170b8628fa
function old new delta decode_base64 195 180 -15 Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
274 lines
7.2 KiB
C
274 lines
7.2 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* Copyright 2003, Glenn McGrath
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* Copyright 2006, Rob Landley <rob@landley.net>
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* Copyright 2010, Denys Vlasenko
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*
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* Licensed under GPLv2 or later, see file LICENSE in this source tree.
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*/
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#include "libbb.h"
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/* Conversion tables */
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/* for base 64 */
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const char bb_uuenc_tbl_base64[65 + 1] ALIGN1 = {
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'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H',
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'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',
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'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X',
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'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f',
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'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',
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'o', 'p', 'q', 'r', 's', 't', 'u', 'v',
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'w', 'x', 'y', 'z', '0', '1', '2', '3',
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'4', '5', '6', '7', '8', '9', '+', '/',
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'=' /* termination character */,
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'\0' /* needed for uudecode.c only */
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};
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#if ENABLE_BASE32
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const char bb_uuenc_tbl_base32[33 + 1] ALIGN1 = {
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'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H',
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'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',
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'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X',
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'Y', 'Z', '2', '3', '4', '5', '6', '7',
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'=',
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'\0'
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};
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#endif
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const char bb_uuenc_tbl_std[65] ALIGN1 = {
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'`', '!', '"', '#', '$', '%', '&', '\'',
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'(', ')', '*', '+', ',', '-', '.', '/',
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'0', '1', '2', '3', '4', '5', '6', '7',
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'8', '9', ':', ';', '<', '=', '>', '?',
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'@', 'A', 'B', 'C', 'D', 'E', 'F', 'G',
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'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O',
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'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W',
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'X', 'Y', 'Z', '[', '\\', ']', '^', '_',
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'`' /* termination character */
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};
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/*
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* Encode bytes at S of length LENGTH to uuencode or base64 format and place it
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* to STORE. STORE will be 0-terminated, and must point to a writable
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* buffer of at least 1+BASE64_LENGTH(length) bytes.
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* where BASE64_LENGTH(len) = (4 * ((LENGTH + 2) / 3))
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*/
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void FAST_FUNC bb_uuencode(char *p, const void *src, int length, const char *tbl)
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{
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const unsigned char *s = src;
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/* Transform the 3x8 bits to 4x6 bits */
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while (length > 0) {
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unsigned s1, s2;
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/* Are s[1], s[2] valid or should be assumed 0? */
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s1 = s2 = 0;
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length -= 3; /* can be >=0, -1, -2 */
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if (length >= -1) {
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s1 = s[1];
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if (length >= 0)
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s2 = s[2];
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}
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*p++ = tbl[s[0] >> 2];
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*p++ = tbl[((s[0] & 3) << 4) + (s1 >> 4)];
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*p++ = tbl[((s1 & 0xf) << 2) + (s2 >> 6)];
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*p++ = tbl[s2 & 0x3f];
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s += 3;
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}
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/* Zero-terminate */
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*p = '\0';
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/* If length is -2 or -1, pad last char or two */
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while (length) {
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*--p = tbl[64];
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length++;
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}
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}
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/*
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* Decode base64 encoded string. Stops on NUL after terminating "=" or "==".
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*
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* Returns: pointer to the undecoded part of source.
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* If points to '\0', then the source was fully decoded.
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* (*pp_dst): advanced past the last written byte.
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*/
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const char* FAST_FUNC decode_base64(char **pp_dst, const char *src)
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{
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char *dst = *pp_dst;
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unsigned ch = 0;
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int i = 0;
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while (*src) {
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int t = (unsigned char)*src++;
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/* "if" forest is faster than strchr(bb_uuenc_tbl_base64, t) */
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if (t >= '0' && t <= '9')
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t = t - '0' + 52;
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else if (t >= 'A' && t <= 'Z')
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t = t - 'A';
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else if (t >= 'a' && t <= 'z')
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t = t - 'a' + 26;
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else if (t == '+')
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t = 62;
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else if (t == '/')
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t = 63;
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else if (t == '=' && (i == 3 || (i == 2 && *src == '=')))
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/* the above disallows "==AA", "A===", "AA=A" etc */
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t = 0x1000000;
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else
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//TODO: add BASE64_FLAG_foo to die on bad char?
