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