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jeger/source/jeger.c

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#ifdef __cplusplus
# pragma GCC diagnostic ignored "-Wc++20-extensions"
#endif
#include "jeger.h"
#include <assert.h>
#include <string.h>
#include <limits.h>
#include <stdlib.h>
#define JEGER_INIT_STATE 2
// ------------------
// ### Char tests ###
// ------------------
static inline
bool mystrchr(const char * const str, const char c){
for (const char * s = str; *s != '\00'; s++) {
if (*s == c) {
return true;
}
}
return false;
}
static inline
bool is_quantifier(const char c) {
return mystrchr("=?+*", c);
}
static inline
bool is_hologram_escape(const char c) {
return mystrchr("<>", c);
}
bool is_magic(const char c) {
return is_quantifier(c)
|| mystrchr("\\[].^", c)
;
}
// -----------------
// ### Char sets ###
// -----------------
#define JEGER_CHAR_SET_at "@"
#define JEGER_CHAR_SET_underscore "_"
#define JEGER_CHAR_SET_lower "abcdefghijklmnopqrstuwxyz"
#define JEGER_CHAR_SET_upper "ABCDEFGHIJKLMNOPQRSTUWXYZ"
#define JEGER_CHAR_SET_digits "0123456789"
#define JEGER_CHAR_SET_octal_digits "01234567"
#define JEGER_CHAR_SET_lower_hex "abcdef"
#define JEGER_CHAR_SET_upper_hex "ABCDEF"
#define JEGER_CHAR_SET_oct_241_to_277 \
"\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"
#define JEGER_CHAR_SET_oct_300_to_337 \
"\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"
#define JEGER_CHAR_SET_file_extra "/.-_+,#$%~="
#define JEGER_CHAR_SET_whitespace " \t\v\n"
static const char JEGER_CHAR_very_word_chars[] =
JEGER_CHAR_SET_underscore
JEGER_CHAR_SET_lower
JEGER_CHAR_SET_upper
;
// ----------------------
// ### Internal Types ###
// ----------------------
typedef struct {
int in;
char input;
int to;
int pattern_width;
int match_width;
} delta_t;
typedef struct {
int in;
int to;
int pattern_width;
int match_width;
} offshoot_t;
enum {
DO_CATCH = 0x00000001 << 0,
IS_NEGATIVE = 0x00000001 << 1,
IS_AT_THE_BEGINNING = 0x00000001 << 2,
FORCE_START_OF_STRING = 0x00000001 << 3,
INCREMENT_STATE = 0x00000001 << 4,
};
typedef struct {
int flags;
int state;
int width;
char * whitelist;
char * blacklist;
} compiler_state;
// ----------------------------------
// ### Regex creation/destruction ###
// ----------------------------------
static const int HALT_AND_CATCH_FIRE = INT_MIN;
#define ASSERT_HALT(a) ((a == HALT_AND_CATCH_FIRE) ? HALT_AND_CATCH_FIRE : (cs->state + a))
static
void HOOK_ALL(const int from,
const char * const str,
const int to,
const compiler_state * const cs,
regex_t * regex) {
for (const char * s = str; *s != '\0'; s++) {
delta_t * delta = (delta_t *)malloc(sizeof(delta_t));
*delta = (delta_t){
.in = cs->state + from,
.input = *s,
.to = ASSERT_HALT(to),
.pattern_width = cs->width,
.match_width = 1,
};
vector_push(&regex->delta_table,
&delta);
}
}
static
void ABSOLUTE_OFFSHOOT(const int from,
const int to,
const int width,
const int match_width,
regex_t * regex) {
offshoot_t * offshoot = (offshoot_t *)malloc(sizeof(offshoot_t));
*offshoot = (offshoot_t){
.in = from,
.to = to,
.pattern_width = width,
.match_width = match_width,
};
vector_push(&regex->catch_table,
&offshoot);
}
static
void OFFSHOOT(const int from,
const int to,
const int width,
const int match_width,
const compiler_state * cs,
regex_t * regex) {
ABSOLUTE_OFFSHOOT(cs->state + from, ASSERT_HALT(to), width, match_width, regex);
}
static
int escape_1_to_1(const char c,
const compiler_state * const cs) {
char * target_list = (cs->flags & 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,
const compiler_state * const cs) {
char * target_list = (cs->flags & IS_NEGATIVE) ? cs->blacklist : cs->whitelist;
switch(c) {
case 'i': {
