Ventoy/LZIP/smallz4cat.c
2020-12-12 07:56:52 +08:00

418 lines
13 KiB
C

// //////////////////////////////////////////////////////////
// smallz4cat.c
// Copyright (c) 2016-2019 Stephan Brumme. All rights reserved.
// see https://create.stephan-brumme.com/smallz4/
//
// "MIT License":
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation
// the rights to use, copy, modify, merge, publish, distribute, sublicense,
// and/or sell copies of the Software, and to permit persons to whom the Software
// is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
// PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
// HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
// SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
// This program is a shorter, more readable, albeit slower re-implementation of lz4cat ( https://github.com/Cyan4973/xxHash )
// compile: gcc smallz4cat.c -O3 -o smallz4cat -Wall -pedantic -std=c99 -s
// The static 8k binary was compiled using Clang and dietlibc (see https://www.fefe.de/dietlibc/ )
// Limitations:
// - skippable frames and legacy frames are not implemented (and most likely never will)
// - checksums are not verified (see https://create.stephan-brumme.com/xxhash/ for a simple implementation)
// Replace getByteFromIn() and sendToOut() by your own code if you need in-memory LZ4 decompression.
// Corrupted data causes a call to unlz4error().
// suppress warnings when compiled by Visual C++
#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h> // stdin/stdout/stderr, fopen, ...
#include <stdlib.h> // exit()
#include <string.h> // memcpy
#ifndef FALSE
#define FALSE 0
#define TRUE 1
#endif
/// error handler
static void unlz4error(const char* msg)
{
// smaller static binary than fprintf(stderr, "ERROR: %s\n", msg);
fputs("ERROR: ", stderr);
fputs(msg, stderr);
fputc('\n', stderr);
exit(1);
}
// ==================== I/O INTERFACE ====================
// read one byte from input, see getByteFromIn() for a basic implementation
typedef unsigned char (*GET_BYTE) (void* userPtr);
// write several bytes, see sendBytesToOut() for a basic implementation
typedef void (*SEND_BYTES)(const unsigned char*, unsigned int, void* userPtr);
struct UserPtr
{
// file handles
FILE* in;
FILE* out;
// modify input buffer size as you like ... for most use cases, bigger buffer aren't faster anymore - and even reducing to 1 byte works !
#define READ_BUFFER_SIZE 4*1024
unsigned char readBuffer[READ_BUFFER_SIZE];
unsigned int pos;
unsigned int available;
};
/// read a single byte (with simple buffering)
static unsigned char getByteFromIn(void* userPtr) // parameter "userPtr" not needed
{
/// cast user-specific data
struct UserPtr* user = (struct UserPtr*)userPtr;
// refill buffer
if (user->pos == user->available)
{
user->pos = 0;
user->available = fread(user->readBuffer, 1, READ_BUFFER_SIZE, user->in);
if (user->available == 0)
unlz4error("out of data");
}
// return a byte
return user->readBuffer[user->pos++];
}
/// write a block of bytes
static void sendBytesToOut(const unsigned char* data, unsigned int numBytes, void* userPtr)
{
/// cast user-specific data
struct UserPtr* user = (struct UserPtr*)userPtr;
if (data != NULL && numBytes > 0)
fwrite(data, 1, numBytes, user->out);
}
// ==================== LZ4 DECOMPRESSOR ====================
/// decompress everything in input stream (accessed via getByte) and write to output stream (via sendBytes)
void unlz4_userPtr(GET_BYTE getByte, SEND_BYTES sendBytes, const char* dictionary, void* userPtr)
{
// signature
unsigned char signature1 = getByte(userPtr);
unsigned char signature2 = getByte(userPtr);
unsigned char signature3 = getByte(userPtr);
unsigned char signature4 = getByte(userPtr);
unsigned int signature = (signature4 << 24) | (signature3 << 16) | (signature2 << 8) | signature1;
unsigned char isModern = (signature == 0x184D2204);
