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| | #ifndef COMMON_H
#define COMMON_H
#include "git-compat-util.h"
#include "wrapper.h"
#include "usage.h"
/*
* ARRAY_SIZE - get the number of elements in a visible array
* @x: the array whose size you want.
*
* This does not work on pointers, or arrays declared as [], or
* function parameters. With correct compiler support, such usage
* will cause a build error (see the build_assert_or_zero macro).
*/
#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]) + BARF_UNLESS_AN_ARRAY(x))
#define bitsizeof(x) (CHAR_BIT * sizeof(x))
#define maximum_signed_value_of_type(a) \
(INTMAX_MAX >> (bitsizeof(intmax_t) - bitsizeof(a)))
#define maximum_unsigned_value_of_type(a) \
(UINTMAX_MAX >> (bitsizeof(uintmax_t) - bitsizeof(a)))
/*
* Signed integer overflow is undefined in C, so here's a helper macro
* to detect if the sum of two integers will overflow.
*
* Requires: a >= 0, typeof(a) equals typeof(b)
*/
#define signed_add_overflows(a, b) \
((b) > maximum_signed_value_of_type(a) - (a))
#define unsigned_add_overflows(a, b) \
((b) > maximum_unsigned_value_of_type(a) - (a))
/*
* Returns true if the multiplication of "a" and "b" will
* overflow. The types of "a" and "b" must match and must be unsigned.
* Note that this macro evaluates "a" twice!
*/
#define unsigned_mult_overflows(a, b) \
((a) && (b) > maximum_unsigned_value_of_type(a) / (a))
/*
* Returns true if the left shift of "a" by "shift" bits will
* overflow. The type of "a" must be unsigned.
*/
#define unsigned_left_shift_overflows(a, shift) \
((shift) < bitsizeof(a) && \
(a) > maximum_unsigned_value_of_type(a) >> (shift))
#define MSB(x, bits) ((x) & TYPEOF(x)(~0ULL << (bitsizeof(x) - (bits))))
#define HAS_MULTI_BITS(i) ((i) & ((i) - 1)) /* checks if an integer has more than 1 bit set */
#define DIV_ROUND_UP(n,d) (((n) + (d) - 1) / (d))
/* Approximation of the length of the decimal representation of this type. */
#define decimal_length(x) ((int)(sizeof(x) * 2.56 + 0.5) + 1)
/*
* If the string "str" begins with the string found in "prefix", return 1.
* The "out" parameter is set to "str + strlen(prefix)" (i.e., to the point in
* the string right after the prefix).
*
* Otherwise, return 0 and leave "out" untouched.
*
* Examples:
*
* [extract branch name, fail if not a branch]
* if (!skip_prefix(ref, "refs/heads/", &branch)
* return -1;
*
* [skip prefix if present, otherwise use whole string]
* skip_prefix(name, "refs/heads/", &name);
*/
static inline int skip_prefix(const char *str, const char *prefix,
const char **out)
{
do {
if (!*prefix) {
*out = str;
return 1;
}
} while (*str++ == *prefix++);
return 0;
}
/*
* Like skip_prefix, but promises never to read past "len" bytes of the input
* buffer, and returns the remaining number of bytes in "out" via "outlen".
*/
static inline int skip_prefix_mem(const char *buf, size_t len,
const char *prefix,
const char **out, size_t *outlen)
{
size_t prefix_len = strlen(prefix);
if (prefix_len <= len && !memcmp(buf, prefix, prefix_len)) {
*out = buf + prefix_len;
*outlen = len - prefix_len;
return 1;
}
return 0;
}
/*
* If buf ends with suffix, return 1 and subtract the length of the suffix
* from *len. Otherwise, return 0 and leave *len untouched.
*/
static inline int strip_suffix_mem(const char *buf, size_t *len,
const char *suffix)
{
size_t suflen = strlen(suffix);
if (*len < suflen || memcmp(buf + (*len - suflen), suffix, suflen))
return 0;
*len -= suflen;
return 1;
}
/*
* If str ends with suffix, return 1 and set *len to the size of the string
* without the suffix. Otherwise, return 0 and set *len to the size of the
* string.
