1 files changed, 231 insertions, 0 deletions
diff --git a/libnetdata/storage_number/storage_number.c b/libnetdata/storage_number/storage_number.c
new file mode 100644
index 0000000..7511f3a
--- /dev/null
+++ b/libnetdata/storage_number/storage_number.c
@@ -0,0 +1,231 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#include "../libnetdata.h"
+
+storage_number pack_storage_number(NETDATA_DOUBLE value, SN_FLAGS flags) {
+    // bit 32 = sign 0:positive, 1:negative
+    // bit 31 = 0:divide, 1:multiply
+    // bit 30, 29, 28 = (multiplier or divider) 0-7 (8 total)
+    // bit 27 SN_EXISTS_100
+    // bit 26 SN_EXISTS_RESET
+    // bit 25 SN_ANOMALY_BIT = 0: anomalous, 1: not anomalous
+    // bit 24 to bit 1 = the value
+
+    if(unlikely(fpclassify(value) == FP_NAN || fpclassify(value) == FP_INFINITE))
+        return SN_EMPTY_SLOT;
+
+    storage_number r = flags & SN_USER_FLAGS;
+
+    if(unlikely(fpclassify(value) == FP_ZERO || fpclassify(value) == FP_SUBNORMAL))
+        return r;
+
+    int m = 0;
+    NETDATA_DOUBLE n = value, factor = 10;
+
+    // if the value is negative
+    // add the sign bit and make it positive
+    if(n < 0) {
+        r += SN_FLAG_NEGATIVE; // the sign bit 32
+        n = -n;
+    }
+
+    if(n / 10000000.0 > 0x00ffffff) {
+        factor = 100;
+        r |= SN_FLAG_NOT_EXISTS_MUL100;
+    }
+
+    // make its integer part fit in 0x00ffffff
+    // by dividing it by 10 up to 7 times
+    // and increasing the multiplier
+    while(m < 7 && n > (NETDATA_DOUBLE)0x00ffffff) {
+        n /= factor;
+        m++;
+    }
+
+    if(m) {
+        // the value was too big, and we divided it
+        // so, we add a multiplier to unpack it
+        r += SN_FLAG_MULTIPLY + (m << 27); // the multiplier m
+
+        if(n > (NETDATA_DOUBLE)0x00ffffff) {
+            #ifdef NETDATA_INTERNAL_CHECKS
+            error("Number " NETDATA_DOUBLE_FORMAT " is too big.", value);
+            #endif
+            r += 0x00ffffff;
+            return r;
+        }
+    }
+    else {
+        // 0x0019999e is the number that can be multiplied
+        // by 10 to give 0x00ffffff
+        // while the value is below 0x0019999e we can
+        // multiply it by 10, up to 7 times, increasing
+        // the multiplier
+        while(m < 7 && n < (NETDATA_DOUBLE)0x0019999e) {
+            n *= 10;
+            m++;
+        }
+
+        if (unlikely(n > (NETDATA_DOUBLE)0x00ffffff)) {
+            n /= 10;
+            m--;
+        }
+        // the value was small enough, and we multiplied it
+        // so, we add a divider to unpack it
+        r += (m << 27); // the divider m
+    }
+
+#ifdef STORAGE_WITH_MATH
+    // without this there are rounding problems
+    // example: 0.9 becomes 0.89
+    r += lrint((double) n);
+#else
+    r += (storage_number)n;
+#endif
+
+    return r;
+}
+
+// Lookup table to make storage number unpacking efficient.
+NETDATA_DOUBLE unpack_storage_number_lut10x[4 * 8];
+
+__attribute__((constructor)) void initialize_lut(void) {
+    // The lookup table is partitioned in 4 subtables based on the
+    // values of the factor and exp bits.
