mirror of https://github.com/pbatard/rufus.git
533 lines
14 KiB
C
533 lines
14 KiB
C
/*
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*
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* Mini regex-module inspired by Rob Pike's regex code described in:
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*
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* http://www.cs.princeton.edu/courses/archive/spr09/cos333/beautiful.html
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*
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*
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*
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* Supports:
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* ---------
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* '.' Dot, matches any character
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* '^' Start anchor, matches beginning of string
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* '$' End anchor, matches end of string
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* '*' Asterisk, match zero or more (greedy)
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* '+' Plus, match one or more (greedy)
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* '?' Question, match zero or one (non-greedy)
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* '[abc]' Character class, match if one of {'a', 'b', 'c'}
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* '[^abc]' Inverted class, match if NOT one of {'a', 'b', 'c'} -- NOTE: feature is currently broken!
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* '[a-zA-Z]' Character ranges, the character set of the ranges { a-z | A-Z }
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* '\s' Whitespace, \t \f \r \n \v and spaces
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* '\S' Non-whitespace
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* '\w' Alphanumeric, [a-zA-Z0-9_]
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* '\W' Non-alphanumeric
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* '\d' Digits, [0-9]
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* '\D' Non-digits
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*
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*
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*/
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#include "re.h"
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#include <stdio.h>
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#include <ctype.h>
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/* Definitions: */
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#define MAX_REGEXP_OBJECTS 30 /* Max number of regex symbols in expression. */
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#define MAX_CHAR_CLASS_LEN 40 /* Max length of character-class buffer in. */
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/* ALPHA may be defined for Rufus ALPHA releases => undefine it */
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#ifdef ALPHA
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#undef ALPHA
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#endif
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enum { UNUSED, DOT, BEGIN, END, QUESTIONMARK, STAR, PLUS, CHAR, CHAR_CLASS, INV_CHAR_CLASS, DIGIT, NOT_DIGIT, ALPHA, NOT_ALPHA, WHITESPACE, NOT_WHITESPACE, /* BRANCH */ };
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typedef struct regex_t
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{
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unsigned char type; /* CHAR, STAR, etc. */
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union
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{
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unsigned char ch; /* the character itself */
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unsigned char* ccl; /* OR a pointer to characters in class */
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} u;
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} regex_t;
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/* Private function declarations: */
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static int matchpattern(regex_t* pattern, const char* text, int* matchlength);
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static int matchcharclass(char c, const char* str);
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static int matchstar(regex_t p, regex_t* pattern, const char* text, int* matchlength);
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static int matchplus(regex_t p, regex_t* pattern, const char* text, int* matchlength);
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static int matchone(regex_t p, char c);
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static int matchdigit(char c);
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static int matchalpha(char c);
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static int matchwhitespace(char c);
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static int matchmetachar(char c, const char* str);
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static int matchrange(char c, const char* str);
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static int matchdot(char c);
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static int ismetachar(char c);
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/* Public functions: */
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int re_match(const char* pattern, const char* text, int* matchlength)
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{
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return re_matchp(re_compile(pattern), text, matchlength);
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}
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int re_matchp(re_t pattern, const char* text, int* matchlength)
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{
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*matchlength = 0;
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if (pattern != 0)
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{
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if (pattern[0].type == BEGIN)
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{
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return ((matchpattern(&pattern[1], text, matchlength)) ? 0 : -1);
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}
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else
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{
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int idx = -1;
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do
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{
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idx += 1;
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if (matchpattern(pattern, text, matchlength))
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{
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if (text[0] == '\0')
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return -1;
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return idx;
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}
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}
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while (*text++ != '\0');
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}
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}
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return -1;
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}
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re_t re_compile(const char* pattern)
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{
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/* The sizes of the two static arrays below substantiates the static RAM usage of this module.
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MAX_REGEXP_OBJECTS is the max number of symbols in the expression.
