Security Limits & Decoder API Enhancement

[afshawnlotfi]

Overview

This PR introduces security-focused parameter validation and enhances the vertex buffer decoding API for better flexibility and type safety.

Changes

1. Security Limits (MeshoptLimits class)

New limits.py module providing configurable security limits to prevent DoS attacks via memory exhaustion:

Configurable Limits:

Limit	Default Value
MAX_TOTAL_BYTES	1 GB
MAX_VERTEX_SIZE	256 bytes
MAX_VERTEX_COUNT	100 million
MAX_INDEX_COUNT	500 million

Validation Methods:

• validate_vertex_params() - Validates vertex count, vertex size, alignment (must be multiple of 4), and total allocation
• validate_index_params() - Validates index count and index size (must be 2 or 4)

All encoder/decoder functions now validate parameters before memory allocation.

2. Enhanced decode_vertex_buffer() API

Added optional dtype parameter for direct decoding to custom numpy dtypes:

# Default behavior (float32 with auto-reshaping)
vertices = decode_vertex_buffer(count, size, buffer)

# Direct decoding to custom dtype
vertices = decode_vertex_buffer(count, size, buffer, dtype=my_custom_dtype)

This consolidates the previous decode_vertex_buffer_raw() function into the main API, reducing code duplication while maintaining backward compatibility.

Version

0.2.20a5 → 0.2.30a