From 4bbc88f9909b84359b54ba94b255f2f485134aee Mon Sep 17 00:00:00 2001 From: Mirek Kratochvil Date: Sat, 1 Dec 2012 18:54:42 +0100 Subject: [PATCH] sencode working --- include/codecrypt.h | 46 +++++++++++++++++ lib/sencode.cpp | 118 ++++++++++++++++++++++++++++++++++++++++---- lib/sencode.h | 67 ------------------------- 3 files changed, 154 insertions(+), 77 deletions(-) delete mode 100644 lib/sencode.h diff --git a/include/codecrypt.h b/include/codecrypt.h index ebb02b7..855ed16 100644 --- a/include/codecrypt.h +++ b/include/codecrypt.h @@ -19,6 +19,7 @@ #ifndef _CODECRYPT_H_ #define _CODECRYPT_H_ +#include #include //little STL helper, because writing (*this)[i] everywhere is clumsy @@ -38,6 +39,51 @@ namespace ccr { +/* + * data serialization format + */ + +class sencode +{ +public: + virtual std::string encode() = 0; + virtual void destroy() {} +}; + +bool sencode_decode (const std::string&, sencode**); +void sencode_destroy (sencode*); + +class sencode_list: public sencode +{ +public: + std::vector items; + + virtual std::string encode(); + virtual void destroy(); +}; + +class sencode_int: public sencode +{ +public: + unsigned int i; + sencode_int (unsigned int I) { + i = I; + } + + virtual std::string encode(); +}; + +class sencode_bytes: public sencode +{ +public: + std::string b; + sencode_bytes (const std::string&s) { + b = s; + } + + virtual std::string encode(); +}; + /* * typedef. uint should be able to comfortably hold the field elements of * underlying calculations (esp. with polynomials. Switching to 64bits is diff --git a/lib/sencode.cpp b/lib/sencode.cpp index a7fc955..47e1df5 100644 --- a/lib/sencode.cpp +++ b/lib/sencode.cpp @@ -16,16 +16,116 @@ * along with Codecrypt. If not, see . */ -#include "sencode.h" -#include +#include "codecrypt.h" +using namespace ccr; -bool sencode_decode (const std::string& str, sencode**out) +#include +#include + +static void parse_int (const std::string&str, int&pos, int len, + unsigned int&res) { + res = 0; + ++pos; //skip 'i' + if (pos >= len) goto fail; + for (;;) { + if (pos >= len) goto fail; //not terminated + else if (str[pos] == 'e') break; //done good + else if ( (str[pos] >= '0') and (str[pos] <= '9') ) //integer + res = (10 * res) + (unsigned int) (str[pos] - '0'); + else goto fail; //something weird! + ++pos; + } + + return; +fail: + pos = -1; +} + +static void parse_string (const std::string&str, int&pos, int len, + std::string&res) +{ + //first, read the amount of bytes + unsigned int bytes = 0; + for (;;) { + if (pos >= len) goto fail; + else if (str[pos] == ':') break; //got it + else if ( (str[pos] >= '0') and (str[pos] <= '9') ) //integer + bytes = (10 * bytes) + (unsigned int) (str[pos] - '0'); + else goto fail; //weird! + ++pos; + } + + ++pos; + if (pos + bytes >= len) goto fail; + res = str.substr (pos, bytes); + pos += bytes; + --pos; //last char of the bytestring + return; +fail: + pos = -1; +} + +bool ccr::sencode_decode (const std::string& str, sencode**out) +{ + std::list stk; + int pos = 0; + int len = str.length(); + + for (; pos < len; ++pos) { + + /* try to get a token */ + if (str[pos] == 's') { + //push a new s-exp and don't allow closing it yet. + stk.push_back (new sencode_list); + continue; + } else if (str[pos] == 'e') { + //push nothing (so the TOS s-exp gets terminated) + } else if (str[pos] == 'i') { + //parse an integer (it's unsigned!) + unsigned int res; + parse_int (str, pos, len, res); + if (pos < 0) break; + stk.push_back (new sencode_int (res) ); + + } else if ( (str[pos] >= '0') && (str[pos] <= '9') ) { + //parse a bytestring + std::string res; + parse_string (str, pos, len, res); + if (pos < 0) break; + stk.push_back (new sencode_bytes (res) ); + } + + /* if there's nothing on the stack now, it's an error. */ + if (stk.empty() ) break; + + /* reduce stack. (return positively if it would + * get empty and there's nothing more to parse.) */ + if (stk.size() > 1) { + std::list::iterator i = stk.end(); + --i; + sencode*tos = *i; + --i; + sencode_list*se = dynamic_cast (*i); + if (!se) break; //shouldn't happen, but keep eyes open! + se->items.push_back (tos); + stk.pop_back(); + } else if (pos + 1 == len) { + *out = stk.front(); + return true; + } + } + + /* error handling. Destroy the stack, return false. */ + + for (std::list::iterator i = stk.begin(), e = stk.end(); + i != e; ++i) + sencode_destroy (*i); return false; } -void sencode_destroy (sencode*x) +void ccr::sencode_destroy (sencode*x) { x->destroy(); delete x; @@ -57,17 +157,15 @@ std::string sencode_list::encode() std::string sencode_int::encode() { - std::string r; - std::stringstream ss (r); + std::stringstream ss; ss << 'i' << i << 'e'; - return r; + return ss.str(); } std::string sencode_bytes::encode() { - std::string r; - std::stringstream ss (r); + std::stringstream ss; ss << b.length() << ':' << b; - return r; + return ss.str(); } diff --git a/lib/sencode.h b/lib/sencode.h deleted file mode 100644 index daf912d..0000000 --- a/lib/sencode.h +++ /dev/null @@ -1,67 +0,0 @@ - -/* - * This file is part of Codecrypt. - * - * Codecrypt is free software: you can redistribute it and/or modify it - * under the terms of the GNU Lesser General Public License as published by - * the Free Software Foundation, either version 3 of the License, or (at - * your option) any later version. - * - * Codecrypt is distributed in the hope that it will be useful, but WITHOUT - * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or - * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public - * License for more details. - * - * You should have received a copy of the GNU Lesser General Public License - * along with Codecrypt. If not, see . - */ - -#ifndef _sencode_h_ -#define _sencode_h_ - -#include -#include - -class sencode -{ -public: - virtual std::string encode() = 0; - virtual void destroy() {} -}; - -bool sencode_decode (const std::string&, sencode**); -void sencode_destroy (sencode**); - -class sencode_list: public sencode -{ -public: - std::vector items; - - virtual std::string encode(); - virtual void destroy(); -}; - -class sencode_int: public sencode -{ -public: - int i; - sencode_int (int I) { - i = I; - } - - virtual std::string encode(); -}; - -class sencode_bytes: public sencode -{ -public: - std::string b; - sencode_bytes (const std::string&s) { - b = s; - } - - virtual std::string encode(); -}; - -#endif -