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MAX_CHAR_CLASS_LEN determines the size of buffer for chars in all char-classes in the expression. */
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static regex_t re_compiled[MAX_REGEXP_OBJECTS];
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static unsigned char ccl_buf[MAX_CHAR_CLASS_LEN];
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int ccl_bufidx = 1;
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char c; /* current char in pattern */
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int i = 0; /* index into pattern */
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int j = 0; /* index into re_compiled */
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while (pattern[i] != '\0' && (j+1 < MAX_REGEXP_OBJECTS))
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{
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c = pattern[i];
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switch (c)
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{
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/* Meta-characters: */
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case '^': { re_compiled[j].type = BEGIN; } break;
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case '$': { re_compiled[j].type = END; } break;
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case '.': { re_compiled[j].type = DOT; } break;
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case '*': { re_compiled[j].type = STAR; } break;
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case '+': { re_compiled[j].type = PLUS; } break;
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case '?': { re_compiled[j].type = QUESTIONMARK; } break;
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/* case '|': { re_compiled[j].type = BRANCH; } break; <-- not working properly */
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/* Escaped character-classes (\s \w ...): */
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case '\\':
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{
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if (pattern[i+1] != '\0')
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{
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/* Skip the escape-char '\\' */
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i += 1;
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/* ... and check the next */
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switch (pattern[i])
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{
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/* Meta-character: */
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case 'd': { re_compiled[j].type = DIGIT; } break;
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case 'D': { re_compiled[j].type = NOT_DIGIT; } break;
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case 'w': { re_compiled[j].type = ALPHA; } break;
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case 'W': { re_compiled[j].type = NOT_ALPHA; } break;
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case 's': { re_compiled[j].type = WHITESPACE; } break;
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case 'S': { re_compiled[j].type = NOT_WHITESPACE; } break;
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/* Escaped character, e.g. '.' or '$' */
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default:
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{
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re_compiled[j].type = CHAR;
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re_compiled[j].u.ch = pattern[i];
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} break;
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}
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}
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/* '\\' as last char in pattern -> invalid regular expression. */
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/*
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else
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{
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re_compiled[j].type = CHAR;
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re_compiled[j].ch = pattern[i];
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}
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*/
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} break;
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/* Character class: */
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case '[':
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{
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/* Remember where the char-buffer starts. */
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int buf_begin = ccl_bufidx;
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/* Look-ahead to determine if negated */
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if (pattern[i+1] == '^')
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{
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re_compiled[j].type = INV_CHAR_CLASS;
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i += 1; /* Increment i to avoid including '^' in the char-buffer */
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if (pattern[i+1] == 0) /* incomplete pattern, missing non-zero char after '^' */
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{
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return 0;
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}
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}
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else
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{
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re_compiled[j].type = CHAR_CLASS;
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}
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/* Copy characters inside [..] to buffer */
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while ( (pattern[++i] != ']')
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&& (pattern[i] != '\0')) /* Missing ] */
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{
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if (pattern[i] == '\\')
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{
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if (ccl_bufidx >= MAX_CHAR_CLASS_LEN - 1)
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{
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//fputs("exceeded internal buffer!\n", stderr);
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return 0;
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}
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if (pattern[i+1] == 0) /* incomplete pattern, missing non-zero char after '\\' */
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{
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return 0;
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}
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ccl_buf[ccl_bufidx++] = pattern[i++];
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}
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else if (ccl_bufidx >= MAX_CHAR_CLASS_LEN)
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{
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//fputs("exceeded internal buffer!\n", stderr);
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return 0;
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}
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ccl_buf[ccl_bufidx++] = pattern[i];
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}
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if (ccl_bufidx >= MAX_CHAR_CLASS_LEN)
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{
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/* Catches cases such as [00000000000000000000000000000000000000][ */
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//fputs("exceeded internal buffer!\n", stderr);
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return 0;
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}
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/* Null-terminate string end */
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ccl_buf[ccl_bufidx++] = 0;
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re_compiled[j].u.ccl = &ccl_buf[buf_begin];
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} break;
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/* Other characters: */
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default:
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{
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re_compiled[j].type = CHAR;
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re_compiled[j].u.ch = c;
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} break;
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}
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/* no buffer-out-of-bounds access on invalid patterns - see https://github.com/kokke/tiny-regex-c/commit/1a279e04014b70b0695fba559a7c05d55e6ee90b */
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if (pattern[i] == 0)
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{
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return 0;
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}
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i += 1;
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j += 1;
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}
