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#include "serialise.hh"
#include "util.hh"
#include <cstring>
#include <cerrno>
namespace nix {
void FdSink::operator () (const unsigned char * data, unsigned int len)
{
if (!buffer) buffer = new unsigned char[bufSize];
while (len) {
/* Optimisation: bypass the buffer if the data exceeds the
buffer size and there is no unflushed data. */
if (bufPos == 0 && len >= bufSize) {
writeFull(fd, data, len);
break;
}
/* Otherwise, copy the bytes to the buffer. Flush the buffer
when it's full. */
size_t n = bufPos + len > bufSize ? bufSize - bufPos : len;
memcpy(buffer + bufPos, data, n);
data += n; bufPos += n; len -= n;
if (bufPos == bufSize) flush();
}
}
void FdSink::flush()
{
if (fd == -1 || bufPos == 0) return;
writeFull(fd, buffer, bufPos);
bufPos = 0;
}
void FdSource::operator () (unsigned char * data, unsigned int len)
{
if (!buffer) buffer = new unsigned char[bufSize];
while (len) {
if (!bufPosIn) {
/* Read as much data as is available (up to the buffer
size). */
checkInterrupt();
ssize_t n = read(fd, (char *) buffer, bufSize);
if (n == -1) {
if (errno == EINTR) continue;
throw SysError("reading from file");
}
if (n == 0) throw EndOfFile("unexpected end-of-file");
bufPosIn = n;
}
/* Copy out the data in the buffer. */
size_t n = len > bufPosIn - bufPosOut ? bufPosIn - bufPosOut : len;
memcpy(data, buffer + bufPosOut, n);
data += n; bufPosOut += n; len -= n;
if (bufPosIn == bufPosOut) bufPosIn = bufPosOut = 0;
}
}
void writePadding(unsigned int len, Sink & sink)
{
if (len % 8) {
unsigned char zero[8];
memset(zero, 0, sizeof(zero));
sink(zero, 8 - (len % 8));
}
}
void writeInt(unsigned int n, Sink & sink)
{
unsigned char buf[8];
memset(buf, 0, sizeof(buf));
buf[0] = n & 0xff;
buf[1] = (n >> 8) & 0xff;
buf[2] = (n >> 16) & 0xff;
buf[3] = (n >> 24) & 0xff;
sink(buf, sizeof(buf));
}
void writeLongLong(unsigned long long n, Sink & sink)
{
unsigned char buf[8];
buf[0] = n & 0xff;
buf[1] = (n >> 8) & 0xff;
buf[2] = (n >> 16) & 0xff;
buf[3] = (n >> 24) & 0xff;
buf[4] = (n >> 32) & 0xff;
buf[5] = (n >> 40) & 0xff;
buf[6] = (n >> 48) & 0xff;
buf[7] = (n >> 56) & 0xff;
sink(buf, sizeof(buf));
}
void writeString(const string & s, Sink & sink)
{
unsigned int len = s.length();
writeInt(len, sink);
sink((const unsigned char *) s.c_str(), len);
writePadding(len, sink);
}
void writeStringSet(const StringSet & ss, Sink & sink)
{
writeInt(ss.size(), sink);
for (StringSet::iterator i = ss.begin(); i != ss.end(); ++i)
writeString(*i, sink);
}
void readPadding(unsigned int len, Source & source)
{
if (len % 8) {
unsigned char zero[8];
unsigned int n = 8 - (len % 8);
source(zero, n);
for (unsigned int i = 0; i < n; i++)
if (zero[i]) throw SerialisationError("non-zero padding");
}
}
unsigned int readInt(Source & source)
{
unsigned char buf[8];
source(buf, sizeof(buf));
if (buf[4] || buf[5] || buf[6] || buf[7])
throw SerialisationError("implementation cannot deal with > 32-bit integers");
return
buf[0] |
(buf[1] << 8) |
(buf[2] << 16) |
(buf[3] << 24);
}
unsigned long long readLongLong(Source & source)
{
unsigned char buf[8];
source(buf, sizeof(buf));
return
((unsigned long long) buf[0]) |
((unsigned long long) buf[1] << 8) |
((unsigned long long) buf[2] << 16) |
((unsigned long long) buf[3] << 24) |
((unsigned long long) buf[4] << 32) |
((unsigned long long) buf[5] << 40) |
((unsigned long long) buf[6] << 48) |
((unsigned long long) buf[7] << 56);
}
string readString(Source & source)
{
unsigned int len = readInt(source);
unsigned char * buf = new unsigned char[len];
AutoDeleteArray<unsigned char> d(buf);
source(buf, len);
readPadding(len, source);
return string((char *) buf, len);
}
StringSet readStringSet(Source & source)
{
unsigned int count = readInt(source);
StringSet ss;
while (count--)
ss.insert(readString(source));
return ss;
}
}
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