619 lines
17 KiB
C
619 lines
17 KiB
C
/* regex.c
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* Copyright 2023 Anon Anonson, Ognjen 'xolatile' Milan Robovic, Emil Williams
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* SPDX Identifier: GPL-3.0-only / NO WARRANTY / NO GUARANTEE */
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#include "regex.h"
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#include <assert.h>
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#include <string.h>
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#include <limits.h>
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#include <stdlib.h>
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#include <stdbool.h>
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// ------------------
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// ### Char tests ###
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// ------------------
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static bool is_quantifier(const char c) {
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for (const char * s = "+*?="; *s != '\00'; s++) {
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if (*s == c) {
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return true;
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}
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}
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return false;
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}
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bool is_magic(const char c) {
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if (is_quantifier(c)) {
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return true;
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}
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for (const char * s = "\\[].^"; *s != '\00'; s++) {
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if (*s == c) {
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return true;
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}
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}
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return false;
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}
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// ----------------------
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// ### Internal Types ###
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// ----------------------
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typedef struct {
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int in;
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char input;
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int to;
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int width;
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} delta_t;
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typedef struct {
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int in;
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int to;
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int width;
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} offshoot_t;
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typedef struct {
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bool * do_catch;
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bool * is_negative;
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// these might be obsolite but im leaving them for now
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bool * do_loop_hook;
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bool * do_follow_hook;
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bool * do_loop_shoot;
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bool * do_follow_shoot;
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// ---
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int * state;
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int * width;
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char * whitelist;
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char * blacklist;
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regex_t * regex;
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} compiler_state;
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// ----------------------------------
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// ### Regex creation/destruction ###
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// ----------------------------------
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static int escape_1_to_1(const char c, compiler_state * cs) {
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char * target_list = (*cs->is_negative) ? cs->blacklist : cs->whitelist;
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switch (c) {
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case 't': {
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strcat(target_list, "\t");
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} return 1;
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case 'n': {
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strcat(target_list, "\n");
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} return 1;
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case 'r': {
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strcat(target_list, "\r");
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} return 1;
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case 'b': {
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strcat(target_list, "\b");
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} return 1;
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case '[': {
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strcat(target_list, "[");
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} return 1;
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case ']': {
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strcat(target_list, "]");
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} return 1;
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case '.': {
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strcat(target_list, ".");
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} return 1;
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case '^': {
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strcat(target_list, "^");
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} return 1;
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case '=': {
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strcat(target_list, "=");
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} return 1;
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case '?': {
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strcat(target_list, "?");
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} return 1;
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case '+': {
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strcat(target_list, "+");
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} return 1;
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case '*': {
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strcat(target_list, "*");
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} return 1;
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case '\\': {
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strcat(target_list, "\\");
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} return 1;
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}
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return 0;
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}
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static int escape_1_to_N(const char c, compiler_state * cs) {
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char * target_list = (*cs->is_negative) ? cs->blacklist : cs->whitelist;
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switch(c) {
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case 'i': {
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const char identifier_chars[] = "@0123456789_"
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"\300\301\302\303\304"
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"\305\306\307\310\311"
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"\312\313\314\315\316"
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"\317\320\321\322\323"
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"\324\325\326\327\330"
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"\331\332\333\334\335"
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"\336\337";
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strcpy(target_list, identifier_chars);
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return sizeof(identifier_chars)-1;
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};
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case 'I': {
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const char identifier_chars[] = "@_"
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"\300\301\302\303\304"
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"\305\306\307\310\311"
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"\312\313\314\315\316"
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"\317\320\321\322\323"
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"\324\325\326\327\330"
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"\331\332\333\334\335"
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"\336\337";
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strcpy(target_list, identifier_chars);
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return sizeof(identifier_chars)-1;
