package jiexi;
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public class HexUtils {
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// 十六进制字符快速转换表 (ASCII范围内)
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private static final int[] HEX_VALUES = new int[128];
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static {
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for (int i = 0; i < HEX_VALUES.length; i++) {
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char c = (char) i;
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if (c >= '0' && c <= '9') HEX_VALUES[i] = c - '0';
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else if (c >= 'A' && c <= 'F') HEX_VALUES[i] = 10 + (c - 'A');
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else if (c >= 'a' && c <= 'f') HEX_VALUES[i] = 10 + (c - 'a');
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else HEX_VALUES[i] = -1;
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}
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}
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// 线程安全的字符缓冲区 (初始大小256)
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private static final ThreadLocal<char[]> CHAR_BUF_CACHE =
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ThreadLocal.withInitial(() -> new char[256]);
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/**
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* 获取线程本地字符缓冲区
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* @return 可复用的char[256]缓冲区
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*/
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public static char[] getThreadLocalBuffer() {
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return CHAR_BUF_CACHE.get();
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}
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/**
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* 快速将两个十六进制字符转换为字节
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* @param c1 高位字符 (0-9, A-F, a-f)
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* @param c2 低位字符 (0-9, A-F, a-f)
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* @return 转换后的字节值 (无效字符返回0)
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*/
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public static int fastHexToByte(char c1, char c2) {
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int high = (c1 < 128) ? HEX_VALUES[c1] : -1;
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int low = (c2 < 128) ? HEX_VALUES[c2] : -1;
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if (high < 0 || low < 0) return 0;
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return (high << 4) | low;
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}
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}
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