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judy

Judy is a project mainly written in C, based on the View license.

A C library for creating and accessing dynamic arrays with near O(log-base-256) scalability into the peta-element range

     Judy - C library creating and accessing dynamic arrays
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Content

  1. Introduction
  2. Directory Contents
  3. How to install
  4. License
  5. Change History
  6. Reporting Bugs
  7. Known Issues
  1. INTRODUCTION

This tree contains sources, documents, tests, and tools for the Judy package. This file is in a form that can be validated using the tool/readme script.

NOTE: The README files here describe some files that are not included in every Judy source package.

WHAT IS JUDY? (see below for list of top-level directories and files)

Judy is a C library that implements a dynamic array. Empty Judy arrays are declared with null pointers. A Judy array consumes memory only when populated yet can grow to take advantage of all available memory. Judy's key benefits are: scalability, performance, memory efficiency, and ease of use. Judy arrays are designed to grow without tuning into the peta-element range, scaling near O(log-base-256) -- 1 more RAM access at 256 X population.

Judy arrays are accessed with insert, retrieve, and delete calls for number or string indexes. Configuration and tuning are not required -- in fact not possible. Judy offers sorting, counting, and neighbor/empty searching. Indexes can be sequential, clustered, periodic, or random -- it doesn't matter to the algorithm. Judy arrays can be arranged hierarchically to handle any bit patterns -- large indexes, sets of keys, etc.

Judy is often an improvement over common data structures such as: arrays, sparse arrays, hash tables, B-trees, binary trees, linear lists, skiplists, other sort and search algorithms, and counting functions.

  1. JUDY TOP DIRECTORY CONTENTS:

AUTHORS Judy authors and contributors README This file. INSTALL Summary instructions to build, check and install Judy. COPYING Judy deliverable license notice (the LGPL). ChangeLog List of changes per version of Judy.

configure Autoconf configure script to allow a portable build e environment.

src/ Header and source files used to build the package. doc/ Documents, both external (to the package) and internal. test/ Test support and some timing programs. tool/ Primitive tool (jhton) to convert *.html files to "man" pages. and build tables used by Judy to malloc() sizes of memory.

  1. HOW TO INSTALL

For a quick description see the INSTALL file.

Judy is now based on the GNU Auto tools. This means that you can do the standard configure, make, make check and make install and everything should work, with one minor difference and a little caveat.

Judy is capable of being built as a 32-bit or a 64-bit library. Configure will test to detect the native environment and default to that. Therefor if you explicitly want to to compile for the non-native environment you need to tell Judy what you want. You can run ./configure with one of the following flags:

  --enable-32-bit 
      --enable-64-bit 

The caveat comes in on machines that support both at 32-bit and 64-bit runtime environments such as RISC platforms and x86-64. In this case your compiler will either use 32-bit or 64-bit as default. If you plan to use the default you can follow the above instructions and be finished.

However, if you wish to compile for the non-default target type. YOU ARE RESPONSIBLE FOR SETTING THE CORRECT FLAGS! Such as CFLAGS to make your compiler switch modes LDFLAGS to make your linker behave, etc.

For example: On HP-UX PA-RISC the compiler generates 32-bit code by default. If I wish to stick with the defaults I can simply build Judy by: ./configure make make check make install

If I want to build Judy as a 64-bit library on HP-UX PA-RISC I have to do: CFLAGS=+DD64 ./configure --enable-64-bit make make check make install

If I want to build Judy native (64-bit) on Linux AMD64 I have to do: ./configure make make check make install

If I want to build Judy 32-bit on Linux AMD64 I have to do: ./configure --enable-32-bit make make check make install

  1. LICENSE

The user library is licensed under the GNU Lesser Public License (LGPL) Version 2.1, February 1999. The full text of the LGPL is located at:

COPYING

  1. CHAGE HISTORY

See the ChangeLog file.

  1. REPORTING BUGS

If you encounter a bug, please submit it to the project bug list, located on the project page:

https://sourceforge.net/projects/judy/
  1. KNOWN ISSUES

When compiling on HP-UX, you may get a message like: error 1000: Unexpected symbol:

This is a problem with the HP's compiler in that it doesn't like a typedef'ed type following a static inline.

You can work around it by running this command from the Judy directory.

find ./ -name *.[ch] | xargs perl -i.BAK -pe 's/static inline/static/g'