*
* Note that we do _not_ NUL-terminate str to the new length.
*/
static inline int strip_suffix(const char *str, const char *suffix, size_t *len)
{
*len = strlen(str);
return strip_suffix_mem(str, len, suffix);
}
#define SWAP(a, b) do { \
void *_swap_a_ptr = &(a); \
void *_swap_b_ptr = &(b); \
unsigned char _swap_buffer[sizeof(a)]; \
memcpy(_swap_buffer, _swap_a_ptr, sizeof(a)); \
memcpy(_swap_a_ptr, _swap_b_ptr, sizeof(a) + \
BUILD_ASSERT_OR_ZERO(sizeof(a) == sizeof(b))); \
memcpy(_swap_b_ptr, _swap_buffer, sizeof(a)); \
} while (0)
static inline size_t st_add(size_t a, size_t b)
{
if (unsigned_add_overflows(a, b))
die("size_t overflow: %"PRIuMAX" + %"PRIuMAX,
(uintmax_t)a, (uintmax_t)b);
return a + b;
}
#define st_add3(a,b,c) st_add(st_add((a),(b)),(c))
#define st_add4(a,b,c,d) st_add(st_add3((a),(b),(c)),(d))
static inline size_t st_mult(size_t a, size_t b)
{
if (unsigned_mult_overflows(a, b))
die("size_t overflow: %"PRIuMAX" * %"PRIuMAX,
(uintmax_t)a, (uintmax_t)b);
return a * b;
}
static inline size_t st_sub(size_t a, size_t b)
{
if (a < b)
die("size_t underflow: %"PRIuMAX" - %"PRIuMAX,
(uintmax_t)a, (uintmax_t)b);
return a - b;
}
static inline size_t st_left_shift(size_t a, unsigned shift)
{
if (unsigned_left_shift_overflows(a, shift))
die("size_t overflow: %"PRIuMAX" << %u",
(uintmax_t)a, shift);
return a << shift;
}
static inline unsigned long cast_size_t_to_ulong(size_t a)
{
if (a != (unsigned long)a)
die("object too large to read on this platform: %"
PRIuMAX" is cut off to %lu",
(uintmax_t)a, (unsigned long)a);
return (unsigned long)a;
}
static inline int cast_size_t_to_int(size_t a)
{
if (a > INT_MAX)
die("number too large to represent as int on this platform: %"PRIuMAX,
(uintmax_t)a);
return (int)a;
}
/*
* FREE_AND_NULL(ptr) is like free(ptr) followed by ptr = NULL. Note
* that ptr is used twice, so don't pass e.g. ptr++.
*/
#define FREE_AND_NULL(p) do { free(p); (p) = NULL; } while (0)
#define alloc_nr(x) (((x)+16)*3/2)
/**
* Dynamically growing an array using realloc() is error prone and boring.
*
* Define your array with:
*
* - a pointer (`item`) that points at the array, initialized to `NULL`
* (although please name the variable based on its contents, not on its
* type);
*
* - an integer variable (`alloc`) that keeps track of how big the current
* allocation is, initialized to `0`;
*
* - another integer variable (`nr`) to keep track of how many elements the
* array currently has, initialized to `0`.
*
* Then before adding `n`th element to the item, call `ALLOC_GROW(item, n,
* alloc)`. This ensures that the array can hold at least `n` elements by
* calling `realloc(3)` and adjusting `alloc` variable.
*
* ------------
* sometype *item;
* size_t nr;
* size_t alloc
*
* for (i = 0; i < nr; i++)
* if (we like item[i] already)
* return;
*
* // we did not like any existing one, so add one
* ALLOC_GROW(item, nr + 1, alloc);
* item[nr++] = value you like;
* ------------
*
* You are responsible for updating the `nr` variable.
*
* If you need to specify the number of elements to allocate explicitly
* then use the macro `REALLOC_ARRAY(item, alloc)` instead of `ALLOC_GROW`.
