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POCan I read in binary data with istream in c++?
 

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  1. POCan I read in binary data with istream in c++?
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    <p>Right now I am using istream to read in data. I have both text which I would like to read in as strings and numbers, and hashes which are read into character arrays. Since hashes are effectively random, I am hitting snags when I try to read it back in and hit EOF (which is part of the hash). Is there a way to accomplish this without resorting to fread. Also, is there a to use both istream and fread some I don't have to parse the integers and strings by hand. Finally, what is the best way to use fgets to get a string of unknown length.</p> <p>Thanks, Eric</p> <p>EDIT: Here is the code:</p> <pre><code>string dummy; ifstream in(fileName); for(int i=0; i&lt;numVals; i++) { int hashLen; in&gt;&gt;hashLen; char cc; in.get(cc);//Get the space in between cout&lt;&lt;"Got first byte: "&lt;&lt;(int)cc&lt;&lt;endl; char * hashChars = new char[hashLen]; in.read(hashChars, hashLen); for(int j =0; j &lt;hashLen; j++) { char c = hashChars[j]; unsigned char cc = reinterpret_cast&lt;unsigned char&amp;&gt;(c); cout&lt;&lt;"Got byte: "&lt;&lt;(int)c&lt;&lt;(int)cc&lt;&lt;endl; if(in.fail()) { cout&lt;&lt;"Failed! "&lt;&lt;in.eof()&lt;&lt;" "&lt;&lt;in.bad()&lt;&lt;endl; } } delete hashChars; getline(in,dummy);//get a dummy line cout&lt;&lt;"Dummy: "&lt;&lt;dummy&lt;&lt;" numvals: "&lt;&lt;numVals&lt;&lt;" i: "&lt;&lt;i&lt;&lt;" hashLength: "&lt;&lt;hashLen&lt;&lt;endl; } </code></pre> <p>My output looks like:</p> <p>1>Got first byte: 32</p> <p>1>Got byte: 4 4</p> <p>1>Got byte: -14 242</p> <p>1>Got byte: 108 108</p> <p>1>Got byte: 87 87</p> <p>1>Got byte: 113 113</p> <p>1>Got byte: -116 140</p> <p>1>Got byte: -106 150</p> <p>1>Got byte: -35 221</p> <p>1>Got byte: 0 0</p> <p>1>Got byte: -91 165</p> <p>1>Got byte: 39 39</p> <p>1>Got byte: 111 111</p> <p>1>Got byte: 7 7</p> <p>1>Got byte: 126 126</p> <p>1>Got byte: 16 16</p> <p>1>Got byte: -42 214</p> <p>1>Dummy: numvals: 35 i: 12 hashLength: 16</p> <p>1>Got first byte: 32</p> <p>1>Got byte: 14 14</p> <p>1>Failed! 1 0</p> <p>1>Got byte: -65 191</p> <p>1>Failed! 1 0</p> <p>1>Got byte: -107 149</p> <p>1>Failed! 1 0</p> <p>1>Got byte: -44 212</p> <p>1>Failed! 1 0</p> <p>1>Got byte: -60 196</p> <p>1>Failed! 1 0</p> <p>1>Got byte: -51 205</p> <p>1>Failed! 1 0</p> <p>1>Got byte: -51 205</p> <p>1>Failed! 1 0</p>
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    1. USEric Kulcyk
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    1. COA sample of your data and the code you're using to read it would go a *long* way in getting answers to what is going wrong. And regarding parsing integers and strings by hand, formatted extractors with `istream`s are the cats pajamas.
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      1. POCan I read in binary data with istream in c++?
      1. USWhozCraig
    2. COEOF cannot be part of the hash, because EOF is a concept that cannot be embedded inside of a file. However you are reading in data, that's wrong.
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      1. POCan I read in binary data with istream in c++?
      1. USMooing Duck
    3. COYes streams can read binary data. Streams come with functions for parsing integers and strings of varying lengths. Do not use fgets, fread, or other c functions in C++ please.
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      1. POCan I read in binary data with istream in c++?
      1. USMooing Duck
 

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