ucw/ff-varint.c

   1 /*
   2  *      UCW Library: Reading and writing Varints on Fastbuf Streams
   3  *
   4  *      (c) 2013 Tomas Valla <tom@ucw.cz>
   5  *
   6  *      This software may be freely distributed and used according to the terms
   7  *      of the GNU Lesser General Public License.
   8  */
   9
  10 #include <ucw/lib.h>
  11 #include <ucw/fastbuf.h>
  12 #include <ucw/varint.h>
  13 #include <ucw/ff-varint.h>
  14 #include <ucw/ff-binary.h>
  15
  16
  17 u64 bget_varint_slow(struct fastbuf *b, u64 repl)
  18 {
  19         uns h = bgetc(b);
  20         uns l = varint_len(h);
  21         byte buf[l];
  22         buf[0] = h;
  23         l--;
  24         if (breadb(b, buf+1, l) < l)
  25                 return repl;
  26         varint_get(buf, &repl);
  27         return repl;
  28 }
  29
  30 void bput_varint_slow(struct fastbuf *b, u64 u)
  31 {
  32         byte buf[9];
  33         uns l = varint_put(buf, u);
  34         bwrite(b, buf, l);
  35 }
  36
  37 #ifdef TEST
  38
  39 #include <stdlib.h>
  40 #include <stdio.h>
  41
  42 int main(int argc, char **argv)
  43 {
  44         #define FUNCS \
  45                 F(BGET_VARINT) F(BPUT_VARINT)
  46
  47         enum {
  48                 #define F(x) FUNC_##x,
  49                 FUNCS
  50                 #undef F
  51         };
  52         char *names[] = {
  53                 #define F(x) [FUNC_##x] = #x,
  54                 FUNCS
  55                 #undef F
  56         };
  57
  58         uns func = ~0U;
  59         if (argc > 1)
  60                 for (uns i = 0; i < ARRAY_SIZE(names); i++)
  61                         if (!strcasecmp(names[i], argv[1]))
  62                                 func = i;
  63         if (!~func) {
  64                 fprintf(stderr, "Invalid usage!\n");
  65                 return 1;
  66         }
  67
  68         struct fastbuf *b = fbgrow_create(8);
  69         switch (func) {
  70                 uns u;
  71                 u64 r;
  72                 int i;
  73                 case FUNC_BGET_VARINT:
  74                         while (scanf("%x", &u) == 1)
  75                                 bputc(b, u);
  76                         fbgrow_rewind(b);
  77                         while (bpeekc(b) >= 0) {
  78                                 if (btell(b))
  79                                         putchar(' ');
  80                                 r = bget_varint_slow(b, ~0LLU);
  81                                 printf("%lx", r);
  82                         }
  83                         putchar('\n');
  84                         break;
  85
  86                 case FUNC_BPUT_VARINT:
  87                         i = 0;
  88                         while (scanf("%lx", &r) == 1)
  89                                 bput_varint_slow(b, r);
  90                         fbgrow_rewind(b);
  91                         while (bpeekc(b) >= 0) {
  92                                 if (i++)
  93                                         putchar(' ');
  94                                 printf("%02x", bgetc(b));
  95                         }
  96                         putchar('\n');
  97                         break;
  98                 default:
  99                         ASSERT(0);
 100         }
 101
 102         bclose(b);
 103         return 0;
 104 }
 105
 106 #endif