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 #include "reftable-basics.h"
  18
  19 /* Bigendian en/decoding of integers */
  20
  21 void put_be24(uint8_t *out, uint32_t i);
  22 uint32_t get_be24(uint8_t *in);
  23 void put_be16(uint8_t *out, uint16_t i);
  24
  25 /*
  26  * find smallest index i in [0, sz) at which `f(i) > 0`, assuming that f is
  27  * ascending. Return sz if `f(i) == 0` for all indices. The search is aborted
  28  * and `sz` is returned in case `f(i) < 0`.
  29  *
  30  * Contrary to bsearch(3), this returns something useful if the argument is not
  31  * found.
  32  */
  33 size_t binsearch(size_t sz, int (*f)(size_t k, void *args), void *args);
  34
  35 /*
  36  * Frees a NULL terminated array of malloced strings. The array itself is also
  37  * freed.
  38  */
  39 void free_names(char **a);
  40
  41 /*
  42  * Parse a newline separated list of names. `size` is the length of the buffer,
  43  * without terminating '\0'. Empty names are discarded. Returns a `NULL`
  44  * pointer when allocations fail.
  45  */
  46 char **parse_names(char *buf, int size);
  47
  48 /* compares two NULL-terminated arrays of strings. */
  49 int names_equal(const char **a, const char **b);
  50
  51 /* returns the array size of a NULL-terminated array of strings. */
  52 size_t names_length(const char **names);
  53
  54 /* Allocation routines; they invoke the functions set through
  55  * reftable_set_alloc() */
  56 void *reftable_malloc(size_t sz);
  57 void *reftable_realloc(void *p, size_t sz);
  58 void reftable_free(void *p);
  59 void *reftable_calloc(size_t nelem, size_t elsize);
  60 char *reftable_strdup(const char *str);
  61
  62 #define REFTABLE_ALLOC_ARRAY(x, alloc) (x) = reftable_malloc(st_mult(sizeof(*(x)), (alloc)))
  63 #define REFTABLE_CALLOC_ARRAY(x, alloc) (x) = reftable_calloc((alloc), sizeof(*(x)))
  64 #define REFTABLE_REALLOC_ARRAY(x, alloc) (x) = reftable_realloc((x), st_mult(sizeof(*(x)), (alloc)))
  65 #define REFTABLE_ALLOC_GROW(x, nr, alloc) \
  66         do { \
  67                 if ((nr) > alloc) { \
  68                         alloc = 2 * (alloc) + 1; \
  69                         if (alloc < (nr)) \
  70                                 alloc = (nr); \
  71                         REFTABLE_REALLOC_ARRAY(x, alloc); \
  72                 } \
  73         } while (0)
  74 #define REFTABLE_FREE_AND_NULL(p) do { reftable_free(p); (p) = NULL; } while (0)
  75
  76 #ifndef REFTABLE_ALLOW_BANNED_ALLOCATORS
  77 # define REFTABLE_BANNED(func) use_reftable_##func##_instead
  78 # undef malloc
  79 # define malloc(sz) REFTABLE_BANNED(malloc)
  80 # undef realloc
  81 # define realloc(ptr, sz) REFTABLE_BANNED(realloc)
  82 # undef free
  83 # define free(ptr) REFTABLE_BANNED(free)
  84 # undef calloc
  85 # define calloc(nelem, elsize) REFTABLE_BANNED(calloc)
  86 # undef strdup
  87 # define strdup(str) REFTABLE_BANNED(strdup)
  88 #endif
  89
  90 /* Find the longest shared prefix size of `a` and `b` */
  91 struct strbuf;
  92 int common_prefix_size(struct strbuf *a, struct strbuf *b);
  93
  94 int hash_size(uint32_t id);
  95
  96 #endif