1 #include 
     
        2   3 #define SECTOR_SIZE_DEFAULT   512LL  4 #define KILOBYTE_SIZE 1000LL  5 #define MEGABYTE_SIZE 1000000LL  6 #define GIGABYTE_SIZE 1000000000LL  7 #define TERABYTE_SIZE 1000000000000LL  8 #define KIBIBYTE_SIZE 1024LL  9 #define MEBIBYTE_SIZE 1048576LL 10 #define GIBIBYTE_SIZE 1073741824LL 11 #define TEBIBYTE_SIZE 1099511627776LL 12  13 typedef enum { 14     DIGIT_UNIT_BYTE, 15     DIGIT_UNIT_KILOBYTE, 16     DIGIT_UNIT_MEGABYTE, 17     DIGIT_UNIT_GIGABYTE, 18     DIGIT_UNIT_TERABYTE, 19     DIGIT_UNIT_KIBIBYTE, 20     DIGIT_UNIT_MEBIBYTE, 21     DIGIT_UNIT_GIBIBYTE, 22     DIGIT_UNIT_TEBIBYTE 23 } DigitUnit; 24  25 /* Inefficiently removes all spaces from a string, in-place. */ 26 static void 27 strip_string (char* str) 28 { 29     int i; 30  31     for (i = 0; str[i] != 0; i++) { 32         if (isspace (str[i])) { 33             int j; 34             for (j = i + 1; str[j] != 0; j++) 35                 str[j - 1] = str[j]; 36         } 37     } 38 } 39  40 /* Find non-number suffix.  Eg: find_suffix("32Mb") returns a pointer to 41  * "Mb". */ 42 static char* 43 find_suffix (const char* str) 44 { 45     while (str[0] != 0 && (isdigit (str[0]) || strchr(",.-", str[0]))) 46         str++; 47     return (char *) str; 48 } 49  50 static DigitUnit 51 parse_unit_suffix (const char* suffix) 52 { 53     if (strlen (suffix) > 1 && tolower (suffix[1]) == 'i') { 54         switch (tolower (suffix[0])) { 55             case 'k': return DIGIT_UNIT_KIBIBYTE; 56             case 'm': return DIGIT_UNIT_MEBIBYTE; 57             case 'g': return DIGIT_UNIT_GIBIBYTE; 58             case 't': return DIGIT_UNIT_TEBIBYTE; 59         } 60     } else if (strlen (suffix) > 0) { 61         switch (tolower (suffix[0])) { 62             case 'b': return DIGIT_UNIT_BYTE; 63             case 'k': return DIGIT_UNIT_KILOBYTE; 64             case 'm': return DIGIT_UNIT_MEGABYTE; 65             case 'g': return DIGIT_UNIT_GIGABYTE; 66             case 't': return DIGIT_UNIT_TERABYTE; 67         } 68     } 69  70     return -1; 71 } 72  73 long long unit_parse (const char *str) 74 { 75     char *suffix; 76     long long byte = -1; 77     long long byte_block = 1; 78  79     strip_string (str); 80     suffix = find_suffix (str); 81  82     DigitUnit unit = parse_unit_suffix (suffix); 83  84     switch (unit) { 85     case DIGIT_UNIT_BYTE: 86         break; 87     case DIGIT_UNIT_KILOBYTE: 88         byte_block = KILOBYTE_SIZE; 89         break; 90     case DIGIT_UNIT_MEGABYTE: 91         byte_block = MEGABYTE_SIZE; 92         break; 93     case DIGIT_UNIT_GIGABYTE: 94         byte_block = GIGABYTE_SIZE; 95         break; 96     case DIGIT_UNIT_TERABYTE: 97         byte_block = TERABYTE_SIZE; 98         break; 99     case DIGIT_UNIT_KIBIBYTE:100         byte_block = KIBIBYTE_SIZE;101         break;102     case DIGIT_UNIT_MEBIBYTE:103         byte_block = MEBIBYTE_SIZE;104         break;105     case DIGIT_UNIT_GIBIBYTE:106         byte_block = GIBIBYTE_SIZE;107         break;108     case DIGIT_UNIT_TEBIBYTE:109         byte_block = TEBIBYTE_SIZE;110         break;111     }112 113     double temp = 0;114     if (sscanf (str, "%lf", &temp) == 1)115         byte = temp * byte_block;116 117     return byte;118 }119 120 121 int main (int argc, char **argv)122 {123     if (argc > 1)124         printf ("%lld\n", unit_parse (argv[1]));125     return 0;126 }