--- /dev/null
+ GNU GENERAL PUBLIC LICENSE
+ Version 2, June 1991
+
+ Copyright (C) 1989, 1991 Free Software Foundation, Inc.,
+ 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
+
+ Preamble
+
+ The licenses for most software are designed to take away your
+freedom to share and change it. By contrast, the GNU General Public
+License is intended to guarantee your freedom to share and change free
+software--to make sure the software is free for all its users. This
+General Public License applies to most of the Free Software
+Foundation's software and to any other program whose authors commit to
+using it. (Some other Free Software Foundation software is covered by
+the GNU Lesser General Public License instead.) You can apply it to
+your programs, too.
+
+ When we speak of free software, we are referring to freedom, not
+price. Our General Public Licenses are designed to make sure that you
+have the freedom to distribute copies of free software (and charge for
+this service if you wish), that you receive source code or can get it
+if you want it, that you can change the software or use pieces of it
+in new free programs; and that you know you can do these things.
+
+ To protect your rights, we need to make restrictions that forbid
+anyone to deny you these rights or to ask you to surrender the rights.
+These restrictions translate to certain responsibilities for you if you
+distribute copies of the software, or if you modify it.
+
+ For example, if you distribute copies of such a program, whether
+gratis or for a fee, you must give the recipients all the rights that
+you have. You must make sure that they, too, receive or can get the
+source code. And you must show them these terms so they know their
+rights.
+
+ We protect your rights with two steps: (1) copyright the software, and
+(2) offer you this license which gives you legal permission to copy,
+distribute and/or modify the software.
+
+ Also, for each author's protection and ours, we want to make certain
+that everyone understands that there is no warranty for this free
+software. If the software is modified by someone else and passed on, we
+want its recipients to know that what they have is not the original, so
+that any problems introduced by others will not reflect on the original
+authors' reputations.
+
+ Finally, any free program is threatened constantly by software
+patents. We wish to avoid the danger that redistributors of a free
+program will individually obtain patent licenses, in effect making the
+program proprietary. To prevent this, we have made it clear that any
+patent must be licensed for everyone's free use or not licensed at all.
+
+ The precise terms and conditions for copying, distribution and
+modification follow.
+
+ GNU GENERAL PUBLIC LICENSE
+ TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
+
+ 0. This License applies to any program or other work which contains
+a notice placed by the copyright holder saying it may be distributed
+under the terms of this General Public License. The "Program", below,
+refers to any such program or work, and a "work based on the Program"
+means either the Program or any derivative work under copyright law:
+that is to say, a work containing the Program or a portion of it,
+either verbatim or with modifications and/or translated into another
+language. (Hereinafter, translation is included without limitation in
+the term "modification".) Each licensee is addressed as "you".
+
+Activities other than copying, distribution and modification are not
+covered by this License; they are outside its scope. The act of
+running the Program is not restricted, and the output from the Program
+is covered only if its contents constitute a work based on the
+Program (independent of having been made by running the Program).
+Whether that is true depends on what the Program does.
+
+ 1. You may copy and distribute verbatim copies of the Program's
+source code as you receive it, in any medium, provided that you
+conspicuously and appropriately publish on each copy an appropriate
+copyright notice and disclaimer of warranty; keep intact all the
+notices that refer to this License and to the absence of any warranty;
+and give any other recipients of the Program a copy of this License
+along with the Program.
+
+You may charge a fee for the physical act of transferring a copy, and
+you may at your option offer warranty protection in exchange for a fee.
+
+ 2. You may modify your copy or copies of the Program or any portion
+of it, thus forming a work based on the Program, and copy and
+distribute such modifications or work under the terms of Section 1
+above, provided that you also meet all of these conditions:
+
+ a) You must cause the modified files to carry prominent notices
+ stating that you changed the files and the date of any change.
+
+ b) You must cause any work that you distribute or publish, that in
+ whole or in part contains or is derived from the Program or any
+ part thereof, to be licensed as a whole at no charge to all third
+ parties under the terms of this License.
