330 lines
8.2 KiB
C++
330 lines
8.2 KiB
C++
#include <assert.h>
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#include <string.h>
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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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} delta_t;
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typedef struct {
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int in;
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int to;
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} offshoot_t;
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typedef struct {
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char * str;
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std::vector<delta_t> delta_table;
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std::vector<offshoot_t> catch_table;
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int accepting_state;
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} regex_t;
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#define HALT_AND_CATCH_FIRE -1
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#define HOOK_ALL(from, str, to) do { \
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for (char * s = str; *s != '\00'; s++) { \
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reg.delta_table.push_back( \
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delta_t{state + from, *s, state + to} \
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); \
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} \
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if (do_catch) { \
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reg.catch_table.push_back( \
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{state + from, state + to} \
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); \
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} \
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} while (0)
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#define EAT(n) do { \
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s += n; \
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} while (0)
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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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int escape_1_to_1(const char c, char * whitelist) {
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switch(c) {
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case 't': {
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strcat(whitelist, "\t");
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} return 1;
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case 'n': {
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strcat(whitelist, "\n");
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} return 1;
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case 'r': {
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strcat(whitelist, "\r");
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} return 1;
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case 'b': {
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strcat(whitelist, "\b");
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} return 1;
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case '[': {
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strcat(whitelist, "[");
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} return 1;
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case ']': {
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strcat(whitelist, "]");
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} return 1;
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case '.': {
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strcat(whitelist, ".");
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} return 1;
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case '?': {
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strcat(whitelist, "?");
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} return 1;
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case '+': {
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strcat(whitelist, "+");
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} return 1;
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case '*': {
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strcat(whitelist, "*");
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} return 1;
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case '\\': {
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strcat(whitelist, "\\");
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} return 1;
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}
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return 0;
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}
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int escape_1_to_N(const char c, char * whitelist) {
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switch(c) {
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case 'i': {
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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";
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strcpy(whitelist, 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[] = "@_\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";
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strcpy(whitelist, 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_\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";
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strcpy(whitelist, 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[] = "@_\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";
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strcpy(whitelist, 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/.-_+,#$%~=";
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strcpy(whitelist, keyword_chars);
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return sizeof(keyword_chars)-1;
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};
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case 'F': {
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const char filename_chars[] = "@/.-_+,#$%~=";
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strcpy(whitelist, keyword_chars);
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return sizeof(keyword_chars)-1;
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};
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case 'p': {
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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";
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strcpy(whitelist, 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[] = "@\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";
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strcpy(whitelist, 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(whitelist, 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(whitelist, 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[] = "0123456789abcdefABCDEF";
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strcpy(whitelist, 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(whitelist, 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[] = "0123456789abcdefghijklmnopqrstuwxyzABCDEFGHIJKLMNOPQRSTUWXYZ_";
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strcpy(whitelist, 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[] = "abcdefghijklmnopqrstuwxyzABCDEFGHIJKLMNOPQRSTUWXYZ_";
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strcpy(whitelist, 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[] = "abcdefghijklmnopqrstuwxyzABCDEFGHIJKLMNOPQRSTUWXYZ";
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strcpy(whitelist, 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(whitelist, 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(whitelist, 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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int compile_range(const char * const range,
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char * whitelist) {
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assert(range[0] == '[' && "Not a range.");
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int r = 0;
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const char * s;
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for (s = range+1; *s != ']'; s++) {
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assert(*s != '\00' && "Unclosed range.");
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char c = *s;
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if (escape_1_to_1(c, whitelist)
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|| escape_1_to_N(c, whitelist)) {
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;
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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(whitelist, &cc, 1);
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strncat(whitelist, "\00", 1);
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}
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s += 2;
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} else {
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++r;
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strncat(whitelist, &c, 1);
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strncat(whitelist, "\00", 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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regex_t * regex_compile(const char * const pattern) {
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regex_t * r = new regex_t;
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regex_t ® = *r;
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reg.str = strdup(pattern);
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int state = 0;
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char whitelist[64];
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bool do_catch;
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for (const char * s = pattern; *s != '\00';) {
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// Get token
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assert(!is_quantifier(*pattern) && "Pattern starts with quantifier.");
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whitelist[0] = '\00';
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do_catch = false;
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switch (*s) {
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case '.': {
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do_catch = true;
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} break;
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case '\\': {
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EAT(1);
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if(escape_1_to_1(*s, whitelist)
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|| escape_1_to_N(*s, whitelist)){
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;
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} else {
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assert(!"Unknown escape.");
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}
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} break;
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case '[': {
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EAT(compile_range(s, whitelist)-1);
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} break;
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default: {
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whitelist[0] = *s;
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whitelist[1] = '\00';
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} break;
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}
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EAT(1);
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// Quantifier
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switch (*s) {
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case '?': {
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HOOK_ALL(0, whitelist, +1);
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EAT(1);
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} break;
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case '*': {
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HOOK_ALL(0, whitelist, 0);
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EAT(1);
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} break;
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case '+': {
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HOOK_ALL(0, whitelist, +1);
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state += 1;
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HOOK_ALL(0, whitelist, 0);
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EAT(1);
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} break;
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default: { // Literal
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HOOK_ALL(0, whitelist, +1);
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state += 1;
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} break;
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}
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}
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reg.accepting_state = state;
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return r;
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}
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inline bool catch_(const regex_t * regex,
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int & state) {
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const regex_t ® = *regex;
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for (int i = 0; i < reg.catch_table.size(); i++){
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if (reg.catch_table[i].in == state) {
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state = reg.catch_table[i].to;
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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 regex_assert(const regex_t * const regex,
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const char * const string,
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int state) {
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const regex_t ® = *regex;
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for (const char * s = string; *s != '\00'; s++) {
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// delta
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for (int i = 0; i < reg.delta_table.size(); i++) {
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if ((reg.delta_table[i].in == state)
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&& (reg.delta_table[i].input == *s)) {
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if(regex_assert(regex, s+1, reg.delta_table[i].to)){
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return true;
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}
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}
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}
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if (catch_(regex, state)) {
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continue;
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}
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return false;
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}
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return (state == regex->accepting_state);
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}
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bool regex_search( regex_t * regex,
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const char * const string) {
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if (regex == NULL) {
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return false;
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}
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if (string == NULL) {
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return true;
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}
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return regex_assert(regex, string, 0);
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}
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