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