rte_hash_crc.h(3)

🦋 rte_hash_crc.h(3) — the Library Functions Manual glow-up ✨

okay bestie, so this is rte_hash_crc.h from the DPDK crew — it lives in the Library Functions Manual and it's literally all about CRC hashing. sit with me, I got you 💖

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✨ NAME ✨

rte_hash_crc.h — no cap, that's the whole name. iconic, lowkey.

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🌸 SYNOPSIS 🌸

first up, the includes you gotta pull in:

#include <stdint.h>
#include <rte_branch_prediction.h>
#include <rte_common.h>
#include <rte_config.h>
#include 'rte_crc_sw.h'
#include 'rte_crc_generic.h'

🎀 Functions

here's the whole friend group, signatures exactly as they are:

void rte_hash_crc_set_alg (uint8_t alg)
static uint32_t rte_hash_crc_1byte (uint8_t data, uint32_t init_val)
static uint32_t rte_hash_crc_2byte (uint16_t data, uint32_t init_val)
static uint32_t rte_hash_crc_4byte (uint32_t data, uint32_t init_val)
static uint32_t rte_hash_crc_8byte (uint64_t data, uint32_t init_val)
static uint32_t rte_hash_crc (const void *data, uint32_t data_len,
    uint32_t init_val)

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💜 Detailed Description 💜

RTE CRC Hash

that's the vibe. it's literally called "RTE CRC Hash" in the source, periodt.

Definition in file rte_hash_crc.h.

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👑 Function Documentation 👑

🌈 void rte_hash_crc_set_alg (uint8_t alg)

ok so this one is the bouncer at the club 🚪 — it lets you allow or disallow use of the SSE4.2 / ARMv8 intrinsics for CRC32 hash calculation. like, you're telling the code whether it's allowed to flex the fancy hardware instructions or not.

Parameters

• alg — an OR of the following flags, bestie:
  • (CRC32_SW) — don't use SSE4.2/ARMv8 intrinsics. this is the default when you're non-[x86/ARMv8], iykyk.
  • (CRC32_SSE42) — use SSE4.2 intrinsics if available.
  • (CRC32_SSE42_x64) — use the 64-bit SSE4.2 intrinsic if available. this is the default on x86 🔥
  • (CRC32_ARM64) — use the ARMv8 CRC intrinsic if available. default for ARMv8 🧚

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🍓 uint32_t rte_hash_crc_1byte (uint8_t data, uint32_t init_val) [inline], [static]

uses a single CRC32 instruction to hash a byte value. one byte, one instruction, ate. 💅

Parameters

• data — the data you're hashing, bb.
• init_val — the value that initialises the hash generator.

Returns

a 32bit calculated hash value. ✨

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🌸 uint32_t rte_hash_crc_2byte (uint16_t data, uint32_t init_val) [inline], [static]

same energy, but for a 2 bytes value — one CRC32 instruction does the whole thing. so efficient of it.

Parameters

• data — the data to perform the hash on.
• init_val — the value that initialises the hash generator.

Returns

32bit calculated hash value, as always 💖

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🦋 uint32_t rte_hash_crc_4byte (uint32_t data, uint32_t init_val) [inline], [static]

you guessed it — single CRC32 instruction, hashing a 4 bytes value. main character behaviour.

Parameters

• data — the data to hash.
• init_val — initialises the hash generator.

Returns

32bit calculated hash value ⭐

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💜 uint32_t rte_hash_crc_8byte (uint64_t data, uint32_t init_val) [inline], [static]

and now the big one — one CRC32 instruction, hashing an 8 bytes value. absolute unit. 🔥

Parameters

• data — the data to hash.
• init_val — initialises the hash generator.

Returns

32bit calculated hash value, no notes 🫶

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💅 uint32_t rte_hash_crc (const void * data, uint32_t data_len, uint32_t init_val) [inline], [static]

this is the generalist of the group 🌈 — it calculates a CRC32 hash on a user-supplied byte array. any length, you're in charge.

Parameters

• data — the data you want to hash.
• data_len — literally how many bytes to use to calculate the hash value.
• init_val — the value that initialises the hash generator.

Returns

32bit calculated hash value 💫

Definition at line 125 of file rte_hash_crc.h.

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🌟 Author 🌟

Generated automatically by Doxygen for DPDK from the source code. so technically the author is a robot, but she's doing her best 🎀

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aaaand that's the whole page! shoutout to DPDK Version 25.11.3 for making rte_hash_crc.h(3) happen — go forth and hash responsibly, bestie 💖✨🦋