cGit-UI for Git Repositories

     5         kx 
     5         kx #ifdef HAVE_CONFIG_H
     5         kx #include <config.h>
     5         kx #endif
     5         kx 
     5         kx #include <stdint.h>
     5         kx #include <string.h>
     5         kx #include <ctype.h>
     5         kx 
     5         kx /* states: S_N: normal, S_I: comparing integral part, S_F: comparing
     5         kx            fractionnal parts, S_Z: idem but with leading Zeroes only */
     5         kx #define  S_N    0x0
     5         kx #define  S_I    0x3
     5         kx #define  S_F    0x6
     5         kx #define  S_Z    0x9
     5         kx 
     5         kx /* result_type: CMP: return diff; LEN: compare using len_diff/diff */
     5         kx #define  CMP    2
     5         kx #define  LEN    3
     5         kx 
     5         kx 
     5         kx /* Compare S1 and S2 as strings holding indices/version numbers,
     5         kx    returning less than, equal to or greater than zero if S1 is less than,
     5         kx    equal to or greater than S2 (for more info, see the texinfo doc).
     5         kx */
     5         kx 
     5         kx int cmp_version( const char *s1, const char *s2 )
     5         kx {
     5         kx   const unsigned char *p1 = (const unsigned char *)s1;
     5         kx   const unsigned char *p2 = (const unsigned char *)s2;
     5         kx 
     5         kx   /* Symbol(s)    0       [1-9]   others
     5         kx      Transition   (10) 0  (01) d  (00) x   */
     5         kx   static const uint8_t next_state[] =
     5         kx   {
     5         kx       /* state    x    d    0  */
     5         kx       /* S_N */  S_N, S_I, S_Z,
     5         kx       /* S_I */  S_N, S_I, S_I,
     5         kx       /* S_F */  S_N, S_F, S_F,
     5         kx       /* S_Z */  S_N, S_F, S_Z
     5         kx   };
     5         kx 
     5         kx   static const int8_t result_type[] =
     5         kx   {
     5         kx       /* state   x/x  x/d  x/0  d/x  d/d  d/0  0/x  0/d  0/0  */
     5         kx 
     5         kx       /* S_N */  CMP, CMP, CMP, CMP, LEN, CMP, CMP, CMP, CMP,
     5         kx       /* S_I */  CMP, -1,  -1,  +1,  LEN, LEN, +1,  LEN, LEN,
     5         kx       /* S_F */  CMP, CMP, CMP, CMP, CMP, CMP, CMP, CMP, CMP,
     5         kx       /* S_Z */  CMP, +1,  +1,  -1,  CMP, CMP, -1,  CMP, CMP
     5         kx   };
     5         kx 
     5         kx   if( p1 == p2 ) return 0;
     5         kx 
     5         kx   unsigned char c1 = *p1++;
     5         kx   unsigned char c2 = *p2++;
     5         kx   /* Hint: '0' is a digit too.  */
     5         kx   int state = S_N + ((c1 == '0') + (isdigit (c1) != 0));
     5         kx 
     5         kx   int diff;
     5         kx   while( (diff = c1 - c2) == 0 )
     5         kx     {
     5         kx       if( c1 == '\0' ) return diff;
     5         kx 
     5         kx       state  = next_state[state];
     5         kx       c1     = *p1++;
     5         kx       c2     = *p2++;
     5         kx       state += (c1 == '0') + (isdigit (c1) != 0);
     5         kx     }
     5         kx 
     5         kx   state = result_type[state * 3 + (((c2 == '0') + (isdigit (c2) != 0)))];
     5         kx 
     5         kx   switch (state)
     5         kx   {
     5         kx     case CMP:
     5         kx       return diff;
     5         kx 
     5         kx     case LEN:
     5         kx       while( isdigit (*p1++) )
     5         kx         if( !isdigit (*p2++) )
     5         kx           return 1;
     5         kx 
     5         kx       return isdigit (*p2) ? -1 : diff;
     5         kx 
     5         kx     default:
     5         kx       return state;
     5         kx   }
     5         kx }
     5         kx 
     5         kx 
     5         kx const char *max_version( const char *s1, const char *s2 )
     5         kx {
     5         kx   if( cmp_version( s1, s2 ) < 0 ) return s2;
     5         kx   else                            return s1;
     5         kx }