+    for (int i = 0; i < 8; i++) {
+        // factor = 0
+        unpack_storage_number_lut10x[0 * 8 + i] = 1 / pow(10, i);    // exp = 0
+        unpack_storage_number_lut10x[1 * 8 + i] = pow(10, i);        // exp = 1
+
+        // factor = 1
+        unpack_storage_number_lut10x[2 * 8 + i] = 1 / pow(100, i);   // exp = 0
+        unpack_storage_number_lut10x[3 * 8 + i] = pow(100, i);       // exp = 1
+    }
+}
+
+/*
+int print_netdata_double(char *str, NETDATA_DOUBLE value)
+{
+    char *wstr = str;
+
+    int sign = (value < 0) ? 1 : 0;
+    if(sign) value = -value;
+
+#ifdef STORAGE_WITH_MATH
+    // without llrintl() there are rounding problems
+    // for example 0.9 becomes 0.89
+    unsigned long long uvalue = (unsigned long long int) llrintl(value * (NETDATA_DOUBLE)100000);
+#else
+    unsigned long long uvalue = value * (NETDATA_DOUBLE)100000;
+#endif
+
+    wstr = print_number_llu_r_smart(str, uvalue);
+
+    // make sure we have 6 bytes at least
+    while((wstr - str) < 6) *wstr++ = '0';
+
+    // put the sign back
+    if(sign) *wstr++ = '-';
+
+    // reverse it
+    char *begin = str, *end = --wstr, aux;
+    while (end > begin) aux = *end, *end-- = *begin, *begin++ = aux;
+    // wstr--;
+    // strreverse(str, wstr);
+
+    // remove trailing zeros
+    int decimal = 5;
+    while(decimal > 0 && *wstr == '0') {
+        *wstr-- = '\0';
+        decimal--;
+    }
+
+    // terminate it, one position to the right
+    // to let space for a dot
+    wstr[2] = '\0';
+
+    // make space for the dot
+    int i;
+    for(i = 0; i < decimal ;i++) {
+        wstr[1] = wstr[0];
+        wstr--;
+    }
+
+    // put the dot
+    if(wstr[2] == '\0') { wstr[1] = '\0'; decimal--; }
+    else wstr[1] = '.';
+
+    // return the buffer length
+    return (int) ((wstr - str) + 2 + decimal );
+}
+*/
+
+int print_netdata_double(char *str, NETDATA_DOUBLE value) {
+    // info("printing number " NETDATA_DOUBLE_FORMAT, value);
+    char integral_str[50], fractional_str[50];
+
+    char *wstr = str;
+
+    if(unlikely(value < 0)) {
+        *wstr++ = '-';
+        value = -value;
+    }
+
+    NETDATA_DOUBLE integral, fractional;
+
+#ifdef STORAGE_WITH_MATH
+    fractional = modfndd(value, &integral) * 10000000.0;
+#else
+    integral = (NETDATA_DOUBLE)((unsigned long long)(value * 10000000ULL) / 10000000ULL);
+    fractional = (NETDATA_DOUBLE)((unsigned long long)(value * 10000000ULL) % 10000000ULL);
+#endif
+
+    unsigned long long integral_int = (unsigned long long)integral;
+    unsigned long long fractional_int = (unsigned long long)llrintndd(fractional);
+    if(unlikely(fractional_int >= 10000000)) {
+        integral_int += 1;
+        fractional_int -= 10000000;
+    }
+
+    // info("integral " NETDATA_DOUBLE_FORMAT " (%llu), fractional " NETDATA_DOUBLE_FORMAT " (%llu)", integral, integral_int, fractional, fractional_int);
+
+    char *istre;
+    if(unlikely(integral_int == 0)) {
+        integral_str[0] = '0';
+        istre = &integral_str[1];
+    }
+    else
+        // convert the integral part to string (reversed)
+        istre = print_number_llu_r_smart(integral_str, integral_int);
+
+    // copy reversed the integral string
+    istre--;
+    while( istre >= integral_str ) *wstr++ = *istre--;
+
+    if(likely(fractional_int != 0)) {
+        // add a dot
+        *wstr++ = '.';
+
+        // convert the fractional part to string (reversed)
+        char *fstre = print_number_llu_r_smart(fractional_str, fractional_int);
+
+        // prepend zeros to reach 7 digits length
+        int decimal = 7;
+        int len = (int)(fstre - fractional_str);
+        while(len < decimal) {
+            *wstr++ = '0';
+            len++;
+        }
+
+        char *begin = fractional_str;
+        while(begin < fstre && *begin == '0') begin++;
+
+        // copy reversed the fractional string
+        fstre--;
+        while( fstre >= begin ) *wstr++ = *fstre--;
+    }
+
+    *wstr = '\0';
+    // info("printed number '%s'", str);
+    return (int)(wstr - str);
+}