Add generic 'strbuf_readlink()' helper function
[git/git.git] / strbuf.c
1 #include "cache.h"
2
3 int prefixcmp(const char *str, const char *prefix)
4 {
5 for (; ; str++, prefix++)
6 if (!*prefix)
7 return 0;
8 else if (*str != *prefix)
9 return (unsigned char)*prefix - (unsigned char)*str;
10 }
11
12 /*
13 * Used as the default ->buf value, so that people can always assume
14 * buf is non NULL and ->buf is NUL terminated even for a freshly
15 * initialized strbuf.
16 */
17 char strbuf_slopbuf[1];
18
19 void strbuf_init(struct strbuf *sb, size_t hint)
20 {
21 sb->alloc = sb->len = 0;
22 sb->buf = strbuf_slopbuf;
23 if (hint)
24 strbuf_grow(sb, hint);
25 }
26
27 void strbuf_release(struct strbuf *sb)
28 {
29 if (sb->alloc) {
30 free(sb->buf);
31 strbuf_init(sb, 0);
32 }
33 }
34
35 char *strbuf_detach(struct strbuf *sb, size_t *sz)
36 {
37 char *res = sb->alloc ? sb->buf : NULL;
38 if (sz)
39 *sz = sb->len;
40 strbuf_init(sb, 0);
41 return res;
42 }
43
44 void strbuf_attach(struct strbuf *sb, void *buf, size_t len, size_t alloc)
45 {
46 strbuf_release(sb);
47 sb->buf = buf;
48 sb->len = len;
49 sb->alloc = alloc;
50 strbuf_grow(sb, 0);
51 sb->buf[sb->len] = '\0';
52 }
53
54 void strbuf_grow(struct strbuf *sb, size_t extra)
55 {
56 if (sb->len + extra + 1 <= sb->len)
57 die("you want to use way too much memory");
58 if (!sb->alloc)
59 sb->buf = NULL;
60 ALLOC_GROW(sb->buf, sb->len + extra + 1, sb->alloc);
61 }
62
63 void strbuf_trim(struct strbuf *sb)
64 {
65 char *b = sb->buf;
66 while (sb->len > 0 && isspace((unsigned char)sb->buf[sb->len - 1]))
67 sb->len--;
68 while (sb->len > 0 && isspace(*b)) {
69 b++;
70 sb->len--;
71 }
72 memmove(sb->buf, b, sb->len);
73 sb->buf[sb->len] = '\0';
74 }
75 void strbuf_rtrim(struct strbuf *sb)
76 {
77 while (sb->len > 0 && isspace((unsigned char)sb->buf[sb->len - 1]))
78 sb->len--;
79 sb->buf[sb->len] = '\0';
80 }
81
82 void strbuf_ltrim(struct strbuf *sb)
83 {
84 char *b = sb->buf;
85 while (sb->len > 0 && isspace(*b)) {
86 b++;
87 sb->len--;
88 }
89 memmove(sb->buf, b, sb->len);
90 sb->buf[sb->len] = '\0';
91 }
92
93 void strbuf_tolower(struct strbuf *sb)
94 {
95 int i;
96 for (i = 0; i < sb->len; i++)
97 sb->buf[i] = tolower(sb->buf[i]);
98 }
99
100 struct strbuf **strbuf_split(const struct strbuf *sb, int delim)
101 {
102 int alloc = 2, pos = 0;
103 char *n, *p;
104 struct strbuf **ret;
105 struct strbuf *t;
106
107 ret = xcalloc(alloc, sizeof(struct strbuf *));
108 p = n = sb->buf;
109 while (n < sb->buf + sb->len) {
110 int len;
111 n = memchr(n, delim, sb->len - (n - sb->buf));
112 if (pos + 1 >= alloc) {
113 alloc = alloc * 2;
114 ret = xrealloc(ret, sizeof(struct strbuf *) * alloc);
115 }
116 if (!n)
117 n = sb->buf + sb->len - 1;
118 len = n - p + 1;
119 t = xmalloc(sizeof(struct strbuf));
120 strbuf_init(t, len);
121 strbuf_add(t, p, len);
122 ret[pos] = t;
123 ret[++pos] = NULL;
124 p = ++n;
125 }
126 return ret;
127 }
128
129 void strbuf_list_free(struct strbuf **sbs)
130 {
131 struct strbuf **s = sbs;
132
133 while (*s) {
134 strbuf_release(*s);
135 free(*s++);
136 }
137 free(sbs);
138 }
139
140 int strbuf_cmp(const struct strbuf *a, const struct strbuf *b)
141 {
142 int cmp;
143 if (a->len < b->len) {
144 cmp = memcmp(a->buf, b->buf, a->len);
145 return cmp ? cmp : -1;
146 } else {
147 cmp = memcmp(a->buf, b->buf, b->len);
148 return cmp ? cmp : a->len != b->len;
149 }
150 }
151
152 void strbuf_splice(struct strbuf *sb, size_t pos, size_t len,
153 const void *data, size_t dlen)
154 {
155 if (pos + len < pos)
156 die("you want to use way too much memory");
157 if (pos > sb->len)
158 die("`pos' is too far after the end of the buffer");
159 if (pos + len > sb->len)
160 die("`pos + len' is too far after the end of the buffer");
161
162 if (dlen >= len)
163 strbuf_grow(sb, dlen - len);
164 memmove(sb->buf + pos + dlen,
165 sb->buf + pos + len,
166 sb->len - pos - len);
167 memcpy(sb->buf + pos, data, dlen);
168 strbuf_setlen(sb, sb->len + dlen - len);
169 }
170
171 void strbuf_insert(struct strbuf *sb, size_t pos, const void *data, size_t len)
172 {
173 strbuf_splice(sb, pos, 0, data, len);
174 }
175
176 void strbuf_remove(struct strbuf *sb, size_t pos, size_t len)
177 {
178 strbuf_splice(sb, pos, len, NULL, 0);
179 }
180
181 void strbuf_add(struct strbuf *sb, const void *data, size_t len)
182 {
183 strbuf_grow(sb, len);
184 memcpy(sb->buf + sb->len, data, len);
185 strbuf_setlen(sb, sb->len + len);
186 }
187
188 void strbuf_adddup(struct strbuf *sb, size_t pos, size_t len)
189 {
190 strbuf_grow(sb, len);
191 memcpy(sb->buf + sb->len, sb->buf + pos, len);
192 strbuf_setlen(sb, sb->len + len);
193 }
194
195 void strbuf_addf(struct strbuf *sb, const char *fmt, ...)