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};
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case 'k': {
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const char keyword_chars[] = "@0123456789_"
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"\300\301\302\303\304"
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"\305\306\307\310\311"
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"\312\313\314\315\316"
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"\317\320\321\322\323"
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"\324\325\326\327\330"
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"\331\332\333\334\335"
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"\336\337";
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strcpy(target_list, keyword_chars);
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return sizeof(keyword_chars)-1;
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};
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case 'K': {
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const char keyword_chars[] = "@_"
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"\300\301\302\303\304"
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"\305\306\307\310\311"
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"\312\313\314\315\316"
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"\317\320\321\322\323"
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"\324\325\326\327\330"
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"\331\332\333\334\335"
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"\336\337";
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strcpy(target_list, keyword_chars);
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return sizeof(keyword_chars)-1;
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};
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case 'f': {
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const char filename_chars[] = "@0123456789/.-_+,#$%~=";
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strcpy(target_list, filename_chars);
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return sizeof(filename_chars)-1;
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};
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case 'F': {
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const char filename_chars[] = "@/.-_+,#$%~=";
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strcpy(target_list, filename_chars);
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return sizeof(filename_chars)-1;
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};
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case 'p': {
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const char printable_chars[] = "@"
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"\241\242\243\244\245"
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"\246\247\250\251\252"
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"\253\254\255\256\257"
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"\260\261\262\263\264"
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"\265\266\267\270\271"
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"\272\273\274\275\276"
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"\277"
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"\300\301\302\303\304"
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"\305\306\307\310\311"
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"\312\313\314\315\316"
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"\317\320\321\322\323"
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"\324\325\326\327\330"
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"\331\332\333\334\335"
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"\336\337";
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strcpy(target_list, printable_chars);
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return sizeof(printable_chars)-1;
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};
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case 'P': {
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const char printable_chars[] = "@"
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"\241\242\243\244\245"
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"\246\247\250\251\252"
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"\253\254\255\256\257"
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"\260\261\262\263\264"
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"\265\266\267\270\271"
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"\272\273\274\275\276"
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"\277"
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"\300\301\302\303\304"
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"\305\306\307\310\311"
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"\312\313\314\315\316"
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"\317\320\321\322\323"
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"\324\325\326\327\330"
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"\331\332\333\334\335"
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"\336\337";
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strcpy(target_list, printable_chars);
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return sizeof(printable_chars)-1;
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};
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case 's': {
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const char whitespace_chars[] = " \t\v\n";
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strcpy(target_list, whitespace_chars);
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return sizeof(whitespace_chars)-1;
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};
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case 'd': {
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const char digit_chars[] = "0123456789";
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strcpy(target_list, digit_chars);
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return sizeof(digit_chars)-1;
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};
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case 'x': {
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const char hex_chars[] = "0123456789"
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"abcdef"
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"ABCDEF";
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strcpy(target_list, hex_chars);
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return sizeof(hex_chars)-1;
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};
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case 'o': {
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const char oct_chars[] = "01234567";
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strcpy(target_list, oct_chars);
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return sizeof(oct_chars)-1;
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};
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case 'w': {
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const char word_chars[] = "0123456789"
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"abcdefghijklmnopqrstuwxyz"
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"ABCDEFGHIJKLMNOPQRSTUWXYZ"
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"_";
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strcpy(target_list, word_chars);
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return sizeof(word_chars)-1;
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};
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case 'h': {
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const char very_word_chars[] = "abcdefghijklmnopqrstuwxyz"
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"ABCDEFGHIJKLMNOPQRSTUWXYZ"
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"_";
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strcpy(target_list, very_word_chars);
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return sizeof(very_word_chars)-1;
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};
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case 'a': {
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const char alpha_chars[] = "abcdefghijklmnopqrstuwxyz"
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"ABCDEFGHIJKLMNOPQRSTUWXYZ";
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strcpy(target_list, alpha_chars);
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return sizeof(alpha_chars)-1;
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};
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case 'l': {
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const char lower_alpha_chars[] = "abcdefghijklmnopqrstuwxyz";
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strcpy(target_list, lower_alpha_chars);
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return sizeof(lower_alpha_chars)-1;
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};
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case 'u': {
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const char upper_alpha_chars[] = "ABCDEFGHIJKLMNOPQRSTUWXYZ";
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strcpy(target_list, upper_alpha_chars);
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return sizeof(upper_alpha_chars)-1;
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};
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}
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return 0;
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}
