mirror of
https://github.com/thug1src/thug.git
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393 lines
12 KiB
C++
393 lines
12 KiB
C++
#include <core/compress.h>
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#define N 4096 /* size of ring buffer */
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#define F 18 /* upper limit for match_length */
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#define THRESHOLD 2 /* encode string into position and length
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if match_length is greater than this */
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#define NIL N /* index for root of binary search trees */
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unsigned long int
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textsize = 0, /* text size counter */
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codesize = 0, /* code size counter */
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printcount = 0; /* counter for reporting progress every 1K bytes */
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//unsigned char text_buf[N + F - 1]; //ring buffer of size N, with extra F-1 bytes to facilitate string comparison
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int match_position, match_length; // of longest match. These are set by the InsertNode() procedure.
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//int lson[N + 1], rson[N + 257], dad[N + 1]; // left & right children & parents -- These constitute binary search trees.
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unsigned char *text_buf;
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int *lson;
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int *rson;
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int *dad;
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#define readc() *pIn++
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#define writec(x) *pOut++ = x
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void InitTree(void) /* initialize trees */
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{
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int i;
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Mem::Manager::sHandle().PushContext(Mem::Manager::sHandle().TopDownHeap());
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text_buf = new unsigned char[N + F - 1];
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lson = new int[N+1];
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rson = new int[N+257];
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dad = new int[N+1];
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Mem::Manager::sHandle().PopContext(); //Mem::Manager::sHandle().TopDownHeap());
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/* For i = 0 to N - 1, rson[i] and lson[i] will be the right and
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left children of node i. These nodes need not be initialized.
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Also, dad[i] is the parent of node i. These are initialized to
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NIL (= N), which stands for 'not used.'
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For i = 0 to 255, rson[N + i + 1] is the root of the tree
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for strings that begin with character i. These are initialized
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to NIL. Note there are 256 trees. */
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for ( i = N + 1; i <= N + 256; i++ ) rson[i] = NIL;
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for ( i = 0; i < N; i++ ) dad[i] = NIL;
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}
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void DeInitTree(void) /* free up the memory */
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{
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delete [] text_buf;
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delete [] lson;
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delete [] rson;
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delete [] dad;
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}
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void InsertNode(int r)
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/* Inserts string of length F, text_buf[r..r+F-1], into one of the
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trees (text_buf[r]'th tree) and returns the longest-match position
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and length via the global variables match_position and match_length.
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If match_length = F, then removes the old node in favor of the new
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one, because the old one will be deleted sooner.
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Note r plays double role, as tree node and position in buffer. */
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{
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int i, p, cmp;
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unsigned char *key;
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cmp = 1; key = &text_buf[r]; p = N + 1 + key[0];
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rson[r] = lson[r] = NIL; match_length = 0;
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for ( ; ; )
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{
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if ( cmp >= 0 )
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{
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if ( rson[p] != NIL )
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{
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p = rson[p];
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}
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else
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{
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rson[p] = r; dad[r] = p; return;
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}
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}
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else
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{
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if ( lson[p] != NIL )
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{
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p = lson[p];
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}
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else
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{
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lson[p] = r; dad[r] = p; return;
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}
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}
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for ( i = 1; i < F; i++ )
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{
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if ( (cmp = key[i] - text_buf[p + i]) != 0 ) break;
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}
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if ( i > match_length )
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{
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match_position = p;
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if ( (match_length = i) >= F )
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{
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break;
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}
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}
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}
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dad[r] = dad[p]; lson[r] = lson[p]; rson[r] = rson[p];
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dad[lson[p]] = r; dad[rson[p]] = r;
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if ( rson[dad[p]] == p )
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{
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rson[dad[p]] = r;
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}
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else
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{
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lson[dad[p]] = r;
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}
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dad[p] = NIL; /* remove p */
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}
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void DeleteNode(int p) /* deletes node p from tree */
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{
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int q;
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if ( dad[p] == NIL ) return; /* not in tree */
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if ( rson[p] == NIL ) q = lson[p];
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else if ( lson[p] == NIL ) q = rson[p];
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else
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{
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q = lson[p];
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if ( rson[q] != NIL )
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{
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do
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{
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q = rson[q];
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} while ( rson[q] != NIL );
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rson[dad[q]] = lson[q]; dad[lson[q]] = dad[q];
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lson[q] = lson[p]; dad[lson[p]] = q;
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}
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rson[q] = rson[p]; dad[rson[p]] = q;
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}
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dad[q] = dad[p];
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if ( rson[dad[p]] == p ) rson[dad[p]] = q;
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else lson[dad[p]] = q;
