/*
* Contributor(s):
*
* Eric des Courtis <eric.des.courtis@benbria.com>
* Piotr Gregor <piotrgregor@rsyncme.org>
*/
#ifndef WIN32 /* currently we support fast acosf computation only on UNIX/Linux */
#include <switch.h>
#include <stdio.h>
#include <stdlib.h>
#ifndef _MSC_VER
#include <stdint.h>
#endif
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#ifndef _MSC_VER
#include <sys/mman.h>
#endif
#include <assert.h>
#include <errno.h>
#include <math.h>
#include <string.h>
#ifndef _MSC_VER
#include <unistd.h>
#endif
#include "avmd_fast_acosf.h"
#include "avmd_options.h"
typedef union {
uint32_t i;
float f;
} float_conv_t;
/*
* Manipulate these parameters to change
* mapping's resolution. The sine tone
* of 1600Hz is detected even with 20
* bits discarded in float integer representation
* with only slightly increased amount of false
* positives (keeping variance threshold on 0.0001).
* 12 bits seem to be good choice when there is
* a need to compute faster and/or decrease mapped file
* size on disk while keeping false positives low.
*/
#define ACOS_TABLE_CONST_EXPONENT (0x70)
#define ACOS_TABLE_CONST_EXPONENT_BITS (3)
#define ACOS_TABLE_DISCARDED_BITS (3)
/* rosolution:
3: 15 728 640 indices spreading range [0.0, 1.0], table size on disk 134 217 728 bytes (default)
4: 7 364 320 indices spreading range [0.0, 1.0], table size on disk 67 108 864 bytes
5: 3 932 160 indices spreading range [0.0, 1.0], table size on disk 33 554 432 bytes
12: 30 720 indices spreading range [0.0, 1.0], table size on disk 262 144 bytes
16: 1 920 indices spreading range [0.0, 1.0], table size on disk 16 384 bytes
20: 120 indices spreading range [0.0, 1.0], table size on disk 1 024 bytes
24: 7 indices spreading range [0.0, 1.0], table size on disk 64 bytes
26: 1 indices spreading range [0.0, 1.0], table size on disk 16 bytes
*/
#define ACOS_TABLE_FREE_EXPONENT_BITS (7 - ACOS_TABLE_CONST_EXPONENT_BITS)
#define ACOS_TABLE_DATA_BITS (31 - ACOS_TABLE_CONST_EXPONENT_BITS - ACOS_TABLE_DISCARDED_BITS)
#define ACOS_TABLE_LENGTH (1 << (31 - ACOS_TABLE_CONST_EXPONENT_BITS - ACOS_TABLE_DISCARDED_BITS))
#define VARIA_DATA_MASK (0x87FFFFFF & ~((1 << ACOS_TABLE_DISCARDED_BITS) - 1))
#define CONST_DATA_MASK (((1 << ACOS_TABLE_CONST_EXPONENT_BITS) - 1) \
<< (ACOS_TABLE_DATA_BITS - 1 + ACOS_TABLE_DISCARDED_BITS))
#define SIGN_UNPACK_MASK (1 << (ACOS_TABLE_DATA_BITS - 1))
#define DATA_UNPACK_MASK ((1 << (ACOS_TABLE_DATA_BITS - 1)) - 1)
#define SIGN_MASK (0x80000000)
#define DATA_MASK (DATA_UNPACK_MASK << ACOS_TABLE_DISCARDED_BITS)
#define ACOS_TABLE_FILENAME "/tmp/acos_table.dat"
static uint32_t index_from_float(float f);
static float float_from_index(uint32_t d);
static float *acos_table = NULL;
static int acos_fd = -1;
#ifdef FAST_ACOSF_TESTING
#define INF(x) printf("[%s] [%u]\n", #x, x)
