114 lines
2.1 KiB
C
114 lines
2.1 KiB
C
#include <ctype.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <stdint.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <strings.h>
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#include <unistd.h>
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#define DICTIONARY "/usr/share/dict/words"
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struct trie {
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struct trie *children[26];
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uint8_t terminal;
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};
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void new_trie(struct trie *tree) {
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uint8_t idx = 0;
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for(; idx < 26; idx += 1) {
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tree->children[idx] = NULL;
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}
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tree->terminal = 0;
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}
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void trie_insert(struct trie *tree, const char *str, uint8_t len) {
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struct trie *node = tree;
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uint8_t idx = 0;
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for(; idx < len; idx += 1) {
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uint8_t pos = tolower(str[idx]) - 'a';
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if(node->children[pos] == NULL) {
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void *mem = malloc(sizeof(struct trie));
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if(mem == NULL) {
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fprintf(stderr, "could not allocate memory: %s\n", strerror(errno));
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exit(1);
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}
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node->children[pos] = mem;
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new_trie(node->children[pos]);
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}
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node = node->children[pos];
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}
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node->terminal = 1;
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}
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uint8_t trie_has(struct trie *tree, const char *str, uint8_t len) {
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struct trie *node = tree;
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uint8_t idx = 0;
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for(; idx < len; idx += 1) {
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uint8_t pos = tolower(str[idx]) - 'a';
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if(node->children[pos] == NULL) {
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return 0;
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}
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node = node->children[pos];
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}
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return node->terminal;
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}
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int main(int argc, char **argv) {
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struct trie dict;
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new_trie(&dict);
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int fd = open(DICTIONARY, O_RDONLY);
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if(fd < 0) {
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fprintf(stderr, "could not open %s: %s\n", DICTIONARY, strerror(errno));
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return 1;
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}
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ssize_t bytes = 0;
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char buf[1024] = { 0 };
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char word[128] = { 0 };
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uint8_t len = 0;
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while((bytes = read(fd, buf, sizeof(buf))) > 0) {
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ssize_t idx = 0;
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for(; idx < bytes; idx += 1) {
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if(buf[idx] == '\n') {
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trie_insert(&dict, word, len);
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len = 0;
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bzero(word, sizeof(word));
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} else if(len < sizeof(word)) {
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word[len] = buf[idx];
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len += 1;
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}
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}
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}
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if(bytes < 0) {
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fprintf(stderr, "could not read from %s: %s\n", DICTIONARY, strerror(errno));
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return 1;
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}
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const char *check = "paladin";
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if(argc > 1) {
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check = argv[1];
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}
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return !trie_has(&dict, check, strlen(check));
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}
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