1#include <stdlib.h> 2#include <stdio.h> 3#include <string.h> 4 5#include "../compiler/compiler.h" 6#include "num2str.h" 7 8#define ARRAY_SIZE(x) (sizeof((x)) / (sizeof((x)[0]))) 9 10/** 11 * num2str() - Cheesy number->string conversion, complete with carry rounding error. 12 * @num: quantity (e.g., number of blocks, bytes or bits) 13 * @maxlen: max number of digits in the output string (not counting prefix and units, but counting .) 14 * @base: multiplier for num (e.g., if num represents Ki, use 1024) 15 * @pow2: select unit prefix - 0=power-of-10 decimal SI, nonzero=power-of-2 binary IEC 16 * @units: select units - N2S_* macros defined in num2str.h 17 * @returns a malloc'd buffer containing "number[<unit prefix>][<units>]" 18 */ 19char *num2str(uint64_t num, int maxlen, int base, int pow2, int units) 20{ 21 const char *sistr[] = { "", "k", "M", "G", "T", "P" }; 22 const char *iecstr[] = { "", "Ki", "Mi", "Gi", "Ti", "Pi" }; 23 const char **unitprefix; 24 const char *unitstr[] = { "", "/s", "B", "bit", "B/s", "bit/s" }; 25 const unsigned int thousand[] = { 1000, 1024 }; 26 unsigned int modulo; 27 int unit_index = 0, post_index, carry = 0; 28 char tmp[32], fmt[32]; 29 char *buf; 30 31 compiletime_assert(sizeof(sistr) == sizeof(iecstr), "unit prefix arrays must be identical sizes"); 32 33 buf = malloc(128); 34 if (!buf) 35 return NULL; 36 37 if (pow2) 38 unitprefix = iecstr; 39 else 40 unitprefix = sistr; 41 42 for (post_index = 0; base > 1; post_index++) 43 base /= thousand[!!pow2]; 44 45 switch (units) { 46 case N2S_PERSEC: 47 unit_index = 1; 48 break; 49 case N2S_BYTE: 50 unit_index = 2; 51 break; 52 case N2S_BIT: 53 unit_index = 3; 54 num *= 8; 55 break; 56 case N2S_BYTEPERSEC: 57 unit_index = 4; 58 break; 59 case N2S_BITPERSEC: 60 unit_index = 5; 61 num *= 8; 62 break; 63 } 64 65 /* 66 * Divide by K/Ki until string length of num <= maxlen. 67 */ 68 modulo = -1U; 69 while (post_index < sizeof(sistr)) { 70 sprintf(tmp, "%llu", (unsigned long long) num); 71 if (strlen(tmp) <= maxlen) 72 break; 73 74 modulo = num % thousand[!!pow2]; 75 num /= thousand[!!pow2]; 76 carry = modulo >= thousand[!!pow2] / 2; 77 post_index++; 78 } 79 80 /* 81 * If no modulo, then we're done. 82 */ 83 if (modulo == -1U) { 84done: 85 if (post_index >= ARRAY_SIZE(sistr)) 86 post_index = 0; 87 88 sprintf(buf, "%llu%s%s", (unsigned long long) num, 89 unitprefix[post_index], unitstr[unit_index]); 90 return buf; 91 } 92 93 /* 94 * If no room for decimals, then we're done. 95 */ 96 sprintf(tmp, "%llu", (unsigned long long) num); 97 if ((int)(maxlen - strlen(tmp)) <= 1) { 98 if (carry) 99 num++; 100 goto done; 101 } 102 103 /* 104 * Fill in everything and return the result. 105 */ 106 assert(maxlen - strlen(tmp) - 1 > 0); 107 assert(modulo < thousand[!!pow2]); 108 sprintf(fmt, "%%.%df", (int)(maxlen - strlen(tmp) - 1)); 109 sprintf(tmp, fmt, (double)modulo / (double)thousand[!!pow2]); 110 111 sprintf(buf, "%llu.%s%s%s", (unsigned long long) num, &tmp[2], 112 unitprefix[post_index], unitstr[unit_index]); 113 return buf; 114} 115