{"id":4801,"date":"2020-11-06T14:43:07","date_gmt":"2020-11-06T06:43:07","guid":{"rendered":"https:\/\/damogame.cn\/wordpress\/?p=4801"},"modified":"2020-11-06T14:43:07","modified_gmt":"2020-11-06T06:43:07","slug":"%e6%b7%b1%e5%85%a5%e6%b5%85%e5%87%balz4%e5%8e%8b%e7%bc%a9%e7%ae%97%e6%b3%95","status":"publish","type":"post","link":"https:\/\/i007.cc\/wordpress\/archives\/4801","title":{"rendered":"\u6df1\u5165\u6d45\u51falz4\u538b\u7f29\u7b97\u6cd5"},"content":{"rendered":"<div class=\"rEsl9f\">\n<div class=\"_2mYfmT\">\n<div>\n<div class=\"s-dsoj\"><a href=\"https:\/\/www.jianshu.com\/p\/824e1cf4f920\">\u539f\u6587\u5730\u5740<\/a><\/div>\n<div><\/div>\n<\/div>\n<\/div>\n<\/div>\n<article class=\"_2rhmJa\">\n<h4>\u7b80\u4ecb<\/h4>\n<p>lz4\u662f\u76ee\u524d\u7efc\u5408\u6765\u770b\u6548\u7387\u6700\u9ad8\u7684\u538b\u7f29\u7b97\u6cd5\uff0c\u66f4\u52a0\u4fa7\u91cd\u538b\u7f29\u89e3\u538b\u901f\u5ea6\uff0c\u538b\u7f29\u6bd4\u5e76\u4e0d\u662f\u7b2c\u4e00\u3002\u5728\u5f53\u524d\u7684\u5b89\u5353\u548c\u82f9\u679c\u64cd\u4f5c\u7cfb\u7edf\u4e2d\uff0c\u5185\u5b58\u538b\u7f29\u6280\u672f\u5c31\u4f7f\u7528\u7684\u662flz4\u7b97\u6cd5\uff0c\u53ca\u65f6\u538b\u7f29\u624b\u673a\u5185\u5b58\u4ee5\u5e26\u6765\u66f4\u591a\u7684\u5185\u5b58\u7a7a\u95f4\u3002\u672c\u8d28\u4e0a\u662f\u65f6\u95f4\u6362\u7a7a\u95f4\u3002<\/p>\n<h4>\u538b\u7f29\u539f\u7406<\/h4>\n<p>lz4\u538b\u7f29\u7b97\u6cd5\u5176\u5b9e\u5f88\u7b80\u5355\uff0c\u4e3e\u4e2a\u538b\u7f29\u7684\u6817\u5b50<\/p>\n<div class=\"_2Uzcx_\"><button class=\"VJbwyy\" type=\"button\" aria-label=\"\u590d\u5236\u4ee3\u7801\"><i class=\"anticon anticon-copy\" aria-label=\"icon: copy\"><\/i><\/button><\/p>\n<pre class=\"line-numbers  language-undefined\"><code class=\"  language-undefined\">\u8f93\u5165\uff1aabcde_bcdefgh_abcdefghxxxxxxx\r\n\u8f93\u51fa\uff1aabcde_(5,4)fgh_(14,5)fghxxxxxxx\r\n<\/code><\/pre>\n<\/div>\n<p>\u5176\u4e2d\u4e24\u4e2a\u62ec\u53f7\u5185\u7684\u4fbf\u4ee3\u8868\u7684\u662f\u538b\u7f29\u65f6\u68c0\u6d4b\u5230\u7684\u91cd\u590d\u9879\uff0c(5,4) \u4ee3\u8868\u5411\u524d5\u4e2abyte\uff0c\u5339\u914d\u5230\u7684\u5185\u5bb9\u957f\u5ea6\u67094\uff0c\u5373&#8221;bcde&#8221;\u662f\u4e00\u4e2a\u91cd\u590d\u3002\u5f53\u7136\u4e5f\u53ef\u4ee5\u8bf4&#8221;cde&#8221;\u662f\u4e2a\u91cd\u590d\u9879\uff0c\u4f46\u662f\u6839\u636e\u7b97\u6cd5\u5b9e\u73b0\u7684\u8f93\u5165\u6d41\u626b\u63cf\u987a\u5e8f\uff0c\u6211\u4eec\u53d6\u5230\u7684\u662f\u7b2c\u4e00\u4e2a\u5339\u914d\u5230\u7684\uff0c\u5e76\u4e14\u957f\u5ea6\u6700\u957f\u7684\u4f5c\u4e3a\u5339\u914d\u3002<\/p>\n<h6>1.\u538b\u7f29\u683c\u5f0f<\/h6>\n<p>\u538b\u7f29\u540e\u7684\u6570\u636e\u662f\u4e0b\u9762\u7684\u683c\u5f0f<\/p>\n<div class=\"image-package\">\n<div class=\"image-container\">\n<div class=\"image-container-fill\"><\/div>\n<div class=\"image-view\" data-width=\"632\" data-height=\"132\"><img decoding=\"async\" class=\"\" src=\"https:\/\/upload-images.jianshu.io\/upload_images\/529932-b2fac0006dad4582.jpg?imageMogr2\/auto-orient\/strip|imageView2\/2\/w\/632\/format\/webp\" data-original-src=\"\/\/upload-images.jianshu.io\/upload_images\/529932-b2fac0006dad4582.jpg\" data-original-width=\"632\" data-original-height=\"132\" data-original-format=\"image\/png\" data-original-filesize=\"5883\" data-image-index=\"0\" \/><\/div>\n<\/div>\n<\/div>\n<div class=\"_2Uzcx_\"><button class=\"VJbwyy\" type=\"button\" aria-label=\"\u590d\u5236\u4ee3\u7801\"><i class=\"anticon anticon-copy\" aria-label=\"icon: copy\"><\/i><\/button><\/p>\n<pre class=\"line-numbers  language-css\"><code class=\"  language-css\">\u8f93\u5165\uff1aabcde_bcdefgh_abcdefghxxxxxxx\r\n\u8f93\u51fa\uff1atokenabcde_<span class=\"token punctuation\">(<\/span>5<span class=\"token punctuation\">,<\/span>4<span class=\"token punctuation\">)<\/span>fgh_<span class=\"token punctuation\">(<\/span>14<span class=\"token punctuation\">,<\/span>5<span class=\"token punctuation\">)<\/span>fghxxxxxxx\r\n\u683c\u5f0f\uff1a[token]<span class=\"token function\">literals<\/span><span class=\"token punctuation\">(<\/span>offset<span class=\"token punctuation\">,<\/span>match length<span class=\"token punctuation\">)<\/span>[token]<span class=\"token function\">literals<\/span><span class=\"token punctuation\">(<\/span>offset<span class=\"token punctuation\">,<\/span>match length<span class=\"token punctuation\">)<\/span>....\r\n<\/code><\/pre>\n<\/div>\n<p>\u5176\u4ed6\u60c5\u51b5\u4e5f\u53ef\u80fd\u6709\u8fde\u7eed\u7684\u5339\u914d\uff1a<\/p>\n<div class=\"_2Uzcx_\"><button class=\"VJbwyy\" type=\"button\" aria-label=\"\u590d\u5236\u4ee3\u7801\"><i class=\"anticon anticon-copy\" aria-label=\"icon: copy\"><\/i><\/button><\/p>\n<pre class=\"line-numbers  language-rust\"><code class=\"  language-rust\">\u8f93\u5165\uff1afghabcde_bcdefgh_abcdefghxxxxxxx\r\n\u8f93\u51fa\uff1a<span class=\"token function\">fghabcde_<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">5<\/span><span class=\"token punctuation\">,<\/span><span class=\"token number\">4<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">13<\/span><span class=\"token punctuation\">,<\/span><span class=\"token number\">3<\/span><span class=\"token punctuation\">)<\/span><span class=\"token function\">_<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">14<\/span><span class=\"token punctuation\">,<\/span><span class=\"token number\">5<\/span><span class=\"token punctuation\">)<\/span>fghxxxxxxx\r\n\u683c\u5f0f\uff1a<span class=\"token punctuation\">[<\/span>token<span class=\"token punctuation\">]<\/span><span class=\"token function\">literals<\/span><span class=\"token punctuation\">(<\/span>offset<span class=\"token punctuation\">,<\/span><span class=\"token keyword\">match<\/span> length<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">[<\/span>token<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">(<\/span>offset<span class=\"token punctuation\">,<\/span><span class=\"token keyword\">match<\/span> length<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">...<\/span><span class=\"token punctuation\">.