unsigned char isLegacy = (signature == 0x184C2102);
if (!isModern && !isLegacy)
unlz4error("invalid signature");
unsigned char hasBlockChecksum = FALSE;
unsigned char hasContentSize = FALSE;
unsigned char hasContentChecksum = FALSE;
unsigned char hasDictionaryID = FALSE;
if (isModern)
{
// flags
unsigned char flags = getByte(userPtr);
hasBlockChecksum = flags & 16;
hasContentSize = flags & 8;
hasContentChecksum = flags & 4;
hasDictionaryID = flags & 1;
// only version 1 file format
unsigned char version = flags >> 6;
if (version != 1)
unlz4error("only LZ4 file format version 1 supported");
// ignore blocksize
char numIgnore = 1;
// ignore, skip 8 bytes
if (hasContentSize)
numIgnore += 8;
// ignore, skip 4 bytes
if (hasDictionaryID)
numIgnore += 4;
// ignore header checksum (xxhash32 of everything up this point & 0xFF)
numIgnore++;
// skip all those ignored bytes
while (numIgnore--)
getByte(userPtr);
}
// don't lower this value, backreferences can be 64kb far away
#define HISTORY_SIZE 64*1024
// contains the latest decoded data
unsigned char history[HISTORY_SIZE];
// next free position in history[]
unsigned int pos = 0;
// dictionary compression is a recently introduced feature, just move its contents to the buffer
if (dictionary != NULL)
{
// open dictionary
FILE* dict = fopen(dictionary, "rb");
if (!dict)
unlz4error("cannot open dictionary");
// get dictionary's filesize
fseek(dict, 0, SEEK_END);
long dictSize = ftell(dict);
// only the last 64k are relevant
long relevant = dictSize < 65536 ? 0 : dictSize - 65536;
fseek(dict, relevant, SEEK_SET);
if (dictSize > 65536)
dictSize = 65536;
// read it and store it at the end of the buffer
fread(history + HISTORY_SIZE - dictSize, 1, dictSize, dict);
fclose(dict);
}
// parse all blocks until blockSize == 0
while (1)
{
// block size
unsigned int blockSize = getByte(userPtr);
blockSize |= (unsigned int)getByte(userPtr) << 8;
blockSize |= (unsigned int)getByte(userPtr) << 16;
blockSize |= (unsigned int)getByte(userPtr) << 24;
// highest bit set ?
unsigned char isCompressed = isLegacy || (blockSize & 0x80000000) == 0;
if (isModern)
blockSize &= 0x7FFFFFFF;
// stop after last block
if (blockSize == 0)
break;
if (isCompressed)
{
// decompress block
unsigned int blockOffset = 0;
unsigned int numWritten = 0;
while (blockOffset < blockSize)
{
// get a token
unsigned char token = getByte(userPtr);
blockOffset++;
// determine number of literals
unsigned int numLiterals = token >> 4;
if (numLiterals == 15)
{
// number of literals length encoded in more than 1 byte
unsigned char current;
do
{
current = getByte(userPtr);
numLiterals += current;
blockOffset++;
} while (current == 255);
}
blockOffset += numLiterals;
// copy all those literals
if (pos + numLiterals < HISTORY_SIZE)
{
// fast loop
while (numLiterals-- > 0)
history[pos++] = getByte(userPtr);
}
else
{
// slow loop
while (numLiterals-- > 0)
{
history[pos++] = getByte(userPtr);
// flush output buffer
if (pos == HISTORY_SIZE)
{
sendBytes(history, HISTORY_SIZE, userPtr);
numWritten += HISTORY_SIZE;
pos = 0;
}
}
}
// last token has only literals
if (blockOffset == blockSize)
break;
// match distance is encoded in two bytes (little endian)
unsigned int delta = getByte(userPtr);
delta |= (unsigned int)getByte(userPtr) << 8;
// zero isn't allowed
if (delta == 0)
unlz4error("invalid offset");
blockOffset += 2;
// match length (always >= 4, therefore length is stored minus 4)
unsigned int matchLength = 4 + (token & 0x0F);
if (matchLength == 4 + 0x0F)
{
unsigned char current;
do // match length encoded in more than 1 byte
{
current = getByte(userPtr);
matchLength += current;
blockOffset++;
} while (current == 255);
}
// copy match
unsigned int referencePos = (pos >= delta) ? (pos - delta) : (HISTORY_SIZE + pos - delta);
// start and end within the current 64k block ?
