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Commit | Line | Data |
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c15648cb | 1 | /* |
359fc2d2 | 2 | * Copyright (C) the libgit2 contributors. All rights reserved. |
c15648cb | 3 | * |
bb742ede VM |
4 | * This file is part of libgit2, distributed under the GNU GPL v2 with |
5 | * a Linking Exception. For full terms see the included COPYING file. | |
c15648cb SP |
6 | */ |
7 | ||
b3be0fc7 | 8 | #include "common.h" |
44908fe7 | 9 | #include "git2/oid.h" |
58519018 | 10 | #include "repository.h" |
c15648cb | 11 | #include <string.h> |
26022f07 | 12 | #include <limits.h> |
c15648cb | 13 | |
af795e49 | 14 | static char to_hex[] = "0123456789abcdef"; |
c15648cb | 15 | |
7c7ff7d1 RB |
16 | static int oid_error_invalid(const char *msg) |
17 | { | |
18 | giterr_set(GITERR_INVALID, "Unable to parse OID - %s", msg); | |
19 | return -1; | |
20 | } | |
21 | ||
d5afc039 | 22 | int git_oid_fromstrn(git_oid *out, const char *str, size_t length) |
c15648cb | 23 | { |
0ef9d2aa | 24 | size_t p; |
e724b058 | 25 | int v; |
d5afc039 VM |
26 | |
27 | if (length > GIT_OID_HEXSZ) | |
13640d1b | 28 | return oid_error_invalid("too long"); |
d5afc039 | 29 | |
e724b058 | 30 | for (p = 0; p < length - 1; p += 2) { |
eb8de747 | 31 | v = (git__fromhex(str[p + 0]) << 4) |
32 | | git__fromhex(str[p + 1]); | |
d5afc039 | 33 | |
c15648cb | 34 | if (v < 0) |
7c7ff7d1 | 35 | return oid_error_invalid("contains invalid characters"); |
d5afc039 VM |
36 | |
37 | out->id[p / 2] = (unsigned char)v; | |
c15648cb | 38 | } |
d5afc039 | 39 | |
e724b058 | 40 | if (length % 2) { |
eb8de747 | 41 | v = (git__fromhex(str[p + 0]) << 4); |
0e058e78 | 42 | if (v < 0) |
7c7ff7d1 | 43 | return oid_error_invalid("contains invalid characters"); |
0e058e78 | 44 | |
e724b058 DI |
45 | out->id[p / 2] = (unsigned char)v; |
46 | p += 2; | |
47 | } | |
48 | ||
6d8d3f19 | 49 | memset(out->id + p / 2, 0, (GIT_OID_HEXSZ - p) / 2); |
d5afc039 | 50 | |
7c7ff7d1 | 51 | return 0; |
c15648cb | 52 | } |
af795e49 | 53 | |
0c8efb38 X |
54 | int git_oid_fromstrp(git_oid *out, const char *str) |
55 | { | |
1e7b7523 | 56 | return git_oid_fromstrn(out, str, strlen(str)); |
0c8efb38 X |
57 | } |
58 | ||
d5afc039 VM |
59 | int git_oid_fromstr(git_oid *out, const char *str) |
60 | { | |
61 | return git_oid_fromstrn(out, str, GIT_OID_HEXSZ); | |
62 | } | |
63 | ||
213e720c | 64 | GIT_INLINE(char) *fmt_one(char *str, unsigned int val) |
af795e49 SP |
65 | { |
66 | *str++ = to_hex[val >> 4]; | |
67 | *str++ = to_hex[val & 0xf]; | |
68 | return str; | |
69 | } | |
70 | ||
660d59ca | 71 | void git_oid_nfmt(char *str, size_t n, const git_oid *oid) |
af795e49 | 72 | { |
660d59ca RB |
73 | size_t i, max_i; |
74 | ||
75 | if (!oid) { | |
76 | memset(str, 0, n); | |
77 | return; | |
78 | } | |
79 | if (n > GIT_OID_HEXSZ) { | |
80 | memset(&str[GIT_OID_HEXSZ], 0, n - GIT_OID_HEXSZ); | |
81 | n = GIT_OID_HEXSZ; | |
82 | } | |
83 | ||