const char identifier_chars[] = JEGER_CHAR_SET_at
JEGER_CHAR_SET_underscore
JEGER_CHAR_SET_digits
JEGER_CHAR_SET_oct_300_to_337
;
strcpy(target_list, identifier_chars);
return sizeof(identifier_chars)-1;
};
case 'I': {
const char identifier_chars[] = JEGER_CHAR_SET_at
JEGER_CHAR_SET_underscore
JEGER_CHAR_SET_oct_300_to_337
;
strcpy(target_list, identifier_chars);
return sizeof(identifier_chars)-1;
};
case 'k': {
const char keyword_chars[] = JEGER_CHAR_SET_at
JEGER_CHAR_SET_underscore
JEGER_CHAR_SET_digits
JEGER_CHAR_SET_oct_300_to_337
;
strcpy(target_list, keyword_chars);
return sizeof(keyword_chars)-1;
};
case 'K': {
const char keyword_chars[] = JEGER_CHAR_SET_at
JEGER_CHAR_SET_underscore
JEGER_CHAR_SET_oct_300_to_337
;
strcpy(target_list, keyword_chars);
return sizeof(keyword_chars)-1;
};
case 'f': {
const char filename_chars[] = JEGER_CHAR_SET_at
JEGER_CHAR_SET_digits
JEGER_CHAR_SET_file_extra
;
strcpy(target_list, filename_chars);
return sizeof(filename_chars)-1;
};
case 'F': {
const char filename_chars[] = JEGER_CHAR_SET_at
JEGER_CHAR_SET_file_extra
;
strcpy(target_list, filename_chars);
return sizeof(filename_chars)-1;
};
case 'p': {
const char printable_chars[] = JEGER_CHAR_SET_at
JEGER_CHAR_SET_oct_241_to_277
JEGER_CHAR_SET_oct_300_to_337
;
strcpy(target_list, printable_chars);
return sizeof(printable_chars)-1;
};
case 'P': {
const char printable_chars[] = JEGER_CHAR_SET_at
JEGER_CHAR_SET_oct_241_to_277
JEGER_CHAR_SET_oct_300_to_337
;
strcpy(target_list, printable_chars);
return sizeof(printable_chars)-1;
};
case 's': {
const char whitespace_chars[] = JEGER_CHAR_SET_whitespace;
strcpy(target_list, whitespace_chars);
return sizeof(whitespace_chars)-1;
};
case 'd': {
const char digit_chars[] = JEGER_CHAR_SET_digits;
strcpy(target_list, digit_chars);
return sizeof(digit_chars)-1;
};
case 'x': {
const char hex_chars[] = JEGER_CHAR_SET_digits
JEGER_CHAR_SET_lower_hex
JEGER_CHAR_SET_upper_hex
;
strcpy(target_list, hex_chars);
return sizeof(hex_chars)-1;
};
case 'o': {
const char oct_chars[] = JEGER_CHAR_SET_octal_digits;
strcpy(target_list, oct_chars);
return sizeof(oct_chars)-1;
};
case 'w': {
const char word_chars[] = JEGER_CHAR_SET_underscore
JEGER_CHAR_SET_digits
JEGER_CHAR_SET_lower
JEGER_CHAR_SET_upper
;
strcpy(target_list, word_chars);
return sizeof(word_chars)-1;
};
case 'h': {
// #global JEGER_CHAR_very_word_chars
strcpy(target_list, JEGER_CHAR_very_word_chars);
return sizeof(JEGER_CHAR_very_word_chars)-1;
};
case 'a': {
const char alpha_chars[] = JEGER_CHAR_SET_lower
JEGER_CHAR_SET_upper
;
strcpy(target_list, alpha_chars);
return sizeof(alpha_chars)-1;
};
case 'l': {
const char lower_alpha_chars[] = JEGER_CHAR_SET_lower;
strcpy(target_list, lower_alpha_chars);
return sizeof(lower_alpha_chars)-1;
};
case 'u': {
const char upper_alpha_chars[] = JEGER_CHAR_SET_upper;
strcpy(target_list, upper_alpha_chars);
return sizeof(upper_alpha_chars)-1;
};
}
return 0;
}
static inline
int escape_to_negative(const char c,
compiler_state * const cs) {
switch (c) {
case 'D': {
const char digit_chars[] = JEGER_CHAR_SET_digits;
strcpy(cs->blacklist, digit_chars);
cs->flags |= IS_NEGATIVE;
return sizeof(digit_chars)-1;
};
case 'X': {
const char hex_chars[] = JEGER_CHAR_SET_digits
JEGER_CHAR_SET_lower_hex
JEGER_CHAR_SET_upper_hex
;
strcpy(cs->blacklist, hex_chars);
cs->flags |= IS_NEGATIVE;
return sizeof(hex_chars)-1;
};
case 'O': {
const char oct_chars[] = JEGER_CHAR_SET_octal_digits;
strcpy(cs->blacklist, oct_chars);
cs->flags |= IS_NEGATIVE;
return sizeof(oct_chars)-1;
};
case 'W': {
const char word_chars[] = JEGER_CHAR_SET_underscore
JEGER_CHAR_SET_digits
JEGER_CHAR_SET_lower
JEGER_CHAR_SET_upper
;
strcpy(cs->blacklist, word_chars);
