94 lines
		
	
	
		
			2.1 KiB
		
	
	
	
		
			C
		
	
	
			
		
		
	
	
			94 lines
		
	
	
		
			2.1 KiB
		
	
	
	
		
			C
		
	
	
| #include "cache.h"
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| 
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| /*
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|  * versioncmp(): copied from string/strverscmp.c in glibc commit
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|  * ee9247c38a8def24a59eb5cfb7196a98bef8cfdc, reformatted to Git coding
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|  * style. The implementation is under LGPL-2.1 and Git relicenses it
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|  * to GPLv2.
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|  */
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| 
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| /*
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|  * states: S_N: normal, S_I: comparing integral part, S_F: comparing
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|  * fractionnal parts, S_Z: idem but with leading Zeroes only
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|  */
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| #define  S_N    0x0
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| #define  S_I    0x3
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| #define  S_F    0x6
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| #define  S_Z    0x9
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| 
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| /* result_type: CMP: return diff; LEN: compare using len_diff/diff */
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| #define  CMP    2
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| #define  LEN    3
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| 
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| 
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| /*
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|  * Compare S1 and S2 as strings holding indices/version numbers,
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|  * returning less than, equal to or greater than zero if S1 is less
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|  * than, equal to or greater than S2 (for more info, see the texinfo
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|  * doc).
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|  */
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| 
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| int versioncmp(const char *s1, const char *s2)
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| {
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| 	const unsigned char *p1 = (const unsigned char *) s1;
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| 	const unsigned char *p2 = (const unsigned char *) s2;
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| 	unsigned char c1, c2;
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| 	int state, diff;
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| 
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| 	/*
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| 	 * Symbol(s)    0       [1-9]   others
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| 	 * Transition   (10) 0  (01) d  (00) x
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| 	 */
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| 	static const uint8_t next_state[] = {
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| 		/* state    x    d    0  */
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| 		/* S_N */  S_N, S_I, S_Z,
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| 		/* S_I */  S_N, S_I, S_I,
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| 		/* S_F */  S_N, S_F, S_F,
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| 		/* S_Z */  S_N, S_F, S_Z
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| 	};
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| 
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| 	static const int8_t result_type[] = {
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| 		/* state   x/x  x/d  x/0  d/x  d/d  d/0  0/x  0/d  0/0  */
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| 
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| 		/* S_N */  CMP, CMP, CMP, CMP, LEN, CMP, CMP, CMP, CMP,
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| 		/* S_I */  CMP, -1,  -1,  +1,  LEN, LEN, +1,  LEN, LEN,
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| 		/* S_F */  CMP, CMP, CMP, CMP, CMP, CMP, CMP, CMP, CMP,
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| 		/* S_Z */  CMP, +1,  +1,  -1,  CMP, CMP, -1,  CMP, CMP
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| 	};
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| 
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| 	if (p1 == p2)
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| 		return 0;
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| 
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| 	c1 = *p1++;
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| 	c2 = *p2++;
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| 	/* Hint: '0' is a digit too.  */
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| 	state = S_N + ((c1 == '0') + (isdigit (c1) != 0));
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| 
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| 	while ((diff = c1 - c2) == 0) {
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| 		if (c1 == '\0')
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| 			return diff;
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| 
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| 		state = next_state[state];
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| 		c1 = *p1++;
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| 		c2 = *p2++;
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| 		state += (c1 == '0') + (isdigit (c1) != 0);
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| 	}
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| 
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| 	state = result_type[state * 3 + (((c2 == '0') + (isdigit (c2) != 0)))];
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| 
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| 	switch (state) {
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| 	case CMP:
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| 		return diff;
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| 
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| 	case LEN:
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| 		while (isdigit (*p1++))
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| 			if (!isdigit (*p2++))
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| 				return 1;
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| 
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| 		return isdigit (*p2) ? -1 : diff;
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| 
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| 	default:
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| 		return state;
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| 	}
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| }
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