+
+ c) If the modified program normally reads commands interactively
+ when run, you must cause it, when started running for such
+ interactive use in the most ordinary way, to print or display an
+ announcement including an appropriate copyright notice and a
+ notice that there is no warranty (or else, saying that you provide
+ a warranty) and that users may redistribute the program under
+ these conditions, and telling the user how to view a copy of this
+ License. (Exception: if the Program itself is interactive but
+ does not normally print such an announcement, your work based on
+ the Program is not required to print an announcement.)
+
+These requirements apply to the modified work as a whole. If
+identifiable sections of that work are not derived from the Program,
+and can be reasonably considered independent and separate works in
+themselves, then this License, and its terms, do not apply to those
+sections when you distribute them as separate works. But when you
+distribute the same sections as part of a whole which is a work based
+on the Program, the distribution of the whole must be on the terms of
+this License, whose permissions for other licensees extend to the
+entire whole, and thus to each and every part regardless of who wrote it.
+
+Thus, it is not the intent of this section to claim rights or contest
+your rights to work written entirely by you; rather, the intent is to
+exercise the right to control the distribution of derivative or
+collective works based on the Program.
+
+In addition, mere aggregation of another work not based on the Program
+with the Program (or with a work based on the Program) on a volume of
+a storage or distribution medium does not bring the other work under
+the scope of this License.
+
+ 3. You may copy and distribute the Program (or a work based on it,
+under Section 2) in object code or executable form under the terms of
+Sections 1 and 2 above provided that you also do one of the following:
+
+ a) Accompany it with the complete corresponding machine-readable
+ source code, which must be distributed under the terms of Sections
+ 1 and 2 above on a medium customarily used for software interchange; or,
+
+ b) Accompany it with a written offer, valid for at least three
+ years, to give any third party, for a charge no more than your
+ cost of physically performing source distribution, a complete
+ machine-readable copy of the corresponding source code, to be
+ distributed under the terms of Sections 1 and 2 above on a medium
+ customarily used for software interchange; or,
+
+ c) Accompany it with the information you received as to the offer
+ to distribute corresponding source code. (This alternative is
+ allowed only for noncommercial distribution and only if you
+ received the program in object code or executable form with such
+ an offer, in accord with Subsection b above.)
+
+The source code for a work means the preferred form of the work for
+making modifications to it. For an executable work, complete source
+code means all the source code for all modules it contains, plus any
+associated interface definition files, plus the scripts used to
+control compilation and installation of the executable. However, as a
+special exception, the source code distributed need not include
+anything that is normally distributed (in either source or binary
+form) with the major components (compiler, kernel, and so on) of the
+operating system on which the executable runs, unless that component
+itself accompanies the executable.
+
+If distribution of executable or object code is made by offering
+access to copy from a designated place, then offering equivalent
+access to copy the source code from the same place counts as
+distribution of the source code, even though third parties are not
+compelled to copy the source along with the object code.
+
+ 4. You may not copy, modify, sublicense, or distribute the Program
+except as expressly provided under this License. Any attempt
+otherwise to copy, modify, sublicense or distribute the Program is
+void, and will automatically terminate your rights under this License.
+However, parties who have received copies, or rights, from you under
+this License will not have their licenses terminated so long as such
+parties remain in full compliance.
+
+ 5. You are not required to accept this License, since you have not
+signed it. However, nothing else grants you permission to modify or
+distribute the Program or its derivative works. These actions are
+prohibited by law if you do not accept this License. Therefore, by
+modifying or distributing the Program (or any work based on the
+Program), you indicate your acceptance of this License to do so, and
+all its terms and conditions for copying, distributing or modifying
+the Program or works based on it.
+
+ 6. Each time you redistribute the Program (or any work based on the
+Program), the recipient automatically receives a license from the
+original licensor to copy, distribute or modify the Program subject to
+these terms and conditions. You may not impose any further
+restrictions on the recipients' exercise of the rights granted herein.
+You are not responsible for enforcing compliance by third parties to
+this License.
