Main.java Source code

Introduction

Here is the source code for Main.java

Source

//package com.java2s;

public class Main {
    public static int parseInt(String string) throws Throwable {
        return parseInt(string, 10);
    }

    public static int parseInt(String string, int radix) throws Throwable {
        if (radix >= 2 && radix <= 36) {
            if (string == null) {
                throw invalidInt(string);
            } else {
                int length = string.length();
                int i = 0;
                if (length == 0) {
                    throw invalidInt(string);
                } else {
                    boolean negative = string.charAt(i) == 45;
                    if (negative) {
                        ++i;
                        if (i == length) {
                            throw invalidInt(string);
                        }
                    }

                    return parseInt(string, i, radix, negative);
                }
            }
        } else {
            throw new Throwable("Invalid radix: " + radix);
        }
    }

    private static int parseInt(String string, int offset, int radix, boolean negative) throws Throwable {
        int max = -2147483648 / radix;
        int result = 0;

        int next;
        for (int length = string.length(); offset < length; result = next) {
            int digit = digit(string.charAt(offset++), radix);
            if (digit == -1) {
                throw invalidInt(string);
            }

            if (max > result) {
                throw invalidInt(string);
            }

            next = result * radix - digit;
            if (next > result) {
                throw invalidInt(string);
            }
        }

        if (!negative) {
            result = -result;
            if (result < 0) {
                throw invalidInt(string);
            }
        }

        return result;
    }

    private static Throwable invalidInt(String s) throws Throwable {
        throw new Throwable("Invalid int: \"" + s + "\"");
    }

    private static int digit(int codePoint, int radix) {
        if (radix >= 2 && radix <= 36) {
            int result = -1;
            if (48 <= codePoint && codePoint <= 57) {
                result = codePoint - 48;
            } else if (97 <= codePoint && codePoint <= 122) {
                result = 10 + (codePoint - 97);
            } else if (65 <= codePoint && codePoint <= 90) {
                result = 10 + (codePoint - 65);
            }

            return result < radix ? result : -1;
        } else {
            return -1;
        }
    }
}