commit 528205043ebc7cbb001c647cd3dcc1377e648647 Author: Tomás Touceda <chiiph@torproject.org> Date: Wed Jul 4 21:09:56 2012 -0300 Add base16_decode implementation based on tor's --- src/common/stringutil.cpp | 47 +++++++++++++++++++++++++++++++++++++++++++++ src/common/stringutil.h | 1 + 2 files changed, 48 insertions(+), 0 deletions(-) diff --git a/src/common/stringutil.cpp b/src/common/stringutil.cpp index 8b9b64d..9ce9dbd 100644 --- a/src/common/stringutil.cpp +++ b/src/common/stringutil.cpp @@ -122,6 +122,53 @@ base16_encode(const QByteArray &buf) return hex; } +/** Helper: given a hex digit, return its value, or -1 if it isn't hex. */ +inline int +_hex_decode_digit(char c) +{ + switch (c) { + case '0': return 0; + case '1': return 1; + case '2': return 2; + case '3': return 3; + case '4': return 4; + case '5': return 5; + case '6': return 6; + case '7': return 7; + case '8': return 8; + case '9': return 9; + case 'A': case 'a': return 10; + case 'B': case 'b': return 11; + case 'C': case 'c': return 12; + case 'D': case 'd': return 13; + case 'E': case 'e': return 14; + case 'F': case 'f': return 15; + default: + return -1; + } +} + +/** Given a hexadecimal string of <b>srclen</b> bytes in <b>src</b>, decode it + * and store the result in the <b>destlen</b>-byte buffer at <b>dest</b>. + * Return 0 on success, -1 on failure. */ +QString +base16_decode(const QByteArray &buf) +{ + int v1,v2; + QString dest; + + if ((buf.size() % 2) != 0) + return QString(); + for(int i = 0; i < buf.size(); i+=2) { + v1 = _hex_decode_digit(buf[i]); + v2 = _hex_decode_digit(buf[i+1]); + if (v1<0||v2<0) + return QString(); + dest.append((v1<<4)|v2); + } + return dest; +} + /** Given an ASCII string <b>str</b>, this function returns a quoted string * with all escaped characters unescaped. Non-ASCII characters in the string * will be converted to the local 8-bit character encoding and encoded using diff --git a/src/common/stringutil.h b/src/common/stringutil.h index 24cac74..0e2f9fe 100644 --- a/src/common/stringutil.h +++ b/src/common/stringutil.h @@ -47,6 +47,7 @@ QString string_wrap(const QString &str, int width, * returns the result. This function is derived from base16_encode() in Tor's * util.c. See LICENSE for details on Tor's license. */ QString base16_encode(const QByteArray &buf); +QString base16_decode(const QByteArray &buf); /** Given a string <b>str</b>, this function returns a quoted string with all * '"' and '\' characters escaped with a single '\'. */