src/libnetdata/parsers/entries.c
// SPDX-License-Identifier: GPL-3.0-or-later
#include "entries.h"
// Define multipliers for base 10 (decimal) units
#define ENTRIES_MULTIPLIER_BASE10 1000ULL
#define ENTRIES_MULTIPLIER_K (ENTRIES_MULTIPLIER_BASE10)
#define ENTRIES_MULTIPLIER_M (ENTRIES_MULTIPLIER_K * ENTRIES_MULTIPLIER_BASE10)
#define ENTRIES_MULTIPLIER_G (ENTRIES_MULTIPLIER_M * ENTRIES_MULTIPLIER_BASE10)
#define ENTRIES_MULTIPLIER_T (ENTRIES_MULTIPLIER_G * ENTRIES_MULTIPLIER_BASE10)
#define ENTRIES_MULTIPLIER_P (ENTRIES_MULTIPLIER_T * ENTRIES_MULTIPLIER_BASE10)
#define ENTRIES_MULTIPLIER_E (ENTRIES_MULTIPLIER_P * ENTRIES_MULTIPLIER_BASE10)
#define ENTRIES_MULTIPLIER_Z (ENTRIES_MULTIPLIER_E * ENTRIES_MULTIPLIER_BASE10)
#define ENTRIES_MULTIPLIER_Y (ENTRIES_MULTIPLIER_Z * ENTRIES_MULTIPLIER_BASE10)
// Define a structure to map size units to their multipliers
static const struct size_unit {
const char *unit;
const bool formatter; // true when this unit should be used when formatting to string
const uint64_t multiplier;
} entries_units[] = {
// the order of this table is important: smaller to bigger units!
{ .unit = "", .formatter = true, .multiplier = 1ULL },
{ .unit = "k", .formatter = false, .multiplier = ENTRIES_MULTIPLIER_K },
{ .unit = "K", .formatter = true, .multiplier = ENTRIES_MULTIPLIER_K },
{ .unit = "M", .formatter = true, .multiplier = ENTRIES_MULTIPLIER_M },
{ .unit = "G", .formatter = true, .multiplier = ENTRIES_MULTIPLIER_G },
{ .unit = "T", .formatter = true, .multiplier = ENTRIES_MULTIPLIER_T },
{ .unit = "P", .formatter = true, .multiplier = ENTRIES_MULTIPLIER_P },
{ .unit = "E", .formatter = true, .multiplier = ENTRIES_MULTIPLIER_E },
{ .unit = "Z", .formatter = true, .multiplier = ENTRIES_MULTIPLIER_Z },
{ .unit = "Y", .formatter = true, .multiplier = ENTRIES_MULTIPLIER_Y },
};
static inline const struct size_unit *entries_find_unit(const char *unit) {
if (!unit || !*unit) unit = "";
for (size_t i = 0; i < sizeof(entries_units) / sizeof(entries_units[0]); i++) {
const struct size_unit *su = &entries_units[i];
if ((uint8_t)unit[0] == (uint8_t)su->unit[0] && strcmp(unit, su->unit) == 0)
return su;
}
return NULL;
}
static inline double entries_round_to_resolution_dbl2(uint64_t value, uint64_t resolution) {
double converted = (double)value / (double)resolution;
return round(converted * 100.0) / 100.0;
}
static inline uint64_t entries_round_to_resolution_int(uint64_t value, uint64_t resolution) {
return (value + (resolution / 2)) / resolution;
}
// -------------------------------------------------------------------------------------------------------------------
// parse a size string
bool entries_parse(const char *entries_str, uint64_t *result, const char *default_unit) {
if (!entries_str || !*entries_str) {
*result = 0;
return false;
}
const struct size_unit *su_def = entries_find_unit(default_unit);
if(!su_def) {
*result = 0;
return false;
}
const char *s = entries_str;
// Skip leading spaces
while (isspace((uint8_t)*s)) s++;
if(strcmp(s, "off") == 0) {
*result = 0;
return true;
}
// Parse the number
const char *number_start = s;
NETDATA_DOUBLE value = strtondd(s, (char **)&s);
// If no valid number found, return false
if (s == number_start || value < 0) {
*result = 0;
return false;
}
// Skip spaces between number and unit
while (isspace((uint8_t)*s)) s++;
const char *unit_start = s;
while (isalpha((uint8_t)*s)) s++;
char unit[4];
size_t unit_len = s - unit_start;
const struct size_unit *su;
if (unit_len == 0)
su = su_def;
else {
if (unit_len >= sizeof(unit)) unit_len = sizeof(unit) - 1;
strncpy(unit, unit_start, unit_len);
unit[unit_len] = '\0';
su = entries_find_unit(unit);
if (!su) {
*result = 0;
return false;
}
}
uint64_t bytes = (uint64_t)round(value * (NETDATA_DOUBLE)su->multiplier);
*result = entries_round_to_resolution_int(bytes, su_def->multiplier);
return true;
}
// --------------------------------------------------------------------------------------------------------------------
// generate a string to represent a size
ssize_t entries_snprintf(char *dst, size_t dst_size, uint64_t value, const char *unit, bool accurate) {
if (!dst || dst_size == 0) return -1;
if (dst_size == 1) {
dst[0] = '\0';
return -2;
}
if (value == 0)
return snprintfz(dst, dst_size, "off");
const struct size_unit *su_def = entries_find_unit(unit);
if(!su_def) return -3;
// use the units multiplier to find the units
uint64_t bytes = value * su_def->multiplier;
// Find the best unit to represent the size with up to 2 fractional digits
const struct size_unit *su_best = su_def;
for (size_t i = 0; i < sizeof(entries_units) / sizeof(entries_units[0]); i++) {
const struct size_unit *su = &entries_units[i];
if (su->multiplier < su_def->multiplier || // the multiplier is too small
(!su->formatter && su != su_def) || // it is not to be used in formatting (except our unit)
(bytes < su->multiplier && su != su_def) ) // the converted value will be <1.0
continue;
double converted = entries_round_to_resolution_dbl2(bytes, su->multiplier);
uint64_t reversed_bytes = (uint64_t)(converted * (double)su->multiplier);
if(accurate) {
// no precision loss is required
if (reversed_bytes == bytes)
// no precision loss, this is good to use
su_best = su;
}
else {
if(converted > 1.0)
su_best = su;
}
}
double converted = entries_round_to_resolution_dbl2(bytes, su_best->multiplier);
// print it either with 0, 1 or 2 fractional digits
int written;
if(converted == (double)((uint64_t)converted))
written = snprintfz(dst, dst_size, "%.0f%s", converted, su_best->unit);
else if(converted * 10.0 == (double)((uint64_t)(converted * 10.0)))
written = snprintfz(dst, dst_size, "%.1f%s", converted, su_best->unit);
else
written = snprintfz(dst, dst_size, "%.2f%s", converted, su_best->unit);
if (written < 0)
return -4;
if ((size_t)written >= dst_size)
return (ssize_t)(dst_size - 1);
return written;
}