<\/span>\r\n\u8fd9\u91cc<span class=\"token punctuation\">(<\/span><span class=\"token number\">13<\/span><span class=\"token punctuation\">,<\/span><span class=\"token number\">3<\/span><span class=\"token punctuation\">)<\/span>\u957f\u5ea6<span class=\"token number\">3<\/span>\u5176\u5b9e\u5e76\u4e0d\u5bf9\uff0c<span class=\"token keyword\">match<\/span> length\u5339\u914d\u7684\u957f\u5ea6\u9ed8\u8ba4\u662f<span class=\"token number\">4<\/span>\r\n<\/code><\/pre>\n<\/div>\n<p><strong>Literals<\/strong>\u6307\u6ca1\u6709\u91cd\u590d\u3001\u9996\u6b21\u51fa\u73b0\u7684\u5b57\u8282\u6d41\uff0c\u5373\u4e0d\u53ef\u538b\u7f29\u7684\u90e8\u5206<br \/>\n<strong>Match<\/strong>\u6307\u91cd\u590d\u9879\uff0c\u53ef\u4ee5\u538b\u7f29\u7684\u90e8\u5206<br \/>\n<strong>Token<\/strong>\u8bb0\u5f55literal\u957f\u5ea6\uff0cmatch\u957f\u5ea6\u3002\u4f5c\u4e3a\u89e3\u538b\u65f6\u5019memcpy\u7684\u53c2\u6570<\/p>\n<h6>2.\u538b\u7f29\u7387<\/h6>\n<p>\u53ef\u4ee5\u60f3\u5230\uff0c\u5982\u679c\u91cd\u590d\u9879\u8d8a\u591a\u6216\u8005\u8d8a\u957f\uff0c\u538b\u7f29\u7387\u5c31\u4f1a\u8d8a\u9ad8\u3002\u4e0a\u8ff0\u4f8b\u5b50\u4e2d&#8221;bcde&#8221;\u5728\u538b\u7f29\u540e\uff0c\u7528(5,4)\u8868\u793a\uff0c\u5373\u4ece4\u4e2abytes\u538b\u7f29\u6210\u4e863\u4e2abytes\u6765\u8868\u793a\uff0c\u5176\u4e2doffset 2bytes, match length 1byte\uff0c\u80fd\u8282\u77011\u4e2abyte\u3002<\/p>\n<h6>3.\u538b\u7f29\u7b97\u6cd5\u5b9e\u73b0<\/h6>\n<p>\u5927\u81f4\u6d41\u7a0b\uff0c\u538b\u7f29\u8fc7\u7a0b\u4ee5\u81f3\u5c114\u4e2abytes\u4e3a\u626b\u63cf\u7a97\u53e3\u67e5\u627e\u5339\u914d\uff0c\u6bcf\u6b21\u79fb\u52a81byte\u8fdb\u884c\u626b\u63cf\uff0c\u9047\u5230\u91cd\u590d\u7684\u5c31\u8fdb\u884c\u538b\u7f29\u3002<br \/>\n\u7531\u4e8eoffset\u75282bytes\u8868\u793a\uff0c\u53ea\u80fd\u67e5\u627e\u5230\u52302^16(64kb)\u8ddd\u79bb\u7684\u5339\u914d\uff0c\u5bf9\u4e8e\u538b\u7f294Kb\u7684\u5185\u6838\u9875\uff0c\u53ea\u9700\u8981\u7528\u523012\u4f4d\u3002<br \/>\n\u626b\u63cf\u7684\u6b65\u957f1byte\u662f\u53ef\u4ee5\u8c03\u6574\u7684\uff0c\u5373\u5bf9\u5e94LZ4_compress_fast\u673a\u5236\uff0c\u6b65\u957f\u53d8\u957f\u53ef\u4ee5\u63d0\u9ad8\u538b\u7f29\u89e3\u538b\u901f\u5ea6\uff0c\u51cf\u5c11\u538b\u7f29\u7387\u3002<\/p>\n<div class=\"image-package\">\n<div class=\"image-container\">\n<div class=\"image-container-fill\"><\/div>\n<div class=\"image-view\" data-width=\"604\" data-height=\"256\"><img decoding=\"async\" class=\"\" src=\"https:\/\/upload-images.jianshu.io\/upload_images\/529932-588be4e2d0de3a68.PNG?imageMogr2\/auto-orient\/strip|imageView2\/2\/w\/604\/format\/webp\" data-original-src=\"\/\/upload-images.jianshu.io\/upload_images\/529932-588be4e2d0de3a68.PNG\" data-original-width=\"604\" data-original-height=\"256\" data-original-format=\"image\/png\" data-original-filesize=\"13004\" data-image-index=\"1\" \/><\/div>\n<\/div>\n<\/div>\n<p>\u6211\u4eec\u6765\u770b\u4e0b<a href=\"https:\/\/links.jianshu.com\/go?to=https%3A%2F%2Fgithub.com%2Fapple%2Fdarwin-xnu%2Fblob%2F0a798f6738bc1db01281fc08ae024145e84df927%2Fosfmk%2Fvm%2Flz4.c\" target=\"_blank\" rel=\"noopener noreferrer\">apple\u7684lz4\u5b9e\u73b0<\/a><\/p>\n<div class=\"_2Uzcx_\"><button class=\"VJbwyy\" type=\"button\" aria-label=\"\u590d\u5236\u4ee3\u7801\"><i class=\"anticon anticon-copy\" aria-label=\"icon: copy\"><\/i><\/button><\/p>\n<pre class=\"line-numbers  language-cpp\"><code class=\"  language-cpp\"><span class=\"token comment\">\/\/src\u662f\u8f93\u5165\u6d41\uff0cdst\u662f\u8f93\u51fa\uff0c\u8fd8\u9700\u8981\u4f7f\u7528\u4e00\u4e2ahash\u8868\u8bb0\u5f55\u524d\u9762\u4e00\u6bb5\u8ddd\u79bb\u5185\u7684\u5b57\u7b26\u4e32\uff0c\u7528\u6765\u67e5\u627e\u4e4b\u524d\u662f\u5426\u6709\u5339\u914d<\/span>\r\n<span class=\"token keyword\">void<\/span> <span class=\"token function\">lz4_encode_2gb<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">uint8_t<\/span> <span class=\"token operator\">*<\/span><span class=\"token operator\">*<\/span> dst_ptr<span class=\"token punctuation\">,<\/span>\r\n                    size_t dst_size<span class=\"token punctuation\">,<\/span>\r\n                    <span class=\"token keyword\">const<\/span> <span class=\"token keyword\">uint8_t<\/span> <span class=\"token operator\">*<\/span><span class=\"token operator\">*<\/span> src_ptr<span class=\"token punctuation\">,<\/span>\r\n                    <span class=\"token keyword\">const<\/span> <span class=\"token keyword\">uint8_t<\/span> <span class=\"token operator\">*<\/span> src_begin<span class=\"token punctuation\">,<\/span>\r\n                    size_t src_size<span class=\"token punctuation\">,<\/span>\r\n                    lz4_hash_entry_t hash_table<span class=\"token punctuation\">[<\/span>LZ4_COMPRESS_HASH_ENTRIES<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">,<\/span>\r\n                    <span class=\"token keyword\">int<\/span> skip_final_literals<span class=\"token punctuation\">)<\/span>\r\n<span class=\"token punctuation\">{<\/span>\r\n  <span class=\"token keyword\">uint8_t<\/span> <span class=\"token operator\">*<\/span>dst <span class=\"token operator\">=<\/span> <span class=\"token operator\">*<\/span>dst_ptr<span class=\"token punctuation\">;<\/span>        <span class=\"token comment\">\/\/ current output stream position<\/span>\r\n  <span class=\"token keyword\">uint8_t<\/span> <span class=\"token operator\">*<\/span>end <span class=\"token operator\">=<\/span> dst <span class=\"token operator\">+<\/span> dst_size <span class=\"token operator\">-<\/span> LZ4_GOFAST_SAFETY_MARGIN<span class=\"token punctuation\">;<\/span>\r\n  <span class=\"token keyword\">const<\/span> <span class=\"token keyword\">uint8_t<\/span> <span class=\"token operator\">*<\/span>src <span class=\"token operator\">=<\/span> <span class=\"token operator\">*<\/span>src_ptr<span class=\"token punctuation\">;<\/span>  <span class=\"token comment\">\/\/ current input stream literal to encode<\/span>\r\n  <span class=\"token keyword\">const<\/span> <span class=\"token keyword\">uint8_t<\/span> <span class=\"token operator\">*<\/span>src_end <span class=\"token operator\">=<\/span> src <span class=\"token operator\">+<\/span> src_size <span class=\"token operator\">-<\/span> LZ4_GOFAST_SAFETY_MARGIN<span class=\"token punctuation\">;<\/span>\r\n  <span class=\"token keyword\">const<\/span> <span class=\"token keyword\">uint8_t<\/span> <span class=\"token operator\">*<\/span>match_begin <span class=\"token operator\">=<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span> <span class=\"token comment\">\/\/ first byte of matched sequence<\/span>\r\n  <span class=\"token keyword\">const<\/span> <span class=\"token keyword\">uint8_t<\/span> <span class=\"token operator\">*<\/span>match_end <span class=\"token operator\">=<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span>   <span class=\"token comment\">\/\/ first byte after matched sequence<\/span>\r\n<span class=\"token comment\">\/\/\u82f9\u679c\u8fd9\u91cc\u4f7f\u7528\u4e86\u4e00\u4e2aearly abort\u673a\u5236\uff0c\u5373\u8f93\u5165\u6d41\u626b\u63cf\u5230lz4_do_abort_eval\u4f4d\u7f6e\u7684\u65f6\u5019\uff0c\u4ecd\u7136\u6ca1\u6709\u5339\u914d\uff0c\u5219\u8ba4\u4e3a\u8be5\u8f93\u5165\u65e0\u6cd5\u538b\u7f29\uff0c\u63d0\u524d\u7ed3\u675f\u4e0d\u7528\u5168\u90e8\u626b\u63cf\u5b8c<\/span>\r\n<span class=\"token macro property\">#<span class=\"token directive keyword\">if<\/span> LZ4_EARLY_ABORT<\/span>\r\n  <span class=\"token keyword\">uint8_t<\/span> <span class=\"token operator\">*<\/span> <span class=\"token keyword\">const<\/span> dst_begin <span class=\"token operator\">=<\/span> dst<span class=\"token punctuation\">;<\/span>\r\n  <span class=\"token keyword\">uint32_t<\/span> lz4_do_abort_eval <span class=\"token operator\">=<\/span> lz4_do_early_abort<span class=\"token punctuation\">;<\/span>\r\n<span class=\"token macro property\">#<span class=\"token directive keyword\">endif<\/span><\/span>\r\n  \r\n  <span class=\"token keyword\">while<\/span> <span class=\"token punctuation\">(<\/span>dst <span class=\"token operator\">&lt;<\/span> end<span class=\"token punctuation\">)<\/span>\r\n  <span class=\"token punctuation\">{<\/span>\r\n    ptrdiff_t match_distance <span class=\"token operator\">=<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span>\r\n    <span class=\"token comment\">\/\/for\u5faa\u73af\u4e00\u6b21\u67e5\u627e\u5230\u4e00\u4e2amatch\u5373\u8df3\u51fa\u5230EXPAND_FORWARD<\/span>\r\n    <span class=\"token keyword\">for<\/span> <span class=\"token punctuation\">(<\/span>match_begin <span class=\"token operator\">=<\/span> src<span class=\"token punctuation\">;<\/span> match_begin <span class=\"token operator\">&lt;<\/span> src_end<span class=\"token punctuation\">;<\/span> match_begin <span class=\"token operator\">+=<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span>\r\n      <span class=\"token keyword\">const<\/span> <span class=\"token keyword\">uint32_t<\/span> pos <span class=\"token operator\">=<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token keyword\">uint32_t<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">(<\/span>match_begin <span class=\"token operator\">-<\/span> src_begin<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\r\n      <span class=\"token comment\">\/\/\u82f9\u679c\u8fd9\u91cc\u5b9e\u73b0\u6bd4\u8f83\u5947\u602a\uff0c\u8fd8\u5728\u601d\u8003\u4e3a\u4f55\u540c\u65f6\u67e5\u627e\u8fde\u7eed\u56db\u4e2abytes\u7684\u5339\u914d<\/span>\r\n      <span class=\"token keyword\">const<\/span> <span class=\"token keyword\">uint32_t<\/span> w0 <span class=\"token operator\">=<\/span> <span class=\"token function\">load4<\/span><span class=\"token punctuation\">(<\/span>match_begin<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><span class=\"token comment\">\/\/\u8be5\u4f4d\u7f6e4\u4e2abytes\u7684\u5185\u5bb9<\/span>\r\n      <span class=\"token keyword\">const<\/span> <span class=\"token keyword\">uint32_t<\/span> w1 <span class=\"token operator\">=<\/span> <span class=\"token function\">load4<\/span><span class=\"token punctuation\">(<\/span>match_begin <span class=\"token operator\">+<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\r\n      <span class=\"token keyword\">const<\/span> <span class=\"token keyword\">uint32_t<\/span> w2 <span class=\"token operator\">=<\/span> <span class=\"token function\">load4<\/span><span class=\"token punctuation\">(<\/span>match_begin <span class=\"token operator\">+<\/span> <span class=\"token number\">2<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\r\n      <span class=\"token keyword\">const<\/span> <span class=\"token keyword\">uint32_t<\/span> w3 <span class=\"token operator\">=<\/span> <span class=\"token function\">load4<\/span><span class=\"token punctuation\">(<\/span>match_begin <span class=\"token operator\">+<\/span> <span class=\"token number\">3<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\r\n      <span class=\"token keyword\">const<\/span> <span class=\"token keyword\">int<\/span> i0 <span class=\"token operator\">=<\/span> <span class=\"token function\">lz4_hash<\/span><span class=\"token punctuation\">(<\/span>w0<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\r\n      <span class=\"token keyword\">const<\/span> <span class=\"token keyword\">int<\/span> i1 <span class=\"token operator\">=<\/span> <span class=\"token function\">lz4_hash<\/span><span class=\"token punctuation\">(<\/span>w1<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\r\n      <span class=\"token keyword\">const<\/span> <span class=\"token keyword\">int<\/span> i2 <span class=\"token operator\">=<\/span> <span class=\"token function\">lz4_hash<\/span><span class=\"token punctuation\">(<\/span>w2<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\r\n      <span class=\"token keyword\">const<\/span> <span class=\"token keyword\">int<\/span> i3 <span class=\"token operator\">=<\/span> <span class=\"token function\">lz4_hash<\/span><span class=\"token punctuation\">(<\/span>w3<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\r\n      <span class=\"token keyword\">const<\/span> <span class=\"token keyword\">uint8_t<\/span> <span class=\"token operator\">*<\/span>c0 <span class=\"token operator\">=<\/span> src_begin <span class=\"token operator\">+<\/span> hash_table<span class=\"token punctuation\">[<\/span>i0<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">.<\/span>offset<span class=\"token punctuation\">;<\/span>\r\n      <span class=\"token keyword\">const<\/span> <span class=\"token keyword\">uint8_t<\/span> <span class=\"token operator\">*<\/span>c1 <span class=\"token operator\">=<\/span> src_begin <span class=\"token operator\">+<\/span> hash_table<span class=\"token punctuation\">[<\/span>i1<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">.<\/span>offset<span class=\"token punctuation\">;<\/span>\r\n      <span class=\"token keyword\">const<\/span> <span class=\"token keyword\">uint8_t<\/span> <span class=\"token operator\">*<\/span>c2 <span class=\"token operator\">=<\/span> src_begin <span class=\"token operator\">+<\/span> hash_table<span class=\"token punctuation\">[<\/span>i2<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">.