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dad[p] = NIL;
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}
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int Encode(char *pIn, char *pOut, int bytes_to_read, bool print_progress)
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{
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int i, c, len, r, s, last_match_length, code_buf_ptr;
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unsigned char code_buf[17], mask;
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textsize = 0; /* text size counter */
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codesize = 0; /* code size counter */
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printcount = 0; /* counter for reporting progress every 1K bytes */
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InitTree(); /* initialize trees */
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code_buf[0] = 0; /* code_buf[1..16] saves eight units of code, and
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code_buf[0] works as eight flags, "1" representing that the unit
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is an unencoded letter (1 byte), "0" a position-and-length pair
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(2 bytes). Thus, eight units require at most 16 bytes of code. */
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code_buf_ptr = mask = 1;
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s = 0; r = N - F;
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for ( i = s; i < r; i++ ) text_buf[i] = ' '; /* Clear the buffer with
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any character that will appear often. */
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for ( len = 0; len < F && bytes_to_read; len++ )
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{
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c = readc();
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bytes_to_read--;
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text_buf[r + len] = c; /* Read F bytes into the last F bytes of
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the buffer */
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}
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if ( (textsize = len) == 0 )
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{
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DeInitTree();
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return 0; /* text of size zero */
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}
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for ( i = 1; i <= F; i++ ) InsertNode(r - i); /* Insert the F strings,
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each of which begins with one or more 'space' characters. Note
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the order in which these strings are inserted. This way,
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degenerate trees will be less likely to occur. */
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InsertNode(r); /* Finally, insert the whole string just read. The
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global variables match_length and match_position are set. */
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do
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{
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if ( match_length > len ) match_length = len; /* match_length
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may be spuriously long near the end of text. */
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if ( match_length <= THRESHOLD )
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{
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match_length = 1; /* Not long enough match. Send one byte. */
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code_buf[0] |= mask; /* 'send one byte' flag */
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code_buf[code_buf_ptr++] = text_buf[r]; /* Send uncoded. */
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}
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else
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{
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code_buf[code_buf_ptr++] = (unsigned char) match_position;
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code_buf[code_buf_ptr++] = (unsigned char)
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(((match_position >> 4) & 0xf0)
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| (match_length - (THRESHOLD + 1))); /* Send position and
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length pair. Note match_length > THRESHOLD. */
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}
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if ( (mask <<= 1) == 0 )
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{ /* Shift mask left one bit. */
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for ( i = 0; i < code_buf_ptr; i++ ) /* Send at most 8 units of */
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writec(code_buf[i]); /* code together */
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codesize += code_buf_ptr;
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code_buf[0] = 0; code_buf_ptr = mask = 1;
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}
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last_match_length = match_length;
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for ( i = 0; i < last_match_length &&
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bytes_to_read; i++ )
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{
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c = readc();
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bytes_to_read--;
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DeleteNode(s); /* Delete old strings and */
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text_buf[s] = c; /* read new bytes */
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if ( s < F - 1 ) text_buf[s + N] = c; /* If the position is
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near the end of buffer, extend the buffer to make
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string comparison easier. */
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s = (s + 1) & (N - 1); r = (r + 1) & (N - 1);
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/* Since this is a ring buffer, increment the position
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modulo N. */
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InsertNode(r); /* Register the string in text_buf[r..r+F-1] */
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}
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if ( (textsize += i) > printcount )
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{
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// printf("%12ld\r", textsize); printcount += 1024;
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/* Reports progress each time the textsize exceeds
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multiples of 1024. */
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}
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while ( i++ < last_match_length )
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{ /* After the end of text, */
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DeleteNode(s); /* no need to read, but */
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s = (s + 1) & (N - 1); r = (r + 1) & (N - 1);
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if ( --len ) InsertNode(r); /* buffer may not be empty. */
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}
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} while ( len > 0 ); /* until length of string to be processed is zero */
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if ( code_buf_ptr > 1 )
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{ /* Send remaining code. */
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for ( i = 0; i < code_buf_ptr; i++ ) writec(code_buf[i]);
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codesize += code_buf_ptr;
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}
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if ( print_progress )
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{
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printf(" In : %ld bytes\n", textsize); /* Encoding is done. */
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printf(" Out: %ld bytes\n", codesize);
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printf(" Out/In: %.3f\n", (double)codesize / textsize);
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}
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DeInitTree();
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return codesize;
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}
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///////////////////////////////////////////////////////////////////////////////////////
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//
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// Decompression code, cut & pasted from pre.cpp
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//
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///////////////////////////////////////////////////////////////////////////////////////
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#define RINGBUFFERSIZE 4096 /* N size of ring buffer */
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#define MATCHLIMIT 18 /* F upper limit for match_length */
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#define THRESHOLD 2 /* encode string into position and length */
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//#define WriteOut(x) {Dbg_MsgAssert(pOut<pIn,("Oops! Decompression overlap!\nIncrease IN_PLACE_DECOMPRESSION_MARGIN in sys\\file\\pip.cpp")); *pOut++ = x;}
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#define WriteOut(x) {*pOut++ = x;}
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#define USE_BUFFER 1 // we don't need no stinking buffer!!!!