cs->flags |= IS_NEGATIVE;
return sizeof(word_chars)-1;
};
case 'L': {
const char lower_alpha_chars[] = JEGER_CHAR_SET_lower;
strcpy(cs->blacklist, lower_alpha_chars);
cs->flags |= IS_NEGATIVE;
return sizeof(lower_alpha_chars)-1;
};
case 'U': {
const char upper_alpha_chars[] = JEGER_CHAR_SET_upper;
strcpy(cs->blacklist, upper_alpha_chars);
cs->flags |= IS_NEGATIVE;
return sizeof(upper_alpha_chars)-1;
};
}
return 0;
}
static inline
int compile_dot(compiler_state * const cs) {
cs->flags |= DO_CATCH;
return true;
}
static inline
int compile_escape(const char c,
compiler_state * const cs) {
return escape_1_to_1(c, cs)
|| escape_1_to_N(c, cs)
|| escape_to_negative(c, cs)
;
}
static
int compile_range(const char * const range,
compiler_state * const cs) {
assert((range[0] == '[') && "Not a range.");
const char * s;
if (range[1] == '^') {
cs->flags |= IS_NEGATIVE;
s = range + 2;
} else {
s = range + 1;
}
char * target_list = (cs->flags & IS_NEGATIVE) ? cs->blacklist : cs->whitelist;
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);
}
static
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:
;
}
}
regex_t * regex_compile(const char * const pattern) {
regex_t * regex = (regex_t *)malloc(sizeof(regex_t));
regex->str = strdup(pattern);
vector_init(&regex->delta_table, sizeof(delta_t*), 0UL);
vector_init(&regex->catch_table, sizeof(offshoot_t*), 0UL);
char whitelist[64];
char blacklist[64];
compiler_state cs = {
.flags = IS_AT_THE_BEGINNING,
.state = JEGER_INIT_STATE,
.whitelist = whitelist,
.blacklist = blacklist,
};
for (const char * s = pattern; *s != '\00';) {
assert(!is_quantifier(*s) && "Pattern starts with quantifier.");
// Reset the compiler
whitelist[0] = '\0';
blacklist[0] = '\0';
cs.flags &= (IS_AT_THE_BEGINNING | FORCE_START_OF_STRING);
cs.width = 1;
// Translate char
switch (*s) {
case '^': {
;
} break;
case '.': {
compile_dot(&cs);
s += 1;
} break;
case '\\': {
s += 1;
if (compile_escape(*s, &cs)) {
s += 1;
} else if (is_hologram_escape(*s)) {
;
} else {
assert("Unknown escape.");
}
} break;
case '[': {
s += compile_range(s, &cs);
} break;
default: { // Literal
whitelist[0] = *s;
whitelist[1] = '\0';
s += 1;
} break;
}
// Compile char
switch (*s) {
// holograms
case '^': {
whitelist[0] = '\n';
whitelist[1] = '\0';
HOOK_ALL(0, whitelist, 0, &cs, regex);
if (cs.flags & IS_AT_THE_BEGINNING) {
cs.flags |= FORCE_START_OF_STRING;
} else {
cs.flags |= INCREMENT_STATE;
}
s += 1;
} break;
case '<': {
cs.flags |= IS_NEGATIVE | INCREMENT_STATE;
if (cs.flags & IS_AT_THE_BEGINNING) {
ABSOLUTE_OFFSHOOT(0, JEGER_INIT_STATE+1, 0, 0, regex);
}
strcat(blacklist, JEGER_CHAR_very_word_chars);
OFFSHOOT(0, 0, 1, 0, &cs, regex);
s += 1;
} break;
case '>': {
cs.flags |= IS_NEGATIVE | INCREMENT_STATE;
strcat(blacklist, JEGER_CHAR_very_word_chars);
OFFSHOOT(0, 1, 0, 0, &cs, regex);
s += 1;
} break;
// quantifiers
case '=':
case '?': {
HOOK_ALL(0, whitelist, +1, &cs, regex);
if ((cs.flags & DO_CATCH)
|| (cs.flags & IS_NEGATIVE)) {
OFFSHOOT(0, +1, 1, 1, &cs, regex);
}
s += 1;
} break;
case '*': {
HOOK_ALL(0, whitelist, 0, &cs, regex);
if ((cs.flags & DO_CATCH)
|| (cs.flags & IS_NEGATIVE)) {
OFFSHOOT(0, 0, 1, 1, &cs, regex);
}
s += 1;
} break;
case '+': {
cs.flags |= INCREMENT_STATE;
HOOK_ALL(0, whitelist, +1, &cs, regex);
if ((cs.flags & DO_CATCH)
|| (cs.flags & IS_NEGATIVE)) {
OFFSHOOT(0, +1, 1, 1, &cs, regex);
}
HOOK_ALL(+1, whitelist, +1, &cs, regex);
if ((cs.flags & DO_CATCH)
|| (cs.flags & IS_NEGATIVE)) {
OFFSHOOT(+1, +1, 1, 1, &cs, regex);
}
s += 1;
} break;
default: { // Literal
cs.flags |= INCREMENT_STATE;
HOOK_ALL(0, whitelist, +1, &cs, regex);
if ((cs.flags & DO_CATCH)
|| (cs.flags & IS_NEGATIVE)) {
OFFSHOOT(0, +1, 1, 1, &cs, regex);