<\/span>offset<span class=\"token punctuation\">;<\/span>\r\n      <span class=\"token keyword\">const<\/span> <span class=\"token keyword\">uint8_t<\/span> <span class=\"token operator\">*<\/span>c3 <span class=\"token operator\">=<\/span> src_begin <span class=\"token operator\">+<\/span> hash_table<span class=\"token punctuation\">[<\/span>i3<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">.<\/span>offset<span class=\"token punctuation\">;<\/span>\r\n      <span class=\"token keyword\">const<\/span> <span class=\"token keyword\">uint32_t<\/span> m0 <span class=\"token operator\">=<\/span> hash_table<span class=\"token punctuation\">[<\/span>i0<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">.<\/span>word<span class=\"token punctuation\">;<\/span><span class=\"token comment\">\/\/\u53d6\u51fahash\u8868\u4e2d\u4ee5\u524d\u6709\u6ca1\u6709\u4e00\u6837\u7684\u503c<\/span>\r\n      <span class=\"token keyword\">const<\/span> <span class=\"token keyword\">uint32_t<\/span> m1 <span class=\"token operator\">=<\/span> hash_table<span class=\"token punctuation\">[<\/span>i1<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">.<\/span>word<span class=\"token punctuation\">;<\/span>\r\n      <span class=\"token keyword\">const<\/span> <span class=\"token keyword\">uint32_t<\/span> m2 <span class=\"token operator\">=<\/span> hash_table<span class=\"token punctuation\">[<\/span>i2<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">.<\/span>word<span class=\"token punctuation\">;<\/span>\r\n      <span class=\"token keyword\">const<\/span> <span class=\"token keyword\">uint32_t<\/span> m3 <span class=\"token operator\">=<\/span> hash_table<span class=\"token punctuation\">[<\/span>i3<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">.<\/span>word<span class=\"token punctuation\">;<\/span>\r\n      hash_table<span class=\"token punctuation\">[<\/span>i0<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">.<\/span>offset <span class=\"token operator\">=<\/span> pos<span class=\"token punctuation\">;<\/span>\r\n      hash_table<span class=\"token punctuation\">[<\/span>i0<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">.<\/span>word <span class=\"token operator\">=<\/span> w0<span class=\"token punctuation\">;<\/span>\r\n      hash_table<span class=\"token punctuation\">[<\/span>i1<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">.<\/span>offset <span class=\"token operator\">=<\/span> pos <span class=\"token operator\">+<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span>\r\n      hash_table<span class=\"token punctuation\">[<\/span>i1<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">.<\/span>word <span class=\"token operator\">=<\/span> w1<span class=\"token punctuation\">;<\/span>\r\n\r\n      hash_table<span class=\"token punctuation\">[<\/span>i2<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">.<\/span>offset <span class=\"token operator\">=<\/span> pos <span class=\"token operator\">+<\/span> <span class=\"token number\">2<\/span><span class=\"token punctuation\">;<\/span>\r\n      hash_table<span class=\"token punctuation\">[<\/span>i2<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">.<\/span>word <span class=\"token operator\">=<\/span> w2<span class=\"token punctuation\">;<\/span>\r\n      hash_table<span class=\"token punctuation\">[<\/span>i3<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">.<\/span>offset <span class=\"token operator\">=<\/span> pos <span class=\"token operator\">+<\/span> <span class=\"token number\">3<\/span><span class=\"token punctuation\">;<\/span>\r\n      hash_table<span class=\"token punctuation\">[<\/span>i3<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">.<\/span>word <span class=\"token operator\">=<\/span> w3<span class=\"token punctuation\">;<\/span>\r\n\r\n      match_distance <span class=\"token operator\">=<\/span> <span class=\"token punctuation\">(<\/span>match_begin <span class=\"token operator\">-<\/span> c0<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\r\n      <span class=\"token comment\">\/\/\u6bd4\u8f83hash\u8868\u4e2d\u7684\u503c\u548c\u5f53\u524d\u6307\u9488\u4f4d\u7f6e\u7684hash\u503c<\/span>\r\n      <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>w0 <span class=\"token operator\">==<\/span> m0 <span class=\"token operator\">&amp;&amp;<\/span> match_distance <span class=\"token operator\">&lt;<\/span> <span class=\"token number\">0x10000<\/span> <span class=\"token operator\">&amp;&amp;<\/span> match_distance <span class=\"token operator\">&gt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span>\r\n        match_end <span class=\"token operator\">=<\/span> match_begin <span class=\"token operator\">+<\/span> <span class=\"token number\">4<\/span><span class=\"token punctuation\">;<\/span>\r\n        <span class=\"token keyword\">goto<\/span> EXPAND_FORWARD<span class=\"token punctuation\">;<\/span>\r\n      <span class=\"token punctuation\">}<\/span>\r\n\r\n      match_begin<span class=\"token operator\">++<\/span><span class=\"token punctuation\">;<\/span>\r\n      match_distance <span class=\"token operator\">=<\/span> <span class=\"token punctuation\">(<\/span>match_begin <span class=\"token operator\">-<\/span> c1<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\r\n      <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>w1 <span class=\"token operator\">==<\/span> m1 <span class=\"token operator\">&amp;&amp;<\/span> match_distance <span class=\"token operator\">&lt;<\/span> <span class=\"token number\">0x10000<\/span> <span class=\"token operator\">&amp;&amp;<\/span> match_distance <span class=\"token operator\">&gt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span>\r\n        match_end <span class=\"token operator\">=<\/span> match_begin <span class=\"token operator\">+<\/span> <span class=\"token number\">4<\/span><span class=\"token punctuation\">;<\/span>\r\n        <span class=\"token keyword\">goto<\/span> EXPAND_FORWARD<span class=\"token punctuation\">;<\/span>\r\n      <span class=\"token punctuation\">}<\/span>\r\n\r\n      match_begin<span class=\"token operator\">++<\/span><span class=\"token punctuation\">;<\/span>\r\n      match_distance <span class=\"token operator\">=<\/span> <span class=\"token punctuation\">(<\/span>match_begin <span class=\"token operator\">-<\/span> c2<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\r\n      <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>w2 <span class=\"token operator\">==<\/span> m2 <span class=\"token operator\">&amp;&amp;<\/span> match_distance <span class=\"token operator\">&lt;<\/span> <span class=\"token number\">0x10000<\/span> <span class=\"token operator\">&amp;&amp;<\/span> match_distance <span class=\"token operator\">&gt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span>\r\n        match_end <span class=\"token operator\">=<\/span> match_begin <span class=\"token operator\">+<\/span> <span class=\"token number\">4<\/span><span class=\"token punctuation\">;<\/span>\r\n        <span class=\"token keyword\">goto<\/span> EXPAND_FORWARD<span class=\"token punctuation\">;<\/span>\r\n      <span class=\"token punctuation\">}<\/span>\r\n\r\n      match_begin<span class=\"token operator\">++<\/span><span class=\"token punctuation\">;<\/span>\r\n      match_distance <span class=\"token operator\">=<\/span> <span class=\"token punctuation\">(<\/span>match_begin <span class=\"token operator\">-<\/span> c3<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\r\n      <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>w3 <span class=\"token operator\">==<\/span> m3 <span class=\"token operator\">&amp;&amp;<\/span> match_distance <span class=\"token operator\">&lt;<\/span> <span class=\"token number\">0x10000<\/span> <span class=\"token operator\">&amp;&amp;<\/span> match_distance <span class=\"token operator\">&gt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span>\r\n        match_end <span class=\"token operator\">=<\/span> match_begin <span class=\"token operator\">+<\/span> <span class=\"token number\">4<\/span><span class=\"token punctuation\">;<\/span>\r\n        <span class=\"token keyword\">goto<\/span> EXPAND_FORWARD<span class=\"token punctuation\">;<\/span>\r\n      <span class=\"token punctuation\">}<\/span>\r\n\r\n<span class=\"token macro property\">#<span class=\"token directive keyword\">if<\/span> LZ4_EARLY_ABORT<\/span>\r\n      <span class=\"token comment\">\/\/DRKTODO: Evaluate unrolling further. 2xunrolling had some modest benefits<\/span>\r\n      <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>lz4_do_abort_eval <span class=\"token operator\">&amp;&amp;<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">(<\/span>pos<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&gt;=<\/span> LZ4_EARLY_ABORT_EVAL<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span>\r\n          ptrdiff_t dstd <span class=\"token operator\">=<\/span> dst <span class=\"token operator\">-<\/span> dst_begin<span class=\"token punctuation\">;<\/span>\r\n          <span class=\"token comment\">\/\/\u5230\u8fd9\u4ecd\u7136\u6ca1\u6709\u5339\u914d\uff0c\u653e\u5f03<\/span>\r\n          <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>dstd <span class=\"token operator\">==<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span>\r\n              lz4_early_aborts<span class=\"token operator\">++<\/span><span class=\"token punctuation\">;<\/span>\r\n              <span class=\"token keyword\">return<\/span><span class=\"token punctuation\">;<\/span>\r\n          <span class=\"token punctuation\">}<\/span>\r\n\r\n<span class=\"token comment\">\/*        if (dstd &gt;= pos) { *\/<\/span>\r\n<span class=\"token comment\">\/*            return; *\/<\/span>\r\n<span class=\"token comment\">\/*        } *\/<\/span>\r\n<span class=\"token comment\">\/*        ptrdiff_t cbytes = pos - dstd; *\/<\/span>\r\n<span class=\"token comment\">\/*        if ((cbytes * LZ4_EARLY_ABORT_MIN_COMPRESSION_FACTOR) &gt; pos)  { *\/<\/span>\r\n<span class=\"token comment\">\/*            return; *\/<\/span>\r\n<span class=\"token comment\">\/*        } *\/<\/span>\r\n          lz4_do_abort_eval <span class=\"token operator\">=<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span>\r\n      <span class=\"token punctuation\">}<\/span>\r\n<span class=\"token macro property\">#<span class=\"token directive keyword\">endif<\/span><\/span>\r\n    <span class=\"token punctuation\">}<\/span>\r\n    <span class=\"token comment\">\/\/\u5230\u8fd9\uff0c\u6574\u4e2afor\u5faa\u73af\u90fd\u6ca1\u6709\u627e\u5230match\uff0c\u76f4\u63a5\u628a\u6574\u4e2asrc\u62f7\u8d1d\u5230dst\u5373\u53ef<\/span>\r\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>skip_final_literals<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span> <span class=\"token operator\">*<\/span>src_ptr <span class=\"token operator\">=<\/span> src<span class=\"token punctuation\">;<\/span> <span class=\"token operator\">*<\/span>dst_ptr <span class=\"token operator\">=<\/span> dst<span class=\"token punctuation\">;<\/span> <span class=\"token keyword\">return<\/span><span class=\"token punctuation\">;<\/span> <span class=\"token punctuation\">}<\/span> <span class=\"token comment\">\/\/ do not emit the final literal sequence<\/span>\r\n    \r\n    <span class=\"token comment\">\/\/  Emit a trailing literal that covers the remainder of the source buffer,<\/span>\r\n    <span class=\"token comment\">\/\/  if we can do so without exceeding the bounds of the destination buffer.<\/span>\r\n    size_t src_remaining <span class=\"token operator\">=<\/span> src_end <span class=\"token operator\">+<\/span> LZ4_GOFAST_SAFETY_MARGIN <span class=\"token operator\">-<\/span> src<span class=\"token punctuation\">;<\/span>\r\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>src_remaining <span class=\"token operator\">&lt;<\/span> <span class=\"token number\">15<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span>\r\n      <span class=\"token operator\">*<\/span>dst<span class=\"token operator\">++<\/span> <span class=\"token operator\">=<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token keyword\">uint8_t<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">(<\/span>src_remaining <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token number\">4<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\r\n      <span class=\"token function\">memcpy<\/span><span class=\"token punctuation\">(<\/span>dst<span class=\"token punctuation\">,<\/span> src<span class=\"token punctuation\">,<\/span> <span class=\"token number\">16<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span> dst <span class=\"token operator\">+=<\/span> src_remaining<span class=\"token punctuation\">;<\/span>\r\n    <span class=\"token punctuation\">}<\/span> <span class=\"token keyword\">else<\/span> <span class=\"token punctuation\">{<\/span>\r\n      <span class=\"token