84 | max_i = n / 2; | |
af795e49 | 85 | |
660d59ca | 86 | for (i = 0; i < max_i; i++) |
af795e49 | 87 | str = fmt_one(str, oid->id[i]); |
660d59ca RB |
88 | |
89 | if (n & 1) | |
90 | *str++ = to_hex[oid->id[i] >> 4]; | |
91 | } | |
92 | ||
93 | void git_oid_fmt(char *str, const git_oid *oid) | |
94 | { | |
95 | git_oid_nfmt(str, GIT_OID_HEXSZ, oid); | |
af795e49 SP |
96 | } |
97 | ||
98 | void git_oid_pathfmt(char *str, const git_oid *oid) | |
99 | { | |
0ef9d2aa | 100 | size_t i; |
af795e49 SP |
101 | |
102 | str = fmt_one(str, oid->id[0]); | |
103 | *str++ = '/'; | |
104 | for (i = 1; i < sizeof(oid->id); i++) | |
105 | str = fmt_one(str, oid->id[i]); | |
106 | } | |
107 | ||
108 | char *git_oid_allocfmt(const git_oid *oid) | |
109 | { | |
64a47c01 | 110 | char *str = git__malloc(GIT_OID_HEXSZ + 1); |
af795e49 SP |
111 | if (!str) |
112 | return NULL; | |
660d59ca | 113 | git_oid_nfmt(str, GIT_OID_HEXSZ + 1, oid); |
af795e49 SP |
114 | return str; |
115 | } | |
960ca1d7 | 116 | |
5621d809 | 117 | char *git_oid_tostr(char *out, size_t n, const git_oid *oid) |
960ca1d7 | 118 | { |
8fe713cc | 119 | if (!out || n == 0) |
960ca1d7 RJ |
120 | return ""; |
121 | ||
660d59ca RB |
122 | if (n > GIT_OID_HEXSZ + 1) |
123 | n = GIT_OID_HEXSZ + 1; | |
960ca1d7 | 124 | |
660d59ca RB |
125 | git_oid_nfmt(out, n - 1, oid); /* allow room for terminating NUL */ |
126 | out[n - 1] = '\0'; | |
960ca1d7 RJ |
127 | |
128 | return out; | |
129 | } | |
130 | ||
7c7ff7d1 RB |
131 | int git_oid__parse( |
132 | git_oid *oid, const char **buffer_out, | |
133 | const char *buffer_end, const char *header) | |
58519018 VM |
134 | { |
135 | const size_t sha_len = GIT_OID_HEXSZ; | |
136 | const size_t header_len = strlen(header); | |
137 | ||
720d5472 | 138 | const char *buffer = *buffer_out; |
58519018 VM |
139 | |
140 | if (buffer + (header_len + sha_len + 1) > buffer_end) | |
73fe6a8e | 141 | return -1; |
58519018 VM |
142 | |
143 | if (memcmp(buffer, header, header_len) != 0) | |
73fe6a8e | 144 | return -1; |
58519018 VM |
145 | |
146 | if (buffer[header_len + sha_len] != '\n') | |
73fe6a8e | 147 | return -1; |
58519018 | 148 | |
7c7ff7d1 RB |
149 | if (git_oid_fromstr(oid, buffer + header_len) < 0) |
150 | return -1; | |
58519018 VM |
151 | |
152 | *buffer_out = buffer + (header_len + sha_len + 1); | |
153 | ||
7c7ff7d1 | 154 | return 0; |
58519018 VM |
155 | } |
156 | ||
afeecf4f VM |
157 | void git_oid__writebuf(git_buf *buf, const char *header, const git_oid *oid) |
158 | { | |
159 | char hex_oid[GIT_OID_HEXSZ]; | |
160 | ||
161 | git_oid_fmt(hex_oid, oid); | |
162 | git_buf_puts(buf, header); | |
163 | git_buf_put(buf, hex_oid, GIT_OID_HEXSZ); | |
164 | git_buf_putc(buf, '\n'); | |
165 | } | |
166 | ||
fa48608e | 167 | void git_oid_fromraw(git_oid *out, const unsigned char *raw) |
d12299fe VM |
168 | { |
169 | memcpy(out->id, raw, sizeof(out->id)); | |
170 | } | |
171 | ||
172 | void git_oid_cpy(git_oid *out, const git_oid *src) | |
