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/*-------------------------------------------------------------------------
*
* hex.c
* Encoding and decoding routines for hex.
*
* Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* src/common/hex.c
*
*-------------------------------------------------------------------------
*/
#ifndef FRONTEND
#include "postgres.h"
#else
#include "postgres_fe.h"
#endif
#include "common/hex.h"
#ifdef FRONTEND
#include "common/logging.h"
#endif
#include "mb/pg_wchar.h"
static const int8 hexlookup[128] = {
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, -1, -1, -1, -1, -1, -1,
-1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
};
static const char hextbl[] = "0123456789abcdef";
static inline char
get_hex(const char *cp)
{
unsigned char c = (unsigned char) *cp;
int res = -1;
if (c < 127)
res = hexlookup[c];
if (res < 0)
{
#ifdef FRONTEND
pg_log_fatal("invalid hexadecimal digit");
exit(EXIT_FAILURE);
#else
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("invalid hexadecimal digit: \"%.*s\"",
pg_mblen(cp), cp)));
#endif
}
return (char) res;
}
/*
* pg_hex_encode
*
* Encode into hex the given string. Returns the length of the encoded
* string.
*/
uint64
pg_hex_encode(const char *src, size_t srclen, char *dst, size_t dstlen)
{
const char *end = src + srclen;
char *p;
p = dst;
while (src < end)
{
/*
* Leave if there is an overflow in the area allocated for the encoded
* string.
*/
if ((p - dst + 2) > dstlen)
{
#ifdef FRONTEND
pg_log_fatal("overflow of destination buffer in hex encoding");
exit(EXIT_FAILURE);
#else
elog(ERROR, "overflow of destination buffer in hex encoding");
#endif
}
*p++ = hextbl[(*src >> 4) & 0xF];
*p++ = hextbl[*src & 0xF];
src++;
}
Assert((p - dst) <= dstlen);
return p - dst;
}
/*
* pg_hex_decode
*
* Decode the given hex string. Returns the length of the decoded string.
*/
uint64
pg_hex_decode(const char *src, size_t srclen, char *dst, size_t dstlen)
{
const char *s,
*srcend;
char v1,
v2,
*p;
srcend = src + srclen;
s = src;
p = dst;
while (s < srcend)
{
if (*s == ' ' || *s == '\n' || *s == '\t' || *s == '\r')
{
s++;
continue;
}
v1 = get_hex(s) << 4;
s++;
if (s >= srcend)
{
#ifdef FRONTEND
pg_log_fatal("invalid hexadecimal data: odd number of digits");
exit(EXIT_FAILURE);
#else
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("invalid hexadecimal data: odd number of digits")));
#endif
}
v2 = get_hex(s);
s++;
/* overflow check */
if ((p - dst + 1) > dstlen)
{
#ifdef FRONTEND
pg_log_fatal("overflow of destination buffer in hex decoding");
exit(EXIT_FAILURE);
#else
elog(ERROR, "overflow of destination buffer in hex decoding");
#endif
}
*p++ = v1 | v2;
}
Assert((p - dst) <= dstlen);
return p - dst;
}
/*
* pg_hex_enc_len
*
* Returns to caller the length of the string if it were encoded with
* hex based on the length provided by caller. This is useful to estimate
* how large a buffer allocation needs to be done before doing the actual
* encoding.
*/
uint64
pg_hex_enc_len(size_t srclen)
{
return (uint64) srclen << 1;
}
/*
* pg_hex_dec_len
*
* Returns to caller the length of the string if it were to be decoded
* with hex, based on the length given by caller. This is useful to
* estimate how large a buffer allocation needs to be done before doing
* the actual decoding.
*/
uint64
pg_hex_dec_len(size_t srclen)
{
return (uint64) srclen >> 1;
}
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