operator\">*<\/span>dst<span class=\"token operator\">++<\/span> <span class=\"token operator\">=<\/span> <span class=\"token number\">0xf0<\/span><span class=\"token punctuation\">;<\/span>\r\n      dst <span class=\"token operator\">=<\/span> <span class=\"token function\">lz4_store_length<\/span><span class=\"token punctuation\">(<\/span>dst<span class=\"token punctuation\">,<\/span> end<span class=\"token punctuation\">,<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token keyword\">uint32_t<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">(<\/span>src_remaining <span class=\"token operator\">-<\/span> <span class=\"token number\">15<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\r\n      <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>dst <span class=\"token operator\">==<\/span> <span class=\"token number\">0<\/span> <span class=\"token operator\">||<\/span> dst <span class=\"token operator\">+<\/span> src_remaining <span class=\"token operator\">&gt;=<\/span> end<span class=\"token punctuation\">)<\/span> <span class=\"token keyword\">return<\/span><span class=\"token punctuation\">;<\/span>\r\n      <span class=\"token function\">memcpy<\/span><span class=\"token punctuation\">(<\/span>dst<span class=\"token punctuation\">,<\/span> src<span class=\"token punctuation\">,<\/span> src_remaining<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span> dst <span class=\"token operator\">+=<\/span> src_remaining<span class=\"token punctuation\">;<\/span>\r\n    <span class=\"token punctuation\">}<\/span>\r\n    <span class=\"token operator\">*<\/span>dst_ptr <span class=\"token operator\">=<\/span> dst<span class=\"token punctuation\">;<\/span>\r\n    <span class=\"token operator\">*<\/span>src_ptr <span class=\"token operator\">=<\/span> src <span class=\"token operator\">+<\/span> src_remaining<span class=\"token punctuation\">;<\/span>\r\n    <span class=\"token keyword\">return<\/span><span class=\"token punctuation\">;<\/span>\r\n    \r\n  EXPAND_FORWARD<span class=\"token operator\">:<\/span>\r\n    \r\n    <span class=\"token comment\">\/\/ Expand match forward \u67e5\u770b\u5339\u914d\u662f\u5426\u80fd\u5411\u524d\u6269\u5c55\uff0c\u6269\u5927\u5339\u914d\u957f\u5ea6<\/span>\r\n    <span class=\"token punctuation\">{<\/span>\r\n      <span class=\"token keyword\">const<\/span> <span class=\"token keyword\">uint8_t<\/span> <span class=\"token operator\">*<\/span> ref_end <span class=\"token operator\">=<\/span> match_end <span class=\"token operator\">-<\/span> match_distance<span class=\"token punctuation\">;<\/span>\r\n      <span class=\"token keyword\">while<\/span> <span class=\"token punctuation\">(<\/span>match_end <span class=\"token operator\">&lt;<\/span> src_end<span class=\"token punctuation\">)<\/span>\r\n      <span class=\"token punctuation\">{<\/span>\r\n        size_t n <span class=\"token operator\">=<\/span> <span class=\"token function\">lz4_nmatch<\/span><span class=\"token punctuation\">(<\/span>LZ4_MATCH_SEARCH_LOOP_SIZE<span class=\"token punctuation\">,<\/span> ref_end<span class=\"token punctuation\">,<\/span> match_end<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\r\n        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&lt;<\/span> LZ4_MATCH_SEARCH_LOOP_SIZE<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span> match_end <span class=\"token operator\">+=<\/span> n<span class=\"token punctuation\">;<\/span> <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span> <span class=\"token punctuation\">}<\/span>\r\n        match_end <span class=\"token operator\">+=<\/span> LZ4_MATCH_SEARCH_LOOP_SIZE<span class=\"token punctuation\">;<\/span>\r\n        ref_end <span class=\"token operator\">+=<\/span> LZ4_MATCH_SEARCH_LOOP_SIZE<span class=\"token punctuation\">;<\/span>\r\n      <span class=\"token punctuation\">}<\/span>\r\n    <span class=\"token punctuation\">}<\/span>\r\n    \r\n    <span class=\"token comment\">\/\/ Expand match backward \u67e5\u770b\u5339\u914d\u662f\u5426\u80fd\u5411\u540e\u6269\u5c55\uff0c\u6269\u5927\u5339\u914d\u957f\u5ea6<\/span>\r\n    <span class=\"token punctuation\">{<\/span>\r\n      <span class=\"token comment\">\/\/ match_begin_min = max(src_begin + match_distance,literal)<\/span>\r\n      <span class=\"token keyword\">const<\/span> <span class=\"token keyword\">uint8_t<\/span> <span class=\"token operator\">*<\/span> match_begin_min <span class=\"token operator\">=<\/span> src_begin <span class=\"token operator\">+<\/span> match_distance<span class=\"token punctuation\">;<\/span>\r\n      match_begin_min <span class=\"token operator\">=<\/span> <span class=\"token punctuation\">(<\/span>match_begin_min <span class=\"token operator\">&lt;<\/span> src<span class=\"token punctuation\">)<\/span><span class=\"token operator\">?<\/span>src<span class=\"token operator\">:<\/span>match_begin_min<span class=\"token punctuation\">;<\/span>\r\n      <span class=\"token keyword\">const<\/span> <span class=\"token keyword\">uint8_t<\/span> <span class=\"token operator\">*<\/span> ref_begin <span class=\"token operator\">=<\/span> match_begin <span class=\"token operator\">-<\/span> match_distance<span class=\"token punctuation\">;<\/span>\r\n      \r\n      <span class=\"token keyword\">while<\/span> <span class=\"token punctuation\">(<\/span>match_begin <span class=\"token operator\">&gt;<\/span> match_begin_min <span class=\"token operator\">&amp;&amp;<\/span> ref_begin<span class=\"token punctuation\">[<\/span><span class=\"token operator\">-<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">]<\/span> <span class=\"token operator\">==<\/span> match_begin<span class=\"token punctuation\">[<\/span><span class=\"token operator\">-<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">]<\/span> <span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span> match_begin <span class=\"token operator\">-=<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span> ref_begin <span class=\"token operator\">-=<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span> <span class=\"token punctuation\">}<\/span>\r\n    <span class=\"token punctuation\">}<\/span>\r\n    \r\n    <span class=\"token comment\">\/\/ Emit match \u786e\u5b9a\u597dmatch\u7684offset\u548clength\u4ee5\u540e\uff0c\u7f16\u7801\u6210\u538b\u7f29\u540e\u7684\u683c\u5f0f<\/span>\r\n    dst <span class=\"token operator\">=<\/span> <span class=\"token function\">lz4_emit_match<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">uint32_t<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">(<\/span>match_begin <span class=\"token operator\">-<\/span> src<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token keyword\">uint32_t<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">(<\/span>match_end <span class=\"token operator\">-<\/span> match_begin<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token keyword\">uint32_t<\/span><span class=\"token punctuation\">)<\/span>match_distance<span class=\"token punctuation\">,<\/span> dst<span class=\"token punctuation\">,<\/span> end<span class=\"token punctuation\">,<\/span> src<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\r\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token operator\">!