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https://git.postgresql.org/git/postgresql.git
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9d4649ca49
Backpatch-through: certain files through 9.3
200 lines
3.9 KiB
C
200 lines
3.9 KiB
C
/*-------------------------------------------------------------------------
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*
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* base64.c
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* Encoding and decoding routines for base64 without whitespace.
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*
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* Copyright (c) 2001-2018, PostgreSQL Global Development Group
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*
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*
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* IDENTIFICATION
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* src/common/base64.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/base64.h"
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/*
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* BASE64
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*/
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static const 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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/*
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* pg_b64_encode
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*
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* Encode into base64 the given string. Returns the length of the encoded
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* string.
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*/
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int
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pg_b64_encode(const char *src, int len, char *dst)
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{
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char *p;
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const char *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 |= (unsigned char) *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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}
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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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/*
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* pg_b64_decode
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*
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* Decode the given base64 string. Returns the length of the decoded
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* string on success, and -1 in the event of an error.
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*/
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int
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pg_b64_decode(const char *src, int len, char *dst)
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{
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const char *srcend = src + len,
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*s = src;
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char *p = dst;
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char 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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/* Leave if a whitespace is found */
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if (c == ' ' || c == '\t' || c == '\n' || c == '\r')
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return -1;
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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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{
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/*
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* Unexpected "=" character found while decoding base64
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* sequence.
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*/
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return -1;
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}
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}
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b = 0;
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}
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else
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{
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b = -1;
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if (c > 0 && c < 127)
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b = b64lookup[(unsigned char) c];
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if (b < 0)
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{
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/* invalid symbol found */
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return -1;
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}
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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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{
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/*
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* base64 end sequence is invalid. Input data is missing padding, is
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* truncated or is otherwise corrupted.
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*/
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return -1;
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}
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return p - dst;
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}
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/*
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* pg_b64_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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* base64 based on the length provided 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 encoding.
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*/
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int
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pg_b64_enc_len(int srclen)
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{
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/* 3 bytes will be converted to 4 */
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return (srclen + 2) * 4 / 3;
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}
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/*
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* pg_b64_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 base64, 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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int
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pg_b64_dec_len(int srclen)
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{
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return (srclen * 3) >> 2;
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}
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