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php讀寫二進制文件可以使用pack和unpack函數。
今天要處理一個二進制文件的問題，所以需要用一下，特意了解一下pack的用法，unpack用法與此類似。
簡單來說，pack函數就是給一個目標格式，和相應的參數，就可以返回二進制數據了。
下面舉例加以說明，對于四個整數：
pack("L4", 0,1,2,3)pack("LLLL", 0,1,2,3)pack("L", 0).pack("L", 1).pack("L", 2).pack("L", 3)上面的處理結果是一樣的，也就是說，format是描述后面的數據的格式。
至于具體format可以用什么，看看format characters就知道了。
比如一個30字符的 pack("a30", "http://www.jb51.NET") ，就是這個意思，很簡單
pack函數的官方聲明如下：
引用pack(php 3, php 4, php 5)pack -- Pack data into binary stringDescriptionstring pack ( string format [, mixed args [, mixed ...]] )Pack given arguments into binary string according to format. Returns binary string containing data. The idea to this function was taken from Perl and all formatting codes work the same as there, however, there are some formatting codes that are missing such as Perl's "u" format code. The format string consists of format codes followed by an optional repeater argument. The repeater argument can be either an integer value or * for repeating to the end of the input data. For a, A, h, H the repeat count specifies how many characters of one data argument are taken, for @ it is the absolute position where to put the next data, for everything else the repeat count specifies how many data arguments are consumed and packed into the resulting binary string. Currently implemented are表格 1. pack() format charactersCode Description a NUL-padded string A SPACE-padded string h Hex string, low nibble first H Hex string, high nibble first c signed char C unsigned char s signed short (always 16 bit, machine byte order) S unsigned short (always 16 bit, machine byte order) n unsigned short (always 16 bit, big endian byte order) v unsigned short (always 16 bit, little endian byte order) i signed integer (machine dependent size and byte order) I unsigned integer (machine dependent size and byte order) l signed long (always 32 bit, machine byte order) L unsigned long (always 32 bit, machine byte order) N unsigned long (always 32 bit, big endian byte order) V unsigned long (always 32 bit, little endian byte order) f float (machine dependent size and representation) d double (machine dependent size and representation) x NUL byte X Back up one byte @ NUL-fill to absolute position
看累了英文，下面來看看對應的中文解釋：
引用pack()函數的作用是：將數據壓縮成一個二進制字符串。a - NUL-padded string a - NUL- 字符串填滿[padded string] A - SPACE-padded string A - SPACE- 字符串填滿[padded string] h - Hex string, low nibble first h 主站蜘蛛池模板： 日韩高清国产一区在线 | 91国产精品在线 | 免费在线看a | 日韩在线看片 | 亚洲精品乱码久久久久久黑人 | 亚洲精品乱码久久久久久久久久 | 日本精品视频在线 | 三级成人片 | www.操.com| 婷婷精品 | 精品国产色 | 精品一区二区视频 | 欧美激情国产日韩精品一区18 | 久久99精品久久久久久国产越南 | 欧美极品少妇xxxxⅹ免费视频 | 毛片免费观看 | 国内久久 | 欧美性一区二区三区 | 久久成人18免费网站 | 涩爱av一区二区三区 | 成人精品在线观看 | 中文字幕免费观看 | 亚洲精品一区二三区不卡 | 久久精品国产精品青草 | 国产日韩欧美激情 | 亚洲国产成人精品一区二区 | 日韩成人专区 | www九色| 久久久久久久国产精品 | 午夜欧美日韩 | av免费看片| 黄色片网站在线观看 | 欧洲亚洲精品久久久久 | 久日精品| 欧美一二三区 | 国产亚洲精品美女久久久久久久久久 | 黄色大片观看 | 91玖玖| 久久综合久久久 | 欧洲精品久久久久毛片完整版 | 中文字幕国产精品 |