<\/span>dst<span class=\"token punctuation\">)<\/span> <span class=\"token keyword\">return<\/span><span class=\"token punctuation\">;<\/span>\r\n    \r\n    <span class=\"token comment\">\/\/ Update state<\/span>\r\n    src <span class=\"token operator\">=<\/span> match_end<span class=\"token punctuation\">;<\/span>\r\n    \r\n    <span class=\"token comment\">\/\/ Update return values to include the last fully encoded match<\/span>\r\n    <span class=\"token comment\">\/\/\u5237\u65b0src\u548cdst\u4f4d\u7f6e\uff0c\u56de\u5230while\u91cd\u65b0\u5f00\u59cbfor\u5faa\u73af<\/span>\r\n    <span class=\"token operator\">*<\/span>dst_ptr <span class=\"token operator\">=<\/span> dst<span class=\"token punctuation\">;<\/span>\r\n    <span class=\"token operator\">*<\/span>src_ptr <span class=\"token operator\">=<\/span> src<span class=\"token punctuation\">;<\/span>\r\n  <span class=\"token punctuation\">}<\/span>\r\n<span class=\"token punctuation\">}<\/span>\r\n\r\n<\/code><\/pre>\n<\/div>\n<h6>\u5b89\u5353\u5185\u5b58\u4e2d\u538b\u7f29\u7684\u5b9e\u4f8b<\/h6>\n<div class=\"_2Uzcx_\"><button class=\"VJbwyy\" type=\"button\" aria-label=\"\u590d\u5236\u4ee3\u7801\"><i class=\"anticon anticon-copy\" aria-label=\"icon: copy\"><\/i><\/button><\/p>\n<pre class=\"line-numbers  language-css\"><code class=\"  language-css\">\u8be5\u4f8b\u5b50\u662f\u4e00\u4e2a\u8d77\u57400xffffffc06185f000\u76844K\u9875\uff0c\u5927\u90e8\u5206\u662f0\u548c1\uff0c\u7531\u4e8elength\u6216\u8005offset\u8d85\u957f\uff0c\u591a\u4e86\u4e00\u4e9b\u7279\u6b8a\u5904\u7406\uff0c\u8fd9\u90e8\u5206\u53ef\u4ee5\u770b\u5b89\u5353\u7684lz4\u6e90\u7801\r\n\r\n\u53d1\u73b0\u4e24\u4e2a\u5339\u914d\uff0c\u538b\u7f29\u540e\u7684\u6570\u636e\u4e3a31bytes\uff0c\u538b\u7f29\u540e\u6982\u89c8\u5982\u4e0b\r\n09-15 14<span class=\"token punctuation\">:<\/span>35<span class=\"token punctuation\">:<\/span>06.821 &lt;3&gt;[138<span class=\"token punctuation\">,<\/span> kswapd0][  638.194336]  src 0xffffffc06185f000 literallen 1\r\n09-15 14<span class=\"token punctuation\">:<\/span>35<span class=\"token punctuation\">:<\/span>06.821 &lt;3&gt;[138<span class=\"token punctuation\">,<\/span> kswapd0][  638.194349]  src 0xffffffc06185f000 <span class=\"token punctuation\">(<\/span>1<span class=\"token punctuation\">,<\/span>219<span class=\"token punctuation\">)<\/span>   #<span class=\"token punctuation\">(<\/span>offset<span class=\"token punctuation\">,<\/span>match length<span class=\"token punctuation\">)<\/span>\r\n09-15 14<span class=\"token punctuation\">:<\/span>35<span class=\"token punctuation\">:<\/span>06.821 &lt;3&gt;[138<span class=\"token punctuation\">,<\/span> kswapd0][  638.194359]  src 0xffffffc06185f000 literallen 1\r\n09-15 14<span class=\"token punctuation\">:<\/span>35<span class=\"token punctuation\">:<\/span>06.821 &lt;3&gt;[138<span class=\"token punctuation\">,<\/span> kswapd0][  638.194386]  src 0xffffffc06185f000 <span class=\"token punctuation\">(<\/span>3044<span class=\"token punctuation\">,<\/span>7<span class=\"token punctuation\">)<\/span>\r\n09-15 14<span class=\"token punctuation\">:<\/span>35<span class=\"token punctuation\">:<\/span>06.821 &lt;3&gt;[138<span class=\"token punctuation\">,<\/span> kswapd0][  638.194400]  src 0xffffffc06185f000 count 2 compressed 31\r\n---------------------------\u5bf9\u5e94\u538b\u7f29\u540e\u7684\u539f\u59cb\u6570\u636e-----------------------------\r\n\u7b2c\u4e00\u4e2a\u5339\u914d\uff1a\r\n09-15 14<span class=\"token punctuation\">:<\/span>35<span class=\"token punctuation\">:<\/span>06.821 &lt;3&gt;[138<span class=\"token punctuation\">,<\/span> kswapd0][  638.194411]   0xffffffc06185f000 31    #<span class=\"token property\">token<\/span><span class=\"token punctuation\">:<\/span>0001 1111 \u524d\u56db\u4f4d\u662fliteral\u957f\u5ea61\uff0c\u4f4e4\u4f4d15\u8868\u793amatchlength\u957f\u5ea6\u6ea2\u51fa\uff0c\u8981\u770b\u540e\u9762\r\n09-15 14<span class=\"token punctuation\">:<\/span>35<span class=\"token punctuation\">:<\/span>06.821 &lt;3&gt;[138<span class=\"token punctuation\">,<\/span> kswapd0][  638.194422]   0xffffffc06185f000 0     #literal\r\n09-15 14<span class=\"token punctuation\">:<\/span>35<span class=\"token punctuation\">:<\/span>06.821 &lt;3&gt;[138<span class=\"token punctuation\">,<\/span> kswapd0][  638.194433]   0xffffffc06185f000 1     #offset \u5c0f\u7aef\u5e8f01\r\n09-15 14<span class=\"token punctuation\">:<\/span>35<span class=\"token punctuation\">:<\/span>06.821 &lt;3&gt;[138<span class=\"token punctuation\">,<\/span> kswapd0][  638.194444]   0xffffffc06185f000 0     #offset\r\n09-15 14<span class=\"token punctuation\">:<\/span>35<span class=\"token punctuation\">:<\/span>06.821 &lt;3&gt;[138<span class=\"token punctuation\">,<\/span> kswapd0][  638.194459]   0xffffffc06185f000 255   #matchLength begin\r\n09-15 14<span class=\"token punctuation\">:<\/span>35<span class=\"token punctuation\">:<\/span>06.821 &lt;3&gt;[138<span class=\"token punctuation\">,<\/span> kswapd0][  638.194469]   0xffffffc06185f000 255\r\n09-15 14<span class=\"token punctuation\">:<\/span>35<span class=\"token punctuation\">:<\/span>06.822 &lt;3&gt;[138<span class=\"token punctuation\">,<\/span> kswapd0][  638.194483]   0xffffffc06185f000 255\r\n09-15 14<span class=\"token punctuation\">:<\/span>35<span class=\"token punctuation\">:<\/span>06.822 &lt;3&gt;[138<span class=\"token punctuation\">,<\/span> kswapd0][  638.194494]   0xffffffc06185f000 255\r\n09-15 14<span class=\"token punctuation\">:<\/span>35<span class=\"token punctuation\">:<\/span>06.822 &lt;3&gt;[138<span class=\"token punctuation\">,<\/span> kswapd0][  