{"id":1095,"date":"2021-02-21T00:06:18","date_gmt":"2021-02-20T16:06:18","guid":{"rendered":"http:\/\/www.mrtblog.cn\/?p=1095"},"modified":"2023-03-12T15:38:52","modified_gmt":"2023-03-12T07:38:52","slug":"%e5%86%85%e5%ad%98%e5%af%b9%e9%bd%90-%e5%a4%a7%e5%b0%8f%e7%ab%af","status":"publish","type":"post","link":"http:\/\/www.mrtblog.cn\/?p=1095","title":{"rendered":"\u5185\u5b58\u5bf9\u9f50\/\u5927\u5c0f\u7aef"},"content":{"rendered":"
<\/span> 5,623<\/span> Views<\/span><\/div>

\u5fd8\u4e86\u7684\u65f6\u5019\u5c31\u56de\u6765\u770b\u770b\u8fd9\u7bc7\u6587\u7ae0<\/strong><\/p>\n

\u5927\u5c0f\u7aef\u7684\u5b9a\u4e49<\/h3>\n

\u5927\u7aef(BE)\uff1a\u5185\u5b58\u7684\u8d77\u59cb\u5730\u5740\u5b58\u653e\u9ad8\u4f4d\u7684\u6570\u636e
\n\u5c0f\u7aef(LE)\uff1a\u5185\u5b58\u7684\u8d77\u59cb\u5730\u5740\u5b58\u653e\u5730\u4f4d\u7684\u6570\u636e
\n0x12345678 12\u5728\u9ad8\u4f4d 78\u5728\u4f4e\u4f4d
\n\u5927\u7aef\u5b58\u50a8\u4e3a(\u5de6\u81f3\u53f3\u4e3a\u5185\u5b58\u4f4e\u5730\u5740->\u9ad8\u5730\u5740): 12 34 56 78
\n\u5c0f\u7aef\u5b58\u50a8\u4e3a(\u5de6\u81f3\u53f3\u4e3a\u5185\u5b58\u4f4e\u5730\u5740->\u9ad8\u5730\u5740)\uff1a78 56 34 12<\/p>\n

\u4e3a\u4ec0\u4e48\u8981\u6709\u5927\u5c0f\u7aef<\/h3>\n

TCP\u7b49\u534f\u8bae\u89c4\u5b9a\u4f20\u8f93\u65f6\u6570\u636e\u9075\u5faa\u5927\u7aef\u539f\u5219
\n\u5927\u591a\u6570\u7cfb\u7edf\u5185\u5b58\u4e2d\u7684\u6570\u636e\u9075\u5faa\u5c0f\u7aef\u539f\u5219
\n\u56e0\u4e3a\u4e00\u5f00\u59cb\u6ca1\u6709\u7edf\u4e00\u7684\u89c4\u8303\uff0c\u5404\u7cfb\u7edf\u5b9a\u4e49\u4e0d\u540c\uff0c\u9020\u6210\u4e86\u540e\u9762\u8fd9\u79cd\u4e24\u7aef\u5f00\u82b1\u7684\u5c40\u9762<\/p>\n

