87c3afb5a9
This will be useful to handle latitude and longitude numbers for GAD, which is the location estimate representation used for LCS (Location Services). The OsmoSMLC VTY user interface will provide floating-point strings like "23.456" while GAD stores them as micro-degress 23456000. The osmo_gad_to_str* will also convert latitude and longitude to floating-point string. There was code review concerns against adding this API, upon which I tried to use floating point string formats. But I encountered various problems with accuracy and trailing zeros. For global positioning data (latitude and longitude), even inaccuracy on the sixth significant decimal digit causes noticeable positional shift. To achieve sufficient accuracy on the least significant end, I need to use double instead of float. To remove trailing zeros, the idea was to use '%.6g' format, but that can cause rounding. '%.6f' on a double looks ok, but always includes trailing zeros. A test program shows: %.6g of ((double)(int32_t)23230100)/1e6 = "23.2301" <-- good %.6g of ((double)(int32_t)42419993)/1e6 = "42.42" <-- bad rounding %.6g of ((double)(int32_t)23230199)/1e6 = "23.2302" <-- bad rounding %.6f of ((double)(int32_t)23230100)/1e6 = "23.230100" <-- trailing zeros %.6f of ((double)(int32_t)42419993)/1e6 = "42.419993" <-- good %.6f of ((double)(int32_t)23230199)/1e6 = "23.230199" <-- good It looks like when accepting that there will be trailing zeros, using double with '%.6f' would work out, but in the end I am not certain enough that there aren't more hidden rounding / precision glitches. Hence I decided to reinforce the need to add this API: it is glitch free in sufficient precision for latitude and longitude data, because it is based on integer arithmetic. The need for this precision is particular to the (new) OsmoSMLC vty configuration, where reading and writing back user config must not modify the values the user entered. Considering to add these functions to osmo-smlc.git, we might as well add them here to libosmocore utils, and also use them in osmo_gad_to_str_*() functions. Change-Id: Ib9aee749cd331712a4dcdadfb6a2dfa4c26da957 |
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| include | ||
| m4 | ||
| src | ||
| tests | ||
| utils | ||
| .gitignore | ||
| .gitreview | ||
| .mailmap | ||
| COPYING | ||
| Doxyfile.codec.in | ||
| Doxyfile.coding.in | ||
| Doxyfile.core.in | ||
| Doxyfile.ctrl.in | ||
| Doxyfile.gb.in | ||
| Doxyfile.gsm.in | ||
| Doxyfile.vty.in | ||
| Makefile.am | ||
| README.md | ||
| TODO-RELEASE | ||
| configure.ac | ||
| git-version-gen | ||
| libosmocodec.pc.in | ||
| libosmocoding.pc.in | ||
| libosmocore.pc.in | ||
| libosmoctrl.pc.in | ||
| libosmogb.pc.in | ||
| libosmogsm.pc.in | ||
| libosmosim.pc.in | ||
| libosmousb.pc.in | ||
| libosmovty.pc.in | ||
| osmo-release.mk | ||
| osmo-release.sh | ||
README.md
libosmocore - set of Osmocom core libraries
This repository contains a set of C-language libraries that form the core infrastructure of many Osmocom Open Source Mobile Communications projects.
Historically, a lot of this code was developed as part of the OpenBSC project, but which are of a more generic nature and thus useful to (at least) other programs that we develop in the sphere of Free Software / Open Source mobile communications.
There is no clear scope of it. We simply move all shared code between the various Osmocom projects in this library to avoid code duplication.
The libosmocore.git repository build multiple libraries:
- libosmocore contains some general-purpose functions like select-loop abstraction, message buffers, timers, linked lists
- libosmovty contains routines related to the interactive command-line interface called VTY
- libosmogsm contains definitions and helper code related to GSM protocols
- libosmoctrl contains a shared implementation of the Osmocom control interface
- libosmogb contains an implementation of the Gb interface with its NS/BSSGP protocols
- libosmocodec contains an implementation of GSM voice codecs
- libosmocoding contains an implementation of GSM channel coding
- libosmosim contains infrastructure to interface SIM/UICC/USIM cards
Homepage
The official homepage of the project is https://osmocom.org/projects/libosmocore/wiki/Libosmocore
GIT Repository
You can clone from the official libosmocore.git repository using
git clone git://git.osmocom.org/libosmocore.git
There is a cgit interface at http://git.osmocom.org/libosmocore/
Documentation
Doxygen-generated API documentation is generated during the build process, but also available online for each of the sub-libraries at http://ftp.osmocom.org/api/latest/libosmocore/
Mailing List
Discussions related to libosmocore are happening on the openbsc@lists.osmocom.org mailing list, please see https://lists.osmocom.org/mailman/listinfo/openbsc for subscription options and the list archive.
Please observe the Osmocom Mailing List Rules when posting.
Contributing
Our coding standards are described at https://osmocom.org/projects/cellular-infrastructure/wiki/Coding_standards
We us a gerrit based patch submission/review process for managing contributions. Please see https://osmocom.org/projects/cellular-infrastructure/wiki/Gerrit for more details
The current patch queue for libosmocore can be seen at https://gerrit.osmocom.org/#/q/project:libosmocore+status:open