rz_debruijn.h File Reference

#include <rz_types.h>

Go to the source code of this file.

Functions
RZ_API RZ_OWN char *	rz_debruijn_pattern (int size, int start, const char *charset)
	Generate a cyclic pattern following the Debruijn pattern. More...
RZ_API int	rz_debruijn_offset (int start, const char *charset, ut64 value, bool is_big_endian)
	Finds the offset of a given value in a debrujn sequence. More...

Function Documentation

rz_debruijn_offset()

RZ_API int rz_debruijn_offset	(	int	start,
		const char *	charset,
		ut64	value,
		bool	is_big_endian
	)

Finds the offset of a given value in a debrujn sequence.

Parameters

start	Starting offset in the Debruijn pattern
charset	Set of characters to use to generate the sequence
value	Value to search in the sequence
is_big_endian	Endianess of value

Returns

The offset in the sequence where value is found or -1 if not found

Definition at line 112 of file debruijn.c.

                                                                                              {
    int retval = -1;
    // 0x10000 should be long enough. This is how peda works, and nobody complains
    // ... but is slow. Optimize for common case.
    int lens[] = { 0x1000, 0x10000, 0x100000 };
    int j;
 
    if (value == 0) {
        return -1;
    }
 
    for (j = 0; j < RZ_ARRAY_SIZE(lens) && retval == -1; j++) {
        char *pattern = rz_debruijn_pattern(lens[j], start, charset);
        if (!pattern) {
            return -1;
        }
 
        char buf[9];
        buf[8] = '\0';
        if (is_big_endian) {
            rz_write_be64(buf, value);
        } else {
            rz_write_le64(buf, value);
        }
        char *needle;
        for (needle = buf; !*needle; needle++) {
            /* do nothing here */
        }
 
        char *pch = strstr(pattern, needle);
        if (pch) {
            retval = (int)(size_t)(pch - pattern);
        }
        free(pattern);
    }
    return retval;
}

References free(), int, is_big_endian(), RZ_ARRAY_SIZE, rz_debruijn_pattern(), rz_write_be64(), rz_write_le64(), start, and value.

Referenced by rz_main_rz_gg(), and rz_write_debruijn_find_handler().

rz_debruijn_pattern()

RZ_API RZ_OWN char* rz_debruijn_pattern	(	int	size,
		int	start,
		const char *	charset
	)

Generate a cyclic pattern following the Debruijn pattern.

Generate a cyclic pattern of desired size, and charset, return with starting offset of start.

For example, AAABAACAAD is a sequence of size 10, start 0, charset = debruijn_charset.

Parameters

size	Size of the string to return
start	Starting offset in the Debruijn pattern
charset	Set of characters to use to generate the string

Returns

String of length size allocated on the heap

Definition at line 80 of file debruijn.c.

                                                                                  {
    rz_return_val_if_fail(size >= 0, NULL);
    rz_return_val_if_fail(start >= 0, NULL);
    if (!charset) {
        charset = debruijn_charset;
    }
    char *pat = de_bruijn(charset, 3, size + start);
    if (!pat || start == 0) {
        return pat;
    }
 
    char *pat2 = RZ_NEWS0(char, size + 1);
    if (!pat2) {
        free(pat);
        return NULL;
    }
    size_t len = strlen(pat + start);
    rz_return_val_if_fail(len <= size, NULL);
    strcpy(pat2, pat + start);
    free(pat);
    return pat2;
}

References de_bruijn(), debruijn_charset, free(), len, NULL, RZ_NEWS0, rz_return_val_if_fail, and start.

Referenced by __printPattern(), initialize_stack(), rz_debruijn_offset(), rz_egg_pattern(), and rz_write_debruijn_handler().