lix/src/hash.cc

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2003-06-15 13:41:32 +00:00
extern "C" {
#include "md5.h"
}
#include "hash.hh"
#include <iostream>
/* Create a zeroed hash object. */
Hash::Hash()
{
memset(hash, 0, sizeof(hash));
}
/* Check whether two hash are equal. */
bool Hash::operator == (Hash & h2)
{
for (unsigned int i = 0; i < hashSize; i++)
if (hash[i] != h2.hash[i]) return false;
return true;
}
/* Check whether two hash are not equal. */
bool Hash::operator != (Hash & h2)
{
return !(*this == h2);
}
/* Convert a hash code into a hexadecimal representation. */
Hash::operator string() const
{
ostringstream str;
for (unsigned int i = 0; i < hashSize; i++) {
str.fill('0');
str.width(2);
str << hex << (int) hash[i];
}
return str.str();
}
/* Parse a hexadecimal representation of a hash code. */
Hash parseHash(const string & s)
{
Hash hash;
for (unsigned int i = 0; i < Hash::hashSize; i++) {
string s2(s, i * 2, 2);
if (!isxdigit(s2[0]) || !isxdigit(s2[1]))
throw BadRefError("invalid hash: " + s);
istringstream str(s2);
int n;
str >> hex >> n;
hash.hash[i] = n;
}
return hash;
}
/* Verify that a reference is valid (that is, is a MD5 hash code). */
bool isHash(const string & s)
{
if (s.length() != 32) return false;
for (int i = 0; i < 32; i++) {
char c = s[i];
if (!((c >= '0' && c <= '9') ||
(c >= 'a' && c <= 'f')))
return false;
}
return true;
}
/* Compute the MD5 hash of a file. */
Hash hashFile(const string & fileName)
{
Hash hash;
FILE * file = fopen(fileName.c_str(), "rb");
if (!file)
throw Error("file `" + fileName + "' does not exist");
int err = md5_stream(file, hash.hash);
fclose(file);
if (err) throw Error("cannot hash file");
return hash;
}