CRC utilities

Collaboration diagram for CRC utilities:

Streaming update functions for several common CRC variants implemented in src/juno_*.c. Each function updates a running CRC with a data buffer and returns the new CRC value. Initial (seed) values are provided as macros (JUNO_*_CRC_INIT) for first use.

Behavior and usage

• Passing a NULL data pointer or zero length returns 0 (no update). This differs from returning the variant's seed value for some CRCs (e.g., CCITT/CCITT32/ZIP) and is intentional; see tests and callers.
• All functions are pure and reentrant: no global state is modified.
• CRC-32 ZIP applies a final XOR (0xFFFFFFFF) before returning when data is processed. For multi-chunk streaming with ZIP, undo that XOR on the returned value (res ^ 0xFFFFFFFF) before passing it back as the next iCrc.

Example (streaming across two chunks)

// ARC (16-bit, no final XOR):
uint16_t crc = JUNO_ARC_CRC_INIT;
crc = Juno_CrcArcUpdate(crc, chunk1, len1);
crc = Juno_CrcArcUpdate(crc, chunk2, len2);
 
// ZIP (CRC-32) with final XOR at each call boundary:
uint32_t zip = JUNO_ZIP_CRC_INIT;
zip = Juno_CrcZipUpdate(zip, chunk1, len1);           // returns XOR'ed
zip = Juno_CrcZipUpdate(zip ^ 0xFFFFFFFF, chunk2, len2); // undo XOR first