chore: bump version to 1.6.0-rc1 and add contributing guidelines

CHANGELOG.md

@@ -13,6 +13,14 @@ The git repositories are hosted at the following sites:
 * <https://bacnet.sourceforge.net/>
 * <https://github.com/bacnet-stack/bacnet-stack/>
 
+## [Unreleased] - 2026-04-19
+
+### Security
+### Added
+### Changed
+### Fixed
+### Removed
+
 ## [1.5.0] - 2026-04-16
 
 ### Security

CMakeLists.txt

@@ -2,7 +2,7 @@ cmake_minimum_required(VERSION 3.5 FATAL_ERROR)
 
 project(
   bacnet-stack
-  VERSION 1.5.0
+  VERSION 1.6.0
   LANGUAGES C)
 
 #

CONTRIBUTING.md

@@ -0,0 +1,97 @@
+# Contributing to BACnet Stack
+
+Thank you for your interest in contributing to the BACnet stack!
+Please review the following guidelines for contributing new code
+or documentation to the project.
+
+## GitLab Workflow and Versioning
+
+We utilize a GitLab-style workflow for managing changes and releases.
+When developing features or preparing release candidates, please reflect
+the release candidate stages using `-rc1`, `-rc2`, etc., in the
+`src/bacnet/version.h` file.
+
+Specifically, update the `BACNET_VERSION_TEXT` string to include the `-rc`
+suffix during the release candidate phase. For example:
+```c
+#define BACNET_VERSION_TEXT "1.6.0-rc1"
+```
+Once the release is confirmed and finalized, the suffix should be removed for
+the official release version and a new branch created to track any bug fixes
+for that release.
+
+## Pre-commit Hooks
+
+This project uses `pre-commit` to ensure code formatting and quality standards.
+You are expected to install and use it locally so that checks and formatting
+happen automatically before every commit.
+
+To install:
+```bash
+pip install pre-commit
+pre-commit install
+```
+
+This ensures that your code complies with our coding conventions and saves time
+during code review.
+
+## CI Expectations (.github/workflows)
+
+All code contributions are subjected to automated CI testing via GitHub Actions
+defined in `.github/workflows/`.
+The workflows include:
+- Build verification across OS platforms (Linux, macOS, Windows, Raspberry Pi)
+- Build variations across embedded microcontrollers (ESP32, STM32/AT91, xmega/AVR, etc.)
+- Build for C standards: gnu89 (C89+extensions), gnu99, gnu11, gnu17
+- Lint validation using clang-build, cppcheck, and flawfinder
+- pre-commit using clang-format and other tools to enforce code style
+- CodeQL static analysis
+
+Contributions that break the build or introduce new warnings will not be
+merged.
+
+## Naming Conventions
+
+New files should be named in all lowercase snake_case (write_group.c),
+although there is precedent for no underscores (whois.c, iam.c) or BACnet
+standard name acronyms (rpm.c, npdu.c, apdu.c).
+
+New functions should be named in snake_case_with_underscores using
+bacnet_ as a prefix for core BACnet modules, followed by the module name,
+and using a verb suffix to describe the function's action.
+From left to right the name would read general to specific.
+For example:
+`bacnet_address_copy()` - copy an address
+`bacnet_address_from_ascii()` - create an address from an ASCII string
+`bacnet_address_to_ascii()` - create an ASCII string from an address
+
+BACnet ASN.1 types are typically defined in the standard using
+CamelCase and are likewise defined in the code enums and structs
+using the same name as used in the standard, albeit in Snake_Case.
+Most (all?) of the BACnet complex data types are typedef'd using
+uppercase names in snake_case. For example:
+```c
+/* BACnetDate */
+typedef struct BACnet_Date {
+    uint16_t year; /* AD */
+    uint8_t month; /* 1=Jan */
+    uint8_t day; /* 1..31 */
+    uint8_t wday; /* 1=Monday-7=Sunday */
+} BACNET_DATE;
+```
+
+All BACnet enumerations from the ASN.1 standard are defined in bacenum.h and
+mirror the naming convention as the BACnet standard, but in uppercase.
+`_MAX` is added to the end of each enumeration to indicate the maximum value
+which is used for array sizing, loop bounds, or range validation.
+Enumerations always define the value as expressed in the standard.
+Most BACnet enumerations have a text equivalent in bactext.c module
+that is used for EPICS and logging.
+```c
+typedef enum BACnetSuccessFilter {
+    BACNET_SUCCESS_FILTER_ALL = 0,
+    BACNET_SUCCESS_FILTER_SUCCESS_ONLY = 1,
+    BACNET_SUCCESS_FILTER_FAILURES_ONLY = 2,
+    BACNET_SUCCESS_FILTER_MAX = 3
+} BACNET_SUCCESS_FILTER;
+```

src/bacnet/version.h

@@ -15,8 +15,8 @@
 #define BACNET_VERSION(x, y, z) (((x) << 16) + ((y) << 8) + (z))
 #endif
 
-#define BACNET_VERSION_TEXT "1.5.0"
-#define BACNET_VERSION_CODE BACNET_VERSION(1, 5, 0)
+#define BACNET_VERSION_TEXT "1.6.0-rc1"
+#define BACNET_VERSION_CODE BACNET_VERSION(1, 6, 0)
 #define BACNET_VERSION_MAJOR ((BACNET_VERSION_CODE >> 16) & 0xFF)
 #define BACNET_VERSION_MINOR ((BACNET_VERSION_CODE >> 8) & 0xFF)
 #define BACNET_VERSION_MAINTENANCE (BACNET_VERSION_CODE & 0xFF)