196 {
197 int len;
198 va_list ap;
199
200 if (!strbuf_avail(sb))
201 strbuf_grow(sb, 64);
202 va_start(ap, fmt);
203 len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap);
204 va_end(ap);
205 if (len < 0)
206 die("your vsnprintf is broken");
207 if (len > strbuf_avail(sb)) {
208 strbuf_grow(sb, len);
209 va_start(ap, fmt);
210 len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap);
211 va_end(ap);
212 if (len > strbuf_avail(sb)) {
213 die("this should not happen, your snprintf is broken");
214 }
215 }
216 strbuf_setlen(sb, sb->len + len);
217 }
218
219 void strbuf_expand(struct strbuf *sb, const char *format, expand_fn_t fn,
220 void *context)
221 {
222 for (;;) {
223 const char *percent;
224 size_t consumed;
225
226 percent = strchrnul(format, '%');
227 strbuf_add(sb, format, percent - format);
228 if (!*percent)
229 break;
230 format = percent + 1;
231
232 consumed = fn(sb, format, context);
233 if (consumed)
234 format += consumed;
235 else
236 strbuf_addch(sb, '%');
237 }
238 }
239
240 size_t strbuf_expand_dict_cb(struct strbuf *sb, const char *placeholder,
241 void *context)
242 {
243 struct strbuf_expand_dict_entry *e = context;
244 size_t len;
245
246 for (; e->placeholder && (len = strlen(e->placeholder)); e++) {
247 if (!strncmp(placeholder, e->placeholder, len)) {
248 if (e->value)
249 strbuf_addstr(sb, e->value);
250 return len;
251 }
252 }
253 return 0;
254 }
255
256 size_t strbuf_fread(struct strbuf *sb, size_t size, FILE *f)
257 {
258 size_t res;
259
260 strbuf_grow(sb, size);
261 res = fread(sb->buf + sb->len, 1, size, f);
262 if (res > 0) {
263 strbuf_setlen(sb, sb->len + res);
264 }
265 return res;
266 }
267
268 ssize_t strbuf_read(struct strbuf *sb, int fd, size_t hint)
269 {
270 size_t oldlen = sb->len;
271
272 strbuf_grow(sb, hint ? hint : 8192);
273 for (;;) {
274 ssize_t cnt;
275
276 cnt = xread(fd, sb->buf + sb->len, sb->alloc - sb->len - 1);
277 if (cnt < 0) {
278 strbuf_setlen(sb, oldlen);
279 return -1;
280 }
281 if (!cnt)
282 break;
283 sb->len += cnt;
284 strbuf_grow(sb, 8192);
285 }
286
287 sb->buf[sb->len] = '\0';
288 return sb->len - oldlen;
289 }
290
291 #define STRBUF_MAXLINK (2*PATH_MAX)
292
293 int strbuf_readlink(struct strbuf *sb, const char *path, size_t hint)
294 {
295 if (hint < 32)
296 hint = 32;
297
298 while (hint < STRBUF_MAXLINK) {
299 int len;
300
301 strbuf_grow(sb, hint);
302 len = readlink(path, sb->buf, hint);
303 if (len < 0) {
304 if (errno != ERANGE)
305 break;
306 } else if (len < hint) {
307 strbuf_setlen(sb, len);
308 return 0;
309 }
310
311 /* .. the buffer was too small - try again */
312 hint *= 2;
313 }
314 strbuf_release(sb);
315 return -1;
316 }
317
318 int strbuf_getline(struct strbuf *sb, FILE *fp, int term)
319 {
320 int ch;
321
322 strbuf_grow(sb, 0);
323 if (feof(fp))
324 return EOF;
325
326 strbuf_reset(sb);
327 while ((ch = fgetc(fp)) != EOF) {
328 if (ch == term)
329 break;
330 strbuf_grow(sb, 1);
331 sb->buf[sb->len++] = ch;
332 }
333 if (ch == EOF && sb->len == 0)
334 return EOF;
335
336 sb->buf[sb->len] = '\0';
337 return 0;
338 }
339
340 int strbuf_read_file(struct strbuf *sb, const char *path, size_t hint)
341 {
342 int fd, len;
343
344 fd = open(path, O_RDONLY);
345 if (fd < 0)
346 return -1;
347 len = strbuf_read(sb, fd, hint);
348 close(fd);
349 if (len < 0)
350 return -1;
351
352 return len;
353 }