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/*******************************************************************************************
*
* Fast threaded lexical sort routine. Can be compiled to accommodate any element size
* (set WORD_SIZE), and makes only n+1 passes to sort n radix bytes. The radix order
* for the bytes of an element may be sorted in any order as listed in the array bytes
* (that is -1 terminated).
*
* Author : Gene Myers
* First : May 2018
*
********************************************************************************************/
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include <unistd.h>
#include <math.h>
#include <pthread.h>
#include "DB.h"
#include "lsd.sort.h"
typedef unsigned char uint8;
typedef long long int64;
#undef TEST_LSORT
static int RSIZE; // Span between records
static int DSIZE; // Size of record
static int NTHREADS; // # of threads to use
static int VERBOSE; // Print each byte as it is sorted
void Set_LSD_Params(int nthread, int verbose)
{ NTHREADS = nthread;
VERBOSE = verbose;
}
// Global variables for every "lex_thread"
static int LEX_byte; // Current byte to sort on
static int LEX_next; // Next byte to sort on (if >= 0)
static int64 LEX_zdiv; // Size of thread segments (in bytes)
static uint8 *LEX_src; // Source data goes to ...
static uint8 *LEX_trg; // Target data
// Thread control record
typedef struct
{ int64 beg; // Sort [beg,end) of LEX_src
int64 end;
int check[256]; // Not all of bucket will go to the same thread in the next cycle?
int next[256]; // Thread assignment for next cycle (updated if check true)
int64 thresh[256]; // If check then multiple of LEX_zdiv to check for thread assignment
int64 tptr[256]; // Finger for each 8-bit value
int64 *sptr; // Conceptually [256][NTHREADS]. At end of sorting pass
} Lex_Arg; // sprtr[b][n] = # of occurrences of value b in rangd of
// thread n for the *next* pass
// Threaded sorting pass
static void *lex_thread(void *arg)
{ Lex_Arg *data = (Lex_Arg *) arg;
int64 *sptr = data->sptr;
int64 *tptr = data->tptr;
uint8 *src = LEX_src;
uint8 *dig = LEX_src + LEX_byte;
uint8 *nig = LEX_src + LEX_next;
uint8 *trg = LEX_trg;
int64 zdiv = LEX_zdiv;
int *check = data->check;
int *next = data->next;
int64 *thresh = data->thresh;
int64 i, n, x;
uint8 d;
n = data->end;
if (LEX_next < 0)
for (i = data->beg; i < n; i += RSIZE)
{ d = dig[i];
x = tptr[d];
tptr[d] += RSIZE;
memcpy(trg+x,src+i,DSIZE);
}
else
for (i = data->beg; i < n; i += RSIZE)
{ d = dig[i];
x = tptr[d];
tptr[d] += RSIZE;
memcpy(trg+x,src+i,DSIZE);
if (check[d])
{ if (x >= thresh[d])
{ next[d] += 0x100;
thresh[d] += zdiv;
}
}
sptr[next[d] | nig[i]] += 1;
}
return (NULL);
}
// Threaded sort initiation pass: count bucket sizes
static void *lexbeg_thread(void *arg)
{ Lex_Arg *data = (Lex_Arg *) arg;
int64 *tptr = data->tptr;
uint8 *dig = LEX_src + LEX_byte;
int64 i, n;
n = data->end;
for (i = data->beg; i < n; i += RSIZE)
tptr[dig[i]] += 1;
return (NULL);
}
// Radix sort the indicated "bytes" of src, using array trg as the secondary array
// The arrays contains len elements each of "size" bytes.
