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/*
* File: strlib.cpp
* ----------------
* This file implements the strlib.h interface.
*/
#include <cctype>
#include <iomanip>
#include <iostream>
#include <sstream>
#include "error.h"
#include "strlib.h"
using namespace std;
/* Function prototypes */
/*
* Implementation notes: numeric conversion
* ----------------------------------------
* These functions use the <sstream> library to perform the conversion.
*/
string integerToString(int n) {
ostringstream stream;
stream << n;
return stream.str();
}
int stringToInteger(string str) {
istringstream stream(str);
int value;
stream >> value >> ws;
if (stream.fail() || !stream.eof()) {
error("stringToInteger: Illegal integer format (" + str + ")");
}
return value;
}
string realToString(double d) {
ostringstream stream;
stream << uppercase << d;
return stream.str();
}
double stringToReal(string str) {
istringstream stream(str);
double value;
stream >> value >> ws;
if (stream.fail() || !stream.eof()) {
error("stringToReal: Illegal floating-point format (" + str + ")");
}
return value;
}
/*
* Implementation notes: case conversion
* -------------------------------------
* The functions toUpperCase and toLowerCase return a new string whose
* characters appear in the desired case. These implementations rely on
* the fact that the characters in the string are copied when the
* argument is passed to the function, which makes it possible to change
* the case of the copy without affecting the original.
*/
string toUpperCase(string str) {
int nChars = str.length();
for (int i = 0; i < nChars; i++) {
str[i] = toupper(str[i]);
}
return str;
}
string toLowerCase(string str) {
int nChars = str.length();
for (int i = 0; i < nChars; i++) {
str[i] = tolower(str[i]);
}
return str;
}
/*
* Implementation notes: equalsIgnoreCase
* --------------------------------------
* This implementation uses a for loop to cycle through the characters in
* each string. Converting each string to uppercase and then comparing
* the results makes for a shorter but less efficient implementation.
*/
bool equalsIgnoreCase(string s1, string s2) {
if (s1.length() != s2.length()) return false;
int nChars = s1.length();
for (int i = 0; i < nChars; i++) {
if (tolower(s1[i]) != tolower(s2[i])) return false;
}
return true;
}
/*
* Implementation notes: startsWith, endsWith
* ------------------------------------------
* These implementations are overloaded to allow the second argument to
* be either a string or a character.
*/
bool startsWith(string str, string prefix) {
if (str.length() < prefix.length()) return false;
int nChars = prefix.length();
for (int i = 0; i < nChars; i++) {
if (str[i] != prefix[i]) return false;
}
return true;
}
bool startsWith(string str, char prefix) {
return str.length() > 0 && str[0] == prefix;
}
bool endsWith(string str, string suffix) {
int nChars = suffix.length();
int start = str.length() - nChars;
if (start < 0) return false;
for (int i = 0; i < nChars; i++) {
if (str[start + i] != suffix[i]) return false;
}
return true;
}
bool endsWith(string str, char suffix) {
return str.length() > 0 && str[str.length() - 1] == suffix;
}
string trim(string str) {
int finish = str.length() - 1;
while (finish >= 0 && isspace(str[finish])) {
finish--;
}
int start = 0;
while (start <= finish && isspace(str[start])) {
start++;
}
return str.substr(start, finish - start + 1);
}
/*
* Implementation notes: readQuotedString and writeQuotedString
* ------------------------------------------------------------
* Most of the work in these functions has to do with escape sequences.
*/
static const string STRING_DELIMITERS = ",:)}]\n";
bool stringNeedsQuoting(const string & str) {
int n = str.length();
for (int i = 0; i < n; i++) {
char ch = str[i];
if (isspace(ch)) return false;
if (STRING_DELIMITERS.find(ch) != string::npos) return true;
}
return false;
}
void readQuotedString(istream & is, string & str) {
str = "";
char ch;
while (is.get(ch) && isspace(ch)) {
/* Empty */
}
if (is.fail()) return;
if (ch == '\'' || ch == '"') {
char delim = ch;
while (is.get(ch) && ch != delim) {
if (is.fail()) error("Unterminated string");
if (ch == '\\') {
if (!is.get(ch)) error("Unterminated string");
if (isdigit(ch) || ch == 'x') {
int maxDigits = 3;
int base = 8;
if (ch == 'x') {
base = 16;
maxDigits = 2;
}
int result = 0;
int digit = 0;
for (int i = 0; i < maxDigits && ch != delim; i++) {
if (isdigit(ch)) {
digit = ch - '0';
} else if (base == 16 && isxdigit(ch)) {
digit = toupper(ch) - 'A' + 10;
} else {
break;
}
result = base * result + digit;
if (!is.get(ch)) error("Unterminated string");
}
ch = char(result);
is.unget();
} else {
switch (ch) {
case 'a': ch = '\a'; break;
case 'b': ch = '\b'; break;
case 'f': ch = '\f'; break;
case 'n': ch = '\n'; break;
case 'r': ch = '\r'; break;
case 't': ch = '\t'; break;
case 'v': ch = '\v'; break;
case '"': ch = '"'; break;
case '\'': ch = '\''; break;
case '\\': ch = '\\'; break;
}
}
}
str += ch;
}
} else {
str += ch;
int endTrim = 0;
while (is.get(ch) && STRING_DELIMITERS.find(ch) == string::npos) {
str += ch;
if (!isspace(ch)) endTrim = str.length();
}
if (is) is.unget();
str = str.substr(0, endTrim);
}
}
void writeQuotedString(ostream & os, const string & str, bool forceQuotes) {
if (!forceQuotes && stringNeedsQuoting(str)) forceQuotes = true;
if (forceQuotes) os << '"';
int len = str.length();
for (int i = 0; i < len; i++) {
char ch = str.at(i);
switch (ch) {
case '\a': os << "\\a"; break;
case '\b': os << "\\b"; break;
case '\f': os << "\\f"; break;
case '\n': os << "\\n"; break;
case '\r': os << "\\r"; break;
case '\t': os << "\\t"; break;
case '\v': os << "\\v"; break;
case '\\': os << "\\\\"; break;
default:
if (isprint(ch) && ch != '"') {
os << ch;
} else {
ostringstream oss;
oss << oct << setw(3) << setfill('0') << (int(ch) & 0xFF);
os << "\\" << oss.str();
}
}
}
if (forceQuotes) os << '"';
}
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