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https://git.postgresql.org/git/postgresql.git
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382 lines
7.3 KiB
C
382 lines
7.3 KiB
C
/*
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* encode.c
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* Various data encoding/decoding things.
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*
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* Copyright (c) 2001 Marko Kreen
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $Id: encode.c,v 1.6 2001/05/15 04:45:15 momjian Exp $
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*/
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#include "postgres.h"
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#include "fmgr.h"
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#include "encode.h"
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/*
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* NAMEDATALEN is used for hash names
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*/
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#if NAMEDATALEN < 16
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#error "NAMEDATALEN < 16: too small"
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#endif
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static pg_coding *
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find_coding(pg_coding * hbuf, text *name, int silent);
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static pg_coding *
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pg_find_coding(pg_coding * res, char *name);
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/* SQL function: encode(bytea, text) returns text */
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PG_FUNCTION_INFO_V1(encode);
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Datum
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encode(PG_FUNCTION_ARGS)
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{
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text *arg;
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text *name;
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uint len,
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rlen,
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rlen0;
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pg_coding *c,
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cbuf;
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text *res;
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if (PG_ARGISNULL(0) || PG_ARGISNULL(1))
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PG_RETURN_NULL();
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name = PG_GETARG_TEXT_P(1);
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c = find_coding(&cbuf, name, 0); /* will give error if fails */
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arg = PG_GETARG_TEXT_P(0);
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len = VARSIZE(arg) - VARHDRSZ;
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rlen0 = c->encode_len(len);
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res = (text *) palloc(rlen0 + VARHDRSZ);
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rlen = c->encode(VARDATA(arg), len, VARDATA(res));
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VARATT_SIZEP(res) = rlen + VARHDRSZ;
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if (rlen > rlen0)
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elog(FATAL, "pg_encode: overflow, encode estimate too small");
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PG_FREE_IF_COPY(arg, 0);
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PG_FREE_IF_COPY(name, 1);
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PG_RETURN_TEXT_P(res);
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}
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/* SQL function: decode(text, text) returns bytea */
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PG_FUNCTION_INFO_V1(decode);
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Datum
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decode(PG_FUNCTION_ARGS)
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{
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text *arg;
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text *name;
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uint len,
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rlen,
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rlen0;
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pg_coding *c,
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cbuf;
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text *res;
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if (PG_ARGISNULL(0) || PG_ARGISNULL(1))
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PG_RETURN_NULL();
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name = PG_GETARG_TEXT_P(1);
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c = find_coding(&cbuf, name, 0); /* will give error if fails */
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arg = PG_GETARG_TEXT_P(0);
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len = VARSIZE(arg) - VARHDRSZ;
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rlen0 = c->decode_len(len);
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res = (text *) palloc(rlen0 + VARHDRSZ);
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rlen = c->decode(VARDATA(arg), len, VARDATA(res));
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VARATT_SIZEP(res) = rlen + VARHDRSZ;
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if (rlen > rlen0)
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elog(FATAL, "pg_decode: overflow, decode estimate too small");
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PG_FREE_IF_COPY(arg, 0);
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PG_FREE_IF_COPY(name, 1);
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PG_RETURN_TEXT_P(res);
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}
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static pg_coding *
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find_coding(pg_coding * dst, text *name, int silent)
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{
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pg_coding *p;
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char buf[NAMEDATALEN];
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uint len;
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len = VARSIZE(name) - VARHDRSZ;
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if (len >= NAMEDATALEN)
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{
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if (silent)
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return NULL;
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elog(ERROR, "Encoding type does not exist (name too long)");
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}
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memcpy(buf, VARDATA(name), len);
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buf[len] = 0;
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p = pg_find_coding(dst, buf);
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if (p == NULL && !silent)
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elog(ERROR, "Encoding type does not exist: '%s'", buf);
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return p;
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}
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static char *hextbl = "0123456789abcdef";
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uint
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hex_encode(uint8 *src, uint len, uint8 *dst)
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{
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uint8 *end = src + len;
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while (src < end)
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{
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*dst++ = hextbl[(*src >> 4) & 0xF];
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*dst++ = hextbl[*src & 0xF];
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src++;
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}
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return len * 2;
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}
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/* probably should use lookup table */
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static uint8
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get_hex(char c)
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{
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uint8 res = 0;
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if (c >= '0' && c <= '9')
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res = c - '0';
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else if (c >= 'a' && c <= 'f')
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res = c - 'a' + 10;
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else if (c >= 'A' && c <= 'F')
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res = c - 'A' + 10;
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else
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elog(ERROR, "Bad hex code: '%c'", c);
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return res;
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}
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uint
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hex_decode(uint8 *src, uint len, uint8 *dst)
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{
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uint8 *s,
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*srcend,
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v1,
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v2,
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*p = dst;
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srcend = src + len;
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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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if (s >= srcend)