\u5982\u4f55\u5feb\u901f\u505a\u5927\u5c0f\u7aef\u8f6c\u6362<\/h3>\n

socket\u5e38\u7528\u4ee3\u7801<\/p>\n

#include<arpa\/inet.h>\n\nuint64_t i = 0x00010001;\n\/\/ host to net test\ncout << i << " " << htonl(i) << endl;\/\/\u5bf9\u5e94\u7684ntohl\n\/\/ \u8f93\u51fa\u7ed3\u679c\n\/\/ 65537 16777472\n\/\/ \u5206\u522b\u5bf9\u5e94 0x00010001 \u548c 0x01000100<\/code><\/pre>\n
\u600e\u4e48\u5224\u65ad\u7cfb\u7edf\u662f\u5927\u7aef\u8fd8\u662f\u5c0f\u7aef<\/h3>\n
\u5f3a\u5236\u7c7b\u578b\u8f6c\u6362\u6d4b\u8bd5<\/p>\n
\/\/le be test\nif (*(char*)&i == 0x00)\n{\n    cout << "big endian" << endl;\n}\nelse\n{\n    cout << "small endian" << endl;\n}\n\/\/ \u8f93\u51fa\u7ed3\u679c\n\/\/ small endian<\/code><\/pre>\n
\/\/ \u8bf4\u660e\u6211\u7684linux\u670d\u52a1\u5668\u662f\u5c0f\u7aef\u5b58\u50a8<\/p>\n
\u4ec0\u4e48\u662f\u5185\u5b58\u5bf9\u9f50<\/h3>\n
\u4f8b\u5982C++\u4e2d\u5e38\u89c1struct\u7ed3\u6784\u4f53\u5360\u7528\u7684\u5185\u5b58\u5e76\u4e0d\u662f\u7b80\u5355\u6309\u7167\u5143\u7d20\u5360\u7528\u7a7a\u95f4\u7d2f\u52a0
\n\u8ba1\u7b97\u5360\u7528\u7a7a\u95f4\u65f6\u9075\u5faa3\u539f\u5219
\n1.\u6bcf\u4e00\u4e2a\u5143\u7d20\u7684\u8d77\u59cb\u5730\u5740\u5fc5\u987b\u88ab\u81ea\u5df1\u7684\u5927\u5c0f\u6574\u9664
\n2.\u7ed3\u6784\u4f53\u603b\u5927\u5c0f\u5fc5\u987b\u88ab\u6700\u5927\u5143\u7d20\u7684\u5927\u5c0f\u6574\u9664
\n3.\u5982\u679c\u8bbe\u7f6e\u4e86#parma pack(n), \u7b2c2\u70b9\u6539\u4e3a\u7ed3\u6784\u4f53\u603b\u5927\u5c0f\u80fd\u88ab(\u6700\u5927\u5143\u7d20\u548cn\u7684\u8f83\u5c0f\u8005)\u6574\u9664  n\u9ed8\u8ba4\u4e3a4<\/p>\n
struct memOffset\n{\n    uint16_t a;\n    uint32_t b;\n    uint64_t c;\n};\n\/*\n00000000|00000000|0000000000000000\na        b        c\n*\/\n\/\/memoffset test\nmemOffset j;\ncout << "sizeof j is " << sizeof(j) << endl;\n\/\/ \u8f93\u51fa\u7ed3\u679c\n\/\/ size of j is 16<\/code><\/pre>\n
a\u53602\u5b57\u8282,\u8d77\u59cb\u4f4d\u7f6e\u4e3a0
\nb\u53604\u5b57\u8282,\u8d77\u59cb\u4f4d\u7f6e\u4e3a4(\u4e3a\u6ee1\u8db3\u6761\u4ef61, a\u540e\u9762\u586b\u5145\u4e24\u5b57\u8282)
\nc\u53608\u5b57\u8282,\u8d77\u59cb\u4f4d\u7f6e\u4e3a8<\/p>\n
\u8865\u5145\u4e00\u70b9,\u5982\u679c\u7ed3\u6784\u4f53\u4e2d\u5305\u542b\u7ed3\u6784\u4f53,\u5219
\n1.\u5b50\u7ed3\u6784\u4f53\u5185\u7684\u5143\u7d20\u8d77\u59cb\u4f4d\u7f6e\u4e3a\u5b50\u7ed3\u6784\u4f53\u5185\u6700\u5927\u5143\u7d20\u7684\u500d\u6570
\n2.\u5b50\u7ed3\u6784\u4f53\u7684\u603b\u5927\u5c0f(\u5982\u679c\u662f\u7236\u7ed3\u6784\u4f53\u5185\u6240\u6709\u5143\u7d20\u4e2d\u6700\u5927\u7684)\u4e0d\u80fd\u5f53\u4f5c\u7236\u7ed3\u6784\u4f53\u5185\u7684\u6700\u5927\u6210\u5458\u6765\u5224\u65ad,\u6bd4\u5982<\/p>\n
struct A\n{\n    uint16_t i;  \/\/start with 0, size is 2\n    struct\n    {\n        uint8_t j;  \/\/start with 4, size is 1\n        uint32_t k;  \/\/start with 8, size is 4\n    } l;   \/\/all size is 8\n    uint32_t m;  \/\/start with 12, size is 4\n    uint8_t n;\/\/start with 16, size is 1\n};  \/\/all size is 20, not 24\n\/\/ \u8f93\u51fa\u7ed3\u679c\n\/\/ sizeof struct struct is 20<\/code><\/pre>\n
\u4e3a\u4ec0\u4e48\u8981\u505a\u5185\u5b58\u5bf9\u9f50<\/h3>\n
