?alloc: do not return NULL when asked for zero bytes
[git/git.git] / git-compat-util.h
1 #ifndef GIT_COMPAT_UTIL_H
2 #define GIT_COMPAT_UTIL_H
3
4 #include <unistd.h>
5 #include <stdio.h>
6 #include <sys/stat.h>
7 #include <fcntl.h>
8 #include <stddef.h>
9 #include <stdlib.h>
10 #include <stdarg.h>
11 #include <string.h>
12 #include <errno.h>
13 #include <limits.h>
14 #include <sys/param.h>
15 #include <netinet/in.h>
16 #include <sys/types.h>
17 #include <dirent.h>
18
19 #ifdef __GNUC__
20 #define NORETURN __attribute__((__noreturn__))
21 #else
22 #define NORETURN
23 #ifndef __attribute__
24 #define __attribute__(x)
25 #endif
26 #endif
27
28 /* General helper functions */
29 extern void usage(const char *err) NORETURN;
30 extern void die(const char *err, ...) NORETURN __attribute__((format (printf, 1, 2)));
31 extern int error(const char *err, ...) __attribute__((format (printf, 1, 2)));
32
33 #ifdef NO_MMAP
34
35 #ifndef PROT_READ
36 #define PROT_READ 1
37 #define PROT_WRITE 2
38 #define MAP_PRIVATE 1
39 #define MAP_FAILED ((void*)-1)
40 #endif
41
42 #define mmap gitfakemmap
43 #define munmap gitfakemunmap
44 extern void *gitfakemmap(void *start, size_t length, int prot , int flags, int fd, off_t offset);
45 extern int gitfakemunmap(void *start, size_t length);
46
47 #else /* NO_MMAP */
48
49 #include <sys/mman.h>
50
51 #endif /* NO_MMAP */
52
53 #ifdef NO_SETENV
54 #define setenv gitsetenv
55 extern int gitsetenv(const char *, const char *, int);
56 #endif
57
58 #ifdef NO_STRCASESTR
59 #define strcasestr gitstrcasestr
60 extern char *gitstrcasestr(const char *haystack, const char *needle);
61 #endif
62
63 static inline void *xmalloc(size_t size)
64 {
65 void *ret = malloc(size);
66 if (!ret && !size)
67 ret = malloc(1);
68 if (!ret)
69 die("Out of memory, malloc failed");
70 return ret;
71 }
72
73 static inline void *xrealloc(void *ptr, size_t size)
74 {
75 void *ret = realloc(ptr, size);
76 if (!ret && !size)
77 ret = realloc(ptr, 1);
78 if (!ret)
79 die("Out of memory, realloc failed");
80 return ret;
81 }
82
83 static inline void *xcalloc(size_t nmemb, size_t size)
84 {
85 void *ret = calloc(nmemb, size);
86 if (!ret && (!nmemb || !size))
87 ret = calloc(1, 1);
88 if (!ret)
89 die("Out of memory, calloc failed");
90 return ret;
91 }
92
93 static inline ssize_t xread(int fd, void *buf, size_t len)
94 {
95 ssize_t nr;
96 while (1) {
97 nr = read(fd, buf, len);
98 if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
99 continue;
100 return nr;
101 }
102 }
103
104 static inline ssize_t xwrite(int fd, const void *buf, size_t len)
105 {
106 ssize_t nr;
107 while (1) {
108 nr = write(fd, buf, len);
109 if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
110 continue;
111 return nr;
112 }
113 }
114
115 /* Sane ctype - no locale, and works with signed chars */
116 #undef isspace
117 #undef isdigit
118 #undef isalpha
119 #undef isalnum
120 #undef tolower
121 #undef toupper
122 extern unsigned char sane_ctype[256];
123 #define GIT_SPACE 0x01
124 #define GIT_DIGIT 0x02
125 #define GIT_ALPHA 0x04
126 #define sane_istest(x,mask) ((sane_ctype[(unsigned char)(x)] & (mask)) != 0)
127 #define isspace(x) sane_istest(x,GIT_SPACE)
128 #define isdigit(x) sane_istest(x,GIT_DIGIT)
129 #define isalpha(x) sane_istest(x,GIT_ALPHA)
130 #define isalnum(x) sane_istest(x,GIT_ALPHA | GIT_DIGIT)
131 #define tolower(x) sane_case((unsigned char)(x), 0x20)
132 #define toupper(x) sane_case((unsigned char)(x), 0)
133
134 static inline int sane_case(int x, int high)
135 {
136 if (sane_istest(x, GIT_ALPHA))
137 x = (x & ~0x20) | high;
138 return x;
139 }
140
141 #ifndef MAXPATHLEN
142 #define MAXPATHLEN 256
143 #endif
144 #endif