mirror of
https://git.postgresql.org/git/postgresql.git
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347 lines
6.8 KiB
C
347 lines
6.8 KiB
C
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/*-------------------------------------------------------------------------
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*
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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 PostgreSQL Global Development Group
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*
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*
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* IDENTIFICATION
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* $Header: /cvsroot/pgsql/src/backend/utils/adt/encode.c,v 1.1 2001/07/12 14:05:31 momjian Exp $
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*
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*-------------------------------------------------------------------------
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*/
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#include "postgres.h"
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#include <ctype.h>
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#include "utils/builtins.h"
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struct pg_encoding
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{
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unsigned (*encode_len) (unsigned dlen);
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unsigned (*decode_len) (unsigned dlen);
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unsigned (*encode) (const uint8 *data, unsigned dlen, uint8 *res);
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unsigned (*decode) (const uint8 *data, unsigned dlen, uint8 *res);
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};
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static struct pg_encoding * pg_find_encoding(const char *name);
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/*
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* SQL functions.
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*/
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Datum
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binary_encode(PG_FUNCTION_ARGS)
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{
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bytea *data = PG_GETARG_BYTEA_P(0);
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Datum name = PG_GETARG_DATUM(1);
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text *result;
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char *namebuf;
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int namelen, datalen, resultlen, res;
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struct pg_encoding *enc;
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datalen = VARSIZE(data) - VARHDRSZ;
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namelen = VARSIZE(name) - VARHDRSZ;
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namebuf = (char *)DirectFunctionCall1(textout, name);
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enc = pg_find_encoding(namebuf);
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if (enc == NULL)
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elog(ERROR, "No such encoding");
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resultlen = enc->encode_len(datalen);
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result = palloc(VARHDRSZ + resultlen);
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res = enc->encode(VARDATA(data), datalen, VARDATA(result));
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if (res > resultlen)
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elog(ERROR, "Overflow - encode estimate too small");
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VARATT_SIZEP(result) = VARHDRSZ + res;
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PG_RETURN_TEXT_P(result);
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}
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Datum
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binary_decode(PG_FUNCTION_ARGS)
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{
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text *data = PG_GETARG_TEXT_P(0);
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Datum name = PG_GETARG_DATUM(1);
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bytea *result;
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char *namebuf;
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int namelen, datalen, resultlen, res;
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struct pg_encoding *enc;
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datalen = VARSIZE(data) - VARHDRSZ;
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namelen = VARSIZE(name) - VARHDRSZ;
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namebuf = (char *)DirectFunctionCall1(textout, name);
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enc = pg_find_encoding(namebuf);
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if (enc == NULL)
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elog(ERROR, "No such encoding");
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resultlen = enc->decode_len(datalen);
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result = palloc(VARHDRSZ + resultlen);
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res = enc->decode(VARDATA(data), datalen, VARDATA(result));
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if (res > resultlen)
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elog(ERROR, "Overflow - decode estimate too small");
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VARATT_SIZEP(result) = VARHDRSZ + res;
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PG_RETURN_BYTEA_P(result);
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}
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/*
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* HEX
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*/
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static const char *hextbl = "0123456789abcdef";
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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 unsigned
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hex_encode(const uint8 * src, unsigned len, uint8 * dst)
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{
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const 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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static uint8
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get_hex(unsigned c)
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{
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int res = -1;
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if (c > 0 && c < 127)
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res = hexlookup[c];
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if (res < 0)
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elog(ERROR, "Bad hex code: '%c'", c);
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return (uint8)res;
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}
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static unsigned
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hex_decode(const uint8 * src, unsigned len, uint8 * dst)
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{
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const uint8 *s,
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*srcend;
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uint8 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
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hex_enc_len(unsigned srclen)
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{
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return srclen << 1;
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}
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static unsigned
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hex_dec_len(unsigned srclen)
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{
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return srclen >> 1;
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}
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/*
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* BASE64
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*/
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static const unsigned char _base64[] =
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"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
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static const int8 b64lookup[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, 62, -1, -1, -1, 63,
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52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1,
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-1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
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15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1,
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-1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
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41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1,
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};
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static unsigned
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b64_encode(const uint8 * src, unsigned len, uint8 * dst)
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{
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uint8 *p,
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*lend = dst + 76;
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const uint8 *s,
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*end = src + len;
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int pos = 2;
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uint32 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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static unsigned
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b64_decode(const uint8 * src, unsigned len, uint8 * dst)
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{
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const char *srcend = src + len,
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*s = src;
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uint8 *p = dst;
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unsigned c;
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int b = 0;
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uint32 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 == ' ' || c == '\t' || c == '\n' || c == '\r')
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continue;
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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 {
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b = -1;
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if (c > 0 && c < 127)
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b = b64lookup[c];
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if (b < 0)
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elog(ERROR, "base64: Invalid symbol");
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}
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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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static unsigned
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b64_enc_len(unsigned 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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static unsigned
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b64_dec_len(unsigned srclen)
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{
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return (srclen * 3) >> 2;
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}
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/*
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* Common
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*/
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static struct {
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const char *name;
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struct pg_encoding enc;
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} enclist[] = {
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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 struct pg_encoding *
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pg_find_encoding(const char *name)
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{
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int i;
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for (i = 0; enclist[i].name; i++)
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if (!strcasecmp(enclist[i].name, name))
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return &enclist[i].enc;
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return NULL;
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}
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