/* Copyright 2011-2014 David Robillard Permission to use, copy, modify, and/or distribute this software for any purpose with or without fee is hereby granted, provided that the above copyright notice and this permission notice appear in all copies. THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ #define _XOPEN_SOURCE 500 #include #include #include #include #include // #define ZIX_TRIE_LINEAR_SEARCH 1 #include "zix/common.h" #include "zix/patree.h" #include "zix/trie_util.h" typedef size_t n_edges_t; typedef struct { const uint8_t* label_first; /* Start of incoming label */ const uint8_t* label_last; /* End of incoming label */ const uint8_t* str; /* String stored at this node */ n_edges_t n_children; /* Number of outgoing edges */ /** Array of first child characters, followed by parallel array of pointers to ZixPatreeNode pointers. */ uint8_t children[]; } ZixPatreeNode; struct _ZixPatree { ZixPatreeNode* root; /* Root of the tree */ }; /** Round `size` up to the next multiple of the word size. */ ZIX_PRIVATE uint32_t zix_patree_pad(uint32_t size) { return (size + sizeof(void*) - 1) & (~(sizeof(void*) - 1)); } ZIX_PRIVATE ZixPatreeNode** zix_patree_get_children(ZixPatreeNode* node) { return (ZixPatreeNode**)(node->children + zix_patree_pad(node->n_children)); } ZIX_PRIVATE ZixPatreeNode** zix_patree_get_child_ptr(ZixPatreeNode* node, n_edges_t index) { return zix_patree_get_children(node) + index; } ZIX_PRIVATE void zix_patree_print_rec(ZixPatreeNode* node, FILE* fd) { if (node->label_first) { size_t edge_label_len = node->label_last - node->label_first + 1; char* edge_label = (char*)calloc(1, edge_label_len + 1); strncpy(edge_label, (const char*)node->label_first, edge_label_len); fprintf(fd, "\t\"%p\" [label=<" "" "", (void*)node, edge_label); free(edge_label); if (node->str) { fprintf(fd, "", node->str); } fprintf(fd, "
%s
\"%s\"
>,shape=\"plaintext\"] ;\n"); } else { fprintf(fd, "\t\"%p\" [label=\"\"] ;\n", (void*)node); } for (n_edges_t i = 0; i < node->n_children; ++i) { ZixPatreeNode* const child = *zix_patree_get_child_ptr(node, i); zix_patree_print_rec(child, fd); fprintf(fd, "\t\"%p\" -> \"%p\" ;\n", (void*)node, (void*)child); } } ZIX_API void zix_patree_print_dot(const ZixPatree* t, FILE* fd) { fprintf(fd, "digraph Patree { \n"); zix_patree_print_rec(t->root, fd); fprintf(fd, "}\n"); } ZIX_PRIVATE size_t zix_patree_node_size(n_edges_t n_children) { return (sizeof(ZixPatreeNode) + zix_patree_pad(n_children) + (n_children * sizeof(ZixPatreeNode*))); } ZIX_PRIVATE ZixPatreeNode* realloc_node(ZixPatreeNode* n, int n_children) { return (ZixPatreeNode*)realloc(n, zix_patree_node_size(n_children)); } ZIX_API ZixPatree* zix_patree_new(void) { ZixPatree* t = (ZixPatree*)calloc(1, sizeof(ZixPatree)); t->root = calloc(1, sizeof(ZixPatreeNode)); return t; } ZIX_PRIVATE void zix_patree_free_rec(ZixPatreeNode* n) { if (n) { for (n_edges_t i = 0; i < n->n_children; ++i) { zix_patree_free_rec(*zix_patree_get_child_ptr(n, i)); } free(n); } } ZIX_API void zix_patree_free(ZixPatree* t) { zix_patree_free_rec(t->root); free(t); } ZIX_PRIVATE inline bool patree_is_leaf(const ZixPatreeNode* n) { return n->n_children == 0; } ZIX_PRIVATE bool patree_find_edge(const ZixPatreeNode* n, const uint8_t c, n_edges_t* const index) { *index = zix_trie_find_key(n->children, n->n_children, c); return *index < n->n_children && n->children[*index] == c; } #ifndef NDEBUG ZIX_PRIVATE bool zix_patree_node_check(ZixPatreeNode* const n) { for (n_edges_t i = 0; i < n->n_children; ++i) { assert(n->children[i] != '\0'); assert(*zix_patree_get_child_ptr(n, i) != NULL); } return true; } #endif ZIX_PRIVATE void patree_add_edge(ZixPatreeNode** n_ptr, const uint8_t* str, const uint8_t* first, const uint8_t* last) { ZixPatreeNode* n = *n_ptr; assert(last >= first); ZixPatreeNode* const child = realloc_node(NULL, 0); child->label_first = first; child->label_last = last; child->str = str; child->n_children = 0; n = realloc_node(n, n->n_children + 1); #ifdef ZIX_TRIE_LINEAR_SEARCH memmove(n->children + zix_patree_pad(n->n_children + 1), n->children + zix_patree_pad(n->n_children), n->n_children * sizeof(ZixPatreeNode*)); ++n->n_children; n->children[n->n_children - 1] = first[0]; *zix_patree_get_child_ptr(n, n->n_children - 1) = child; #else const n_edges_t l = zix_trie_find_key(n->children, n->n_children, first[0]); ZixPatreeNode* m = malloc(zix_patree_node_size(n->n_children + 1)); m->label_first = n->label_first; m->label_last = n->label_last; m->str = n->str; m->n_children = n->n_children + 1; memcpy(m->children, n->children, l); m->children[l] = first[0]; memcpy(m->children + l + 1, n->children + l, n->n_children - l); memcpy(zix_patree_get_child_ptr(m, 0), zix_patree_get_child_ptr(n, 0), l * sizeof(ZixPatreeNode*)); *zix_patree_get_child_ptr(m, l) = child; memcpy(zix_patree_get_child_ptr(m, l + 1), zix_patree_get_child_ptr(n, l), (n->n_children - l) * sizeof(ZixPatreeNode*)); free(n); n = m; #endif *n_ptr = n; assert(zix_patree_node_check(n)); assert(zix_patree_node_check(child)); } /* Split an outgoing edge (to a child) at the given index */ ZIX_PRIVATE void patree_split_edge(ZixPatreeNode** child_ptr, size_t index) { ZixPatreeNode* child = *child_ptr; const size_t grandchild_size = zix_patree_node_size(child->n_children); ZixPatreeNode* const grandchild = realloc_node(NULL, child->n_children); memcpy(grandchild, child, grandchild_size); grandchild->label_first = child->label_first + index; child = realloc_node(child, 1); child->n_children = 1; child->children[0] = grandchild->label_first[0]; *zix_patree_get_child_ptr(child, 0) = grandchild; child->label_last = child->label_first + (index - 1); child->str = NULL; *child_ptr = child; assert(zix_patree_node_check(child)); assert(zix_patree_node_check(grandchild)); } ZIX_PRIVATE ZixStatus patree_insert_internal(ZixPatreeNode** n_ptr, const uint8_t* str, const uint8_t* first, const size_t len) { ZixPatreeNode* n = *n_ptr; n_edges_t child_i; if (patree_find_edge(n, *first, &child_i)) { ZixPatreeNode** child_ptr = zix_patree_get_child_ptr(n, child_i); ZixPatreeNode* child = *child_ptr; const uint8_t* const label_first = child->label_first; const uint8_t* const label_last = child->label_last; const size_t label_len = label_last - label_first + 1; const size_t split_i = zix_trie_change_index(first, label_first, label_len); if (first[split_i]) { if (split_i == label_len) { return patree_insert_internal(child_ptr, str, first + label_len, len); } else { patree_split_edge(child_ptr, split_i); return patree_insert_internal(child_ptr, str, first + split_i, len); } } else if (label_len != split_i) { patree_split_edge(child_ptr, split_i); if (first[split_i]) { patree_add_edge(child_ptr, str, first + split_i, str + len - 1); } else { assert(!(*child_ptr)->str); (*child_ptr)->str = str; } return ZIX_STATUS_SUCCESS; } else if (label_first[split_i] && !child->str) { child->str = str; } else { return ZIX_STATUS_EXISTS; } } else { patree_add_edge(n_ptr, str, first, str + len - 1); } return ZIX_STATUS_SUCCESS; } ZIX_API ZixStatus zix_patree_insert(ZixPatree* t, const char* str, size_t len) { assert(strlen(str) == len); const uint8_t* ustr = (const uint8_t*)str; return patree_insert_internal(&t->root, ustr, ustr, len); } ZIX_API ZixStatus zix_patree_find(const ZixPatree* t, const char* const str, const char** match) { ZixPatreeNode* n = t->root; n_edges_t child_i; const uint8_t* p = (const uint8_t*)str; while (patree_find_edge(n, p[0], &child_i)) { assert(child_i <= n->n_children); ZixPatreeNode* const child = *zix_patree_get_child_ptr(n, child_i); /* Prefix compare search string and label */ const uint8_t* const l = child->label_first; const size_t len = child->label_last - l + 1; const size_t change_index = zix_trie_change_index(p, l, len); p += change_index; if (!*p) { /* Reached end of search string */ if (l + change_index == child->label_last + 1) { /* Reached end of label string as well, match */ *match = (const char*)child->str; return *match ? ZIX_STATUS_SUCCESS : ZIX_STATUS_NOT_FOUND; } else { /* Label string is longer, no match (prefix match) */ return ZIX_STATUS_NOT_FOUND; } } else { /* Didn't reach end of search string */ if (patree_is_leaf(n)) { /* Hit leaf early, no match */ return ZIX_STATUS_NOT_FOUND; } else { /* Match at this node, continue search downwards (or match) */ n = child; } } } return ZIX_STATUS_NOT_FOUND; }