173 | { | |
174 | memcpy(out->id, src->id, sizeof(out->id)); | |
175 | } | |
176 | ||
b7f167da | 177 | int git_oid_cmp(const git_oid *a, const git_oid *b) |
0c72248b | 178 | { |
b7f167da | 179 | return git_oid__cmp(a, b); |
0c72248b RB |
180 | } |
181 | ||
b8457baa | 182 | int git_oid_ncmp(const git_oid *oid_a, const git_oid *oid_b, size_t len) |
53c0bd81 | 183 | { |
f1d01851 VM |
184 | const unsigned char *a = oid_a->id; |
185 | const unsigned char *b = oid_b->id; | |
186 | ||
8564a022 RB |
187 | if (len > GIT_OID_HEXSZ) |
188 | len = GIT_OID_HEXSZ; | |
189 | ||
190 | while (len > 1) { | |
f1d01851 VM |
191 | if (*a != *b) |
192 | return 1; | |
193 | a++; | |
194 | b++; | |
195 | len -= 2; | |
8564a022 | 196 | }; |
f1d01851 VM |
197 | |
198 | if (len) | |
199 | if ((*a ^ *b) & 0xf0) | |
200 | return 1; | |
201 | ||
202 | return 0; | |
53c0bd81 MP |
203 | } |
204 | ||
aa8f0101 | 205 | int git_oid_strcmp(const git_oid *oid_a, const char *str) |
34aff010 | 206 | { |
aa8f0101 RB |
207 | const unsigned char *a = oid_a->id; |
208 | unsigned char strval; | |
209 | int hexval; | |
210 | ||
211 | for (a = oid_a->id; *str && (a - oid_a->id) < GIT_OID_RAWSZ; ++a) { | |
212 | if ((hexval = git__fromhex(*str++)) < 0) | |
213 | return -1; | |
66566516 | 214 | strval = (unsigned char)(hexval << 4); |
aa8f0101 RB |
215 | if (*str) { |
216 | if ((hexval = git__fromhex(*str++)) < 0) | |
217 | return -1; | |
218 | strval |= hexval; | |
219 | } | |
220 | if (*a != strval) | |
221 | return (*a - strval); | |
222 | } | |
34aff010 | 223 | |
aa8f0101 RB |
224 | return 0; |
225 | } | |
34aff010 | 226 | |
aa8f0101 RB |
227 | int git_oid_streq(const git_oid *oid_a, const char *str) |
228 | { | |
229 | return git_oid_strcmp(oid_a, str) == 0 ? 0 : -1; | |
34aff010 | 230 | } |
231 | ||
74fa4bfa RB |
232 | int git_oid_iszero(const git_oid *oid_a) |
233 | { | |
234 | const unsigned char *a = oid_a->id; | |
235 | unsigned int i; | |
236 | for (i = 0; i < GIT_OID_RAWSZ; ++i, ++a) | |
237 | if (*a != 0) | |
238 | return 0; | |
239 | return 1; | |
240 | } | |
241 | ||
26022f07 VM |
242 | typedef short node_index; |
243 | ||
244 | typedef union { | |
245 | const char *tail; | |
246 | node_index children[16]; | |
247 | } trie_node; | |
248 | ||
249 | struct git_oid_shorten { | |
250 | trie_node *nodes; | |
251 | size_t node_count, size; | |
252 | int min_length, full; | |
253 | }; | |
254 | ||
255 | static int resize_trie(git_oid_shorten *self, size_t new_size) | |
256 | { | |
3286c408 | 257 | self->nodes = git__realloc(self->nodes, new_size * sizeof(trie_node)); |
7c7ff7d1 | 258 | GITERR_CHECK_ALLOC(self->nodes); |
26022f07 VM |
259 | |
260 | if (new_size > self->size) { | |
261 | memset(&self->nodes[self->size], 0x0, (new_size - self->size) * sizeof(trie_node)); | |
262 | } | |
263 | ||
264 | self->size = new_size; | |
7c7ff7d1 | 265 | return 0; |
26022f07 VM |
266 | } |
267 | ||
