146 lines
4.0 KiB
C
146 lines
4.0 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 table. for base 64 */
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const char bb_uuenc_tbl_base64[65 + 2] 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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'\n', '\0' /* needed for uudecode.c */
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};
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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 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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int term_count = 0;
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while (1) {
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unsigned char translated[4];
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int count = 0;
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/* Process one group of 4 chars */
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while (count < 4) {
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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_base64[] contains this string:
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* 0 1 2 3 4 5 6
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* 012345678901234567890123456789012345678901234567890123456789012345
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* "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=\n"
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*/
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do {
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ch = fgetc(src_stream);
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if (ch == exit_char && count == 0)
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return;
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if (ch == EOF)
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bb_error_msg_and_die("truncated base64 input");
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table_ptr = strchr(bb_uuenc_tbl_base64, ch);
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//TODO: add BASE64_FLAG_foo to die on bad char?
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//Note that then we may need to still allow '\r' (for mail processing)
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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_base64;
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if (ch == 65 /* '\n' */) {
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/* Terminating "====" line? */
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if (uu_style_end && term_count == 4)
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return; /* yes */
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term_count = 0;
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continue;
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}
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/* ch is 64 if char was '=', otherwise 0..63 */
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translated[count] = ch & 63; /* 64 -> 0 */
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if (ch == 64) {
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term_count++;
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break;
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}
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count++;
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term_count = 0;
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}
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/* Merge 6 bit chars to 8 bit.
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* count can be < 4 when we decode the tail:
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* "eQ==" -> "y", not "y NUL NUL"
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*/
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if (count > 1)
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fputc(translated[0] << 2 | translated[1] >> 4, dst_stream);
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if (count > 2)
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fputc(translated[1] << 4 | translated[2] >> 2, dst_stream);
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if (count > 3)
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fputc(translated[2] << 6 | translated[3], dst_stream);
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} /* while (1) */
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}
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