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static int escape_to_negative(const char c,
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compiler_state * cs) {
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switch (c) {
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case 'D': {
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const char digit_chars[] = "0123456789";
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strcpy(cs->blacklist, digit_chars);
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*cs->is_negative = true;
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return sizeof(digit_chars)-1;
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};
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}
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return 0;
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}
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//static int compile_hologram(char * hologram, char * whitelist) {
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// if (hologram[0] == '\\') {
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// switch (hologram[1]) {
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// case '<': {
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// const char very_word_chars[] = "abcdefghijklmnopqrstuwxyz"
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// "ABCDEFGHIJKLMNOPQRSTUWXYZ"
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// "_";
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// strcat(whitelist, very_word_chars);
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// is_negative = true;
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// HOOK_ALL(0, whitelist, 0)
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// } break;
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// }
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// }
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//}
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static int compile_dot(compiler_state * cs) {
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*cs->do_catch = true;
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return true;
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}
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static int compile_escape(const char c,
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compiler_state * cs) {
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return escape_1_to_1(c, cs)
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|| escape_1_to_N(c, cs)
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|| escape_to_negative(c, cs)
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//|| compile_hologram(*s, whitelist)
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;
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}
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static int compile_range(const char * const range,
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compiler_state * cs) {
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assert((range[0] == '[') && "Not a range.");
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char * target_list = (*cs->is_negative) ? cs->blacklist : cs->whitelist;
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const char * s;
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if (range[1] == '^') {
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*cs->is_negative = true;
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s = range + 2;
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} else {
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s = range + 1;
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}
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for (; *s != ']'; s++) {
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assert((*s != '\0') && "Unclosed range.");
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char c = *s;
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if (c == '\\') {
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s += 1;
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assert(compile_escape(*s, cs) && "Unknown escape.");
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} else if (*(s+1) == '-') {
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char end = *(s+2);
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assert((c < end) && "Endless range.");
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for (char cc = c; cc < end+1; cc++) {
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strncat(target_list, &cc, 1);
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strncat(target_list, "\0", 1);
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}
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s += 2;
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} else {
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strncat(target_list, &c, 1);
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}
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}
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return ((s - range) + 1);
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}
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void filter_blacklist(const char * whitelist,
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const char * blacklist,
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char * filtered) {
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for (; *blacklist != '\0'; blacklist++) {
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for(; *whitelist != '\0'; whitelist++) {
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if (*blacklist == *whitelist) {
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goto long_continue;
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}
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}
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strncat(filtered, blacklist, 1);
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long_continue:;
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}
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}
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#define HALT_AND_CATCH_FIRE INT_MIN
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void HOOK_ALL( int from,
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const char * const str,
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int to,
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compiler_state * cs) {
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int hook_to = (to == HALT_AND_CATCH_FIRE) ? HALT_AND_CATCH_FIRE : ((*cs->state) + to);
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for (const char * s = str; *s != '\0'; s++) {
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delta_t * delta = malloc(sizeof(delta_t));
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delta->in = *cs->state + from;
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delta->input = *s;
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delta->to = hook_to;
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delta->width = *cs->width;
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vector_push(&cs->regex->delta_table,
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&delta);
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}
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}
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void ABSOLUTE_OFFSHOOT(int from,
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int to,
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int width,
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compiler_state * cs) {
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offshoot_t * offshoot = malloc(sizeof(offshoot_t));
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offshoot->in = from;
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offshoot->to = to;
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offshoot->width = width;
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vector_push(&cs->regex->catch_table,
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&offshoot);
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}
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void OFFSHOOT(int from,
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int to,
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int width,
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compiler_state * cs) {
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ABSOLUTE_OFFSHOOT(*cs->state + from, *cs->state + to, width, cs);
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}
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regex_t * regex_compile(const char * const pattern) {
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regex_t * regex = (regex_t *)malloc(sizeof(regex_t));
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regex->str = strdup(pattern);
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vector_init(®ex->delta_table, sizeof(delta_t*), 0UL);
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vector_init(®ex->catch_table, sizeof(offshoot_t*), 0UL);
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int state = 2;
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bool do_catch;
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bool is_negative;
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bool do_loop_hook;
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bool do_follow_hook;
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bool do_loop_shoot;
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bool do_follow_shoot;
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int width;
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char whitelist[64];