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elog(ERROR, "hex_decode: invalid data");
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v2 = get_hex(*s++);
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*p++ = v1 | v2;
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}
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return p - dst;
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}
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static unsigned char _base64[] =
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"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
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uint
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b64_encode(uint8 *src, uint len, uint8 *dst)
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{
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uint8 *s,
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*p,
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*end = src + len,
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*lend = dst + 76;
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int pos = 2;
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unsigned long buf = 0;
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s = src;
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p = dst;
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while (s < end)
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{
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buf |= *s << (pos << 3);
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pos--;
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s++;
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/* write it out */
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if (pos < 0)
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{
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*p++ = _base64[(buf >> 18) & 0x3f];
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*p++ = _base64[(buf >> 12) & 0x3f];
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*p++ = _base64[(buf >> 6) & 0x3f];
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*p++ = _base64[buf & 0x3f];
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pos = 2;
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buf = 0;
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}
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if (p >= lend)
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{
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*p++ = '\n';
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lend = p + 76;
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}
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}
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if (pos != 2)
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{
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*p++ = _base64[(buf >> 18) & 0x3f];
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*p++ = _base64[(buf >> 12) & 0x3f];
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*p++ = (pos == 0) ? _base64[(buf >> 6) & 0x3f] : '=';
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*p++ = '=';
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}
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return p - dst;
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}
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/* probably should use lookup table */
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uint
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b64_decode(uint8 *src, uint len, uint8 *dst)
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{
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char *srcend = src + len,
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*s = src;
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uint8 *p = dst;
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char c;
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uint b = 0;
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unsigned long buf = 0;
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int pos = 0,
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end = 0;
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while (s < srcend)
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{
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c = *s++;
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if (c >= 'A' && c <= 'Z')
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b = c - 'A';
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else if (c >= 'a' && c <= 'z')
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b = c - 'a' + 26;
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else if (c >= '0' && c <= '9')
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b = c - '0' + 52;
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else if (c == '+')
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b = 62;
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else if (c == '/')
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b = 63;
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else if (c == '=')
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{
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/* end sequence */
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if (!end)
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{
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if (pos == 2)
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end = 1;
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else if (pos == 3)
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end = 2;
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else
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elog(ERROR, "base64: unexpected '='");
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}
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b = 0;
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}
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else if (c == ' ' || c == '\t' || c == '\n' || c == '\r')
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continue;
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else
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elog(ERROR, "base64: Invalid symbol");
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/* add it to buffer */
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buf = (buf << 6) + b;
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pos++;
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if (pos == 4)
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{
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*p++ = (buf >> 16) & 255;
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if (end == 0 || end > 1)
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*p++ = (buf >> 8) & 255;
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if (end == 0 || end > 2)
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*p++ = buf & 255;
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buf = 0;
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pos = 0;
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}
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}
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if (pos != 0)
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elog(ERROR, "base64: invalid end sequence");
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return p - dst;
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}
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uint
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hex_enc_len(uint srclen)
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{
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return srclen << 1;
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}
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uint
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hex_dec_len(uint srclen)
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{
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return srclen >> 1;
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}
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uint
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b64_enc_len(uint srclen)
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{
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/* 3 bytes will be converted to 4, linefeed after 76 chars */
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return (srclen + 2) * 4 / 3 + srclen / (76 * 3 / 4);
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}
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uint
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b64_dec_len(uint srclen)
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{
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return (srclen * 3) >> 2;
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}
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static pg_coding
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encoding_list[] = {
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{"hex", hex_enc_len, hex_dec_len, hex_encode, hex_decode},
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{"base64", b64_enc_len, b64_dec_len, b64_encode, b64_decode},
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{NULL, NULL, NULL, NULL, NULL}
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};
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static pg_coding *
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pg_find_coding(pg_coding * res, char *name)
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{
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pg_coding *p;
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for (p = encoding_list; p->name; p++)
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{
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if (!strcasecmp(p->name, name))
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return p;
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}
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return NULL;
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}
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