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/* 'UNUSED' is a sentinel used to indicate end-of-pattern */
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re_compiled[j].type = UNUSED;
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return (re_t) re_compiled;
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}
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void re_print(regex_t* pattern)
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{
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const char* types[] = { "UNUSED", "DOT", "BEGIN", "END", "QUESTIONMARK", "STAR", "PLUS", "CHAR", "CHAR_CLASS", "INV_CHAR_CLASS", "DIGIT", "NOT_DIGIT", "ALPHA", "NOT_ALPHA", "WHITESPACE", "NOT_WHITESPACE", "BRANCH" };
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int i;
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int j;
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char c;
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for (i = 0; i < MAX_REGEXP_OBJECTS; ++i)
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{
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if (pattern[i].type == UNUSED)
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{
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break;
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}
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printf("type: %s", types[pattern[i].type]);
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if (pattern[i].type == CHAR_CLASS || pattern[i].type == INV_CHAR_CLASS)
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{
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printf(" [");
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for (j = 0; j < MAX_CHAR_CLASS_LEN; ++j)
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{
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c = pattern[i].u.ccl[j];
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if ((c == '\0') || (c == ']'))
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{
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break;
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}
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printf("%c", c);
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}
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printf("]");
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}
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else if (pattern[i].type == CHAR)
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{
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printf(" '%c'", pattern[i].u.ch);
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}
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printf("\n");
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}
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}
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/* Private functions: */
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static int matchdigit(char c)
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{
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return isdigit(c);
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}
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static int matchalpha(char c)
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{
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return isalpha(c);
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}
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static int matchwhitespace(char c)
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{
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return isspace(c);
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}
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static int matchalphanum(char c)
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{
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return ((c == '_') || matchalpha(c) || matchdigit(c));
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}
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static int matchrange(char c, const char* str)
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{
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return ( (c != '-')
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&& (str[0] != '\0')
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&& (str[0] != '-')
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&& (str[1] == '-')
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&& (str[2] != '\0')
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&& ( (c >= str[0])
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&& (c <= str[2])));
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}
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static int matchdot(char c)
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{
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#if defined(RE_DOT_MATCHES_NEWLINE) && (RE_DOT_MATCHES_NEWLINE == 1)
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(void)c;
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return 1;
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#else
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return c != '\n' && c != '\r';
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#endif
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}
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static int ismetachar(char c)
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{
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return ((c == 's') || (c == 'S') || (c == 'w') || (c == 'W') || (c == 'd') || (c == 'D'));
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}
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static int matchmetachar(char c, const char* str)
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{
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switch (str[0])
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{
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case 'd': return matchdigit(c);
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case 'D': return !matchdigit(c);
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case 'w': return matchalphanum(c);
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case 'W': return !matchalphanum(c);
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case 's': return matchwhitespace(c);
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case 'S': return !matchwhitespace(c);
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default: return (c == str[0]);
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}
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}
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static int matchcharclass(char c, const char* str)
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{
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do
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{
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if (matchrange(c, str))
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{
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return 1;
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}
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else if (str[0] == '\\')
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{
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/* Escape-char: increment str-ptr and match on next char */
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str += 1;
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if (matchmetachar(c, str))
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{
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return 1;
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}
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else if ((c == str[0]) && !ismetachar(c))
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{
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return 1;
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}
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}
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else if (c == str[0])
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{
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if (c == '-')
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{
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return ((str[-1] == '\0') || (str[1] == '\0'));
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}
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else
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{
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return 1;
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}
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}
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}
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while (*str++ != '\0');
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return 0;
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}
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static int matchone(regex_t p, char c)
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{
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switch (p.type)
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{
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case DOT: return matchdot(c);
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case CHAR_CLASS: return matchcharclass(c, (const char*)p.u.ccl);
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case INV_CHAR_CLASS: return !matchcharclass(c, (const char*)p.u.ccl);
