l[i]!=r[j]) {
             return l[i]-r[j];
@@ -19,8 +19,8 @@ int strcmp(char *l, char *r) {
     return -1;
 }
 
-int strcmpi(char *l, char *r) {
-    int i=0,j=0;
+int strcmpi(const char *l, const char *r) {
+    int i=0, j=0;
     while(l[i]!='\0' && r[j]!='\0') {
         char a = tolower(l[i]);
         char b = tolower(r[j]);
@@ -38,7 +38,7 @@ int strcmpi(char *l, char *r) {
     return -1;
 }
 
-int strlen(char *str) {
+int strlen(const char *str) {
     int n=0;
     while((*str)!='\0') {
         n++;

src/usr/local/src/simplecpp.cpp

@@ -74,6 +74,10 @@ int main(int argc, char *argv[]) {
         std::cout << "list[" << (int)i << "] = " << list[i] << std::endl;
     }
 
+    // std::string
+    std::string cpp_string("i am c++ string");
+    std::cout << "Out: " << cpp_string << std::endl;
+
     std::cout << "Exiting..." << std::endl;
     return 0;
 }