+
+ 7. If, as a consequence of a court judgment or allegation of patent
+infringement or for any other reason (not limited to patent issues),
+conditions are imposed on you (whether by court order, agreement or
+otherwise) that contradict the conditions of this License, they do not
+excuse you from the conditions of this License. If you cannot
+distribute so as to satisfy simultaneously your obligations under this
+License and any other pertinent obligations, then as a consequence you
+may not distribute the Program at all. For example, if a patent
+license would not permit royalty-free redistribution of the Program by
+all those who receive copies directly or indirectly through you, then
+the only way you could satisfy both it and this License would be to
+refrain entirely from distribution of the Program.
+
+If any portion of this section is held invalid or unenforceable under
+any particular circumstance, the balance of the section is intended to
+apply and the section as a whole is intended to apply in other
+circumstances.
+
+It is not the purpose of this section to induce you to infringe any
+patents or other property right claims or to contest validity of any
+such claims; this section has the sole purpose of protecting the
+integrity of the free software distribution system, which is
+implemented by public license practices. Many people have made
+generous contributions to the wide range of software distributed
+through that system in reliance on consistent application of that
+system; it is up to the author/donor to decide if he or she is willing
+to distribute software through any other system and a licensee cannot
+impose that choice.
+
+This section is intended to make thoroughly clear what is believed to
+be a consequence of the rest of this License.
+
+ 8. If the distribution and/or use of the Program is restricted in
+certain countries either by patents or by copyrighted interfaces, the
+original copyright holder who places the Program under this License
+may add an explicit geographical distribution limitation excluding
+those countries, so that distribution is permitted only in or among
+countries not thus excluded. In such case, this License incorporates
+the limitation as if written in the body of this License.
+
+ 9. The Free Software Foundation may publish revised and/or new versions
+of the General Public License from time to time. Such new versions will
+be similar in spirit to the present version, but may differ in detail to
+address new problems or concerns.
+
+Each version is given a distinguishing version number. If the Program
+specifies a version number of this License which applies to it and "any
+later version", you have the option of following the terms and conditions
+either of that version or of any later version published by the Free
+Software Foundation. If the Program does not specify a version number of
+this License, you may choose any version ever published by the Free Software
+Foundation.
+
+ 10. If you wish to incorporate parts of the Program into other free
+programs whose distribution conditions are different, write to the author
+to ask for permission. For software which is copyrighted by the Free
+Software Foundation, write to the Free Software Foundation; we sometimes
+make exceptions for this. Our decision will be guided by the two goals
+of preserving the free status of all derivatives of our free software and
+of promoting the sharing and reuse of software generally.
+
+ NO WARRANTY
+
+ 11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
+FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN
+OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
+PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED
+OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS
+TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE
+PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING,
+REPAIR OR CORRECTION.
+
+ 12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
+WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
+REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES,
+INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING
+OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED
+TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY
+YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER
+PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGES.
+
+ END OF TERMS AND CONDITIONS
+
+ How to Apply These Terms to Your New Programs
+
+ If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+ To do so, attach the following notices to the program. It is safest
+to attach them to the start of each source file to most effectively
+convey the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+ <one line to give the program's name and a brief idea of what it does.>
+ Copyright (C) <year> <name of 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 program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License along
+ with this program; if not, write to the Free Software Foundation, Inc.,
+ 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+Also add information on how to contact you by electronic and paper mail.
+
+If the program is interactive, make it output a short notice like this
+when it starts in an interactive mode:
+
+ Gnomovision version 69, Copyright (C) year name of author
+ Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
+ This is free software, and you are welcome to redistribute it
+ under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate
+parts of the General Public License. Of course, the commands you use may
+be called something other than `show w' and `show c'; they could even be
+mouse-clicks or menu items--whatever suits your program.
+
+You should also get your employer (if you work as a programmer) or your
+school, if any, to sign a "copyright disclaimer" for the program, if
+necessary. Here is a sample; alter the names:
+
+ Yoyodyne, Inc., hereby disclaims all copyright interest in the program
+ `Gnomovision' (which makes passes at compilers) written by James Hacker.
