【www.gdgbn.com--php常用代码】

<%@language="javascript"%>
<%
/*
 * Copyright (c) 2006 Hardway Hou
 * Distributed under the BSD License
 * Inspired from PNGlet http://www.elf.org/pnglets/
 */
var ASCII=new Array(36);
ASCII[0] = "1110000111110111101111011110111101111011110111101111011110111101111011110111101111011110111110000111";
ASCII[1] = "1111011111110001111111110111111111011111111101111111110111111111011111111101111111110111111100000111";
ASCII[2] = "1110000111110111101111011110111111111011111111011111111011111111011111111011111111011110111100000011";
ASCII[3] = "1110000111110111101111011110111111110111111100111111111101111111111011110111101111011110111110000111";
ASCII[4] = "1111101111111110111111110011111110101111110110111111011011111100000011111110111111111011111111000011";
ASCII[5] = "1100000011110111111111011111111101000111110011101111111110111111111011110111101111011110111110000111";
ASCII[6] = "1111000111111011101111011111111101111111110100011111001110111101111011110111101111011110111110000111";
ASCII[7] = "1100000011110111011111011101111111101111111110111111110111111111011111111101111111110111111111011111";
ASCII[8] = "1110000111110111101111011110111101111011111000011111101101111101111011110111101111011110111110000111";
ASCII[9] = "1110001111110111011111011110111101111011110111001111100010111111111011111111101111011101111110001111";
ASCII[10] = "1111011111111101111111101011111110101111111010111111101011111100000111110111011111011101111000100011";
ASCII[11] = "1000000111110111101111011110111101110111110000111111011101111101111011110111101111011110111000000111";
ASCII[12] = "1110000011110111101110111110111011111111101111111110111111111011111111101111101111011101111110001111";
ASCII[13] = "0000001111110111011111011110111101111011110111101111011110111101111011110111101111011101110000001111";
ASCII[14] = "1000000111110111101111011011111101101111110000111111011011111101101111110111111111011110111000000111";
ASCII[15] = "1000000111110111101111011011111101101111110000111111011011111101101111110111111111011111111000111111";
ASCII[16] = "0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000";

var FONT_WIDTH=10;
var FONT_HEIGHT=10;

// Note.
// Assume all the strings are formed by BYTE.
// That is, a single character is a BYTE.
// It will be converted to real BYTE at output phase.

// Using index color, depth 8
var WIDTH=160;
var HEIGHT=40;
var DEPTH=8;
var MAP=new Array((WIDTH+1)*HEIGHT);

function B4(b){
 return String.fromCharCode((b>>24)&0xFF, (b>>16)&0xFF, (b>>8)&0xFF, b&0xFF);
}
function B2(b){
 return String.fromCharCode((b>>8)&0xFF, b&0xFF);
}
function B1(b){
 return String.fromCharCode(b&0xFF);
}

var CRC_TABLE=new Array(256);
// Make crc table
function CRC32_Init(){
 var n=0, k=0;
 var c;
 for(n=0; n<256; n++){
  c=n;
  for(k=0; k<8; k++){
   if (c&1)
    c=0xedb88320^(c>>>1);
   else
    c=c>>>1;
  }
  CRC_TABLE[n]=c;
 }
}
CRC32_Init();

function CRC32(str){
 var c=0xFFFFFFFF;
 var n=0;
 for(n=0; n   c=CRC_TABLE[(c^str.charCodeAt(n))&0xFF]^(c>>>8);
 }
 return c^0xFFFFFFFF;
}

function png_signature(){
 return [0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a];
}

function png_chunk(type, str){
 var ary=[], i=0;
 var crc;
 
 crc=CRC32(type+str);
 str=B4(str.length)+type+str;
 str=str+B4(crc);
 
 for(i=0; i   ary.push(str.charCodeAt(i));
 return ary;
}

function png_IHDR(){
 return png_chunk("IHDR", B4(WIDTH)+B4(HEIGHT)+B1(DEPTH)+B1(3)+B1(0)+B1(0)+B1(0));
}

function png_PLTE(){
 return png_chunk("PLTE",
  B1(255)+B1(255)+B1(255) //0
  +B1(224)+B1(224)+B1(224) //1
  +B1(192)+B1(192)+B1(192) //2
  +B1(160)+B1(160)+B1(160) //3
  +B1(128)+B1(128)+B1(128) //4
  +B1(96)+B1(96)+B1(96) //5
  +B1(64)+B1(64)+B1(64) //6
  +B1(32)+B1(32)+B1(32) //7
  +B1(0)+B1(0)+B1(0) //8
  );
}

function png_IDAT(){
 var h=HEIGHT
 var strip=WIDTH+1;
 var x, y;
  
 var data=""
 for(y=0; y   data=data+String.fromCharCode(MAP[x+y*strip]);
 var LEN=data.length;
 var NLEN=LEN^0xFFFFFFFF;
 
