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author | Federico Ceratto <federico.ceratto@gmail.com> | 2016-03-30 21:40:42 +0000 |
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committer | Federico Ceratto <federico.ceratto@gmail.com> | 2016-03-30 21:40:42 +0000 |
commit | 9ce153ce7167c11adba8ac225edc7a707e97c6eb (patch) | |
tree | 9f6e849cce2dcc7e5b4e9e6252c843dc2d0787a2 /src/storage_number.c | |
download | netdata-9ce153ce7167c11adba8ac225edc7a707e97c6eb.tar.xz netdata-9ce153ce7167c11adba8ac225edc7a707e97c6eb.zip |
Imported Upstream version 1.0.0upstream/1.0.0
Diffstat (limited to 'src/storage_number.c')
-rwxr-xr-x | src/storage_number.c | 206 |
1 files changed, 206 insertions, 0 deletions
diff --git a/src/storage_number.c b/src/storage_number.c new file mode 100755 index 000000000..225cf0348 --- /dev/null +++ b/src/storage_number.c @@ -0,0 +1,206 @@ +#ifdef HAVE_CONFIG_H +#include <config.h> +#endif +#ifdef STORAGE_WITH_MATH +#include <math.h> +#endif + +#include "common.h" +#include "log.h" +#include "storage_number.h" + +#if __GNUC__ +#if __x86_64__ || __ppc64__ +#define ENVIRONMENT64 +#else +#define ENVIRONMENT32 +#endif +#endif + +storage_number pack_storage_number(calculated_number value, uint32_t flags) +{ + // bit 32 = sign 0:positive, 1:negative + // bit 31 = 0:divide, 1:multiply + // bit 30, 29, 28 = (multiplier or divider) 0-6 (7 total) + // bit 27, 26, 25 flags + // bit 24 to bit 1 = the value + + storage_number r = get_storage_number_flags(flags); + if(!value) return r; + + int m = 0; + calculated_number n = value; + + // if the value is negative + // add the sign bit and make it positive + if(n < 0) { + r += (1 << 31); // the sign bit 32 + n = -n; + } + + // make its integer part fit in 0x00ffffff + // by dividing it by 10 up to 7 times + // and increasing the multiplier + while(m < 7 && n > (calculated_number)0x00ffffff) { + n /= 10; + m++; + } + + if(m) { + // the value was too big and we divided it + // so we add a multiplier to unpack it + r += (1 << 30) + (m << 27); // the multiplier m + + if(n > (calculated_number)0x00ffffff) { + error("Number " CALCULATED_NUMBER_FORMAT " is too big.", value); + 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 < (calculated_number)0x0019999e) { + n *= 10; + m++; + } + + // the value was small enough and we multiplied it + // so we add a divider to unpack it + r += (0 << 30) + (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; +} + +calculated_number unpack_storage_number(storage_number value) +{ + if(!value) return 0; + + int sign = 0, exp = 0; + + value ^= get_storage_number_flags(value); + + if(value & (1 << 31)) { + sign = 1; + value ^= 1 << 31; + } + + if(value & (1 << 30)) { + exp = 1; + value ^= 1 << 30; + } + + int mul = value >> 27; + value ^= mul << 27; + + calculated_number n = value; + + // fprintf(stderr, "UNPACK: %08X, sign = %d, exp = %d, mul = %d, n = " CALCULATED_NUMBER_FORMAT "\n", value, sign, exp, mul, n); + + while(mul > 0) { + if(exp) n *= 10; + else n /= 10; + mul--; + } + + if(sign) n = -n; + return n; +} + +#ifdef ENVIRONMENT32 +// This trick seems to give an 80% speed increase in 32bit systems +// print_calculated_number_llu_r() will just print the digits up to the +// point the remaining value fits in 32 bits, and then calls +// print_calculated_number_lu_r() to print the rest with 32 bit arithmetic. + +static char *print_calculated_number_lu_r(char *str, unsigned long uvalue) { + char *wstr = str; + + // print each digit + do *wstr++ = (char)(48 + (uvalue % 10)); while(uvalue /= 10); + return wstr; +} + +static char *print_calculated_number_llu_r(char *str, unsigned long long uvalue) { + char *wstr = str; + + // print each digit + do *wstr++ = (char)(48 + (uvalue % 10)); while((uvalue /= 10) && uvalue > (unsigned long long)0xffffffff); + if(uvalue) return print_calculated_number_lu_r(wstr, uvalue); + return wstr; +} +#endif + +int print_calculated_number(char *str, calculated_number value) +{ + char *wstr = str; + + int sign = (value < 0) ? 1 : 0; + if(sign) value = -value; + +#ifdef STORAGE_WITH_MATH + // without llrint() there are rounding problems + // for example 0.9 becomes 0.89 + unsigned long long uvalue = (unsigned long long int) llrint(value * (calculated_number)100000); +#else + unsigned long long uvalue = value * (calculated_number)100000; +#endif + +#ifdef ENVIRONMENT32 + if(uvalue > (unsigned long long)0xffffffff) + wstr = print_calculated_number_llu_r(str, uvalue); + else + wstr = print_calculated_number_lu_r(str, uvalue); +#else + do *wstr++ = (char)(48 + (uvalue % 10)); while(uvalue /= 10); +#endif + + // 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 ); +} |