47 lines
1.2 KiB
Plaintext
47 lines
1.2 KiB
Plaintext
// Copyright (C) 2010, Guy Barrand. All rights reserved.
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// See the file tools.license for terms.
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#ifndef tools_gzip
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#define tools_gzip
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#include "signature"
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namespace tools {
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namespace file {
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inline bool is_gzip(const std::string& a_file,bool& a_is){
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unsigned char head[4];
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{unsigned int num = 4;
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if(!signature(a_file,head,num)) {a_is = false;return false;}
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if(num!=4) {a_is = false;return true;}}
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if(head[0]!=31) {a_is = false;return true;}
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if(head[1]!=139) {a_is = false;return true;}
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//if(head[2]!=8) {a_is = false;return true;}
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//if(head[3]!=8) {a_is = false;return true;}
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a_is = true;
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return true;
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}
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inline bool gzip_usize(const std::string& a_file,unsigned int& a_usz){
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bool is;
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if(!is_gzip(a_file,is)) {a_usz=0;return false;}
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if(!is) {a_usz=0;return false;}
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FILE* file = ::fopen(a_file.c_str(),"rb");
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if(!file) {a_usz=0;return false;}
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::fseek(file,-4,SEEK_END);
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unsigned char buf[4];
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size_t n = ::fread(buf,1,4,file);
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::fclose(file);
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if(n!=4) {a_usz=0;return false;}
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unsigned int b4 = buf[0];
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unsigned int b3 = buf[1];
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unsigned int b2 = buf[2];
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unsigned int b1 = buf[3];
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a_usz = (b1 << 24) | ((b2 << 16) + (b3 << 8) + b4);
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return true;
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}
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}}
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#endif
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