diff options
| -rw-r--r-- | libbb/uuencode.c | 84 |
1 files changed, 34 insertions, 50 deletions
diff --git a/libbb/uuencode.c b/libbb/uuencode.c index 2e9edb219..7c7f1cf1c 100644 --- a/libbb/uuencode.c +++ b/libbb/uuencode.c @@ -82,7 +82,7 @@ void FAST_FUNC bb_uuencode(char *p, const void *src, int length, const char *tbl } /* - * Decode base64 encoded string. Stops on NUL after terminating "=" or "==". + * Decode base64 encoded string. * * Returns: pointer to the undecoded part of source. * If points to '\0', then the source was fully decoded. @@ -139,61 +139,45 @@ const char* FAST_FUNC decode_base64(char **pp_dst, const char *src) const char* FAST_FUNC decode_base32(char **pp_dst, const char *src) { char *dst = *pp_dst; - const char *src_tail; - - while (1) { - unsigned char five_bit[8]; - int count = 0; - - /* Fetch up to eight 5-bit values */ - src_tail = src; - while (count < 8) { - char *table_ptr; - int ch; + uint64_t ch = 0; + int i = 0; - /* Get next _valid_ character. - * bb_uuenc_tbl_base32[] contains this string: - * 0 1 2 3 - * 01234567890123456789012345678901 - * "ABCDEFGHIJKLMNOPQRSTUVWXYZ234567=" - */ - do { - ch = *src; - if (ch == '\0') { - if (count == 0) { - src_tail = src; - } - goto ret; - } - src++; - table_ptr = strchr(bb_uuenc_tbl_base32, toupper(ch)); - } while (!table_ptr); + while (*src) { + int t = (unsigned char)*src++; - /* Convert encoded character to decimal */ - ch = table_ptr - bb_uuenc_tbl_base32; + /* "if" forest is faster than strchr(bb_uuenc_tbl_base32, t) */ + if (t >= '2' && t <= '7') + t = t - '2' + 26; + else if ((t|0x20) >= 'a' && (t|0x20) <= 'z') + t = (t|0x20) - 'a'; + else if (t == '=' && i > 1) + t = 0; + else +//TODO: add BASE64_FLAG_foo to die on bad char? + continue; - /* ch is 32 if char was '=', otherwise 0..31 */ - if (ch == 32) + ch = (ch << 5) | t; + if (++i == 8) { + *dst++ = (char) (ch >> 32); + *dst++ = (char) (ch >> 24); + *dst++ = (char) (ch >> 16); + *dst++ = (char) (ch >> 8); + *dst++ = (char) ch; + if (t == 0 && src[-1] == '=') { /* was last input char '='? */ + const char *s = src; + while (*--s == '=' && --i != 0) + continue; + i = 8 - i; /* count of =, must be 1, 3, 4 or 6 */ + dst -= (i+1) * 2 / 3; /* discard last 1, 2, 3 or 4 bytes */ + i = 0; break; - five_bit[count] = ch; - count++; + } + i = 0; } - - /* Transform 5-bit values to 8-bit ones */ - if (count > 1) // xxxxx xxx-- ----- ----- ----- ----- ----- ----- - *dst++ = five_bit[0] << 3 | five_bit[1] >> 2; - if (count > 3) // ----- ---xx xxxxx x---- ----- ----- ----- ----- - *dst++ = five_bit[1] << 6 | five_bit[2] << 1 | five_bit[3] >> 4; - if (count > 4) // ----- ----- ----- -xxxx xxxx- ----- ----- ----- - *dst++ = five_bit[3] << 4 | five_bit[4] >> 1; - if (count > 6) // ----- ----- ----- ----- ----x xxxxx xx--- ----- - *dst++ = five_bit[4] << 7 | five_bit[5] << 2 | five_bit[6] >> 3; - if (count > 7) // ----- ----- ----- ----- ----- ----- --xxx xxxxx - *dst++ = five_bit[6] << 5 | five_bit[7]; - } /* while (1) */ - ret: + } *pp_dst = dst; - return src_tail; + /* i should be zero here if full 8-char block was decoded */ + return src - i; } #endif |