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/*
* librdkafka - The Apache Kafka C/C++ library
*
* Copyright (c) 2016 Magnus Edenhill
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* 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 A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef _RDVARINT_H
#define _RDVARINT_H
#include "rd.h"
#include "rdbuf.h"
/**
* @name signed varint zig-zag encoder/decoder
* @{
*
*/
/**
* @brief unsigned-varint encodes unsigned integer \p num into buffer
* at \p dst of size \p dstsize.
* @returns the number of bytes written to \p dst, or 0 if not enough space.
*/
static RD_INLINE RD_UNUSED size_t rd_uvarint_enc_u64(char *dst,
size_t dstsize,
uint64_t num) {
size_t of = 0;
do {
if (unlikely(of >= dstsize))
return 0; /* Not enough space */
dst[of++] = (num & 0x7f) | (num > 0x7f ? 0x80 : 0);
num >>= 7;
} while (num);
return of;
}
/**
* @brief encodes a signed integer using zig-zag encoding.
* @sa rd_uvarint_enc_u64
*/
static RD_INLINE RD_UNUSED size_t rd_uvarint_enc_i64(char *dst,
size_t dstsize,
int64_t num) {
return rd_uvarint_enc_u64(dst, dstsize, (num << 1) ^ (num >> 63));
}
static RD_INLINE RD_UNUSED size_t rd_uvarint_enc_i32(char *dst,
size_t dstsize,
int32_t num) {
return rd_uvarint_enc_i64(dst, dstsize, num);
}
/**
* @brief Use on return value from rd_uvarint_dec() to check if
* decoded varint fit the size_t.
*
* @returns 1 on overflow, else 0.
*/
#define RD_UVARINT_OVERFLOW(DEC_RETVAL) (DEC_RETVAL > SIZE_MAX)
/**
* @returns 1 if there were not enough bytes to decode the varint, else 0.
*/
#define RD_UVARINT_UNDERFLOW(DEC_RETVAL) (DEC_RETVAL == 0)
/**
* @param DEC_RETVAL the return value from \c rd_uvarint_dec()
* @returns 1 if varint decoding failed, else 0.
* @warning \p DEC_RETVAL will be evaluated twice.
*/
#define RD_UVARINT_DEC_FAILED(DEC_RETVAL) \
(RD_UVARINT_UNDERFLOW(DEC_RETVAL) || RD_UVARINT_OVERFLOW(DEC_RETVAL))
/**
* @brief Decodes the unsigned-varint in buffer \p src of size \p srcsize
* and stores the decoded unsigned integer in \p nump.
*
* @remark Use RD_UVARINT_OVERFLOW(returnvalue) to check if the varint
* could not fit \p nump, and RD_UVARINT_UNDERFLOW(returnvalue) to
* check if there were not enough bytes available in \p src to
* decode the full varint.
*
* @returns the number of bytes read from \p src.
*/
static RD_INLINE RD_UNUSED size_t rd_uvarint_dec(const char *src,
size_t srcsize,
uint64_t *nump) {
size_t of = 0;
uint64_t num = 0;
int shift = 0;
do {
if (unlikely(srcsize-- == 0))
return 0; /* Underflow */
num |= (uint64_t)(src[(int)of] & 0x7f) << shift;
shift += 7;
} while (src[(int)of++] & 0x80);
*nump = num;
return of;
}
static RD_INLINE RD_UNUSED size_t rd_varint_dec_i64(const char *src,
size_t srcsize,
int64_t *nump) {
uint64_t n;
size_t r;
r = rd_uvarint_dec(src, srcsize, &n);
if (likely(!RD_UVARINT_DEC_FAILED(r)))
*nump = (int64_t)(n >> 1) ^ -(int64_t)(n & 1);
return r;
}
/**
* @returns the maximum encoded size for a type
*/
#define RD_UVARINT_ENC_SIZEOF(TYPE) (sizeof(TYPE) + 1 + (sizeof(TYPE) / 7))
/**
* @returns the encoding size of the value 0
*/
#define RD_UVARINT_ENC_SIZE_0() ((size_t)1)
int unittest_rdvarint(void);
/**@}*/
#endif /* _RDVARINT_H */
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