Andrew's git - gitweb.git/blob

a55c23ad57041a6f01b206e940706afb29cf21af
   1#include "cache.h"
   2#include "string-list.h"
   3
   4/*
   5 * versioncmp(): copied from string/strverscmp.c in glibc commit
   6 * ee9247c38a8def24a59eb5cfb7196a98bef8cfdc, reformatted to Git coding
   7 * style. The implementation is under LGPL-2.1 and Git relicenses it
   8 * to GPLv2.
   9 */
  10
  11/*
  12 * states: S_N: normal, S_I: comparing integral part, S_F: comparing
  13 * fractionnal parts, S_Z: idem but with leading Zeroes only
  14 */
  15#define  S_N    0x0
  16#define  S_I    0x3
  17#define  S_F    0x6
  18#define  S_Z    0x9
  19
  20/* result_type: CMP: return diff; LEN: compare using len_diff/diff */
  21#define  CMP    2
  22#define  LEN    3
  23
  24static const struct string_list *prereleases;
  25static int initialized;
  26
  27/*
  28 * off is the offset of the first different character in the two strings
  29 * s1 and s2. If either s1 or s2 contains a prerelease suffix starting
  30 * at that offset, it will be forced to be on top.
  31 *
  32 * If both s1 and s2 contain a (different) suffix at that position,
  33 * their order is determined by the order of those two suffixes in the
  34 * configuration.
  35 *
  36 * Return non-zero if *diff contains the return value for versioncmp()
  37 */
  38static int swap_prereleases(const char *s1,
  39                            const char *s2,
  40                            int off,
  41                            int *diff)
  42{
  43        int i, i1 = -1, i2 = -1;
  44
  45        for (i = 0; i < prereleases->nr; i++) {
  46                const char *suffix = prereleases->items[i].string;
  47                if (i1 == -1 && starts_with(s1 + off, suffix))
  48                        i1 = i;
  49                if (i2 == -1 && starts_with(s2 + off, suffix))
  50                        i2 = i;
  51        }
  52        if (i1 == -1 && i2 == -1)
  53                return 0;
  54        if (i1 >= 0 && i2 >= 0)
  55                *diff = i1 - i2;
  56        else if (i1 >= 0)
  57                *diff = -1;
  58        else /* if (i2 >= 0) */
  59                *diff = 1;
  60        return 1;
  61}
  62
  63/*
  64 * Compare S1 and S2 as strings holding indices/version numbers,
  65 * returning less than, equal to or greater than zero if S1 is less
  66 * than, equal to or greater than S2 (for more info, see the texinfo
  67 * doc).
  68 */
  69
  70int versioncmp(const char *s1, const char *s2)
  71{
  72        const unsigned char *p1 = (const unsigned char *) s1;
  73        const unsigned char *p2 = (const unsigned char *) s2;
  74        unsigned char c1, c2;
  75        int state, diff;
  76
  77        /*
  78         * Symbol(s)    0       [1-9]   others
  79         * Transition   (10) 0  (01) d  (00) x
  80         */
  81        static const uint8_t next_state[] = {
  82                /* state    x    d    0  */
  83                /* S_N */  S_N, S_I, S_Z,
  84                /* S_I */  S_N, S_I, S_I,
  85                /* S_F */  S_N, S_F, S_F,
  86                /* S_Z */  S_N, S_F, S_Z
  87        };
  88
  89        static const int8_t result_type[] = {
  90                /* state   x/x  x/d  x/0  d/x  d/d  d/0  0/x  0/d  0/0  */
  91
  92                /* S_N */  CMP, CMP, CMP, CMP, LEN, CMP, CMP, CMP, CMP,
  93                /* S_I */  CMP, -1,  -1,  +1,  LEN, LEN, +1,  LEN, LEN,
  94                /* S_F */  CMP, CMP, CMP, CMP, CMP, CMP, CMP, CMP, CMP,
  95                /* S_Z */  CMP, +1,  +1,  -1,  CMP, CMP, -1,  CMP, CMP
  96        };
  97
  98        if (p1 == p2)
  99                return 0;
 100
 101        c1 = *p1++;
 102        c2 = *p2++;
 103        /* Hint: '0' is a digit too.  */
 104        state = S_N + ((c1 == '0') + (isdigit (c1) != 0));
 105
 106        while ((diff = c1 - c2) == 0) {
 107                if (c1 == '\0')
 108                        return diff;
 109
 110                state = next_state[state];
 111                c1 = *p1++;
 112                c2 = *p2++;
 113                state += (c1 == '0') + (isdigit (c1) != 0);
 114        }
 115
 116        if (!initialized) {
 117                initialized = 1;
 118                prereleases = git_config_get_value_multi("versionsort.prereleasesuffix");
 119        }
 120        if (prereleases && swap_prereleases(s1, s2, (const char *) p1 - s1 - 1,
 121                                            &diff))
 122                return diff;
 123
 124        state = result_type[state * 3 + (((c2 == '0') + (isdigit (c2) != 0)))];
 125
 126        switch (state) {
 127        case CMP:
 128                return diff;
 129
 130        case LEN:
 131                while (isdigit (*p1++))
 132                        if (!isdigit (*p2++))
 133                                return 1;
 134
 135                return isdigit (*p2) ? -1 : diff;
 136
 137        default:
 138                return state;
 139        }
 140}