\u64cd\u4f5c\u7cfb\u7edf\u4e2d\u8bfb\u53d6\u5185\u5b58\u4ee5\u9875\u4e3a\u5355\u4f4d,\u5982\u679c\u4e0d\u505a\u5185\u5b58\u5bf9\u9f50,\u5373\u8bfb\u53d6\u7684\u5185\u5bb9\u5730\u5740\u4e0d\u662f\u6309\u7167\u9875\u5927\u5c0f\u7684\u6574\u6570\u500d\u5f00\u59cb
\n\u5f88\u53ef\u80fd\u5bfc\u81f4\u539f\u672c\u4e00\u9875\u53ef\u4ee5\u8bfb\u5b8c\u7684\u6570\u636e\u88ab\u5212\u5206\u5230\u591a\u9875\u4e0a\uff0c\u591a\u6b21\u8bfb\u53d6\u548c\u62fc\u63a5\u64cd\u4f5c\u964d\u4f4e\u4e86\u7cfb\u7edf\u6027\u80fd\u3002<\/p>\n
\u5185\u5b58\u5bf9\u9f50\u7ed3\u5408\u5927\u5c0f\u7aef<\/h3>\n
\u628a\u4e4b\u524d\u7684i\u5f3a\u5236\u8f6c\u6362\u6210\u7ed3\u6784\u4f53j<\/p>\n
memset(&j, 0, sizeof(j));\nmemcpy(&j, &i, sizeof(i));\n\/\/i is 01 00 01 00\ncout << j.a << " " << j.b << " " << j.c << endl;\n\/\/ \u8f93\u51fa\u7ed3\u679c\n1 0 0<\/code><\/pre>\n
i\u4e3a 0x00010001,\u8865\u5145\u523064\u4f4d\u4e3a0x0000000000010001
\n\u7cfb\u7edf\u6309\u5c0f\u7aef\u5b58\u50a8,i\u5185\u5b58\u4e2d\u5b9e\u9645\u5185\u5bb9\u4e3a 01 00 01 00 00 00 00 00
\n\u6839\u636e\u7ed3\u6784\u4f53j\u7684\u5bf9\u5176\u89c4\u5219,\u53ca\u5c0f\u7aef\u5b58\u50a8\u539f\u5219
\na\u53602\u5b57\u8282, \u5185\u5bb9\u4e3a01 00
\n\u5bf9\u9f50\u53602\u5b57\u8282, \u5185\u5bb9\u4e3a 01 00
\nb\u53604\u5b57\u8282, \u5185\u5bb9\u4e3a 00 00 00 00
\nc\u53608\u5b57\u8282,\u8d85\u8fc7\u4e86i\u7684\u957f\u5ea6,\u5168\u4e3a0
\n\u6700\u540e\u5c0f\u7aef\u5b58\u50a8\u8f6c\u6362\u4e3a\u5b9e\u9645\u503c
\na = 0x0001
\nb = 0x00000000
\nc = 0x0000000000000000
\n\u7ed3\u679c\u662f1 0 0<\/p>\n","protected":false},"excerpt":{"rendered":"
5,623 Views\u5fd8\u4e86\u7684\u65f6\u5019\u5c31\u56de\u6765\u770b\u770b\u8fd9\u7bc7\u6587\u7ae0 \u5927\u5c0f\u7aef\u7684\u5b9a\u4e49 \u5927\u7aef(BE)\uff1a\u5185\u5b58\u7684\u8d77\u59cb\u5730\u5740\u5b58\u653e\u9ad8\u4f4d\u7684\u6570\u636e  […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[112],"tags":[],"class_list":["post-1095","post","type-post","status-publish","format-standard","hentry","category-112"],"_links":{"self":[{"href":"http:\/\/www.mrtblog.cn\/index.php?rest_route=\/wp\/v2\/posts\/1095","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.mrtblog.cn\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.mrtblog.cn\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.mrtblog.cn\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.mrtblog.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1095"}],"version-history":[{"count":7,"href":"http:\/\/www.mrtblog.cn\/index.php?rest_route=\/wp\/v2\/posts\/1095\/revisions"}],"predecessor-version":[{"id":1260,"href":"http:\/\/www.mrtblog.cn\/index.php?rest_route=\/wp\/v2\/posts\/1095\/revisions\/1260"}],"wp:attachment":[{"href":"http:\/\/www.mrtblog.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1095"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.mrtblog.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1095"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.mrtblog.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1095"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}