kstring.c

   1 #include <stdarg.h>
   2 #include <stdio.h>
   3 #include <ctype.h>
   4 #include <string.h>
   5 #include <stdint.h>
   6 #include "kstring.h"
   7
   8 int ksprintf(kstring_t *s, const char *fmt, ...)
   9 {
  10         va_list ap;
  11         int l;
  12         va_start(ap, fmt);
  13         l = vsnprintf(s->s + s->l, s->m - s->l, fmt, ap); // This line does not work with glibc 2.0. See `man snprintf'.
  14         va_end(ap);
  15         if (l + 1 > s->m - s->l) {
  16                 s->m = s->l + l + 2;
  17                 kroundup32(s->m);
  18                 s->s = (char*)realloc(s->s, s->m);
  19                 va_start(ap, fmt);
  20                 l = vsnprintf(s->s + s->l, s->m - s->l, fmt, ap);
  21         }
  22         va_end(ap);
  23         s->l += l;
  24         return l;
  25 }
  26
  27 // s MUST BE a null terminated string; l = strlen(s)
  28 int ksplit_core(char *s, int delimiter, int *_max, int **_offsets)
  29 {
  30         int i, n, max, last_char, last_start, *offsets, l;
  31         n = 0; max = *_max; offsets = *_offsets;
  32         l = strlen(s);
  33
  34 #define __ksplit_aux do {                                                                                               \
  35                 if (_offsets) {                                                                                                 \
  36                         s[i] = 0;                                                                                                       \
  37                         if (n == max) {                                                                                         \
  38                                 max = max? max<<1 : 2;                                                                  \
  39                                 offsets = (int*)realloc(offsets, sizeof(int) * max);    \
  40                         }                                                                                                                       \
  41                         offsets[n++] = last_start;                                                                      \
  42                 } else ++n;                                                                                                             \
  43         } while (0)
  44
  45         for (i = 0, last_char = last_start = 0; i <= l; ++i) {
  46                 if (delimiter == 0) {
  47                         if (isspace(s[i]) || s[i] == 0) {
  48                                 if (isgraph(last_char)) __ksplit_aux; // the end of a field
  49                         } else {
  50                                 if (isspace(last_char) || last_char == 0) last_start = i;
  51                         }
  52                 } else {
  53                         if (s[i] == delimiter || s[i] == 0) {
  54                                 if (last_char != 0 && last_char != delimiter) __ksplit_aux; // the end of a field
  55                         } else {
  56                                 if (last_char == delimiter || last_char == 0) last_start = i;
  57                         }
  58                 }
  59                 last_char = s[i];
  60         }
  61         *_max = max; *_offsets = offsets;
  62         return n;
  63 }
  64
  65 /**********************
  66  * Boyer-Moore search *
  67  **********************/
  68
  69 // reference: http://www-igm.univ-mlv.fr/~lecroq/string/node14.html
  70 int *ksBM_prep(const uint8_t *pat, int m)
  71 {
  72         int i, *suff, *prep, *bmGs, *bmBc;
  73         prep = calloc(m + 256, 1);
  74         bmGs = prep; bmBc = prep + m;
  75         { // preBmBc()
  76                 for (i = 0; i < 256; ++i) bmBc[i] = m;
  77                 for (i = 0; i < m - 1; ++i) bmBc[pat[i]] = m - i - 1;
  78         }
  79         suff = calloc(m, sizeof(int));
  80         { // suffixes()
  81                 int f = 0, g;
  82                 suff[m - 1] = m;
  83                 g = m - 1;
  84                 for (i = m - 2; i >= 0; --i) {
  85                         if (i > g && suff[i + m - 1 - f] < i - g)
  86                                 suff[i] = suff[i + m - 1 - f];
  87                         else {
  88                                 if (i < g) g = i;
  89                                 f = i;
  90                                 while (g >= 0 && pat[g] == pat[g + m - 1 - f]) --g;
  91                                 suff[i] = f - g;
  92                         }
  93                 }
  94         }
  95         { // preBmGs()
  96                 int j = 0;
  97                 for (i = 0; i < m; ++i) bmGs[i] = m;
  98                 for (i = m - 1; i >= 0; --i)
  99                         if (suff[i] == i + 1)
 100                                 for (; j < m - 1 - i; ++j)
 101                                         if (bmGs[j] == m)
 102                                                 bmGs[j] = m - 1 - i;
 103                 for (i = 0; i <= m - 2; ++i)
 104                         bmGs[m - 1 - suff[i]] = m - 1 - i;
 105         }
 106         free(suff);
 107         return prep;
 108 }
 109
 110 int *ksBM_search(const uint8_t *str, int n, const uint8_t *pat, int m, int *_prep, int *n_matches)
 111 {
 112         int i, j, *prep, *bmGs, *bmBc;
 113         int *matches = 0, mm = 0, nm = 0;
 114         prep = _prep? _prep : ksBM_prep(pat, m);
 115         bmGs = prep; bmBc = prep + m;
 116         j = 0;
 117         while (j <= n - m) {
 118                 for (i = m - 1; i >= 0 && pat[i] == str[i+j]; --i);
 119                 if (i < 0) {
 120                         if (nm == mm) {
 121                                 mm = mm? mm<<1 : 1;
 122                                 matches = realloc(matches, mm * sizeof(int));
 123                         }
 124                         matches[nm++] = j;
 125                         j += bmGs[0];
 126                 } else {
 127                         int max = bmBc[str[i+j]] - m + 1 + i;
 128                         if (max < bmGs[i]) max = bmGs[i];
 129                         j += max;
 130                 }
 131         }
 132         *n_matches = nm;
 133         if (_prep == 0) free(prep);
 134         return matches;
 135 }
 136
 137 #ifdef KSTRING_MAIN
 138 #include <stdio.h>
 139 int main()
 140 {
 141         kstring_t *s;
 142         int *fields, n, i;
 143         s = (kstring_t*)calloc(1, sizeof(kstring_t));
 144         // test ksprintf()
 145         ksprintf(s, " abcdefg:    %d ", 100);
 146         printf("'%s'\n", s->s);
 147         // test ksplit()
 148         fields = ksplit(s, 0, &n);
 149         for (i = 0; i < n; ++i)
 150                 printf("field[%d] = '%s'\n", i, s->s + fields[i]);
 151         free(s);
 152
 153         {
 154                 static char *str = "abcdefgcdg";
 155                 static char *pat = "cd";
 156                 int n, *matches;
 157                 matches = ksBM_search(str, strlen(str), pat, strlen(pat), 0, &n);
 158                 printf("%d: \n", n);
 159                 for (i = 0; i < n; ++i)
 160                         printf("- %d\n", matches[i]);
 161                 free(matches);
 162         }
 163         return 0;
 164 }
 165 #endif