268 | static trie_node *push_leaf(git_oid_shorten *os, node_index idx, int push_at, const char *oid) | |
269 | { | |
270 | trie_node *node, *leaf; | |
271 | node_index idx_leaf; | |
272 | ||
273 | if (os->node_count >= os->size) { | |
7c7ff7d1 | 274 | if (resize_trie(os, os->size * 2) < 0) |
26022f07 VM |
275 | return NULL; |
276 | } | |
277 | ||
278 | idx_leaf = (node_index)os->node_count++; | |
279 | ||
52f537e9 | 280 | if (os->node_count == SHRT_MAX) { |
26022f07 | 281 | os->full = 1; |
52f537e9 AW |
282 | return NULL; |
283 | } | |
26022f07 VM |
284 | |
285 | node = &os->nodes[idx]; | |
286 | node->children[push_at] = -idx_leaf; | |
287 | ||
288 | leaf = &os->nodes[idx_leaf]; | |
289 | leaf->tail = oid; | |
290 | ||
291 | return node; | |
292 | } | |
293 | ||
294 | git_oid_shorten *git_oid_shorten_new(size_t min_length) | |
295 | { | |
296 | git_oid_shorten *os; | |
297 | ||
44ef8b1b RB |
298 | assert((size_t)((int)min_length) == min_length); |
299 | ||
7c7ff7d1 | 300 | os = git__calloc(1, sizeof(git_oid_shorten)); |
26022f07 VM |
301 | if (os == NULL) |
302 | return NULL; | |
303 | ||
7c7ff7d1 | 304 | if (resize_trie(os, 16) < 0) { |
3286c408 | 305 | git__free(os); |
26022f07 VM |
306 | return NULL; |
307 | } | |
308 | ||
309 | os->node_count = 1; | |
44ef8b1b | 310 | os->min_length = (int)min_length; |
26022f07 VM |
311 | |
312 | return os; | |
313 | } | |
314 | ||
315 | void git_oid_shorten_free(git_oid_shorten *os) | |
316 | { | |
3286c408 VM |
317 | git__free(os->nodes); |
318 | git__free(os); | |
26022f07 VM |
319 | } |
320 | ||
321 | ||
322 | /* | |
323 | * What wizardry is this? | |
324 | * | |
325 | * This is just a memory-optimized trie: basically a very fancy | |
326 | * 16-ary tree, which is used to store the prefixes of the OID | |
327 | * strings. | |
328 | * | |
329 | * Read more: http://en.wikipedia.org/wiki/Trie | |
330 | * | |
331 | * Magic that happens in this method: | |
332 | * | |
333 | * - Each node in the trie is an union, so it can work both as | |
334 | * a normal node, or as a leaf. | |
335 | * | |
336 | * - Each normal node points to 16 children (one for each possible | |
337 | * character in the oid). This is *not* stored in an array of | |
932d1baf | 338 | * pointers, because in a 64-bit arch this would be sucking |
826bc4a8 | 339 | * 16*sizeof(void*) = 128 bytes of memory per node, which is |
26022f07 VM |
340 | * insane. What we do is store Node Indexes, and use these indexes |
341 | * to look up each node in the om->index array. These indexes are | |
342 | * signed shorts, so this limits the amount of unique OIDs that | |
343 | * fit in the structure to about 20000 (assuming a more or less uniform | |
344 | * distribution). | |
345 | * | |
346 | * - All the nodes in om->index array are stored contiguously in | |
347 | * memory, and each of them is 32 bytes, so we fit 2x nodes per | |
348 | * cache line. Convenient for speed. | |
349 | * | |
350 | * - To differentiate the leafs from the normal nodes, we store all | |