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char blacklist[64];
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compiler_state cs = {
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.do_catch = &do_catch,
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.is_negative = &is_negative,
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.state = &state,
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.width = &width,
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.whitelist = whitelist,
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.blacklist = blacklist,
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.regex = regex,
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};
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for (const char * s = pattern; *s != '\00';) {
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// Reset the compiler
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assert(!is_quantifier(*pattern) && "Pattern starts with quantifier.");
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whitelist[0] = '\0';
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blacklist[0] = '\0';
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do_catch = false;
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is_negative = false;
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do_loop_hook = false;
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do_follow_hook = false;
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do_loop_shoot = false;
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do_follow_shoot = false;
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width = 1;
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// Translate char
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switch (*s) {
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case '^': {
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if (s == pattern) {
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ABSOLUTE_OFFSHOOT(0, 2, 0, &cs);
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ABSOLUTE_OFFSHOOT(1, HALT_AND_CATCH_FIRE, 0, &cs);
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}
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whitelist[0] = '\n';
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whitelist[1] = '\0';
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HOOK_ALL(0, whitelist, 0, &cs);
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if (s != pattern) {
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state += 1;
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}
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s += 1;
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goto long_continue;
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} break;
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case '.': {
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compile_dot(&cs);
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} break;
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case '\\': {
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s += 1;
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assert(compile_escape(*s, &cs) && "Unknown escape.");
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} break;
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case '[': {
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s += compile_range(s, &cs) - 1;
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} break;
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default: {
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whitelist[0] = *s;
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whitelist[1] = '\0';
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} break;
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}
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|
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s += 1;
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|
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// Compile with quantifier
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switch (*s) {
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case '=':
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case '?': {
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do_loop_hook = true;
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HOOK_ALL(0, whitelist, +1, &cs);
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if (do_catch || is_negative) {
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OFFSHOOT(0, +1, 1, &cs);
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}
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s += 1;
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} break;
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case '*': {
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HOOK_ALL(0, whitelist, 0, &cs);
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if (do_catch) {
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OFFSHOOT(0, +1, 1, &cs);
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} else if (is_negative) {
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OFFSHOOT(0, 0, 1, &cs);
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}
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s += 1;
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} break;
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case '+': {
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HOOK_ALL(0, whitelist, +1, &cs);
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if (do_catch || is_negative) {
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OFFSHOOT(0, +1, 1, &cs);
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}
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state += 1;
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HOOK_ALL(0, whitelist, 0, &cs);
|
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if (do_catch || is_negative) {
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OFFSHOOT(0, 0, 1, &cs);
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}
|
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s += 1;
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} break;
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default: { // Literal
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HOOK_ALL(0, whitelist, +1, &cs);
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if (do_catch || is_negative) {
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OFFSHOOT(0, +1, 1, &cs);
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}
|
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state += 1;
|
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} break;
|
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}
|
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|
|
// Compile blacklist
|
|
if (*blacklist) {
|
|
char filtered_blacklist[64];
|
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filtered_blacklist[0] = '\0';
|
|
filter_blacklist(whitelist, blacklist, filtered_blacklist);
|
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HOOK_ALL(0, filtered_blacklist, HALT_AND_CATCH_FIRE, &cs);
|
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}
|
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long_continue:;
|
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}
|
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|
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regex->accepting_state = state;
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|
|
|
return regex;
|
|
}
|
|
|
|
int regex_free(regex_t * const regex) {
|
|
free(regex->str);
|
|
vector_free(®ex->delta_table);
|
|
vector_free(®ex->catch_table);
|
|
free(regex);
|
|
return 0;
|
|
}
|
|
|
|
|
|
|
|
// -----------------
|
|
// ### Searching ###
|
|
// -----------------
|
|
static int catch_(const regex_t * const regex,
|
|
int * const state) {
|
|
for (size_t i = 0; i < regex->catch_table.element_count; i++){
|
|
const offshoot_t * const offshoot = *(offshoot_t**)vector_get(®ex->catch_table, i);
|
|
if (offshoot->in == *state) {
|
|
*state = offshoot->to;
|
|
return offshoot->width;
|
|
}
|
|
}
|
|
return HALT_AND_CATCH_FIRE;
|
|
}
|
|
|
|
static int regex_assert(const regex_t * const regex,
|
|
const char * const string,
|
|
const int string_offset,
|
|
int state,
|
|
int width) { // XXX: im pretty sure this is actually redundant and the width should be calculated from string - s
|
|
for (const char * s = (string + string_offset); *s != '\00';) {
|
|
// delta
|
|
for (size_t i = 0; i < regex->delta_table.element_count; i++) {
|
|
const delta_t * const delta = *(delta_t**)vector_get(®ex->delta_table, i);
|
|
if ((delta->in == state)
|
|
&& (delta->input == *s)) {
|
|
int r = regex_assert(regex, string, (s - string) + delta->width, delta->to, width + 1);
|
|
if(r){
|
|
return r;
|
|
}
|
|
}
|
|
}
|
|
|
|
const int catch_width = catch_(regex, &state);
|
|
if ((catch_width != HALT_AND_CATCH_FIRE)
|
|
&& (state != HALT_AND_CATCH_FIRE)) {
|
|
s += catch_width;
|
|
continue;
|
|
}
|
|
|
|
return (state == regex->accepting_state) ? width : false;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
int regex_match( regex_t * regex,
|
|
const char * const string,
|
|
const bool is_start_of_string,
|
|
const int string_offset) { // XXX: remove this useless piece of shit of a parameter nigger
|
|
if (regex == NULL) {
|
|
return false;
|
|
}
|
|
if (string == NULL) {
|
|
return true;
|
|
}
|
|
|
|
const int initial_state = (int)(!is_start_of_string);
|
|
|
|
return regex_assert(regex, string, string_offset, initial_state, 0);
|
|
}
|
|
|
|
bool regex_search( regex_t * regex,
|
|
const char * const string) {
|
|
|
|
return (bool)regex_match(regex, string, true, 0);
|
|
}
|