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| <?php | |
| // 知识点 | |
| // 1. 二进制 | |
| // 2. 字节序 | |
| padding(2): a/A | |
| 4(2): h/H | |
| 8(2): c/C | |
| 16(4): s/S/n(Big)/v | |
| 32(4): l/L/N(Big)/V | |
| i/I | |
| // ----------------(4)-------------------------------------- | |
| // s -- 有符号短整数 (16位，主机字节序) | |
| // S -- 无符号短整数 (16位，主机字节序) | |
| // n -- 无符号短整数 (16位, 大端字节序) | |
| // v -- 无符号短整数 (16位, 小端字节序) | |
| // ------------------------------------------------------ | |
| $bin = 'abcd'; | |
| // 小端字节序 | |
| // 0: 25185(ab) | |
| // 1: 25699(cd) | |
| // 0: 0110_0010(b) 0110_0001(a) | |
| // 1: 0110_0100(d) 0110_0011(c) | |
| var_dump(unpack('v*', $bin)); | |
| echo base_convert('25185', 10, 2); | |
| echo base_convert('25699', 10, 2); | |
| // 大端字节序 | |
| // 24930 | |
| // 25444 | |
| // 0: 0110_0001(a) 0110_0010(b) | |
| // 1: 0110_0011(c) 0110_0100(d) | |
| var_dump(unpack('n*', $bin)); | |
| echo base_convert('24930', 10, 2); | |
| echo base_convert('25444', 10, 2); | |
| // --------------------(4)---------------------------------- | |
| // l -- 有符号长整数 (32位，主机字节序) | |
| // L -- 无符号长整数 (32位，主机字节序) | |
| // N -- 无符号长整数 (32位, 大端字节序) | |
| // V -- 无符号长整数 (32位, 小端字节序) | |
| // ------------------------------------------------------ | |
| $bin = 'abcd'; | |
| // 1633837924 | |
| var_dump(unpack('N*', $bin)); | |
| // 0110_0001(a) 0110_0010(b) 0110_0011(c) 0110_0100(d) | |
| echo base_convert('1633837924', 10, 2); | |
| // ------------------------------------------------------ | |
| // H -- 16进制字符串，高位在前以半字节为单位 | |
| // ------------------------------------------------------ | |
| $bin = 'abcd'; | |
| // 0x61(a) 0x62(b) 0x63(c) 0x64(d) | |
| var_dump(unpack('H*', $bin)); | |
| ?> |
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