*
* Consider using ALLOC_GROW_BY instead of ALLOC_GROW as it has some
* added niceties.
*
* DO NOT USE any expression with side-effect for 'x', 'nr', or 'alloc'.
*/
#define ALLOC_GROW(x, nr, alloc) \
do { \
if ((nr) > alloc) { \
if (alloc_nr(alloc) < (nr)) \
alloc = (nr); \
else \
alloc = alloc_nr(alloc); \
REALLOC_ARRAY(x, alloc); \
} \
} while (0)
/*
* Similar to ALLOC_GROW but handles updating of the nr value and
* zeroing the bytes of the newly-grown array elements.
*
* DO NOT USE any expression with side-effect for any of the
* arguments.
*/
#define ALLOC_GROW_BY(x, nr, increase, alloc) \
do { \
if (increase) { \
size_t new_nr = nr + (increase); \
if (new_nr < nr) \
BUG("negative growth in ALLOC_GROW_BY"); \
ALLOC_GROW(x, new_nr, alloc); \
memset((x) + nr, 0, sizeof(*(x)) * (increase)); \
nr = new_nr; \
} \
} while (0)
#define ALLOC_ARRAY(x, alloc) (x) = xmalloc(st_mult(sizeof(*(x)), (alloc)))
#define CALLOC_ARRAY(x, alloc) (x) = xcalloc((alloc), sizeof(*(x)))
#define REALLOC_ARRAY(x, alloc) (x) = xrealloc((x), st_mult(sizeof(*(x)), (alloc)))
#define COPY_ARRAY(dst, src, n) copy_array((dst), (src), (n), sizeof(*(dst)) + \
BARF_UNLESS_COPYABLE((dst), (src)))
static inline void copy_array(void *dst, const void *src, size_t n, size_t size)
{
if (n)
memcpy(dst, src, st_mult(size, n));
}
#define MOVE_ARRAY(dst, src, n) move_array((dst), (src), (n), sizeof(*(dst)) + \
BARF_UNLESS_COPYABLE((dst), (src)))
static inline void move_array(void *dst, const void *src, size_t n, size_t size)
{
if (n)
memmove(dst, src, st_mult(size, n));
}
#define DUP_ARRAY(dst, src, n) do { \
size_t dup_array_n_ = (n); \
COPY_ARRAY(ALLOC_ARRAY((dst), dup_array_n_), (src), dup_array_n_); \
} while (0)
/*
* These functions help you allocate structs with flex arrays, and copy
* the data directly into the array. For example, if you had:
*
* struct foo {
* int bar;
* char name[FLEX_ARRAY];
* };
*
* you can do:
*
* struct foo *f;
* FLEX_ALLOC_MEM(f, name, src, len);
*
* to allocate a "foo" with the contents of "src" in the "name" field.
* The resulting struct is automatically zero'd, and the flex-array field
* is NUL-terminated (whether the incoming src buffer was or not).
*
* The FLEXPTR_* variants operate on structs that don't use flex-arrays,
* but do want to store a pointer to some extra data in the same allocated
* block. For example, if you have:
*
* struct foo {
* char *name;
* int bar;
* };
*
* you can do:
*
* struct foo *f;
* FLEXPTR_ALLOC_STR(f, name, src);
*
* and "name" will point to a block of memory after the struct, which will be
* freed along with the struct (but the pointer can be repointed anywhere).
*
* The *_STR variants accept a string parameter rather than a ptr/len
* combination.
*
* Note that these macros will evaluate the first parameter multiple
* times, and it must be assignable as an lvalue.
