From 14c7f45cdae826f88dc539c8c38dd95caf305731 Mon Sep 17 00:00:00 2001 From: Maurus Cuelenaere Date: Fri, 11 Jul 2008 15:50:46 +0000 Subject: Add zook's ZenUtils to SVN git-svn-id: svn://svn.rockbox.org/rockbox/trunk@18010 a1c6a512-1295-4272-9138-f99709370657 --- utils/zenutils/source/shared/cenc.cpp | 333 ++++++++++++++++++++++++++++++++++ 1 file changed, 333 insertions(+) create mode 100755 utils/zenutils/source/shared/cenc.cpp (limited to 'utils/zenutils/source/shared/cenc.cpp') diff --git a/utils/zenutils/source/shared/cenc.cpp b/utils/zenutils/source/shared/cenc.cpp new file mode 100755 index 0000000000..932bee4625 --- /dev/null +++ b/utils/zenutils/source/shared/cenc.cpp @@ -0,0 +1,333 @@ +/* zenutils - Utilities for working with creative firmwares. + * Copyright 2007 (c) Rasmus Ry + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program 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 General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + +#include "cenc.h" +#include +#include + + +namespace { +const byte CODE_MASK = 0xC0; +const byte ARGS_MASK = 0x3F; + +const byte REPEAT_CODE = 0x00; +const byte BLOCK_CODE = 0x40; +const byte LONG_RUN_CODE = 0x80; +const byte SHORT_RUN_CODE = 0xC0; + +const byte BLOCK_ARGS = 0x1F; +const byte BLOCK_MODE = 0x20; + + +void decode_run(byte* dst, word len, byte val, + int& dstidx) +{ + memset(dst + dstidx, val, len); + dstidx += len; +} + +void decode_pattern(byte* src, byte* dst, + word len, int& srcidx, int& dstidx, + bool bdecode, int npasses) +{ + for (int i = 0; i < npasses; i++) + { + if (bdecode) + { + for (int j = 0; j < len; j++) + { + word c, d; + c = src[srcidx + j]; + d = (c >> 5) & 7; + c = (c << 3) & 0xF8; + src[srcidx + j] = static_cast(c | d); + } + bdecode = false; + } + memcpy(dst + dstidx, src + srcidx, len); + dstidx += len; + } + srcidx += len; +} +}; //namespace + +int zen::cenc_decode(byte* src, int srclen, byte* dst, int dstlen) +{ + if (!src || !srclen || !dst || !dstlen) + { + throw std::invalid_argument("Invalid argument(s)."); + } + + int i = 0, j = 0; + do + { + word c, d, e; + c = src[i++]; + switch (c & CODE_MASK) + { + case REPEAT_CODE: // 2 bytes + d = src[i++]; + d = d + 2; + + e = (c & ARGS_MASK) + 2; + + decode_pattern(src, dst, e, i, j, false, d); + break; + + case BLOCK_CODE: // 1/2/3 bytes + d = c & BLOCK_ARGS; + if (!(c & BLOCK_MODE)) + { + e = src[i++]; + e = (d << 8) + (e + 0x21); + + d = static_cast(i ^ j); + } + else + { + e = d + 1; + + d = static_cast(i ^ j); + } + if (d & 1) + { + i++; + } + + decode_pattern(src, dst, e, i, j, true, 1); + break; + + case LONG_RUN_CODE: // 3 bytes + d = src[i++]; + e = ((c & ARGS_MASK) << 8) + (d + 0x42); + + d = src[i++]; + d = ((d & 7) << 5) | ((d >> 3) & 0x1F); + + decode_run(dst, e, static_cast(d), j); + break; + + case SHORT_RUN_CODE: // 2 bytes + d = src[i++]; + d = ((d & 3) << 6) | ((d >> 2) & 0x3F); + + e = (c & ARGS_MASK) + 2; + + decode_run(dst, e, static_cast(d), j); + break; + }; + } while (i < srclen && j < dstlen); + + return j; +} + +namespace { +int encode_run(byte* dst, int& dstidx, byte val, int len, int dstlen) +{ + if (len < 2) + throw std::invalid_argument("Length is too small."); + + int ret = 0; + if (len <= 0x41) + { + if ((dstidx + 2) > dstlen) + throw std::runtime_error("Not enough space to store run."); + + dst[dstidx++] = SHORT_RUN_CODE | (((len - 2) & ARGS_MASK)); + dst[dstidx++] = ((val >> 6) & 3) | ((val & 0x3F) << 2); + + ret = 2; + } + else if (len <= 0x4041) + { + if ((dstidx + 3) > dstlen) + throw std::runtime_error("Not enough space to store run."); + + byte b1 = (len - 0x42) >> 8; + byte b2 = (len - 0x42) & 0xFF; + + dst[dstidx++] = LONG_RUN_CODE | ((b1 & ARGS_MASK)); + dst[dstidx++] = b2; + dst[dstidx++] = ((val >> 5) & 7) | ((val & 0x1F) << 3); + + ret = 3; + } + else + { + int long_count = len / 0x4041; + int short_len = len % 0x4041; + bool toosmall = short_len == 1; + + int run_len = 0x4041; + for (int i = 0; i < long_count; i++) + { + if (toosmall && (i == (long_count-1))) + { + run_len--; + toosmall = false; + } + int tmp = encode_run(dst, dstidx, val, run_len, dstlen); + if (!tmp) return 0; + ret += tmp; + len -= run_len; + } + + if (len) + { + int short_count = len / 0x41; + int short_rest = short_count ? (len % 0x41) : 0; + toosmall = short_rest == 1; + + run_len = 0x41; + for (int i = 0; i < short_count; i++) + { + if (toosmall && (i == (short_count-1))) + { + run_len--; + toosmall = false; + } + int tmp = encode_run(dst, dstidx, val, run_len, dstlen); + if (!tmp) return 0; + ret += tmp; + len -= run_len; + } + int tmp = encode_run(dst, dstidx, val, len, dstlen); + if (!tmp) return 0; + ret += tmp; + len -= len; + } + } + + return ret; +} + +int encode_block(byte* dst, int& dstidx, byte* src, int& srcidx, int len, + int dstlen) +{ + if (len < 1) + throw std::invalid_argument("Length is too small."); + + int startidx = dstidx; + if (len < 0x21) + { + if ((dstidx + 2 + len) > dstlen) + throw std::runtime_error("Not enough space to store block."); + + dst[dstidx++] = BLOCK_CODE | BLOCK_MODE | ((len - 1) & BLOCK_ARGS); + if ((dstidx ^ srcidx) & 1) + dst[dstidx++] = 0; + + for (int i = 0; i < len; i++) + { + byte c = src[srcidx++]; + byte d = (c & 7) << 5; + c = (c & 0xF8) >> 3; + dst[dstidx++] = c | d; + } + } + else if (len < 0x2021) + { + if ((dstidx + 3 + len) > dstlen) + throw std::runtime_error("Not enough space to store block."); + + dst[dstidx++] = BLOCK_CODE | (((len - 0x21) >> 8) & BLOCK_ARGS); + dst[dstidx++] = (len - 0x21) & 0xFF; + if ((dstidx ^ srcidx) & 1) + dst[dstidx++] = 0; + + for (int i = 0; i < len; i++) + { + byte c = src[srcidx++]; + byte d = (c & 7) << 5; + c = (c & 0xF8) >> 3; + dst[dstidx++] = c | d; + } + } + else + { + int longblocks = len / 0x2020; + int rest = len % 0x2020; + for (int i = 0; i < longblocks; i++) + { + int tmp = encode_block(dst, dstidx, src, srcidx, 0x2020, dstlen); + if (!tmp) return 0; + } + if (rest) + { + int shortblocks = rest / 0x20; + for (int i = 0; i < shortblocks; i++) + { + int tmp = encode_block(dst, dstidx, src, srcidx, 0x20, dstlen); + if (!tmp) return 0; + } + rest = rest % 0x20; + int tmp = encode_block(dst, dstidx, src, srcidx, rest, dstlen); + if (!tmp) return 0; + } + } + + return (dstidx - startidx); +} +}; //namespace + +int zen::cenc_encode(byte* src, int srclen, byte* dst, int dstlen) +{ + if (!src || !srclen || !dst || !dstlen) + { + throw std::invalid_argument("Invalid argument(s)."); + } + + int i = 0, j = 0, k = 0; + word c, d, e; + int runlen = 0; + while (i < srclen && j < dstlen) + { + k = i; + c = src[i++]; + runlen = 1; + while (i < srclen && src[i] == c) + { + runlen++; + i++; + } + if (runlen >= 2) + { + if (!encode_run(dst, j, c, runlen, dstlen)) + return 0; + } + else + { + runlen = 0; + i = k; + while (i < (srclen - 1) && (src[i] != src[i + 1])) + { + runlen++; + i++; + } + if (i == (srclen - 1)) + { + runlen++; + i++; + } + if (!encode_block(dst, j, src, k, runlen, dstlen)) + return 0; + } + } + + return j; +} -- cgit v1.2.3