mirror of
https://github.com/git/git
synced 2024-10-29 17:08:46 +00:00
1d73b52f5b
Intern strings so they can be compared by address and stored without wasting space. This library uses the macros in the obj_pool.h and trp.h to create a memory pool for strings and expose an API for handling them. [rr: added API docs] [jn: with some API simplifications, new documentation and tests] Signed-off-by: David Barr <david.barr@cordelta.com> Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
102 lines
2.1 KiB
C
102 lines
2.1 KiB
C
/*
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* Licensed under a two-clause BSD-style license.
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* See LICENSE for details.
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*/
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#include "git-compat-util.h"
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#include "trp.h"
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#include "obj_pool.h"
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#include "string_pool.h"
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static struct trp_root tree = { ~0 };
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struct node {
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uint32_t offset;
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struct trp_node children;
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};
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/* Two memory pools: one for struct node, and another for strings */
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obj_pool_gen(node, struct node, 4096)
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obj_pool_gen(string, char, 4096)
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static char *node_value(struct node *node)
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{
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return node ? string_pointer(node->offset) : NULL;
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}
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static int node_cmp(struct node *a, struct node *b)
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{
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return strcmp(node_value(a), node_value(b));
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}
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/* Build a Treap from the node structure (a trp_node w/ offset) */
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trp_gen(static, tree_, struct node, children, node, node_cmp);
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const char *pool_fetch(uint32_t entry)
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{
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return node_value(node_pointer(entry));
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}
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uint32_t pool_intern(const char *key)
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{
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/* Canonicalize key */
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struct node *match = NULL, *node;
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uint32_t key_len;
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if (key == NULL)
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return ~0;
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key_len = strlen(key) + 1;
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node = node_pointer(node_alloc(1));
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node->offset = string_alloc(key_len);
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strcpy(node_value(node), key);
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match = tree_search(&tree, node);
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if (!match) {
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tree_insert(&tree, node);
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} else {
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node_free(1);
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string_free(key_len);
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node = match;
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}
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return node_offset(node);
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}
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uint32_t pool_tok_r(char *str, const char *delim, char **saveptr)
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{
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char *token = strtok_r(str, delim, saveptr);
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return token ? pool_intern(token) : ~0;
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}
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void pool_print_seq(uint32_t len, uint32_t *seq, char delim, FILE *stream)
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{
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uint32_t i;
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for (i = 0; i < len && ~seq[i]; i++) {
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fputs(pool_fetch(seq[i]), stream);
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if (i < len - 1 && ~seq[i + 1])
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fputc(delim, stream);
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}
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}
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uint32_t pool_tok_seq(uint32_t sz, uint32_t *seq, const char *delim, char *str)
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{
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char *context = NULL;
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uint32_t token = ~0;
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uint32_t length;
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if (sz == 0)
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return ~0;
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if (str)
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token = pool_tok_r(str, delim, &context);
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for (length = 0; length < sz; length++) {
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seq[length] = token;
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if (token == ~0)
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return length;
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token = pool_tok_r(NULL, delim, &context);
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}
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seq[sz - 1] = ~0;
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return sz;
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}
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void pool_reset(void)
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{
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node_reset();
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string_reset();
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}
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