+
+ <signature of Ty Coon>, 1 April 1989
+ Ty Coon, President of Vice
+
+This General Public License does not permit incorporating your program into
+proprietary programs. If your program is a subroutine library, you may
+consider it more useful to permit linking proprietary applications with the
+library. If this is what you want to do, use the GNU Lesser General
+Public License instead of this License.
--- /dev/null
+#include <stdio.h>
+#include <string.h>
+#include <algorithm>
+#include <unordered_map>
+#include <string>
+#include <vector>
+#include <chrono>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/mman.h>
+#include <arpa/inet.h>
+#include <endian.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include "vp4.h"
+
+#define P4NENC_BOUND(n) ((n+127)/128+(n+32)*sizeof(uint32_t))
+#define dprintf(...)
+//#define dprintf(...) fprintf(stderr, __VA_ARGS__);
+
+using namespace std;
+using namespace std::chrono;
+
+static inline uint32_t read_unigram(const string &s, size_t idx)
+{
+ if (idx < s.size()) {
+ return (unsigned char)s[idx];
+ } else {
+ return 0;
+ }
+}
+
+static inline uint32_t read_trigram(const string &s, size_t start)
+{
+ return read_unigram(s, start) |
+ (read_unigram(s, start + 1) << 8) |
+ (read_unigram(s, start + 2) << 16);
+}
+
+enum
+{
+ DBE_NORMAL = 0, /* A non-directory file */
+ DBE_DIRECTORY = 1, /* A directory */
+ DBE_END = 2 /* End of directory contents; contains no name */
+};
+
+// From mlocate.
+struct db_header
+{
+ uint8_t magic[8];
+ uint32_t conf_size;
+ uint8_t version;
+ uint8_t check_visibility;
+ uint8_t pad[2];
+};
+
+// From mlocate.
+struct db_directory
+{
+ uint64_t time_sec;
+ uint32_t time_nsec;
+ uint8_t pad[4];
+};
+
+const char *handle_directory(const char *ptr, vector<string> *files)
+{
+ ptr += sizeof(db_directory);
+
+ string dir_path = ptr;
+ ptr += dir_path.size() + 1;
+ if (dir_path == "/") {
+ dir_path = "";
+ }
+
+ for ( ;; ) {
+ uint8_t type = *ptr++;
+ if (type == DBE_NORMAL) {
+ string filename = ptr;
+ files->push_back(dir_path + "/" + filename);
+ ptr += filename.size() + 1;
+ } else if (type == DBE_DIRECTORY) {
+ string dirname = ptr;
+ files->push_back(dir_path + "/" + dirname);
+ ptr += dirname.size() + 1;
+ } else {
+ return ptr;
+ }
+ }
+}
+
+void read_mlocate(const char *filename, vector<string> *files)
+{
+ int fd = open(filename, O_RDONLY);
+ if (fd == -1) {
+ perror(filename);
+ exit(1);
+ }
+ off_t len = lseek(fd, 0, SEEK_END);
+ if (len == -1) {
+ perror("lseek");
+ exit(1);
+ }
+ const char *data = (char *)mmap(nullptr, len, PROT_READ, MAP_SHARED, fd, /*offset=*/0);
+ if (data == MAP_FAILED) {
+ perror("mmap");
+ exit(1);
+ }
+
+ const db_header *hdr = (const db_header *)data;
+
+ // TODO: Care about the base path.
+ string path = data + sizeof(db_header);
+ uint64_t offset = sizeof(db_header) + path.size() + 1 + ntohl(hdr->conf_size);
+
+ const char *ptr = data + offset;
+ while (ptr < data + len) {
+ ptr = handle_directory(ptr, files);
+ }
+
+ munmap((void *)data, len);
+ close(fd);
+}
+
+void do_build(const char *infile, const char *outfile)
+{
+ //steady_clock::time_point start = steady_clock::now();
+
+ vector<string> files;
+ read_mlocate(infile, &files);
+ if (false) { // To read a plain text file.