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case DIGIT: return matchdigit(c);
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case NOT_DIGIT: return !matchdigit(c);
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case ALPHA: return matchalphanum(c);
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case NOT_ALPHA: return !matchalphanum(c);
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case WHITESPACE: return matchwhitespace(c);
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case NOT_WHITESPACE: return !matchwhitespace(c);
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default: return (p.u.ch == c);
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}
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}
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static int matchstar(regex_t p, regex_t* pattern, const char* text, int* matchlength)
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{
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int prelen = *matchlength;
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const char* prepoint = text;
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while ((text[0] != '\0') && matchone(p, *text))
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{
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text++;
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(*matchlength)++;
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}
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while (text >= prepoint)
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{
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if (matchpattern(pattern, text--, matchlength))
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return 1;
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(*matchlength)--;
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}
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*matchlength = prelen;
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return 0;
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}
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static int matchplus(regex_t p, regex_t* pattern, const char* text, int* matchlength)
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{
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const char* prepoint = text;
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while ((text[0] != '\0') && matchone(p, *text))
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{
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text++;
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(*matchlength)++;
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}
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while (text > prepoint)
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{
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if (matchpattern(pattern, text--, matchlength))
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return 1;
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(*matchlength)--;
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}
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return 0;
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}
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static int matchquestion(regex_t p, regex_t* pattern, const char* text, int* matchlength)
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{
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if (p.type == UNUSED)
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return 1;
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if (matchpattern(pattern, text, matchlength))
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return 1;
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if (*text && matchone(p, *text++))
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{
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if (matchpattern(pattern, text, matchlength))
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{
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(*matchlength)++;
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return 1;
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}
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}
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return 0;
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}
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#if 0
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/* Recursive matching */
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static int matchpattern(regex_t* pattern, const char* text, int *matchlength)
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{
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int pre = *matchlength;
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if ((pattern[0].type == UNUSED) || (pattern[1].type == QUESTIONMARK))
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{
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return matchquestion(pattern[1], &pattern[2], text, matchlength);
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}
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else if (pattern[1].type == STAR)
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{
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return matchstar(pattern[0], &pattern[2], text, matchlength);
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}
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else if (pattern[1].type == PLUS)
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{
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return matchplus(pattern[0], &pattern[2], text, matchlength);
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}
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else if ((pattern[0].type == END) && pattern[1].type == UNUSED)
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{
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return text[0] == '\0';
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}
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else if ((text[0] != '\0') && matchone(pattern[0], text[0]))
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{
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(*matchlength)++;
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return matchpattern(&pattern[1], text+1);
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}
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else
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{
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*matchlength = pre;
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return 0;
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}
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}
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#else
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/* Iterative matching */
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static int matchpattern(regex_t* pattern, const char* text, int* matchlength)
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{
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int pre = *matchlength;
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do
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{
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if ((pattern[0].type == UNUSED) || (pattern[1].type == QUESTIONMARK))
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{
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return matchquestion(pattern[0], &pattern[2], text, matchlength);
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}
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else if (pattern[1].type == STAR)
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{
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return matchstar(pattern[0], &pattern[2], text, matchlength);
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}
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else if (pattern[1].type == PLUS)
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{
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return matchplus(pattern[0], &pattern[2], text, matchlength);
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}
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else if ((pattern[0].type == END) && pattern[1].type == UNUSED)
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{
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return (text[0] == '\0');
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}
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/* Branching is not working properly
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else if (pattern[1].type == BRANCH)
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{
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return (matchpattern(pattern, text) || matchpattern(&pattern[2], text));
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}
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*/
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(*matchlength)++;
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}
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while ((text[0] != '\0') && matchone(*pattern++, *text++));
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*matchlength = pre;
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return 0;
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}
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#endif
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