mirror of https://github.com/postgres/postgres
This is a combined revert of the following commits: -pull/68/headc3826f8, a refactoring piece that moved the hex decoding code to src/common/. This code was cleaned up byaef8948, as it originally included no overflow checks in the same way as the base64 routines in src/common/ used by SCRAM, making it unsafe for its purpose. -aef8948, a more advanced refactoring of the hex encoding/decoding code to src/common/ that added sanity checks on the result buffer for hex decoding and encoding. As reported by Hans Buschmann, those overflow checks are expensive, and it is possible to see a performance drop in the decoding/encoding of bytea or LOs the longer they are. Simple SQLs working on large bytea values show a clear difference in perf profile. -ccf4e27, a cleanup made possible byaef8948. The reverts of all those commits bring back the performance of hex decoding and encoding back to what it was in ~13. Fow now and post-beta3, this is the simplest option. Reported-by: Hans Buschmann Discussion: https://postgr.es/m/1629039545467.80333@nidsa.net Backpatch-through: 14
Michael Paquier
4 years ago
parent
2313dda9d4
commit
2576dcfb76
@ -1,192 +0,0 @@ |
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/*-------------------------------------------------------------------------
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* |
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* hex.c |
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* Encoding and decoding routines for hex. |
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* |
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* Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group |
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* Portions Copyright (c) 1994, Regents of the University of California |
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* |
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* IDENTIFICATION |
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* src/common/hex.c |
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* |
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*------------------------------------------------------------------------- |
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*/ |
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#ifndef FRONTEND |
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#include "postgres.h" |
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#else |
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#include "postgres_fe.h" |
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#endif |
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#include "common/hex.h" |
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#ifdef FRONTEND |
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#include "common/logging.h" |
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#endif |
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#include "mb/pg_wchar.h" |
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static const int8 hexlookup[128] = { |
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, |
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, |
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, |
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0, 1, 2, 3, 4, 5, 6, 7, 8, 9, -1, -1, -1, -1, -1, -1, |
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-1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1, |
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, |
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-1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1, |
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, |
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}; |
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static const char hextbl[] = "0123456789abcdef"; |
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static inline char |
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get_hex(const char *cp) |
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{ |
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unsigned char c = (unsigned char) *cp; |
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int res = -1; |
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if (c < 127) |
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res = hexlookup[c]; |
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if (res < 0) |
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{ |
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#ifdef FRONTEND |
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pg_log_fatal("invalid hexadecimal digit"); |
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exit(EXIT_FAILURE); |
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#else |
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ereport(ERROR, |
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(errcode(ERRCODE_INVALID_PARAMETER_VALUE), |
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errmsg("invalid hexadecimal digit: \"%.*s\"", |
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pg_mblen(cp), cp))); |
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#endif |
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} |
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return (char) res; |
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} |
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/*
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* pg_hex_encode |
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* |
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* Encode into hex the given string. Returns the length of the encoded |
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* string. |
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*/ |
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uint64 |
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pg_hex_encode(const char *src, size_t srclen, char *dst, size_t dstlen) |
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{ |
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const char *end = src + srclen; |
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char *p; |
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p = dst; |
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while (src < end) |
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{ |
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/*
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* Leave if there is an overflow in the area allocated for the encoded |
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* string. |
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*/ |
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if ((p - dst + 2) > dstlen) |
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{ |
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#ifdef FRONTEND |
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pg_log_fatal("overflow of destination buffer in hex encoding"); |
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exit(EXIT_FAILURE); |
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#else |
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elog(ERROR, "overflow of destination buffer in hex encoding"); |
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#endif |
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} |
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*p++ = hextbl[(*src >> 4) & 0xF]; |
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*p++ = hextbl[*src & 0xF]; |
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src++; |
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} |
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Assert((p - dst) <= dstlen); |
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return p - dst; |
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} |
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/*
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* pg_hex_decode |
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* |
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* Decode the given hex string. Returns the length of the decoded string. |
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*/ |
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uint64 |
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pg_hex_decode(const char *src, size_t srclen, char *dst, size_t dstlen) |
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{ |
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const char *s, |
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*srcend; |
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char v1, |
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v2, |
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*p; |
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srcend = src + srclen; |
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s = src; |
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p = dst; |
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while (s < srcend) |
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{ |
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if (*s == ' ' || *s == '\n' || *s == '\t' || *s == '\r') |
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{ |
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s++; |
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continue; |
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} |
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v1 = get_hex(s) << 4; |
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s++; |
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if (s >= srcend) |
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{ |
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#ifdef FRONTEND |
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pg_log_fatal("invalid hexadecimal data: odd number of digits"); |
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exit(EXIT_FAILURE); |
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#else |
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ereport(ERROR, |
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(errcode(ERRCODE_INVALID_PARAMETER_VALUE), |
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errmsg("invalid hexadecimal data: odd number of digits"))); |
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#endif |
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} |
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v2 = get_hex(s); |
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s++; |
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/* overflow check */ |
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if ((p - dst + 1) > dstlen) |
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{ |
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#ifdef FRONTEND |
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pg_log_fatal("overflow of destination buffer in hex decoding"); |
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exit(EXIT_FAILURE); |
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#else |
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elog(ERROR, "overflow of destination buffer in hex decoding"); |
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#endif |
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} |
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*p++ = v1 | v2; |
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} |
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Assert((p - dst) <= dstlen); |
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return p - dst; |
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} |
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/*
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* pg_hex_enc_len |
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* |
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* Returns to caller the length of the string if it were encoded with |
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* hex based on the length provided by caller. This is useful to estimate |
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* how large a buffer allocation needs to be done before doing the actual |
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* encoding. |
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*/ |
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uint64 |
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pg_hex_enc_len(size_t srclen) |
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{ |
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return (uint64) srclen << 1; |
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} |
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/*
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* pg_hex_dec_len |
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* |
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* Returns to caller the length of the string if it were to be decoded |
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* with hex, based on the length given by caller. This is useful to |
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* estimate how large a buffer allocation needs to be done before doing |
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* the actual decoding. |
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*/ |
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uint64 |
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pg_hex_dec_len(size_t srclen) |
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{ |
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return (uint64) srclen >> 1; |
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} |
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@ -1,25 +0,0 @@ |
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/*------------------------------------------------------------------------
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* |
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* hex.h |
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* Encoding and decoding routines for hex strings. |
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* |
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* Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group |
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* Portions Copyright (c) 1994, Regents of the University of California |
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* |
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* IDENTIFICATION |
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* src/include/common/hex.h |
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* |
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*------------------------------------------------------------------------ |
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*/ |
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#ifndef COMMON_HEX_H |
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#define COMMON_HEX_H |
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extern uint64 pg_hex_decode(const char *src, size_t srclen, |
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char *dst, size_t dstlen); |
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extern uint64 pg_hex_encode(const char *src, size_t srclen, |
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char *dst, size_t dstlen); |
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extern uint64 pg_hex_enc_len(size_t srclen); |
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extern uint64 pg_hex_dec_len(size_t srclen); |
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#endif /* COMMON_HEX_H */ |
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