+ FILE *fp = fopen(infile, "r");
+ while (!feof(fp)) {
+ char buf[1024];
+ if (fgets(buf, 1024, fp) == nullptr || feof(fp)) {
+ break;
+ }
+ string s(buf);
+ if (s.back() == '\n') s.pop_back();
+ files.push_back(move(s));
+ }
+ fclose(fp);
+ }
+ dprintf("Read %zu files from %s\n", files.size(), infile);
+
+ unordered_map<uint32_t, string> pl;
+ size_t trigrams = 0, longest_posting_list = 0;
+ unordered_map<uint32_t, vector<uint32_t>> invindex;
+ for (size_t i = 0; i < files.size(); ++i) {
+ const string &s = files[i];
+ if (s.size() >= 3) {
+ for (size_t j = 0; j < s.size() - 2; ++j) {
+ uint32_t trgm = read_trigram(s, j);
+ invindex[trgm].push_back(i);
+ }
+ }
+ }
+ string buf;
+ size_t bytes_used = 0;
+ for (auto &[trigram, docids] : invindex) {
+ auto last = unique(docids.begin(), docids.end());
+ docids.erase(last, docids.end());
+ longest_posting_list = max(longest_posting_list, docids.size());
+ trigrams += docids.size();
+
+ size_t bytes_needed = P4NENC_BOUND(docids.size());
+ if (buf.size() < bytes_needed) buf.resize(bytes_needed);
+ size_t bytes = p4nd1enc128v32(&docids[0], docids.size(), reinterpret_cast<unsigned char *>(&buf[0]));
+ pl[trigram] = string(buf.data(), bytes);
+ bytes_used += bytes;
+ }
+ dprintf("%zu files, %zu different trigrams, %zu entries, avg len %.2f, longest %zu\n",
+ files.size(), invindex.size(), trigrams, double(trigrams) / invindex.size(), longest_posting_list);
+
+ dprintf("%zu bytes used for posting lists (%.2f bits/entry)\n", bytes_used, 8 * bytes_used / double(trigrams));
+ //steady_clock::time_point end = steady_clock::now();
+ dprintf("Building posting lists took %.1f ms.\n\n", 1e3 * duration<float>(end - start).count());
+
+ vector<uint32_t> all_trigrams;
+ for (auto &[trigram, docids] : invindex) {
+ all_trigrams.push_back(trigram);
+ }
+ sort(all_trigrams.begin(), all_trigrams.end());
+
+ umask(0027);
+ FILE *outfp = fopen(outfile, "wb");
+
+ // Write the header.
+ uint64_t num_trigrams = invindex.size(); // 64 to get alignment.
+ fwrite(&num_trigrams, sizeof(num_trigrams), 1, outfp);
+
+ // Find out where the posting lists will end.
+ uint64_t offset = sizeof(uint64_t) * 2 + 16 * all_trigrams.size();
+ uint64_t filename_index_offset = offset;
+ for (uint32_t trgm : all_trigrams) {
+ filename_index_offset += pl[trgm].size();
+ }
+ fwrite(&filename_index_offset, sizeof(filename_index_offset), 1, outfp);
+
+ size_t bytes_for_trigrams = 0, bytes_for_posting_lists = 0, bytes_for_filename_index = 0, bytes_for_filenames = 0;
+
+ for (uint32_t trgm : all_trigrams) {
+ // 16 bytes: trgm (4), number of docids (4), byte offset (8)
+ fwrite(&trgm, sizeof(trgm), 1, outfp); // One byte wasted, but OK.
+ uint32_t num_docids = invindex[trgm].size();
+ fwrite(&num_docids, sizeof(num_docids), 1, outfp);
+ fwrite(&offset, sizeof(offset), 1, outfp);
+ offset += pl[trgm].size();
+ bytes_for_trigrams += 16;
+ }
+
+ // Write the actual posting lists.
+ for (uint32_t trgm : all_trigrams) {
+ fwrite(pl[trgm].data(), pl[trgm].size(), 1, outfp);
+ bytes_for_posting_lists += pl[trgm].size();
+ }
+
+ // Write the offsets to the filenames.
+ offset = filename_index_offset + files.size() * sizeof(offset);
+ for (const string &filename : files) {
+ fwrite(&offset, sizeof(offset), 1, outfp);
+ offset += filename.size() + 1;
+ bytes_for_filename_index += sizeof(offset);
+ bytes_for_filenames += filename.size() + 1;
+ }
+
+ // Write the actual filenames.
