sd

Sized-data type and related functions
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sd.h (2181B)

      1 #ifndef SD_H
      2 #define SD_H
      3 
      4 #include <stdint.h>
      5 #include <stdlib.h>
      6 #include <string.h>
      7 
      8 typedef struct {
      9   size_t size;
     10   uint8_t *data;
     11 } sd_t;
     12 
     13 /**
     14  * Initialise a sized data.
     15  *
     16  * Allocates memory that needs to be sd_clear'd.
     17  *
     18  * @param s pointer where to write the sized data obj
     19  * @param size number of bytes in the sd
     20  */
     21 void sd_init(sd_t *s, const size_t size);
     22 
     23 /**
     24  * Clear a sd.
     25  *
     26  * @param s pointer to the sd
     27  */
     28 void sd_clear(sd_t *s);
     29 
     30 /**
     31  * Computes a hash of a sd.
     32  *
     33  * This hash is a simple combination of xoring
     34  * in all the bytes to a uint64_t in different
     35  * positions, then computing the mix64 function
     36  * known as murmur64.
     37  *
     38  * @param s the sd to get hash of
     39  * @return hash of s
     40  */
     41 uint64_t sd_hash(sd_t *s);
     42 
     43 /**
     44  * Compare two sds.
     45  *
     46  * Compares the sd's pointed to by x and y. In the
     47  * following sense: a < b if either a.size < b.size
     48  * or a.data < b.data (in the memcmp order). If
     49  * the sd_t are equal then 0 is returned.
     50  *
     51  * @param x pointer to first sd
     52  * @param y pointer to second sd
     53  * @return comparison number (lex order)
     54  */
     55 int sd_cmp(sd_t *x, sd_t *y);
     56 
     57 /**
     58  * Initialises a sd from a uint64_t.
     59  *
     60  * The size will be 8 bytes, and the order of the
     61  * bytes is raw (host order). Allocates memory that
     62  * needs to be sd_clear'd.
     63  *
     64  * @param s ptr to the sd_t to initialise
     65  * @param x the uint64_t to initialize from
     66  */
     67 void sd_init_u64(sd_t *s, const uint64_t x);
     68 
     69 /**
     70  * Converts a sd_t to a uint64_t.
     71  *
     72  * Gets a uint64_t from a sd_t that has been created
     73  * by sd_init_u64.
     74  *
     75  * @param s ptr to the sd to convert
     76  * @return the uint64_t
     77  */
     78 uint64_t sd_conv_u64(sd_t *s);
     79 
     80 /**
     81  * Initializes a sd from a string.
     82  *
     83  * Copies a string into a sd_t, including the
     84  * terminating null byte. Allocates memory that
     85  * needs to be sd_clear'd.
     86  *
     87  * @param s ptr to the sd to be init'd
     88  * @param str the string to copy into new sd
     89  */
     90 void sd_init_str(sd_t *s, const char *str);
     91 
     92 /**
     93  * Get string stored in sd.
     94  *
     95  * This returns a char* to the data stored in the
     96  * sd_t. This assumes that the data is in fact a
     97  * null terminated string.
     98  *
     99  * @param s ptr to the sd to get string from
    100  */
    101 char *sd_get_str(sd_t *s);
    102 
    103 #endif