 // Calculate Simple Adler-32 checksum
 var BASE=65521, NMAX=5552;
 var s1=1, s2=0, n=NMAX;
 var i;
 for(i=0; i   s1+=data.charCodeAt(i);
  s2+=s1;
  if((n--)==0){
   s1%=BASE;
   s2%=BASE;
   n=NMAX;
  }
 }
 s1%=BASE;
 s2%=BASE;
 
 return png_chunk("IDAT", B1(0x78)+B1(0xDA)+B1(0x01)+ /*uncompressd lz77*/
  String.fromCharCode((LEN)&0xFF, (LEN>>8)&0xFF, (NLEN)&0xFF, (NLEN>>8)&0xFF) +
  data+B4((s2<<16)|s1));
}

function png_IEND(){
 return png_chunk("IEND", "");
}

function png_output(){
 var dat=[], i=0
 var str="";
 dat=dat.concat(png_signature(), png_IHDR(), png_PLTE(), png_IDAT(), png_IEND());
 if(dat.length % 2==1) dat.push(0); // Fill data to make it 2-byte aligned
 for(i=0; i   Response.binaryWrite(String.fromCharCode( dat[i] + (dat[i+1]<<8) ));
 }
}

function Map_Init(){
 var x, y;
 var strip=WIDTH+1;
 for(x=0; x   if(x==0)
   MAP[x+y*strip]=0; // scanline indicator
  else
   MAP[x+y*strip]=8; // bgcolor
 }
}

function putPixel(x, y, c){
 MAP[x+1+y*(WIDTH+1)]=c;
}
function getPixel(x, y, c){
 return MAP[x+1+y*(WIDTH+1)];
}

function putChar(ox, oy, ch){
 var x, y;
 oy+=Math.floor(Math.random()*5-5.5);
 for(y=0;y   ox+=Math.floor(Math.random()*2+0.5)-1;
  for(x=0;x    var c=1-parseInt(ASCII[ch].charAt(x+y*FONT_WIDTH));
   if(c>0){
    c=0;
    // double size, bold and random italic
    putPixel(ox+x*3, oy+y*2, c);
    putPixel(ox+x*3+1, oy+y*2, c);
    putPixel(ox+x*3+2, oy+y*2, c);
    putPixel(ox+x*3, oy+y*2+1, c);
    putPixel(ox+x*3+1, oy+y*2+1, c);
    putPixel(ox+x*3+2, oy+y*2+1, c);
   }
  }
 }
}
function putNoise(n, c){
 var i, x, y;
 for(i=0; i   x=Math.floor(Math.random()*WIDTH);
  y=Math.floor(Math.random()*HEIGHT);
  putPixel(x, y, c);
 }
}
function smooth(){
 var x, y;
 var c0, c1, c2, c3, c4; // center, up, right, down, left
 for(x=0; x   c0=getPixel(x, y);
  c1=(y>0)?getPixel(x, y-1):c0;
  c2=(x   c3=(y   c4=(x>0)?getPixel(x-1, y):c0;
  putPixel(x, y, Math.floor((c0*6+c1+c2+c3+c4)/10+0.5));
 }
}

// MD5
var v1=0;var v2="";var v3=8;function hex_md5(s){return binl2hex(f2(f8(s),s.length*v3));}function b64_md5(s){return binl2b64(f2(f8(s),s.length*v3));}function str_md5(s){return binl2str(f2(f8(s),s.length*v3));}function hex_hmac_md5(key,data){return binl2hex(f9(key,data));}function b64_hmac_md5(key,data){return binl2b64(f9(key,data));}function str_hmac_md5(key,data){return binl2str(f9(key,data));}function f1(){return hex_md5("abc")=="900150983cd24fb0d6963f7d28e17f72";}function f2(x,len){x[len>>5]|=0x80<<((len)%32);x[(((len+64)>>>9)<<4)+14]=len;var a=1732584193;var b=-271733879;var c=-1732584194;var d=271733878;for(var i=0;i16)bkey=f2(bkey,key.length*v3);var ipad=Array(16),opad=Array(16);for(var i=0;i<16;i++){ipad[i]=bkey[i]^0x36363636;opad[i]=bkey[i]^0x5C5C5C5C;}var hash=f2(ipad.concat(f8(data)),512+data.length*v3);return f2(opad.concat(hash),512+128);}function safe_add(x,y){var lsw=(x&0xFFFF)+(y&0xFFFF);var msw=(x>>16)+(y>>16)+(lsw>>16);return(msw<<16)|(lsw&0xFFFF);}function bit_rol(num,cnt){return(num<>>(32-cnt));}function f8(str){var bin=Array();var mask=(1<>5]|=(str.charCodeAt(i/v3)&mask)<<(i%32);return bin;}function binl2str(bin){var str="";var mask=(1<>5]>>>(i%32))&mask);return str;}function binl2hex(binarray){var hex_tab=v1?"0123456789ABCDEF":"0123456789abcdef";var str="";for(var i=0;i>2]>>((i%4)*8+4))&0xF)+hex_tab.charAt((binarray[i>>2]>>((i%4)*8))&0xF);}return str;}function binl2b64(binarray){var tab="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";var str="";for(var i=0;i>2]>>8*(i%4))&0xFF)<<16)|(((binarray[i+1>>2]>>8*((i+1)%4))&0xFF)<<8)|((binarray[i+2>>2]>>8*((i+2)%4))&0xFF);for(var j=0;j<4;j++){if(i*8+j*6>binarray.length*32)str+=v2;else str+=tab.charAt((triplet>>6*(3-j))&0x3F);}}return str;}

function captcha(str){
 Map_Init();
 var ox=FONT_WIDTH/2, oy=(HEIGHT-FONT_HEIGHT)/2;
 var i;
 var idx=0;
 var c;
 for(i=0; i   c=str.charCodeAt(i);
  if(c<=57 && c>=48)
   idx=c-48;
  else if(c<=70 && c>=65)
   idx=c-65+10;
  else idx=16;
  putChar(ox+i*FONT_WIDTH*2.5, oy, idx);
 }
 putNoise(500, 4);
 putNoise(500, 2);
 smooth();
 png_output();
}
%>
<%
Response.Expires=-9999;
Response.addHeader("Pragma","no-cache");
Response.addHeader("Cache-Control","no-cache");
Response.ContentType="image/png";

captcha(hex_md5(Math.random().toString()).substr(0, 6).toUpperCase());
%>

本文来源：http://www.gdgbn.com/jiaocheng/12229/