ahe@google.com
6254729761
This reverts r13961 and r13963. Review URL: https://codereview.chromium.org//11233061 git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@13967 260f80e4-7a28-3924-810f-c04153c831b5
50 lines
1.5 KiB
Dart
50 lines
1.5 KiB
Dart
/**
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* A simple base64 decoder class, used to decode web browser screenshots
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* returned by WebDriver.
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*/
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class Base64Decoder {
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static int getVal(String s, pos) {
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int code = s.charCodeAt(pos);
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if (code >= 65 && code < (65+26)) { // 'A'..'Z'
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return code - 65;
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} else if (code >= 97 && code < (97+26)) { // 'a'..'z'
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return code - 97 + 26;
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} else if (code >= 48 && code < (48+10)) { // '0'..'9'
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return code - 48 + 52;
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} else if (code == 43) { // '+'
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return 62;
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} else if (code == 47) { // '/'
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return 63;
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} else {
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throw 'Invalid character $s';
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}
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}
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static List<int> decode(String s) {
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var rtn = new List<int>();
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var pos = 0;
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while (pos < s.length) {
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if (s[pos+2] =='=') { // Single byte as two chars.
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int v = (getVal(s, pos) << 18 ) | (getVal(s, pos+1) << 12 );
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rtn.add((v >> 16) & 0xff);
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break;
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} else if (s[pos+3] == '=') { // Two bytes as 3 chars.
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int v = (getVal(s, pos) << 18 ) | (getVal(s, pos+1) << 12 ) |
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(getVal(s, pos + 2) << 6);
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rtn.add((v >> 16) & 0xff);
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rtn.add((v >> 8) & 0xff);
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break;
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} else { // Three bytes as 4 chars.
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int v = (getVal(s, pos) << 18 ) | (getVal(s, pos+1) << 12 ) |
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(getVal(s, pos + 2) << 6) | getVal(s, pos+3);
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pos += 4;
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rtn.add((v >> 16 ) & 0xff);
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rtn.add((v >> 8) & 0xff);
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rtn.add(v & 0xff);
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}
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}
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return rtn;
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}
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}
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