// Return a pointer to the array containing the final result.
void *LSD_Sort(int64 nelem, void *src, void *trg, int rsize, int dsize, int *bytes)
{ pthread_t threads[NTHREADS];
Lex_Arg parmx[NTHREADS]; // Thread control record for sorting
uint8 *xch;
int64 x, y, asize;
int i, j, z, b;
asize = nelem*rsize;
RSIZE = rsize;
DSIZE = dsize;
LEX_zdiv = ((nelem-1)/NTHREADS + 1)*RSIZE;
LEX_src = (uint8 *) src;
LEX_trg = (uint8 *) trg;
for (i = 0; i < NTHREADS; i++)
parmx[i].sptr = (int64 *) alloca(NTHREADS*256*sizeof(int64));
// For each requested byte b in order, radix sort
for (b = 0; bytes[b] >= 0; b++)
{ LEX_byte = bytes[b];
LEX_next = bytes[b+1];
if (VERBOSE)
{ printf(" Sorting byte %d\n",LEX_byte);
fflush(stdout);
}
// Setup beg, end, and zero tptr counters
x = 0;
for (i = 0; i < NTHREADS; i++)
{ parmx[i].beg = x;
x = LEX_zdiv*(i+1);
if (x > asize)
x = asize;
parmx[i].end = x;
for (j = 0; j < 256; j++)
parmx[i].tptr[j] = 0;
}
parmx[NTHREADS-1].end = asize;
// If first pass, then explicitly sweep to get tptr counts
// otherwise accumulate from sptr counts of last sweep
if (b == 0)
{ for (i = 1; i < NTHREADS; i++)
pthread_create(threads+i,NULL,lexbeg_thread,parmx+i);
lexbeg_thread(parmx);
for (i = 1; i < NTHREADS; i++)
pthread_join(threads[i],NULL);
}
else
{ int64 *pxt, *pxs;
for (i = 0; i < NTHREADS; i++)
{ pxt = parmx[i].tptr;
for (z = 0; z < NTHREADS; z++)
{ pxs = parmx[z].sptr + (i<<8);
for (j = 0; j < 256; j++)
pxt[j] += pxs[j];
}
}
}
// Zero sptr array counters in preparation of pass
for (i = 0; i < NTHREADS; i++)
for (z = (NTHREADS<<8)-1; z >= 0; z--)
parmx[i].sptr[z] = 0;
// Convert tptr from counts to fingers, and determine thead assignment arrays
// to avoid a division in the inner most loop
{ int64 thr;
int nxt;
thr = LEX_zdiv;
nxt = 0;
x = 0;
for (j = 0; j < 256; j++)
for (i = 0; i < NTHREADS; i++)
{ y = parmx[i].tptr[j]*RSIZE;
parmx[i].tptr[j] = x;
x += y;
parmx[i].next[j] = nxt;
if (x < thr)
parmx[i].check[j] = 0;
else
{ parmx[i].check[j] = 1;
parmx[i].thresh[j] = thr;
while (x >= thr)
{ thr += LEX_zdiv;
nxt += 0x100;
}
}
}
}
// Threaded pass
for (i = 1; i < NTHREADS; i++)
pthread_create(threads+i,NULL,lex_thread,parmx+i);
lex_thread(parmx);
for (i = 1; i < NTHREADS; i++)
pthread_join(threads[i],NULL);
xch = LEX_src;
LEX_src = LEX_trg;
LEX_trg = xch;
#ifdef TEST_LSORT
{ int64 c;
uint8 *psort = LEX_src-RSIZE;
printf("\nLSORT %d\n",LEX_byte);
for (c = 0; c < 1000*RSIZE; c += RSIZE)
{ printf(" %4lld: ",c/RSIZE);
for (j = 0; j < DSIZE; j++)
printf(" %02x",LEX_src[c+j]);
printf("\n");
}
for (c = RSIZE; c < asize; c += RSIZE)
{ for (j = LEX_byte; j >= 2; j--)
if (LEX_src[c+j] > psort[c+j])
break;
else if (LEX_src[c+j] < psort[c+j])
{ printf(" Order: %lld",c/RSIZE);
for (x = 2; x <= LEX_byte; x++)
printf(" %02x",psort[c+x]);
printf(" vs");
for (x = 2; x <= LEX_byte; x++)
printf(" %02x",LEX_src[c+x]);
printf("\n");
break;
}
}
}
#endif
}
return ((void *) LEX_src);
}
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