pack.c

   1 #include <stdio.h>
   2 #include <limits.h>
   3
   4 #include "pack.h"
   5
   6 /* Integer packing. */
   7 #define DEFPACK_BE(bits, type) void pack_ ## bits ## _be ( \
   8         unsigned char *out, type v \
   9 ) { \
  10         unsigned i; \
  11         for (i = 1; i <= bits/8; i++) { \
  12                 out[bits/8 - i] = v % 256; \
  13                 v /= 256; \
  14         } \
  15 }
  16
  17 #define DEFPACK_LE(bits, type) void pack_ ## bits ## _le ( \
  18         unsigned char *out, type v \
  19 ) { \
  20         unsigned i; \
  21         for (i = 0; i < bits/8; i++) { \
  22                 out[i] = v % 256; \
  23                 v /= 256; \
  24         } \
  25 }
  26
  27 DEFPACK_BE(16, unsigned short)
  28 DEFPACK_BE(32, unsigned long)
  29 #ifdef ULLONG_MAX
  30 DEFPACK_BE(64, unsigned long long)
  31 #endif
  32
  33 DEFPACK_LE(16, unsigned short)
  34 DEFPACK_LE(32, unsigned long)
  35 #ifdef ULLONG_MAX
  36 DEFPACK_LE(64, unsigned long long)
  37 #endif
  38
  39 #define DEFUNPACK_BE(bits, type) type unpack_ ## bits ## _be ( \
  40         unsigned char *in \
  41 ) { \
  42         type v = 0; \
  43         unsigned i; \
  44         for (i = 0; i < bits/8; i++) { \
  45                 v *= 256; \
  46                 v += in[i]; \
  47         } \
  48         return v; \
  49 }
  50
  51 #define DEFUNPACK_LE(bits, type) type unpack_ ## bits ## _le ( \
  52         unsigned char *in \
  53 ) { \
  54         type v = 0; \
  55         unsigned i; \
  56         for (i = 1; i <= bits/8; i++) { \
  57                 v *= 256; \
  58                 v += in[bits/8 - i]; \
  59         } \
  60         return v; \
  61 }
  62
  63 DEFUNPACK_BE(16, unsigned short)
  64 DEFUNPACK_BE(32, unsigned long)
  65 #ifdef ULLONG_MAX
  66 DEFUNPACK_BE(64, unsigned long long)
  67 #endif
  68
  69 DEFUNPACK_LE(16, unsigned short)
  70 DEFUNPACK_LE(32, unsigned long)
  71 #ifdef ULLONG_MAX
  72 DEFUNPACK_LE(64, unsigned long long)
  73 #endif