*/
#define FLEX_ALLOC_MEM(x, flexname, buf, len) do { \
size_t flex_array_len_ = (len); \
(x) = xcalloc(1, st_add3(sizeof(*(x)), flex_array_len_, 1)); \
memcpy((void *)(x)->flexname, (buf), flex_array_len_); \
} while (0)
#define FLEXPTR_ALLOC_MEM(x, ptrname, buf, len) do { \
size_t flex_array_len_ = (len); \
(x) = xcalloc(1, st_add3(sizeof(*(x)), flex_array_len_, 1)); \
memcpy((x) + 1, (buf), flex_array_len_); \
(x)->ptrname = (void *)((x)+1); \
} while(0)
#define FLEX_ALLOC_STR(x, flexname, str) \
FLEX_ALLOC_MEM((x), flexname, (str), strlen(str))
#define FLEXPTR_ALLOC_STR(x, ptrname, str) \
FLEXPTR_ALLOC_MEM((x), ptrname, (str), strlen(str))
static inline char *xstrdup_or_null(const char *str)
{
return str ? xstrdup(str) : NULL;
}
static inline size_t xsize_t(off_t len)
{
if (len < 0 || (uintmax_t) len > SIZE_MAX)
die("Cannot handle files this big");
return (size_t) len;
}
/*
* Like skip_prefix, but compare case-insensitively. Note that the comparison
* is done via tolower(), so it is strictly ASCII (no multi-byte characters or
* locale-specific conversions).
*/
static inline int skip_iprefix(const char *str, const char *prefix,
const char **out)
{
do {
if (!*prefix) {
*out = str;
return 1;
}
} while (tolower(*str++) == tolower(*prefix++));
return 0;
}
/*
* Like skip_prefix_mem, but compare case-insensitively. Note that the
* comparison is done via tolower(), so it is strictly ASCII (no multi-byte
* characters or locale-specific conversions).
*/
static inline int skip_iprefix_mem(const char *buf, size_t len,
const char *prefix,
const char **out, size_t *outlen)
{
do {
if (!*prefix) {
*out = buf;
*outlen = len;
return 1;
}
} while (len-- > 0 && tolower(*buf++) == tolower(*prefix++));
return 0;
}
static inline int strtoul_ui(char const *s, int base, unsigned int *result)
{
unsigned long ul;
char *p;
errno = 0;
/* negative values would be accepted by strtoul */
if (strchr(s, '-'))
return -1;
ul = strtoul(s, &p, base);
if (errno || *p || p == s || (unsigned int) ul != ul)
return -1;
*result = ul;
return 0;
}
static inline int strtol_i(char const *s, int base, int *result)
{
long ul;
char *p;
errno = 0;
ul = strtol(s, &p, base);
if (errno || *p || p == s || (int) ul != ul)
return -1;
*result = ul;
return 0;
}
static inline int regexec_buf(const regex_t *preg, const char *buf, size_t size,
size_t nmatch, regmatch_t pmatch[], int eflags)
{
assert(nmatch > 0 && pmatch);
pmatch[0].rm_so = 0;
pmatch[0].rm_eo = size;
return regexec(preg, buf, nmatch, pmatch, eflags | REG_STARTEND);
}
/*
* Our code often opens a path to an optional file, to work on its
* contents when we can successfully open it. We can ignore a failure
* to open if such an optional file does not exist, but we do want to
* report a failure in opening for other reasons (e.g. we got an I/O
* error, or the file is there, but we lack the permission to open).
*
* Call this function after seeing an error from open() or fopen() to
* see if the errno indicates a missing file that we can safely ignore.
*/
static inline int is_missing_file_error(int errno_)
{
return (errno_ == ENOENT || errno_ == ENOTDIR);
}
/*
* container_of - Get the address of an object containing a field.
*
* @ptr: pointer to the field.
* @type: type of the object.
* @member: name of the field within the object.
*/
#define container_of(ptr, type, member) \
((type *) ((char *)(ptr) - offsetof(type, member)))
/*
* helper function for `container_of_or_null' to avoid multiple
* evaluation of @ptr
*/
static inline void *container_of_or_null_offset(void *ptr, size_t offset)
{
return ptr ? (char *)ptr - offset : NULL;
}
/*
* like `container_of', but allows returned value to be NULL
*/
#define container_of_or_null(ptr, type, member) \
(type *)container_of_or_null_offset(ptr, offsetof(type, member))
#endif
|