Add streaming encode support and generators

[ringlej]

This adds a streaming encode path and the related code generation and tests.

• core encode supports streaming writes via callback, with streaming-safe list/map termination and error reporting
• new helper APIs for iterator-based repeated fields and chunked indefinite-length text string encoding
• optional generator support for streaming encode entrypoints and provider structs via --stream-encode-functions
• documentation updates for streaming encode API and generated provider structs
• encode test coverage for streaming across test1_suit, test2_simple, test3_corner_cases, and test4_senml

Replaces #1.

[Copilot]

Pull request overview

This PR adds comprehensive streaming encode support to zcbor, enabling CBOR encoding via callback-based writing instead of requiring a pre-allocated output buffer. This is particularly valuable for resource-constrained embedded systems with limited RAM.

Changes:

• Core streaming encode infrastructure with callback-based write operations and indefinite-length container support
• New generator option --stream-encode-functions to emit streaming-specific entrypoints and provider structs
• Iterator-based APIs for repeated fields and chunk-based APIs for indefinite-length text/byte strings
• State management enhancements to support streaming write callbacks and provider contexts
• Comprehensive test coverage across test1_suit, test2_simple, test3_corner_cases, and test4_senml with streaming variants
• Documentation updates in README.md and ARCHITECTURE.md

Reviewed changes

Copilot reviewed 22 out of 22 changed files in this pull request and generated 16 comments.

Show a summary per file

File	Description
zcbor/zcbor.py	Core code generation logic: added --stream-encode-functions option, streaming provider struct generation, indefinite-length container logic, and streaming-aware function name generation
src/zcbor_encode.c	Streaming write macros (ZCBOR_WRITE_BYTE/BYTES), indefinite-length encode helpers, iterator-based multi-encode, chunk-based string encoding APIs
src/zcbor_common.c	State array layout changes to accommodate larger constant state structure with streaming fields
include/zcbor_encode.h	New streaming API declarations: state initialization, iterator/chunk callbacks, provider getters/setters
include/zcbor_decode.h	State macro updates for new constant state size calculations
include/zcbor_common.h	Extended constant state structure with streaming fields, alignment macros, new error codes, ZCBOR_CONST_STATE_SLOTS calculation
src/zcbor_print.c	Added error strings for new ZCBOR_ERR_STREAM_WRITE_FAILED and ZCBOR_ERR_STREAM_READ_FAILED codes
tests/encode/test{1,2,3,4}_*/src/main.c	Streaming test implementations with stream_write callbacks and provider structs
tests/encode/test{1,2,3,4}_*/CMakeLists.txt	Build system support for STREAMING flag and --stream-encode-functions option
tests/encode/test{1,2,3,4}_*/testcase.yaml	New test variants for streaming and streaming+canonical modes
tests/unit/test1_unit_tests/src/main.c	Error string tests updated for new error codes
README.md	Documentation of streaming encode entrypoints and usage
ARCHITECTURE.md	Documentation of streaming code generation in CodeRenderer

Comments suppressed due to low confidence (1)

zcbor/zcbor.py:1422

• This method requires 1 positional argument, whereas overridden CddlXcoder.var_name may be called with 3. This call correctly calls the base method, but does not match the signature of the overriding method.

    def var_name(self):

---

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