test/core/util/parse_hexstring.c

/*
 *
 * Copyright 2015, Google Inc.
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 * modification, are permitted provided that the following conditions are
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 *
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 * notice, this list of conditions and the following disclaimer.
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 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
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 * this software without specific prior written permission.
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 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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#include "test/core/util/parse_hexstring.h"
#include <grpc/support/log.h>

gpr_slice parse_hexstring(const char *hexstring) {
  size_t nibbles = 0;
  const char *p = 0;
  uint8_t *out;
  uint8_t temp;
  gpr_slice slice;

  for (p = hexstring; *p; p++) {
    nibbles += (*p >= '0' && *p <= '9') || (*p >= 'a' && *p <= 'f');
  }

  GPR_ASSERT((nibbles & 1) == 0);

  slice = gpr_slice_malloc(nibbles / 2);
  out = GPR_SLICE_START_PTR(slice);

  nibbles = 0;
  temp = 0;
  for (p = hexstring; *p; p++) {
    if (*p >= '0' && *p <= '9') {
      temp = (uint8_t)(temp << 4) | (uint8_t)(*p - '0');
      nibbles++;
    } else if (*p >= 'a' && *p <= 'f') {
      temp = (uint8_t)(temp << 4) | (uint8_t)(*p - 'a' + 10);
      nibbles++;
    }
    if (nibbles == 2) {
      *out++ = temp;
      nibbles = 0;
    }
  }

  return slice;
}