}
} 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, regex);
}
if (cs.flags & INCREMENT_STATE) {
++cs.state;
}
cs.flags &= (~IS_AT_THE_BEGINNING);
}
// Init state hookups
ABSOLUTE_OFFSHOOT(0, JEGER_INIT_STATE, 0, 0, regex);
if (cs.flags & FORCE_START_OF_STRING) {
ABSOLUTE_OFFSHOOT(1, HALT_AND_CATCH_FIRE, 0, 0, regex);
} else {
ABSOLUTE_OFFSHOOT(1, JEGER_INIT_STATE, 0, 0, regex);
}
regex->accepting_state = cs.state;
return regex;
}
int regex_free(regex_t * const regex) {
free(regex->str);
vector_free(&regex->delta_table);
vector_free(&regex->catch_table);
free(regex);
return 0;
}
// -----------------
// ### Searching ###
// -----------------
static
const offshoot_t * catch_table_lookup(const regex_t * const regex,
const int * const state) {
for (size_t i = 0; i < regex->catch_table.element_count; i++){
const offshoot_t * const offshoot = *(offshoot_t**)vector_get(&regex->catch_table, i);
if (offshoot->in == *state) {
return offshoot;
}
}
return NULL;
}
static
bool regex_assert(const regex_t * const regex,
const char * const string,
int state,
match_t * const match) {
if (state == HALT_AND_CATCH_FIRE) {
return false;
}
bool last_stand = false;
bool was_found;
const char * s = string;
LOOP: {
was_found = false;
if (*s == '\0') {
last_stand = true;
goto PERFORM_CATCH_LOOKUP;
}
// Jump search for the correct state
const int jump = 10;
size_t i = jump;
while (i < regex->delta_table.element_count) {
const delta_t * const delta = *(delta_t**)vector_get(&regex->delta_table, i);
if (delta->in >= state) {
break;
}
i += jump;
}
i -= jump;
// Linear search finish up
for (; i < regex->delta_table.element_count; i++) {
const delta_t * const delta = *(delta_t**)vector_get(&regex->delta_table, i);
if (delta->in > state) {
break;
}
if ((delta->in == state)
&& (delta->input == *s)) {
was_found = true;
const int r = regex_assert(regex, s + delta->pattern_width, delta->to, match);
if(r){
if (match->position == -1) {
match->position = (s - string);
}
match->width += delta->match_width;
return r;
}
}
}
}
PERFORM_CATCH_LOOKUP: {
if (!was_found) {
const offshoot_t * const my_catch = catch_table_lookup(regex, &state);
if (my_catch && (!my_catch->pattern_width || !last_stand)) {
state = my_catch->to;
s += my_catch->pattern_width;
match->width += my_catch->match_width;
goto LOOP;
}
}
}
return (state == regex->accepting_state);
}
match_t * regex_match(const regex_t * const regex,
const char * const string,
const bool is_start_of_string) {
vector_t matches;
vector_init(&matches, sizeof(match_t), 0);
match_t * match = (match_t *)malloc(sizeof(match_t));
/* Non-existent regex does not match anything.
* Not to be confused with an empty regex.
*/
if (regex == NULL) {
goto FINISH;
}
// Find all matches
{
const char * s = string;
do {
int initial_state;
initial_state = (int)(!(is_start_of_string && (s == string)));
*match = (match_t){
.position = -1,
.width = 0,
};
if (regex_assert(regex, s, initial_state, match)) {
match->position = (s - string);
vector_push(&matches, match);
s += ((match->width > 0) ? match->width : 1);
match = (match_t *)malloc(sizeof(match_t));
} else {
++s;
}
} while (*s != '\0');
}
FINISH:
// Insert sentinel
*match = (match_t){
.position = -1,
.width = -1,
};
vector_push(&matches, match);
// Hide internal vector usage
const size_t data_size = matches.element_size * matches.element_count;
match_t * r = (match_t *)malloc(data_size);
memcpy(r, matches.data, data_size);
vector_free(&matches);
return r;
}
bool regex_search(const regex_t * const regex,
const char * const string) {
match_t * m = regex_match(regex, string, true);
const bool r = (m->position != -1);
free(m);
return r;
}
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