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-rw-r--r--src/eyetil.cc29
-rw-r--r--src/eyetil.h3
2 files changed, 31 insertions, 1 deletions
diff --git a/src/eyetil.cc b/src/eyetil.cc
index 2fbd687..fe816a6 100644
--- a/src/eyetil.cc
+++ b/src/eyetil.cc
@@ -6,2 +6,4 @@
6#include <stdexcept> 6#include <stdexcept>
7#include <algorithm>
8#include <numeric>
7#include <openssl/md5.h> 9#include <openssl/md5.h>
@@ -10,3 +12,2 @@
10binary_t& binary_t::from_hex(const std::string& h) { 12binary_t& binary_t::from_hex(const std::string& h) {
11 /* TODO: algorithmize */
12 std::string::size_type hs = h.length(); 13 std::string::size_type hs = h.length();
@@ -119 +120,27 @@ bool tarchive_t::read_data_into_fd(int fd) {
119} 120}
121
122#pragma pack(1)
123struct block512_t {
124 enum { words = 512 / sizeof(uint16_t) };
125 uint16_t data[words];
126
127 static uint16_t tcpcksum(block512_t& data) {
128 uint32_t sum = std::accumulate(data.data,data.data+words,0);
129 while(uint32_t hw = sum>>16) sum = (sum&0xffff)+hw;
130 return ~sum;
131 }
132
133};
134#pragma pack()
135
136binary_t integrity_digest(const void *ptr,size_t size,const std::string& ukey) {
137 binary_t key; key.from_hex(ukey);
138 std::vector<uint16_t> blksums; blksums.reserve(size/sizeof(block512_t));
139 block512_t *db = (block512_t*)ptr,
140 *de = db + size/sizeof(block512_t);
141 std::transform( db, de, std::back_inserter(blksums), block512_t::tcpcksum );
142 binary_t subject;
143 subject.from_data((void*)&(blksums.front()),blksums.size()*sizeof(uint16_t));
144 std::copy( key.begin(), key.end(), std::back_inserter(subject) );
145 return subject.md5();
146}
diff --git a/src/eyetil.h b/src/eyetil.h
index 195d24f..378f703 100644
--- a/src/eyetil.h
+++ b/src/eyetil.h
@@ -47,2 +47,5 @@ class tarchive_t {
47 47
48binary_t integrity_digest(const void *ptr,size_t size,
49 const std::string& ukey);
50
48#endif /* __EYETIL_H */ 51#endif /* __EYETIL_H */