reftable/basics.h

   1 /*
   2 Copyright 2020 Google LLC
   3
   4 Use of this source code is governed by a BSD-style
   5 license that can be found in the LICENSE file or at
   6 https://developers.google.com/open-source/licenses/bsd
   7 */
   8
   9 #ifndef BASICS_H
  10 #define BASICS_H
  11
  12 /*
  13  * miscellaneous utilities that are not provided by Git.
  14  */
  15
  16 #include "system.h"
  17
  18 /* Bigendian en/decoding of integers */
  19
  20 void put_be24(uint8_t *out, uint32_t i);
  21 uint32_t get_be24(uint8_t *in);
  22 void put_be16(uint8_t *out, uint16_t i);
  23
  24 /*
  25  * find smallest index i in [0, sz) at which `f(i) > 0`, assuming that f is
  26  * ascending. Return sz if `f(i) == 0` for all indices. The search is aborted
  27  * and `sz` is returned in case `f(i) < 0`.
  28  *
  29  * Contrary to bsearch(3), this returns something useful if the argument is not
  30  * found.
  31  */
  32 size_t binsearch(size_t sz, int (*f)(size_t k, void *args), void *args);
  33
  34 /*
  35  * Frees a NULL terminated array of malloced strings. The array itself is also
  36  * freed.
  37  */
  38 void free_names(char **a);
  39
  40 /* parse a newline separated list of names. `size` is the length of the buffer,
  41  * without terminating '\0'. Empty names are discarded. */
  42 void parse_names(char *buf, int size, char ***namesp);
  43
  44 /* compares two NULL-terminated arrays of strings. */
  45 int names_equal(char **a, char **b);
  46
  47 /* returns the array size of a NULL-terminated array of strings. */
  48 size_t names_length(char **names);
  49
  50 /* Allocation routines; they invoke the functions set through
  51  * reftable_set_alloc() */
  52 void *reftable_malloc(size_t sz);
  53 void *reftable_realloc(void *p, size_t sz);
  54 void reftable_free(void *p);
  55 void *reftable_calloc(size_t nelem, size_t elsize);
  56
  57 #define REFTABLE_ALLOC_ARRAY(x, alloc) (x) = reftable_malloc(st_mult(sizeof(*(x)), (alloc)))
  58 #define REFTABLE_CALLOC_ARRAY(x, alloc) (x) = reftable_calloc((alloc), sizeof(*(x)))
  59 #define REFTABLE_REALLOC_ARRAY(x, alloc) (x) = reftable_realloc((x), st_mult(sizeof(*(x)), (alloc)))
  60 #define REFTABLE_ALLOC_GROW(x, nr, alloc) \
  61         do { \
  62                 if ((nr) > alloc) { \
  63                         alloc = 2 * (alloc) + 1; \
  64                         if (alloc < (nr)) \
  65                                 alloc = (nr); \
  66                         REFTABLE_REALLOC_ARRAY(x, alloc); \
  67                 } \
  68         } while (0)
  69
  70 /* Find the longest shared prefix size of `a` and `b` */
  71 struct strbuf;
  72 int common_prefix_size(struct strbuf *a, struct strbuf *b);
  73
  74 #endif