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#if USE_BUFFER
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#ifdef __PLAT_NGPS__
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// ring buffer is just over 4K 4096+17),
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// so fits nicely in the PS2's 8K scratchpad
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static unsigned char sTextBuf[RINGBUFFERSIZE + MATCHLIMIT - 1];
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// Note: if we try to use the scratchpad, like this
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// then the code actually runs slower
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// if we want to optimize this, then it should
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// be hand crafted in assembly, using 128bit registers
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// const unsigned char * sTextBuf = (unsigned char*) 0x70000000;
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#else
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static unsigned char
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sTextBuf[RINGBUFFERSIZE + MATCHLIMIT - 1]; /* ring buffer of size N,
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with extra F-1 bytes to facilitate string comparison */
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#endif
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#endif
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#define ReadInto(x) if (!Len) break; Len--; x = *pIn++
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#define ReadInto2(x) Len--; x = *pIn++ // version that knows Len is Ok
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// Decode an LZSS encoded stream
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// Runs at approx 12MB/s on PS2 without scratchpad (which slows it down in C)
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// a 32x CD would run at 4.8MB/sec, although we seem to get a lot less than this
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// with our current file system, more like 600K per seconds.....
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// Need to write a fast streaming file system....
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// Ken: Made this return the new pOut so I can do some asserts to make sure it has
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// written the expected number of bytes.
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unsigned char *DecodeLZSS(unsigned char *pIn, unsigned char *pOut, int Len) /* Just the reverse of Encode(). */
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{
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int i, j, k, r, c;
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// uint64 LongWord;
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// int bytes = 0;
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// unsigned char *pScratch;
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unsigned int flags;
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// int basetime = (int) Tmr::ElapsedTime(0);
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// int len = Len;
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// int OutBytes = 4;
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// int OutWord = 0;
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#if USE_BUFFER
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for ( i = 0; i < RINGBUFFERSIZE - MATCHLIMIT; i++ )
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sTextBuf[i] = ' ';
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r = RINGBUFFERSIZE - MATCHLIMIT;
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#else
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r = RINGBUFFERSIZE - MATCHLIMIT;
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#endif
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flags = 0;
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for ( ; ; )
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{
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if ( ((flags >>= 1) & 256) == 0 )
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{
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ReadInto(c);
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flags = c | 0xff00; /* uses higher byte cleverly */
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} /* to count eight */
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if ( flags & 1 )
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{
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ReadInto(c);
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// putc(c, outfile);
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WriteOut(c);
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#if USE_BUFFER
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sTextBuf[r++] = c;
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r &= (RINGBUFFERSIZE - 1);
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#else
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r++;
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// r &= (RINGBUFFERSIZE - 1); // don't need to wrap r until it is used
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#endif
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}
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else
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{
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ReadInto(i);
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ReadInto2(j); // note, don't need to check len on this one....
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i |= ((j & 0xf0) << 4); // i is 12 bit offset
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#if !USE_BUFFER
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j = (j & 0x0f) + THRESHOLD+1; // j is 4 bit length (above the threshold)
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unsigned char *pStream;
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r &= (RINGBUFFERSIZE - 1); // wrap r around before it is used
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pStream = pOut - r; // get base of block
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if ( i>=r ) // if offset > r, then
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pStream -= RINGBUFFERSIZE; // it's the previous block
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pStream += i; // add in the offset to the base
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r+=j; // add size to r
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while ( j-- ) // copy j bytes
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WriteOut(*pStream++);
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#else
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j = (j & 0x0f) + THRESHOLD; // j is 4 bit length (above the threshold)
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for ( k = 0; k <= j; k++ ) // just copy the bytes
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{
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c = sTextBuf[(i+k) & (RINGBUFFERSIZE - 1)];
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WriteOut(c);
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sTextBuf[r++] = c;
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r &= (RINGBUFFERSIZE - 1);
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}
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#endif
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}
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}
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// int Time = (int) Tmr::ElapsedTime(basetime);
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// if (Time > 5)
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// {
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// printf("decomp time is %d ms, for %d bytes, %d bytes/second\n", Time,len, len * 1000 /Time );
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// }
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return pOut;
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}
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