versioncmp.con commit khash: rename oid helper functions (e465e7c)
   1#include "cache.h"
   2#include "config.h"
   3#include "string-list.h"
   4
   5/*
   6 * versioncmp(): copied from string/strverscmp.c in glibc commit
   7 * ee9247c38a8def24a59eb5cfb7196a98bef8cfdc, reformatted to Git coding
   8 * style. The implementation is under LGPL-2.1 and Git relicenses it
   9 * to GPLv2.
  10 */
  11
  12/*
  13 * states: S_N: normal, S_I: comparing integral part, S_F: comparing
  14 * fractionnal parts, S_Z: idem but with leading Zeroes only
  15 */
  16#define  S_N    0x0
  17#define  S_I    0x3
  18#define  S_F    0x6
  19#define  S_Z    0x9
  20
  21/* result_type: CMP: return diff; LEN: compare using len_diff/diff */
  22#define  CMP    2
  23#define  LEN    3
  24
  25static const struct string_list *prereleases;
  26static int initialized;
  27
  28struct suffix_match {
  29        int conf_pos;
  30        int start;
  31        int len;
  32};
  33
  34static void find_better_matching_suffix(const char *tagname, const char *suffix,
  35                                        int suffix_len, int start, int conf_pos,
  36                                        struct suffix_match *match)
  37{
  38        /*
  39         * A better match either starts earlier or starts at the same offset
  40         * but is longer.
  41         */
  42        int end = match->len < suffix_len ? match->start : match->start-1;
  43        int i;
  44        for (i = start; i <= end; i++)
  45                if (starts_with(tagname + i, suffix)) {
  46                        match->conf_pos = conf_pos;
  47                        match->start = i;
  48                        match->len = suffix_len;
  49                        break;
  50                }
  51}
  52
  53/*
  54 * off is the offset of the first different character in the two strings
  55 * s1 and s2. If either s1 or s2 contains a prerelease suffix containing
  56 * that offset or a suffix ends right before that offset, then that
  57 * string will be forced to be on top.
  58 *
  59 * If both s1 and s2 contain a (different) suffix around that position,
  60 * their order is determined by the order of those two suffixes in the
  61 * configuration.
  62 * If any of the strings contains more than one different suffixes around
  63 * that position, then that string is sorted according to the contained
  64 * suffix which starts at the earliest offset in that string.
  65 * If more than one different contained suffixes start at that earliest
  66 * offset, then that string is sorted according to the longest of those
  67 * suffixes.
  68 *
  69 * Return non-zero if *diff contains the return value for versioncmp()
  70 */
  71static int swap_prereleases(const char *s1,
  72                            const char *s2,
  73                            int off,
  74                            int *diff)
  75{
  76        int i;
  77        struct suffix_match match1 = { -1, off, -1 };
  78        struct suffix_match match2 = { -1, off, -1 };
  79
  80        for (i = 0; i < prereleases->nr; i++) {
  81                const char *suffix = prereleases->items[i].string;
  82                int start, suffix_len = strlen(suffix);
  83                if (suffix_len < off)
  84                        start = off - suffix_len;
  85                else
  86                        start = 0;
  87                find_better_matching_suffix(s1, suffix, suffix_len, start,
  88                                            i, &match1);
  89                find_better_matching_suffix(s2, suffix, suffix_len, start,
  90                                            i, &match2);
  91        }
  92        if (match1.conf_pos == -1 && match2.conf_pos == -1)
  93                return 0;
  94        if (match1.conf_pos == match2.conf_pos)
  95                /* Found the same suffix in both, e.g. "-rc" in "v1.0-rcX"
  96                 * and "v1.0-rcY": the caller should decide based on "X"
  97                 * and "Y". */
  98                return 0;
  99
 100        if (match1.conf_pos >= 0 && match2.conf_pos >= 0)
 101                *diff = match1.conf_pos - match2.conf_pos;
 102        else if (match1.conf_pos >= 0)
 103                *diff = -1;
 104        else /* if (match2.conf_pos >= 0) */
 105                *diff = 1;
 106        return 1;
 107}
 108
 109/*
 110 * Compare S1 and S2 as strings holding indices/version numbers,
 111 * returning less than, equal to or greater than zero if S1 is less
 112 * than, equal to or greater than S2 (for more info, see the texinfo
 113 * doc).
 114 */
 115
 116int versioncmp(const char *s1, const char *s2)
 117{
 118        const unsigned char *p1 = (const unsigned char *) s1;
 119        const unsigned char *p2 = (const unsigned char *) s2;
 120        unsigned char c1, c2;
 121        int state, diff;
 122
 123        /*
 124         * Symbol(s)    0       [1-9]   others
 125         * Transition   (10) 0  (01) d  (00) x
 126         */
 127        static const uint8_t next_state[] = {
 128                /* state    x    d    0  */
 129                /* S_N */  S_N, S_I, S_Z,
 130                /* S_I */  S_N, S_I, S_I,
 131                /* S_F */  S_N, S_F, S_F,
 132                /* S_Z */  S_N, S_F, S_Z
 133        };
 134
 135        static const int8_t result_type[] = {
 136                /* state   x/x  x/d  x/0  d/x  d/d  d/0  0/x  0/d  0/0  */
 137
 138                /* S_N */  CMP, CMP, CMP, CMP, LEN, CMP, CMP, CMP, CMP,
 139                /* S_I */  CMP, -1,  -1,  +1,  LEN, LEN, +1,  LEN, LEN,
 140                /* S_F */  CMP, CMP, CMP, CMP, CMP, CMP, CMP, CMP, CMP,
 141                /* S_Z */  CMP, +1,  +1,  -1,  CMP, CMP, -1,  CMP, CMP
 142        };
 143
 144        if (p1 == p2)
 145                return 0;
 146
 147        c1 = *p1++;
 148        c2 = *p2++;
 149        /* Hint: '0' is a digit too.  */
 150        state = S_N + ((c1 == '0') + (isdigit (c1) != 0));
 151
 152        while ((diff = c1 - c2) == 0) {
 153                if (c1 == '\0')
 154                        return diff;
 155
 156                state = next_state[state];
 157                c1 = *p1++;
 158                c2 = *p2++;
 159                state += (c1 == '0') + (isdigit (c1) != 0);
 160        }
 161
 162        if (!initialized) {
 163                const struct string_list *deprecated_prereleases;
 164                initialized = 1;
 165                prereleases = git_config_get_value_multi("versionsort.suffix");
 166                deprecated_prereleases = git_config_get_value_multi("versionsort.prereleasesuffix");
 167                if (prereleases) {
 168                        if (deprecated_prereleases)
 169                                warning("ignoring versionsort.prereleasesuffix because versionsort.suffix is set");
 170                } else
 171                        prereleases = deprecated_prereleases;
 172        }
 173        if (prereleases && swap_prereleases(s1, s2, (const char *) p1 - s1 - 1,
 174                                            &diff))
 175                return diff;
 176
 177        state = result_type[state * 3 + (((c2 == '0') + (isdigit (c2) != 0)))];
 178
 179        switch (state) {
 180        case CMP:
 181                return diff;
 182
 183        case LEN:
 184                while (isdigit (*p1++))
 185                        if (!isdigit (*p2++))
 186                                return 1;
 187
 188                return isdigit (*p2) ? -1 : diff;
 189
 190        default:
 191                return state;
 192        }
 193}