#define INFX(x) printf("[%s] [%08x]\n", #x, x)
static void
debug_print(void);
static void
dump_table_summary(void);
#endif /* FAST_ACOSF_TESTING */
extern int compute_table(void)
{
uint32_t i;
float f;
FILE *acos_table_file;
size_t res;
acos_table_file = fopen(ACOS_TABLE_FILENAME, "w");
for (i = 0; i < ACOS_TABLE_LENGTH; i++) {
f = acosf(float_from_index(i));
res = fwrite(&f, sizeof(f), 1, acos_table_file);
if (res != 1) {
goto fail;
}
}
res = fclose(acos_table_file);
if (res != 0) {
return -2;
}
return 0;
fail:
fclose(acos_table_file);
return -1;
}
extern int init_fast_acosf(void)
{
int ret, errsv;
FILE *acos_fp;
char err[150];
if (acos_table == NULL) {
ret = access(ACOS_TABLE_FILENAME, F_OK);
if (ret == -1) {
/* file doesn't exist, bad permissions,
* or some other error occured */
errsv = errno;
strerror_r(errsv, err, 150);
if (errsv != ENOENT) return -1;
else {
switch_log_printf(
SWITCH_CHANNEL_LOG,
SWITCH_LOG_NOTICE,
"File [%s] doesn't exist. Creating file...\n", ACOS_TABLE_FILENAME
);
ret = compute_table();
if (ret != 0) return -2;
}
} else {
switch_log_printf(
SWITCH_CHANNEL_LOG,
SWITCH_LOG_INFO,
"Using previously created file [%s]\n", ACOS_TABLE_FILENAME
);
}
}
acos_fp = fopen(ACOS_TABLE_FILENAME, "r");
if (acos_fp == NULL) return -3;
/* can't fail */
acos_fd = fileno(acos_fp);
acos_table = (float *) mmap(
NULL, /* kernel chooses the address at which to create the mapping */
ACOS_TABLE_LENGTH * sizeof(float),
PROT_READ,
MAP_SHARED | MAP_POPULATE, /* read-ahead on the file. Later accesses to the mapping
* will not be blocked by page faults */
acos_fd,
0
);
if (acos_table == MAP_FAILED) return -4;
return 0;
}
extern int destroy_fast_acosf(void)
{
if (munmap(acos_table, ACOS_TABLE_LENGTH) == -1) return -1;
if (acos_fd != -1) {
if (close(acos_fd) == -1) return -2;
}
/* disable use of fast arc cosine file */
acos_table = NULL;
return 0;
}
extern float fast_acosf(float x)
{
return acos_table[index_from_float(x)];
}
static uint32_t index_from_float(float f)
{
float_conv_t d;
d.f = f;
return ((d.i & SIGN_MASK) >> (32 - ACOS_TABLE_DATA_BITS)) |
((d.i & DATA_MASK) >> ACOS_TABLE_DISCARDED_BITS);
}
static float float_from_index(uint32_t d)
{
float_conv_t f;
f.i = ((d & SIGN_UNPACK_MASK) << (32 - ACOS_TABLE_DATA_BITS)) |
((d & DATA_UNPACK_MASK) << ACOS_TABLE_DISCARDED_BITS) | CONST_DATA_MASK;
return f.f;
}
#ifdef FAST_ACOSF_TESTING
#define INF(x) printf("[%s] [%u]\n", #x, x)
#define INFX(x) printf("[%s] [%08x]\n", #x, x)
static void
debug_print(void)
{
INF(ACOS_TABLE_CONST_EXPONENT);
INF(ACOS_TABLE_CONST_EXPONENT_BITS);
INF(ACOS_TABLE_FREE_EXPONENT_BITS);
INF(ACOS_TABLE_DISCARDED_BITS);
INF(ACOS_TABLE_DATA_BITS);
INF(ACOS_TABLE_LENGTH);
INFX(VARIA_DATA_MASK);
INFX(CONST_DATA_MASK);
INFX(SIGN_UNPACK_MASK);
INFX(DATA_UNPACK_MASK);
INFX(SIGN_MASK);
