📄 string.h

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<!doctype html public "-//W3C//DTD HTML 3.2//EN"><html><head><title>Linux/include/string.h</title><meta http-equiv=Content-Type content="text/html; charset=gb2312"><base href="http://oldlinux.org/lxr/http/"></head><body bgcolor=white><div align=center>   [<b><i>源代码浏览</i></b>] [<a href="diff/include/string.h">区别标定</a>] [<a href="ident">标识符搜索</a>] [<a href="search">文本搜索</a>] [<a href="find">文件搜索</a>]</div><h1 align=center>  <a href="http:/">     OldLinux</a>  <a href="http:blurb.html">    交叉引用</a><br>  <a href="source/">Linux</a>/<a href="source/include/">include</a>/<a href="source/include/string.h">string.h</a></h1><div align=center>    <b>版本:</b>   [<a href="source/include/string.h?v=1.0">1.0</a>] [<a href="source/include/string.h?v=0.99.11">0.99.11</a>] [<a href="source/include/string.h?v=0.99">0.99</a>] [<a href="source/include/string.h?v=0.97">0.97</a>] [<a href="source/include/string.h?v=0.96a">0.96a</a>] [<a href="source/include/string.h?v=0.95">0.95</a>] [<a href="source/include/string.h?v=0.12">0.12</a>] [<b><i>0.11</i></b>] [<a href="source/include/string.h?v=0.01">0.01</a>]  <br>  <b>体系结构:</b>   [<b><i>i386</i></b>]  <br></div><hr><pre>  <a name=L1 href="source/include/string.h#L1">1</a> #ifndef <a href="ident?i=_STRING_H_">_STRING_H_</a>  <a name=L2 href="source/include/string.h#L2">2</a> #define <a href="ident?i=_STRING_H_">_STRING_H_</a>  <a name=L3 href="source/include/string.h#L3">3</a>   <a name=L4 href="source/include/string.h#L4">4</a> #ifndef <a href="ident?i=NULL">NULL</a>  <a name=L5 href="source/include/string.h#L5">5</a> #define <a href="ident?i=NULL">NULL</a> ((void *) 0)  <a name=L6 href="source/include/string.h#L6">6</a> #endif  <a name=L7 href="source/include/string.h#L7">7</a>   <a name=L8 href="source/include/string.h#L8">8</a> #ifndef <a href="ident?i=_SIZE_T">_SIZE_T</a>  <a name=L9 href="source/include/string.h#L9">9</a> #define <a href="ident?i=_SIZE_T">_SIZE_T</a> <a name=L10 href="source/include/string.h#L10">10</a> typedef unsigned int <a href="ident?i=size_t">size_t</a>; <a name=L11 href="source/include/string.h#L11">11</a> #endif <a name=L12 href="source/include/string.h#L12">12</a>  <a name=L13 href="source/include/string.h#L13">13</a> extern char * <a href="ident?i=strerror">strerror</a>(int <a href="ident?i=errno">errno</a>); <a name=L14 href="source/include/string.h#L14">14</a>  <a name=L15 href="source/include/string.h#L15">15</a> <b><i>/*</i></b> <a name=L16 href="source/include/string.h#L16">16</a> <b><i> * This string-include defines all string functions as inline</i></b> <a name=L17 href="source/include/string.h#L17">17</a> <b><i> * functions. Use gcc. It also assumes ds=es=data space, this should be</i></b> <a name=L18 href="source/include/string.h#L18">18</a> <b><i> * normal. Most of the string-functions are rather heavily hand-optimized,</i></b> <a name=L19 href="source/include/string.h#L19">19</a> <b><i> * see especially strtok,strstr,str[c]spn. They should work, but are not</i></b> <a name=L20 href="source/include/string.h#L20">20</a> <b><i> * very easy to understand. Everything is done entirely within the register</i></b> <a name=L21 href="source/include/string.h#L21">21</a> <b><i> * set, making the functions fast and clean. String instructions have been</i></b> <a name=L22 href="source/include/string.h#L22">22</a> <b><i> * used through-out, making for "slightly" unclear code :-)</i></b> <a name=L23 href="source/include/string.h#L23">23</a> <b><i> *</i></b> <a name=L24 href="source/include/string.h#L24">24</a> <b><i> *              (C) 1991 Linus Torvalds</i></b> <a name=L25 href="source/include/string.h#L25">25</a> <b><i> */</i></b> <a name=L26 href="source/include/string.h#L26">26</a>   <a name=L27 href="source/include/string.h#L27">27</a> extern inline char * <a href="ident?i=strcpy">strcpy</a>(char * dest,const char *src) <a name=L28 href="source/include/string.h#L28">28</a> { <a