638.194505]   0xffffffc06185f000 255\r\n09-15 14<span class=\"token punctuation\">:<\/span>35<span class=\"token punctuation\">:<\/span>06.822 &lt;3&gt;[138<span class=\"token punctuation\">,<\/span> kswapd0][  638.194551]   0xffffffc06185f000 255\r\n09-15 14<span class=\"token punctuation\">:<\/span>35<span class=\"token punctuation\">:<\/span>06.822 &lt;3&gt;[138<span class=\"token punctuation\">,<\/span> kswapd0][  638.194565]   0xffffffc06185f000 255\r\n09-15 14<span class=\"token punctuation\">:<\/span>35<span class=\"token punctuation\">:<\/span>06.822 &lt;3&gt;[138<span class=\"token punctuation\">,<\/span> kswapd0][  638.194579]   0xffffffc06185f000 255\r\n09-15 14<span class=\"token punctuation\">:<\/span>35<span class=\"token punctuation\">:<\/span>06.822 &lt;3&gt;[138<span class=\"token punctuation\">,<\/span> kswapd0][  638.194590]   0xffffffc06185f000 255\r\n09-15 14<span class=\"token punctuation\">:<\/span>35<span class=\"token punctuation\">:<\/span>06.822 &lt;3&gt;[138<span class=\"token punctuation\">,<\/span> kswapd0][  638.194602]   0xffffffc06185f000 255\r\n09-15 14<span class=\"token punctuation\">:<\/span>35<span class=\"token punctuation\">:<\/span>06.822 &lt;3&gt;[138<span class=\"token punctuation\">,<\/span> kswapd0][  638.194612]   0xffffffc06185f000 255   \r\n09-15 14<span class=\"token punctuation\">:<\/span>35<span class=\"token punctuation\">:<\/span>06.822 &lt;3&gt;[138<span class=\"token punctuation\">,<\/span> kswapd0][  638.194624]   0xffffffc06185f000 219   #matchLength <span class=\"token property\">end<\/span><span class=\"token punctuation\">:<\/span> 219+255*11 3024\r\n\u7b2c\u4e8c\u4e2a\u5339\u914d\uff1a\r\n09-15 14<span class=\"token punctuation\">:<\/span>35<span class=\"token punctuation\">:<\/span>06.822 &lt;3&gt;[138<span class=\"token punctuation\">,<\/span> kswapd0][  638.194635]   0xffffffc06185f000 31    #<span class=\"token property\">Token<\/span><span class=\"token punctuation\">:<\/span>0001 1111 \u524d\u56db\u4f4d\u662fliteral\u957f\u5ea61\r\n09-15 14<span class=\"token punctuation\">:<\/span>35<span class=\"token punctuation\">:<\/span>06.822 &lt;3&gt;[138<span class=\"token punctuation\">,<\/span> kswapd0][  638.194646]   0xffffffc06185f000 1     #literal\r\n09-15 14<span class=\"token punctuation\">:<\/span>35<span class=\"token punctuation\">:<\/span>06.822 &lt;3&gt;[138<span class=\"token punctuation\">,<\/span> kswapd0][  638.194657]   0xffffffc06185f000 228   #offset\r\n09-15 14<span class=\"token punctuation\">:<\/span>35<span class=\"token punctuation\">:<\/span>06.822 &lt;3&gt;[138<span class=\"token punctuation\">,<\/span> kswapd0][  638.194667]   0xffffffc06185f000 11    #offset <span class=\"token function\">228<\/span><span class=\"token punctuation\">(<\/span>1110 0100<span class=\"token punctuation\">)<\/span> <span class=\"token function\">11<\/span><span class=\"token punctuation\">(<\/span>1011<span class=\"token punctuation\">)<\/span> \u6539\u4e3a\u5c0f\u7aef\u5e8f<span class=\"token punctuation\">(<\/span>1011 1110 0100<span class=\"token punctuation\">)<\/span>\u53733044\r\n09-15 14<span class=\"token punctuation\">:<\/span>35<span class=\"token punctuation\">:<\/span>06.822 &lt;3&gt;[138<span class=\"token punctuation\">,<\/span> kswapd0][  638.194678]   0xffffffc06185f000 255   #matchLength begin\r\n09-15 14<span class=\"token punctuation\">:<\/span>35<span class=\"token punctuation\">:<\/span>06.822 &lt;3&gt;[138<span class=\"token punctuation\">,<\/span> kswapd0][  638.194689]   0xffffffc06185f000 255\r\n09-15 14<span class=\"token punctuation\">:<\/span>35<span class=\"token punctuation\">:<\/span>06.822 &lt;3&gt;[138<span class=\"token punctuation\">,<\/span> kswapd0][  638.194701]   0xffffffc06185f000 255\r\n09-15 14<span class=\"token punctuation\">:<\/span>35<span class=\"token punctuation\">:<\/span>06.822 &lt;3&gt;[138<span class=\"token punctuation\">,<\/span> kswapd0][  638.194712]   0xffffffc06185f000 255\r\n09-15 14<span class=\"token punctuation\">:<\/span>35<span class=\"token punctuation\">:<\/span>06.822 &lt;3&gt;[138<span class=\"token punctuation\">,<\/span> kswapd0][  638.194747]   0xffffffc06185f000 7     #matchLength <span class=\"token property\">end<\/span><span class=\"token punctuation\">:<\/span>255*4+7 1027\r\n<\/code><\/pre>\n<\/div>\n<h4>\u89e3\u538b\u7b97\u6cd5<\/h4>\n<p>\u538b\u7f29\u7406\u89e3\u4e86\u5176\u5b9e\u89e3\u538b\u4e5f\u5f88\u7b80\u5355<\/p>\n<div class=\"_2Uzcx_\"><button class=\"VJbwyy\" type=\"button\" aria-label=\"\u590d\u5236\u4ee3\u7801\"><i class=\"anticon anticon-copy\" aria-label=\"icon: copy\"><\/i><\/button><\/p>\n<pre class=\"line-numbers  language-css\"><code class=\"  language-css\">\u8f93\u5165\uff1a[token]abcde_<span class=\"token punctuation\">(<\/span>5<span class=\"token punctuation\">,<\/span>4<span class=\"token punctuation\">)<\/span>[token]fgh_<span class=\"token punctuation\">(<\/span>14<span class=\"token punctuation\">,<\/span>5<span class=\"token punctuation\">)<\/span>fghxxxxxxx\r\n\u8f93\u51fa\uff1aabcde_bcdefgh_abcdefghxxxxxxx\r\n<\/code><\/pre>\n<\/div>\n<p>\u6839\u636e\u89e3\u538b\u524d\u7684\u6570\u636e\u6d41\uff0c\u53d6\u51fatoken\u5185\u7684length\uff0cliterals\u76f4\u63a5\u590d\u5236\u5230\u8f93\u51fa\uff0c\u5373memcpy(src,dst,length)<br \/>\n\u9047\u5230match\uff0c\u5728\u4ece\u524d\u9762\u5df2\u7ecf\u62f7\u8d1d\u7684literals\u590d\u5236\u5230\u540e\u9762\u5373\u53ef<\/p>\n<\/article>\n","protected":false},"excerpt":{"rendered":"<p>\u539f\u6587\u5730\u5740 \u7b80\u4ecb lz4\u662f\u76ee\u524d\u7efc\u5408\u6765\u770b\u6548\u7387<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"colormag_page_container_layout":"default_layout","colormag_page_sidebar_layout":"default_layout","footnotes":""},"categories":[],"tags":[119],"class_list":["post-4801","post","type-post","status-publish","format-standard","hentry","tag-03-"],"_links":{"self":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/posts\/4801","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/comments?post=4801"}],"version-history":[{"count":0,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/posts\/4801\/revisions"}],"wp:attachment":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/media?parent=4801"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/categories?post=4801"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/tags?post=4801"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}