+ for (const string &filename : files) {
+ fwrite(filename.c_str(), filename.size() + 1, 1, outfp);
+ }
+
+ fclose(outfp);
+
+ dprintf("Trigrams: %'7.1f MB\n", bytes_for_trigrams / 1048576.0);
+ dprintf("Posting lists: %'7.1f MB\n", bytes_for_posting_lists / 1048576.0);
+ dprintf("Filename index: %'7.1f MB\n", bytes_for_filename_index / 1048576.0);
+ dprintf("Filenames: %'7.1f MB\n", bytes_for_filenames / 1048576.0);
+ dprintf("\n");
+}
+
+int main(int argc, char **argv)
+{
+ do_build(argv[1], argv[2]);
+ exit(EXIT_SUCCESS);
+}
--- /dev/null
+#include <stdio.h>
+#include <string.h>
+#include <algorithm>
+#include <unordered_map>
+#include <string>
+#include <vector>
+#include <chrono>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/mman.h>
+#include <arpa/inet.h>
+#include <endian.h>
+
+#include "vp4.h"
+
+#define P4NENC_BOUND(n) ((n+127)/128+(n+32)*sizeof(uint32_t))
+
+using namespace std;
+using namespace std::chrono;
+
+#define dprintf(...)
+//#define dprintf(...) fprintf(stderr, __VA_ARGS__);
+
+static inline uint32_t read_unigram(const string &s, size_t idx)
+{
+ if (idx < s.size()) {
+ return (unsigned char)s[idx];
+ } else {
+ return 0;
+ }
+}
+
+static inline uint32_t read_trigram(const string &s, size_t start)
+{
+ return read_unigram(s, start) |
+ (read_unigram(s, start + 1) << 8) |
+ (read_unigram(s, start + 2) << 16);
+}
+
+bool has_access(const char *filename, unordered_map<string, bool> *access_rx_cache)
+{
+ const char *end = strchr(filename + 1, '/');
+ while (end != nullptr) {
+ string parent_path(filename, end);
+ auto it = access_rx_cache->find(parent_path);
+ bool ok;
+ if (it == access_rx_cache->end()) {
+ ok = access(parent_path.c_str(), R_OK | X_OK) == 0;
+ access_rx_cache->emplace(move(parent_path), ok);
+ } else {
+ ok = it->second;
+ }
+ if (!ok) {
+ return false;
+ }
+ end = strchr(end + 1, '/');
+ }
+
+#if 0
+ // Check for rx first in the cache; if that isn't true, check R_OK uncached.
+ // This is roughly the same thing as mlocate does.
+ auto it = access_rx_cache->find(filename);
+ if (it != access_rx_cache->end() && it->second) {
+ return true;
+ }
+
+ return access(filename, R_OK) == 0;
+#endif
+ return true;
+}
+
+struct Trigram {
+ uint32_t trgm;
+ uint32_t num_docids;
+ uint64_t offset;
+};
+
+void do_search_file(const string &needle, const char *filename)
+{
+ int fd = open(filename, O_RDONLY);
+ if (fd == -1) {
+ perror(filename);
+ exit(1);
+ }
+
+ // Drop privileges.
+ if (setgid(getgid()) != 0) {
+ perror("setgid");
+ exit(EXIT_FAILURE);
+ }
+
+ //steady_clock::time_point start = steady_clock::now();
+ if (access("/", R_OK | X_OK)) {
+ // We can't find anything, no need to bother...