name=L29 href="source/include/string.h#L29">29</a> __asm__(<i>"cld\n"</i> <a name=L30 href="source/include/string.h#L30">30</a>         <i>"1:\tlodsb\n\t"</i> <a name=L31 href="source/include/string.h#L31">31</a>         <i>"stosb\n\t"</i> <a name=L32 href="source/include/string.h#L32">32</a>         <i>"testb %%al,%%al\n\t"</i> <a name=L33 href="source/include/string.h#L33">33</a>         <i>"jne 1b"</i> <a name=L34 href="source/include/string.h#L34">34</a>         ::<i>"S"</i> (src),<i>"D"</i> (dest):<i>"si"</i>,<i>"di"</i>,<i>"ax"</i>); <a name=L35 href="source/include/string.h#L35">35</a> return dest; <a name=L36 href="source/include/string.h#L36">36</a> } <a name=L37 href="source/include/string.h#L37">37</a>  <a name=L38 href="source/include/string.h#L38">38</a> extern inline char * <a href="ident?i=strncpy">strncpy</a>(char * dest,const char *src,int <a href="ident?i=count">count</a>) <a name=L39 href="source/include/string.h#L39">39</a> { <a name=L40 href="source/include/string.h#L40">40</a> __asm__(<i>"cld\n"</i> <a name=L41 href="source/include/string.h#L41">41</a>         <i>"1:\tdecl %2\n\t"</i> <a name=L42 href="source/include/string.h#L42">42</a>         <i>"js 2f\n\t"</i> <a name=L43 href="source/include/string.h#L43">43</a>         <i>"lodsb\n\t"</i> <a name=L44 href="source/include/string.h#L44">44</a>         <i>"stosb\n\t"</i> <a name=L45 href="source/include/string.h#L45">45</a>         <i>"testb %%al,%%al\n\t"</i> <a name=L46 href="source/include/string.h#L46">46</a>         <i>"jne 1b\n\t"</i> <a name=L47 href="source/include/string.h#L47">47</a>         <i>"rep\n\t"</i> <a name=L48 href="source/include/string.h#L48">48</a>         <i>"stosb\n"</i> <a name=L49 href="source/include/string.h#L49">49</a>         <i>"2:"</i> <a name=L50 href="source/include/string.h#L50">50</a>         ::<i>"S"</i> (src),<i>"D"</i> (dest),<i>"c"</i> (<a href="ident?i=count">count</a>):<i>"si"</i>,<i>"di"</i>,<i>"ax"</i>,<i>"cx"</i>); <a name=L51 href="source/include/string.h#L51">51</a> return dest; <a name=L52 href="source/include/string.h#L52">52</a> } <a name=L53 href="source/include/string.h#L53">53</a>  <a name=L54 href="source/include/string.h#L54">54</a> extern inline char * <a href="ident?i=strcat">strcat</a>(char * dest,const char * src) <a name=L55 href="source/include/string.h#L55">55</a> { <a name=L56 href="source/include/string.h#L56">56</a> __asm__(<i>"cld\n\t"</i> <a name=L57 href="source/include/string.h#L57">57</a>         <i>"repne\n\t"</i> <a name=L58 href="source/include/string.h#L58">58</a>         <i>"scasb\n\t"</i> <a name=L59 href="source/include/string.h#L59">59</a>         <i>"decl %1\n"</i> <a name=L60 href="source/include/string.h#L60">60</a>         <i>"1:\tlodsb\n\t"</i> <a name=L61 href="source/include/string.h#L61">61</a>         <i>"stosb\n\t"</i> <a name=L62 href="source/include/string.h#L62">62</a>         <i>"testb %%al,%%al\n\t"</i> <a name=L63 href="source/include/string.h#L63">63</a>         <i>"jne 1b"</i> <a name=L64 href="source/include/string.h#L64">64</a>         ::<i>"S"</i> (src),<i>"D"</i> (dest),<i>"a"</i> (0),<i>"c"</i> (0xffffffff):<i>"si"</i>,<i>"di"</i>,<i>"ax"</i>,<i>"cx"</i>); <a name=L65 href="source/include/string.h#L65">65</a> return dest; <a name=L66 href="source/include/string.h#L66">66</a> } <a name=L67 href="source/include/string.h#L67">67</a>  <a name=L68 href="source/include/string.h#L68">68</a> extern inline char * <a href="ident?i=strncat">strncat</a>(char * dest,const char * src,int <a href="ident?i=count">count</a>) <a name=L69 href="source/include/string.h#L69">69</a> { <a name=L70 href="source/include/string.h#L70">70</a> __asm__(<i>"cld\n\t"</i> <a name=L71 href="source/include/string.h#L71">71</a>         <i>"repne\n\t"</i> <a name=L72 href="source/include/string.h#L72">72</a>         <i>"scasb\n\t"</i> <a name=L73 href="source/include/string.h#L73">73</a>         <i>"decl %1\n\t"</i> <a name=L74 href="source/include/string.h#L74">74</a>         <i>"movl %4,%3\n"</i> <a name=L75 href="source/include/string.h#L75">75</a>         <i>"1:\tdecl %3\n\t"</i> <a name=L76 href="source/include/string.h#L76">76</a>         <i>"js 2f\n\t"</i> <a name=L77 href="source/include/string.h#L77">77</a>         <i>"lodsb\n\t"</i> <a name=L78 href="source/include/string.h#L78">78</a>         <i>"stosb\n\t"</i> <a name=L79 href="source/include/string.h#L79">79</a>         <i>"testb %%al,%%al\n\t"</i> <a name=L80 href="source/include/string.h#L80">80</a>         <i>"jne 1b\n"</i> <a name=L81 href="source/include/string.h#L81">81</a>         <i>"2:\txorl %2,%2\n\t"</i> <a name=L82 href="source/include/string.h#L82">82</a>         <i>"stosb"</i> <a name=L83 href="source/include/string.h#L83">83</a>         ::<i>"S"</i> (src),<i>"D"</i> (dest),<i>"a"</i> (0),<i>"c"</i> (0xffffffff),<i>"g"</i> (<a href="ident?i=count">count</a>) <a name=L84 href="source/include/string.h#L84">84</a>         :<i>"si"</i>,<i>"di"</i>,<i>"ax"</i>,<i>"cx"</i>); <a name=L85 href="source/include/string.h#L85">85</a> return dest; <a name=L86 href="source/include/string.h#L86">86</a> } <a name=L87 href="source/include/string.h#L87">87</a>  <a name=L88 href="source/include/string.h#L88">88</a> extern inline int <a href="ident?i=strcmp">strcmp</a>(const char * cs,const char * ct) <a name=L89 href="source/include/string.h#L89">89</a> { <a name=L90 href="source/include/string.h#L90">90</a> register int __res __asm__(<i>"ax"</i>); <a name=L91 href="source/include/string.h#L91">91</a> __asm__(<i>"cld\n"</i> <a name=L92 href="source/include/string.h#L92">92</a>         <i>"1:\tlodsb\n\t"</i> <a name=L93 href="source/include/string.h#L93">93</a>         <i>"scasb\n\t"</i> <a name=L94 href="source/include/string.h#L94">94</a>         <i>"jne 2f\n\t"</i> <a name=L95 href="source/include/string.h#L95">95</a>         <i>"testb %%al,%%al\n\t"</i> <a name=L96 href="source/include/string.h#L96">96</a>         <i>"jne 1b\n\t"</i> <a name=L97 href="source/include/string.h#L97">97</a>         <i>"xorl %%eax,%%eax\n\t"</i> <a name=L98 href="source/include/string.h#L98">98</a>         <i>"jmp 3f\n"</i> <a name=L99 href="source/include/string.h#L99">99</a>         <i>"2:\tmovl $1,%%eax\n\t"</i><a name=L100 href="source/include/string.h#L100">100</a>         <i>"jl 3f\n\t"</i><a name=L101 href="source/include/string.h#L101">101</a>         <i>"negl %%eax\n"</i><a name=L102 href="source/include/string.h#L102">102</a>         <i>"3:"</i><a name=L103 href="source/include/string.h#L103">103</a>         :<i>"=a"</i> (__res):<i>"D"</i> (cs),<i>"S"</i> (ct):<i>"si"</i>,<i>"di"</i>);<a name=L104 href="source/include/string.h#L104">104</a> return __res;<a name=L105 href="source/include/string.h#L105">105</a> }<a name=L106 href="source/include/string.h#L106">106</a> <a name=L107 href="source/include/string.h#L107">107</a> extern inline int <a href="ident?i=strncmp">strncmp</a>(const char * cs,const char * ct,int <a href="ident?i=count">count</a>)<a name=L108 href="source/include/string.h#L108">108</a> {<a name=L109 href="source/include/string.h#L109">109</a> register int __res __asm__(<i>"ax"</i>);<a name=L110 href="source/include/string.h#L110">110</a> __asm__(<i>"cld\n"</i><a name=L111 href="source/include/string.h#L111">111</a>         <i>"1:\tdecl %3\n\t"</i><a name=L112 href="source/include/string.h#L112">112</a>         <i>"js 2f\n\t"</i><a name=L113 href="source/include/string.h#L113">113</a>         <i>"lodsb\n\t"</i><a name=L114 href="source/include/string.h#L114">114</a>         <i>"scasb\n\t"</i><a name=L115 href="source/include/string.h#L115">115</a>         <i>"jne 3f\n\t"</i><a name=L116 href="source/include/string.h#L116">116</a>         <i>"testb %%al,%%al\n\t"</i><a name=L117 href="source/include/string.h#L117">117</a>         <i>"jne 1b\n"</i><a name=L118 href="source/include/string.h#L118">118</a>         <i>"2:\txorl %%eax,%%eax\n\t"</i>
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