TapTap
0afda6b094
Adds real algorithm selection (xxh64 default, plus md5 via OpenSSL EVP) and a 64-bit seed for the per-file whole-file digest used by the --incremental/ --checksum handshake and basis-dir content verification. The seed also feeds the delta path's per-block xxHash32 strong checksum (low 32 bits) so an explicit seed deterministically changes those digests too. Sender and receiver hash identically: the algorithm id and seed cross the config wire frame and the STATUS_CHECK handshake now carries a length-prefixed, bounded digest instead of a fixed 64-bit value. Unsupported algorithm names are rejected at parse time (never a silent no-op). PROTOCOL_VERSION bumped 2.9.0 -> 2.10.0; defaults (xxh64, seed 0) preserve prior byte-for-byte behavior.
89 lines
3.0 KiB
C
89 lines
3.0 KiB
C
#ifndef DELTA_H
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#define DELTA_H
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#include "data.h"
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#include <stdbool.h>
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#include <stdint.h>
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#include <stddef.h>
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#define DELTA_BLOCK_SIZE_DEFAULT 8192U
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#define DELTA_BLOCK_SIZE_MIN 1024U
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#define DELTA_BLOCK_SIZE_MAX 65536U
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#define DELTA_MIN_FILE_SIZE 16384ULL
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#define DELTA_MAX_FILE_SIZE (256ULL * 1024 * 1024)
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#define DELTA_MAX_SIZE_RATIO 10.0
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#define DELTA_FALLBACK_RATIO 0.7
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#define DELTA_ADLER32_MODULUS 65521U
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#define DELTA_OP_BLOCK_MATCH 0x01
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#define DELTA_OP_LITERAL 0x02
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typedef struct {
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uint32_t adler32;
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uint32_t xxhash;
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} DeltaBlockSig;
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typedef struct {
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uint64_t file_size;
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uint32_t block_size;
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uint32_t block_count;
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DeltaBlockSig* blocks;
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} DeltaSignature;
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typedef enum { DELTA_INSTR_BLOCK_MATCH = 0x01, DELTA_INSTR_LITERAL = 0x02 } DeltaInstrType;
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typedef struct {
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DeltaInstrType type;
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union {
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struct {
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uint32_t block_index;
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uint32_t block_offset;
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uint32_t length;
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} match;
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struct {
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uint8_t* data;
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uint32_t length;
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} literal;
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};
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} DeltaInstruction;
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typedef struct {
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uint64_t new_file_size;
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uint32_t instruction_count;
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DeltaInstruction* instructions;
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uint64_t delta_size;
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} Delta;
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DeltaSignature* delta_signature_create(const void* old_file_data, uint64_t old_file_size,
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uint32_t block_size);
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/* Seeded equivalent of delta_signature_create: the per-block strong (xxHash32)
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* checksum uses `seed` (the low 32 bits of --checksum-seed). Passing seed 0 is
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* identical to the unseeded function. */
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DeltaSignature* delta_signature_create_seeded(const void* old_file_data, uint64_t old_file_size,
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uint32_t block_size, uint32_t seed);
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Data* delta_signature_serialize(const DeltaSignature* sig);
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DeltaSignature* delta_signature_deserialize(const Data* data);
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void delta_signature_destroy(DeltaSignature* sig);
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Delta* delta_compute(const void* new_file_data, uint64_t new_file_size, const DeltaSignature* sig,
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uint32_t block_size);
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/* Seeded equivalent of delta_compute: the per-window strong (xxHash32) check
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* uses `seed` (the low 32 bits of --checksum-seed). The receiver's signature
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* must have been built with the same seed for matching. */
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Delta* delta_compute_seeded(const void* new_file_data, uint64_t new_file_size,
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const DeltaSignature* sig, uint32_t block_size, uint32_t seed);
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Data* delta_serialize(const Delta* delta);
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Delta* delta_deserialize(const Data* data);
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void* delta_apply(const void* old_data, uint64_t old_size, const Delta* delta, uint32_t block_size);
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void delta_destroy(Delta* delta);
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bool delta_should_attempt(uint64_t old_size, uint64_t new_size, uint64_t max_file_size);
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bool delta_is_worthwhile(const Delta* delta, uint64_t new_file_size);
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uint32_t delta_adler32(const void* data, uint32_t len);
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uint32_t delta_xxhash32(const void* data, uint32_t len);
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uint32_t delta_xxhash32_seeded(const void* data, uint32_t len, uint32_t seed);
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uint64_t delta_xxhash64(const void* data, size_t len);
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#endif
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