+++ /dev/null
-/*****************************************************************************\
-* *
-* Name : file_info *
-* Author : Chris Koeritz *
-* *
-*******************************************************************************
-* Copyright (c) 1993-$now By Author. This program is free software; you can *
-* redistribute it and/or modify it under the terms of the GNU General Public *
-* License as published by the Free Software Foundation; either version 2 of *
-* the License or (at your option) any later version. This is online at: *
-* http://www.fsf.org/copyleft/gpl.html *
-* Please send any updates to: fred@gruntose.com *
-\*****************************************************************************/
-
-#include "file_info.h"
-#include "huge_file.h"
-
-#include <basis/astring.h>
-#include <basis/byte_array.h>
-#include <basis/contracts.h>
-#include <basis/functions.h>
-#include <structures/checksums.h>
-#include <structures/object_packers.h>
-
-#include <stdio.h>
-
-#define DEBUG_FILE_INFO
- // uncomment for noisy version.
-
-#undef LOG
-#define LOG(to_print) printf("%s::%s: %s\n", static_class_name(), func, astring(to_print).s())
-
-using namespace basis;
-using namespace structures;
-
-namespace filesystem {
-
-file_info::file_info()
-: filename(astring::empty_string()),
- _file_size(0),
- _time(),
- _checksum(),
- c_secondary(),
- c_attachment()
-{}
-
-file_info::file_info(const filename &to_copy, double file_size,
- const file_time &time, int checksum)
-: filename(to_copy),
- _file_size(file_size),
- _time(time),
- _checksum(checksum),
- c_secondary(),
- c_attachment()
-{}
-
-file_info::file_info(const file_info &to_copy)
-: filename(to_copy),
- _file_size(to_copy._file_size),
- _time(to_copy._time),
- _checksum(to_copy._checksum),
- c_secondary(to_copy.c_secondary),
- c_attachment(to_copy.c_attachment)
-{
-}
-
-file_info::~file_info() {}
-
-const byte_array &file_info::attachment() const { return c_attachment; }
-
-void file_info::attachment(const byte_array &new_attachment)
-{ c_attachment = new_attachment; }
-
-const astring &file_info::secondary() const { return c_secondary; }
-
-void file_info::secondary(const astring &new_sec) { c_secondary = new_sec; }
-
-astring file_info::text_form() const
-{
- astring to_return = raw()
- + a_sprintf(", size=%0.f, chksum=%d", _file_size, _checksum);
- if (c_secondary.t())
- to_return += astring(", 2ndary=") + c_secondary;
- return to_return;
-}
-
-bool file_info::calculate(const astring &prefix, bool just_size, int checksum_edge)
-{
- FUNCDEF("calculate");
- filename full;
- if (prefix.t()) full = prefix + "/" + *this;
- else full = *this;
- if (!full.exists()) {
-#ifdef DEBUG_FILE_INFO
- LOG(astring("failed to find file: ") + full.raw());
-#endif
- return false;
- }
- // get time again.
- _time = file_time(full);
-
-//#ifdef DEBUG_FILE_INFO
-// astring temptext;
-// _time.text_form(temptext);
-// LOG(astring("file calculate on ") + full.raw() + " time=" + temptext);
-//#endif
-
- // open the file for reading.
- huge_file to_read(full.raw(), "rb");
- if (!to_read.good()) {
-#ifdef DEBUG_FILE_INFO
- LOG(astring("file has non-good status: ") + full.raw());
-#endif
- return false; // why did that happen?
- }
- // set the size appropriately.
- _file_size = to_read.length();
- if (just_size)
- return true; // done for that case.
-
- // now read the file and compute a checksum.
- uint16 curr_sum = 0; // the current checksum being computed.
- byte_array chunk; // temporary chunk of data from file.
-
-//hmmm: make this optimization (hack) optional!
-
- // this algorithm takes a chunk on each end of the file for checksums.
- // this saves us from reading a huge amount of data, although it will be
- // fooled if a huge binary file is changed only in the middle and has the
- // same size as before. for most purposes, this is not a problem, although
- // databases that are fixed size might fool us. if records are written in
- // the middle without updating the head or tail sections, then we're hosed.
-
- bool skip_tail = false; // true if we don't need the tail piece.
- double head_start = 0, head_end = 0, tail_start = 0,
- tail_end = _file_size - 1;
- if (_file_size <= double(2 * checksum_edge)) {
- // we're applying a rule for when the file is too small compared to
- // the chunk factor doubled; we'll just read the whole file.
- head_end = _file_size - 1;
- skip_tail = true;
- } else {
- // here we compute the ending of the head piece and the beginning of
- // the tail piece. each will be about checksum_edge in size.
- head_end = minimum(_file_size / 2, double(checksum_edge)) - 1;
- tail_start = _file_size - minimum(_file_size / 2, double(checksum_edge));
- }
-
- // read the head end of the file.
- int size_read = 0;
- outcome ret = to_read.read(chunk, int(head_end - head_start + 1), size_read);
- if (ret != huge_file::OKAY) {
-#ifdef DEBUG_FILE_INFO
- LOG(astring("reading file failed: ") + full.raw());
-#endif
- return false; // failed to read.
- }
- curr_sum = checksums::rolling_fletcher_checksum(curr_sum, chunk.observe(),
- chunk.length());
-
- // read the tail end of the file.
- if (!skip_tail) {
- to_read.seek(tail_start, byte_filer::FROM_START);
- ret = to_read.read(chunk, int(tail_end - tail_start + 1), size_read);
- if (ret != huge_file::OKAY) {
-#ifdef DEBUG_FILE_INFO
- LOG(astring("reading tail of file failed: ") + full.raw());
-#endif
- return false; // failed to read.
- }
- curr_sum = checksums::rolling_fletcher_checksum(curr_sum, chunk.observe(),
- chunk.length());
- }
-
- _checksum = curr_sum;
- return true;
-}
-
-int file_info::packed_size() const
-{
- return filename::packed_size()
- + structures::packed_size(_file_size)
- + _time.packed_size()
- + PACKED_SIZE_INT32
- + c_secondary.packed_size()
- + structures::packed_size(c_attachment);
-}
-
-void file_info::pack(byte_array &packed_form) const
-{
- filename::pack(packed_form);
- attach(packed_form, _file_size);
- _time.pack(packed_form);
- attach(packed_form, _checksum);
- c_secondary.pack(packed_form);
- attach(packed_form, c_attachment);
-}
-
-bool file_info::unpack(byte_array &packed_form)
-{
- if (!filename::unpack(packed_form))
- return false;
- if (!detach(packed_form, _file_size))
- return false;
- if (!_time.unpack(packed_form))
- return false;
- if (!detach(packed_form, _checksum))
- return false;
- if (!c_secondary.unpack(packed_form))
- return false;
- if (!detach(packed_form, c_attachment))
- return false;
- return true;
-}
-
-file_info &file_info::operator = (const file_info &to_copy)
-{
- if (this == &to_copy)
- return *this;
- (filename &)(*this) = (filename &)to_copy;
- c_attachment = to_copy.c_attachment;
- _time = to_copy._time;
- _file_size = to_copy._file_size;
- c_secondary = to_copy.c_secondary;
- _checksum = to_copy._checksum;
- return *this;
-}
-
-} //namespace.
-
projects / feisty_meow.git / blobdiff