INFX(DATA_MASK);
}
static void
dump_table_summary(void)
{
uint32_t i, i_0, i_1, di;
float f;
i = 1;
i_0 = index_from_float(0.0);
i_1 = index_from_float(1.0);
di = (i_1 - i_0)/100;
if (di == 0) di = 1;
for (; i < ACOS_TABLE_LENGTH; i += di )
{
f = float_from_index(i);
printf("-01i[%.10u] : ffi[%f] fa[%f] acos[%f]\n",
i, f, fast_acosf(f), acos(f));
}
i = 1;
for (; i < ACOS_TABLE_LENGTH; i = (i << 1))
{
f = fast_acosf(float_from_index(i));
printf("--i[%.10u] : fa[%f] ffi[%f]\n",
i, f, float_from_index(i));
}
f = 0.0;
printf("i [%d] from float [%f]\n", index_from_float(f), f);
f = 0.1;
printf("i [%d] from float [%f]\n", index_from_float(f), f);
f = 0.2;
printf("i [%d] from float [%f]\n", index_from_float(f), f);
f = 0.3;
printf("i [%d] from float [%f]\n", index_from_float(f), f);
f = 0.4;
printf("i [%d] from float [%f]\n", index_from_float(f), f);
f = 0.5;
printf("i [%d] from float [%f]\n", index_from_float(f), f);
f = 0.6;
printf("i [%d] from float [%f]\n", index_from_float(f), f);
f = 0.7;
printf("i [%d] from float [%f]\n", index_from_float(f), f);
f = 7.5;
printf("i [%d] from float [%f]\n", index_from_float(f), f);
f = 0.8;
printf("i [%d] from float [%f]\n", index_from_float(f), f);
f = 0.9;
printf("i [%d] from float [%f]\n", index_from_float(f), f);
f = 0.95;
printf("i [%d] from float [%f]\n", index_from_float(f), f);
f = 0.99;
printf("i [%d] from float [%f]\n", index_from_float(f), f);
f = 1.0;
printf("i [%d] from float [%f]\n", index_from_float(f), f);
f = 1.1;
printf("i [%d] from float [%f]\n", index_from_float(f), f);
f = 1.2;
printf("i [%d] from float [%f]\n", index_from_float(f), f);
f = 0.0;
printf("i [%d] from float [%f]\n", index_from_float(f), f);
f = -0.1;
printf("i [%d] from float [%f]\n", index_from_float(f), f);
f = -0.2;
printf("i [%d] from float [%f]\n", index_from_float(f), f);
f = -0.3;
printf("i [%d] from float [%f]\n", index_from_float(f), f);
f = -0.4;
printf("i [%d] from float [%f]\n", index_from_float(f), f);
f = -0.5;
printf("i [%d] from float [%f]\n", index_from_float(f), f);
f = -0.6;
printf("i [%d] from float [%f]\n", index_from_float(f), f);
f = -0.7;
printf("i [%d] from float [%f]\n", index_from_float(f), f);
f = -7.5;
printf("i [%d] from float [%f]\n", index_from_float(f), f);
f = -0.8;
printf("i [%d] from float [%f]\n", index_from_float(f), f);
f = -0.9;
printf("i [%d] from float [%f]\n", index_from_float(f), f);
f = -0.95;
printf("i [%d] from float [%f]\n", index_from_float(f), f);
f = -0.99;
printf("i [%d] from float [%f]\n", index_from_float(f), f);
f = -1.0;
printf("i [%d] from float [%f]\n", index_from_float(f), f);
f = -1.1;
printf("i [%d] from float [%f]\n", index_from_float(f), f);
f = -1.2;
printf("i [%d] from float [%f]\n", index_from_float(f), f);
}
#endif /* FAST_ACOSF_TESTING */
#endif /* WIN32 */