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continue;
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ch = (ch << 6) | t;
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if (++i == 4) {
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*dst++ = (char) (ch >> 16);
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*dst++ = (char) (ch >> 8);
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*dst++ = (char) ch;
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i = 0;
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if (ch & 0x1000000) { /* was last input char '='? */
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dst--;
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if (ch & (0x1000000 << 6)) /* was it "=="? */
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dst--;
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break;
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}
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ch = 0;
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}
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}
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*pp_dst = dst;
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/* i should be zero here if full 4-char block was decoded */
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return src - i; /* -i rejects truncations: e.g. "MQ" and "MQ=" (correct encoding is "MQ==" -> "1") */
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}
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#if ENABLE_BASE32
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const char* FAST_FUNC decode_base32(char **pp_dst, const char *src)
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{
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char *dst = *pp_dst;
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const char *src_tail;
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while (1) {
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unsigned char five_bit[8];
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int count = 0;
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/* Fetch up to eight 5-bit values */
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src_tail = src;
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while (count < 8) {
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char *table_ptr;
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int ch;
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/* Get next _valid_ character.
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* bb_uuenc_tbl_base32[] contains this string:
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* 0 1 2 3
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* 01234567890123456789012345678901
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* "ABCDEFGHIJKLMNOPQRSTUVWXYZ234567="
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*/
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do {
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ch = *src;
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if (ch == '\0') {
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if (count == 0) {
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src_tail = src;
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}
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goto ret;
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}
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src++;
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table_ptr = strchr(bb_uuenc_tbl_base32, toupper(ch));
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} while (!table_ptr);
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/* Convert encoded character to decimal */
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ch = table_ptr - bb_uuenc_tbl_base32;
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/* ch is 32 if char was '=', otherwise 0..31 */
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if (ch == 32)
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break;
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five_bit[count] = ch;
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count++;
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}
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/* Transform 5-bit values to 8-bit ones */
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if (count > 1) // xxxxx xxx-- ----- ----- ----- ----- ----- -----
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*dst++ = five_bit[0] << 3 | five_bit[1] >> 2;
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if (count > 3) // ----- ---xx xxxxx x---- ----- ----- ----- -----
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*dst++ = five_bit[1] << 6 | five_bit[2] << 1 | five_bit[3] >> 4;
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if (count > 4) // ----- ----- ----- -xxxx xxxx- ----- ----- -----
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*dst++ = five_bit[3] << 4 | five_bit[4] >> 1;
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if (count > 6) // ----- ----- ----- ----- ----x xxxxx xx--- -----
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*dst++ = five_bit[4] << 7 | five_bit[5] << 2 | five_bit[6] >> 3;
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if (count > 7) // ----- ----- ----- ----- ----- ----- --xxx xxxxx
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*dst++ = five_bit[6] << 5 | five_bit[7];
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} /* while (1) */
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ret:
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*pp_dst = dst;
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return src_tail;
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}
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#endif
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/*
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* Decode base64 encoded stream.
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* Can stop on EOF, specified char, or on uuencode-style "====" line:
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* flags argument controls it.
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*/
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void FAST_FUNC read_base64(FILE *src_stream, FILE *dst_stream, int flags)
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{
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/* Note that EOF _can_ be passed as exit_char too */
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#define exit_char ((int)(signed char)flags)
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#define uu_style_end (flags & BASE64_FLAG_UU_STOP)
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#define base32 (flags & BASE64_32)
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/* uuencoded files have 61 byte lines. Use 64 byte buffer
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* to process line at a time.
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*/
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enum { BUFFER_SIZE = 64 };
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char in_buf[BUFFER_SIZE + 2];
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char out_buf[BUFFER_SIZE / 4 * 3 + 2];
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char *out_tail;
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const char *in_tail;
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int term_seen = 0;
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int in_count = 0;
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while (1) {
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while (in_count < BUFFER_SIZE) {
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int ch = fgetc(src_stream);
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if (ch == exit_char) {
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if (in_count == 0)
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return;
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term_seen = 1;
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break;
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}
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if (ch == EOF) {
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term_seen = 1;
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break;
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}
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/* Prevent "====" line to be split: stop if we see '\n'.
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* We can also skip other whitespace and skirt the problem
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* of files with NULs by stopping on any control char or space:
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*/
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if (ch <= ' ')
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break;
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in_buf[in_count++] = ch;
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}
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in_buf[in_count] = '\0';
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/* Did we encounter "====" line? */
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if (uu_style_end && strcmp(in_buf, "====") == 0)
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return;
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out_tail = out_buf;
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#if ENABLE_BASE32
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if (base32)
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in_tail = decode_base32(&out_tail, in_buf);
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else
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#endif
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in_tail = decode_base64(&out_tail, in_buf);
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fwrite(out_buf, (out_tail - out_buf), 1, dst_stream);
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if (term_seen) {
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/* Did we consume ALL characters? */
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if (*in_tail == '\0')
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return;
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/* No */
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bb_simple_error_msg_and_die("truncated base64 input");
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}
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/* It was partial decode */
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in_count = strlen(in_tail);
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memmove(in_buf, in_tail, in_count);
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}
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}
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