if (pos + matchLength < HISTORY_SIZE && referencePos + matchLength < HISTORY_SIZE)
{
// read/write continuous block (no wrap-around at the end of history[])
// fast copy
if (pos >= referencePos + matchLength || referencePos >= pos + matchLength)
{
// non-overlapping
memcpy(history + pos, history + referencePos, matchLength);
pos += matchLength;
}
else
{
// overlapping, slower byte-wise copy
while (matchLength-- > 0)
history[pos++] = history[referencePos++];
}
}
else
{
// either read or write wraps around at the end of history[]
while (matchLength-- > 0)
{
// copy single byte
history[pos++] = history[referencePos++];
// cannot write anymore ? => wrap around
if (pos == HISTORY_SIZE)
{
// flush output buffer
sendBytes(history, HISTORY_SIZE, userPtr);
numWritten += HISTORY_SIZE;
pos = 0;
}
// wrap-around of read location
referencePos %= HISTORY_SIZE;
}
}
}
// all legacy blocks must be completely filled - except for the last one
if (isLegacy && numWritten + pos < 8*1024*1024)
break;
}
else
{
// copy uncompressed data and add to history, too (if next block is compressed and some matches refer to this block)
while (blockSize-- > 0)
{
// copy a byte ...
history[pos++] = getByte(userPtr);
// ... until buffer is full => send to output
if (pos == HISTORY_SIZE)
{
sendBytes(history, HISTORY_SIZE, userPtr);
pos = 0;
}
}
}
if (hasBlockChecksum)
{
// ignore checksum, skip 4 bytes
getByte(userPtr); getByte(userPtr); getByte(userPtr); getByte(userPtr);
}
}
if (hasContentChecksum)
{
// ignore checksum, skip 4 bytes
getByte(userPtr); getByte(userPtr); getByte(userPtr); getByte(userPtr);
}
// flush output buffer
sendBytes(history, pos, userPtr);
}
/// old interface where getByte and sendBytes use global file handles
void unlz4(GET_BYTE getByte, SEND_BYTES sendBytes, const char* dictionary)
{
unlz4_userPtr(getByte, sendBytes, dictionary, NULL);
}
// ==================== COMMAND-LINE HANDLING ====================
/// parse command-line
int main(int argc, const char* argv[])
{
// default input/output streams
struct UserPtr user =
{
.in = stdin,
.out = stdout,
.pos = 0, // initial input buffer is empty
.available = 0
};
const char* dictionary = NULL;
// first command-line parameter is our input filename / but ignore "-" which stands for STDIN
int parameter;
for (parameter = 1; parameter < argc; parameter++)
{
const char* current = argv[parameter];
// dictionary
if (current[0] == '-' && current[1] == 'D')
{
if (parameter + 1 >= argc)
unlz4error("no dictionary filename found");
dictionary = argv[++parameter];
continue;
}
// filename
// read from STDIN, default behavior
if (current[0] != '-' && current[1] != '\0')
{
// already have a filename - at most one filename is allowed (except for dictionary) ?
if (user.in != stdin)
unlz4error("can only decompress one file at a time");
// get handle
user.in = fopen(argv[1], "rb");
if (!user.in)
unlz4error("file not found");
}
}
// and go !
unlz4_userPtr(getByteFromIn, sendBytesToOut, dictionary, &user);
return 0;
}