+ return;
+ }
+
+ off_t len = lseek(fd, 0, SEEK_END);
+ if (len == -1) {
+ perror("lseek");
+ exit(1);
+ }
+ const char *data = (char *)mmap(nullptr, len, PROT_READ, MAP_SHARED, fd, /*offset=*/0);
+ if (data == MAP_FAILED) {
+ perror("mmap");
+ exit(1);
+ }
+ uint64_t num_trigrams = *(const uint64_t *)data;
+ uint64_t filename_index_offset = *(const uint64_t *)(data + sizeof(uint64_t));
+
+ const Trigram *trgm_begin = (Trigram *)(data + sizeof(uint64_t) * 2);
+ const Trigram *trgm_end = trgm_begin + num_trigrams;
+
+ vector<const Trigram *> trigrams;
+ for (size_t i = 0; i < needle.size() - 2; ++i) {
+ uint32_t trgm = read_trigram(needle, i);
+ const Trigram *trgmptr = lower_bound(trgm_begin, trgm_end, trgm, [](const Trigram &trgm, uint32_t t) {
+ return trgm.trgm < t;
+ });
+ if (trgmptr == trgm_end || trgmptr->trgm != trgm) {
+ dprintf("trigram %06x isn't found, we abort the search\n", trgm);
+ munmap((void *)data, len);
+ close(fd);
+ return;
+ }
+ trigrams.push_back(trgmptr);
+ }
+ sort(trigrams.begin(), trigrams.end());
+ {
+ auto last = unique(trigrams.begin(), trigrams.end());
+ trigrams.erase(last, trigrams.end());
+ }
+ sort(trigrams.begin(), trigrams.end(), [&](const Trigram *a, const Trigram *b) {
+ return a->num_docids < b->num_docids;
+ });
+
+ vector<uint32_t> in1, in2, out;
+ for (const Trigram *trgmptr : trigrams) {
+ //uint32_t trgm = trgmptr->trgm;
+ size_t num = trgmptr->num_docids;
+ unsigned char *pldata = (unsigned char *)(data + trgmptr->offset);
+ if (in1.empty()) {
+ in1.resize(num + 128);
+ p4nd1dec128v32((unsigned char *)pldata, num, &in1[0]);
+ in1.resize(num);
+ dprintf("trigram '%c%c%c' decoded to %zu entries\n", trgm & 0xff, (trgm >> 8) & 0xff, (trgm >> 16) & 0xff, num);
+ } else {
+ if (num > in1.size() * 100) {
+ dprintf("trigram '%c%c%c' has %zu entries, ignoring the rest (will weed out false positives later)\n",
+ trgm & 0xff, (trgm >> 8) & 0xff, (trgm >> 16) & 0xff, num);
+ break;
+ }
+
+ if (in2.size() < num + 128) {
+ in2.resize(num + 128);
+ }
+ p4nd1dec128v32((unsigned char *)pldata, num, &in2[0]);
+
+ out.clear();
+ set_intersection(in1.begin(), in1.end(), in2.begin(), in2.begin() + num, back_inserter(out));
+ swap(in1, out);
+ dprintf("trigram '%c%c%c' decoded to %zu entries, %zu left\n", trgm & 0xff, (trgm >> 8) & 0xff, (trgm >> 16) & 0xff, num, in1.size());
+ if (in1.empty()) {
+ dprintf("no matches (intersection list is empty)\n");
+ break;
+ }
+ }
+ }
+ steady_clock::time_point end = steady_clock::now();
+
+ dprintf("Intersection took %.1f ms. Doing final verification and printing:\n",
+ 1e3 * duration<float>(end - start).count());
+
+ unordered_map<string, bool> access_rx_cache;
+
+ const uint64_t *filename_offsets = (const uint64_t *)(data + filename_index_offset);
+ int matched = 0;
+ for (uint32_t docid : in1) {
+ const char *filename = (const char *)(data + filename_offsets[docid]);
+ if (strstr(filename, needle.c_str()) == nullptr) {
+ continue;
+ }
+ if (has_access(filename, &access_rx_cache)) {
+ ++matched;
+ printf("%s\n", filename);
+ }
+ }
+ end = steady_clock::now();
+ dprintf("Done in %.1f ms, found %d matches.\n",
+ 1e3 * duration<float>(end - start).count(), matched);
+
+ munmap((void *)data, len);
+ close(fd);
+}
+
+int main(int argc, char **argv)
+{
+ //do_search_file(argv[1], "all.trgm");
+ do_search_file(argv[1], "/var/lib/mlocate/plocate.db");
+}
projects / plocate / commitdiff