ceph/src/civetweb/src/third_party/duktape-1.8.0/src-separate/duk_util_bitencoder.c

   1 /*
   2  *  Bitstream encoder.
   3  */
   4
   5 #include "duk_internal.h"
   6
   7 DUK_INTERNAL void duk_be_encode(duk_bitencoder_ctx *ctx, duk_uint32_t data, duk_small_int_t bits) {
   8         duk_uint8_t tmp;
   9
  10         DUK_ASSERT(ctx != NULL);
  11         DUK_ASSERT(ctx->currbits < 8);
  12
  13         /* This limitation would be fixable but adds unnecessary complexity. */
  14         DUK_ASSERT(bits >= 1 && bits <= 24);
  15
  16         ctx->currval = (ctx->currval << bits) | data;
  17         ctx->currbits += bits;
  18
  19         while (ctx->currbits >= 8) {
  20                 if (ctx->offset < ctx->length) {
  21                         tmp = (duk_uint8_t) ((ctx->currval >> (ctx->currbits - 8)) & 0xff);
  22                         ctx->data[ctx->offset++] = tmp;
  23                 } else {
  24                         /* If buffer has been exhausted, truncate bitstream */
  25                         ctx->truncated = 1;
  26                 }
  27
  28                 ctx->currbits -= 8;
  29         }
  30 }
  31
  32 DUK_INTERNAL void duk_be_finish(duk_bitencoder_ctx *ctx) {
  33         duk_small_int_t npad;
  34
  35         DUK_ASSERT(ctx != NULL);
  36         DUK_ASSERT(ctx->currbits < 8);
  37
  38         npad = (duk_small_int_t) (8 - ctx->currbits);
  39         if (npad > 0) {
  40                 duk_be_encode(ctx, 0, npad);
  41         }
  42         DUK_ASSERT(ctx->currbits == 0);
  43 }