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Diffstat (limited to 'labb5/lib/StanfordCPPLib/strlib.cpp')
| -rwxr-xr-x | labb5/lib/StanfordCPPLib/strlib.cpp | 252 |
1 files changed, 252 insertions, 0 deletions
diff --git a/labb5/lib/StanfordCPPLib/strlib.cpp b/labb5/lib/StanfordCPPLib/strlib.cpp new file mode 100755 index 0000000..7e53235 --- /dev/null +++ b/labb5/lib/StanfordCPPLib/strlib.cpp @@ -0,0 +1,252 @@ +/* + * 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 << '"'; +} |