351 | * the indexes towards a leaf as a negative index (indexes to normal | |
352 | * nodes are positives). When we find that one of the children for | |
353 | * a node has a negative value, that means it's going to be a leaf. | |
354 | * This reduces the amount of indexes we have by two, but also reduces | |
355 | * the size of each node by 1-4 bytes (the amount we would need to | |
356 | * add a `is_leaf` field): this is good because it allows the nodes | |
357 | * to fit cleanly in cache lines. | |
358 | * | |
359 | * - Once we reach an empty children, instead of continuing to insert | |
360 | * new nodes for each remaining character of the OID, we store a pointer | |
361 | * to the tail in the leaf; if the leaf is reached again, we turn it | |
362 | * into a normal node and use the tail to create a new leaf. | |
363 | * | |
364 | * This is a pretty good balance between performance and memory usage. | |
365 | */ | |
366 | int git_oid_shorten_add(git_oid_shorten *os, const char *text_oid) | |
367 | { | |
44ef8b1b RB |
368 | int i; |
369 | bool is_leaf; | |
26022f07 VM |
370 | node_index idx; |
371 | ||
d45e9480 L |
372 | if (os->full) { |
373 | giterr_set(GITERR_INVALID, "Unable to shorten OID - OID set full"); | |
7c7ff7d1 | 374 | return -1; |
d45e9480 | 375 | } |
26022f07 | 376 | |
f0ab9fda VM |
377 | if (text_oid == NULL) |
378 | return os->min_length; | |
379 | ||
26022f07 | 380 | idx = 0; |
44ef8b1b | 381 | is_leaf = false; |
26022f07 VM |
382 | |
383 | for (i = 0; i < GIT_OID_HEXSZ; ++i) { | |
eb8de747 | 384 | int c = git__fromhex(text_oid[i]); |
26022f07 VM |
385 | trie_node *node; |
386 | ||
7c7ff7d1 RB |
387 | if (c == -1) { |
388 | giterr_set(GITERR_INVALID, "Unable to shorten OID - invalid hex value"); | |
389 | return -1; | |
390 | } | |
26022f07 VM |
391 | |
392 | node = &os->nodes[idx]; | |
393 | ||
394 | if (is_leaf) { | |
395 | const char *tail; | |
396 | ||
397 | tail = node->tail; | |
398 | node->tail = NULL; | |
399 | ||
eb8de747 | 400 | node = push_leaf(os, idx, git__fromhex(tail[0]), &tail[1]); |
d45e9480 L |
401 | if (node == NULL) { |
402 | if (os->full) | |
403 | giterr_set(GITERR_INVALID, "Unable to shorten OID - OID set full"); | |
404 | return -1; | |
405 | } | |
26022f07 VM |
406 | } |
407 | ||
408 | if (node->children[c] == 0) { | |
d45e9480 L |
409 | if (push_leaf(os, idx, c, &text_oid[i + 1]) == NULL) { |
410 | if (os->full) | |
411 | giterr_set(GITERR_INVALID, "Unable to shorten OID - OID set full"); | |
7c7ff7d1 | 412 | return -1; |
d45e9480 | 413 | } |
26022f07 VM |
414 | break; |
415 | } | |
416 | ||
417 | idx = node->children[c]; | |
44ef8b1b | 418 | is_leaf = false; |
26022f07 VM |
419 | |
420 | if (idx < 0) { | |
421 | node->children[c] = idx = -idx; | |
44ef8b1b | 422 | is_leaf = true; |
26022f07 VM |
423 | } |
424 | } | |
425 | ||
426 | if (++i > os->min_length) | |
427 | os->min_length = i; | |
428 | ||
429 | return os->min_length; | |
430 | } | |
431 |