Add ARC methods 5, 6 and 7, LZW with different hash tables, with and without non-repeat packing, aka crunch.

arc/crunch.c

@@ -0,0 +1,294 @@
+/*
+ * This file is part of the Aaru Data Preservation Suite.
+ * Copyright (c) 2019-2025 Natalia Portillo.
+ * Copyright © 2018-2019 David Ryskalczyk
+ *
+ * This library 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 2.1 of the
+ * License, or (at your option) any later version.
+ *
+ * This library 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 this library; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "../library.h"
+
+#define FALSE   0
+#define TRUE    !FALSE
+#define TABSIZE 4096    // Size of the string table.
+#define NO_PRED 0xFFFF  // Indicates no predecessor in the string table.
+#define EMPTY   0xFFFF  // Indicates an empty stack.
+
+typedef unsigned char  u_char;
+typedef unsigned short u_short;
+
+// Entry in the string table.
+struct entry
+{
+    char    used;         // Is this entry in use?
+    u_char  follower;     // The character that follows the string.
+    u_short next;         // Next entry in a collision chain.
+    u_short predecessor;  // Code for the preceding string.
+};
+
+// Static variables for decompression state.
+static struct entry *string_tab;
+static u_char       *stack;
+static int           sp;
+
+// Buffer management variables.
+static const u_char *in_buf_ptr;
+static size_t        in_len_rem;
+static int           inflag;
+
+// Pointer to the hash function to use.
+static u_short (*h)(u_short, u_char);
+
+// Original hash function from ARC.
+static u_short oldh(u_short pred, u_char foll)
+{
+    long local;
+    local = ((pred + foll) | 0x0800) & 0xFFFF;
+    local *= local;
+    return (local >> 6) & 0x0FFF;
+}
+
+// Newer, faster hash function.
+static u_short newh(u_short pred, u_char foll) { return (((pred + foll) & 0xFFFF) * 15073) & 0xFFF; }
+
+// Finds the end of a collision list.
+static u_short eolist(u_short index)
+{
+    int temp;
+    while((temp = string_tab[index].next)) index = temp;
+    return index;
+}
+
+// Hashes a string to find its position in the table.
+static u_short hash_it(u_short pred, u_char foll)
+{
+    u_short       local, tempnext;
+    struct entry *ep;
+
+    local = (*h)(pred, foll);
+
+    if(!string_tab[local].used)
+        return local;
+    else
+    {
+        local    = eolist(local);
+        tempnext = (local + 101) & 0x0FFF;
+        ep       = &string_tab[tempnext];
+
+        while(ep->used)
+        {
+            if(++tempnext == TABSIZE)
+            {
+                tempnext = 0;
+                ep       = string_tab;
+            }
+            else
+                ++ep;
+        }
+        string_tab[local].next = tempnext;
+        return tempnext;
+    }
+}
+
+// Adds a new string to the table.
+static void upd_tab(u_short pred, u_short foll)
+{
+    struct entry *ep;
+    ep              = &string_tab[hash_it(pred, foll)];
+    ep->used        = TRUE;
+    ep->next        = 0;
+    ep->predecessor = pred;
+    ep->follower    = foll;
+}
+
+// Initializes the string table.
+static void init_tab()
+{
+    memset((char *)string_tab, 0, TABSIZE * sizeof(struct entry));
+    for(unsigned int i = 0; i < 256; i++) upd_tab(NO_PRED, i);
+}
+
+// Reads a 12-bit code from the input buffer.
+static int get_code()
+{
+    int code;
+    if(in_len_rem < 2) return -1;
+
+    if((inflag ^= 1))
+    {
+        code = (*in_buf_ptr++ << 4);
+        code |= (*in_buf_ptr >> 4);
+        in_len_rem--;
+    }
+    else
+    {
+        code = (*in_buf_ptr++ & 0x0f) << 8;
+        code |= (*in_buf_ptr++);
+        in_len_rem -= 2;
+    }
+    return code;
+}
+
+// Pushes a character onto the stack.
+#define PUSH(c)                        \
+    do {                               \
+        stack[sp] = ((char)(c));       \
+        if(++sp >= TABSIZE) return -1; \
+    } while(0)
+
+// Pops a character from the stack.
+#define POP() ((sp > 0) ? (int)stack[--sp] : EMPTY)
+
+// Internal crunch decompression logic.
+static int arc_decompress_crunch_internal(const unsigned char *in_buf, size_t in_len, unsigned char *out_buf,
+                                          size_t *out_len, int new_hash)
+{
+    // Basic validation of pointers.
+    if(!in_buf || !out_buf || !out_len) { return -1; }
+
+    // Allocate memory for tables.
+    string_tab = (struct entry *)malloc(TABSIZE * sizeof(struct entry));
+    stack      = (u_char *)malloc(TABSIZE * sizeof(u_char));
+    if(!string_tab || !stack)
+    {
+        if(string_tab) free(string_tab);
+        if(stack) free(stack);
+        return -1;
+    }
+
+    // Select the hash function.
+    if(new_hash)
+        h = newh;
+    else
+        h = oldh;
+
+    // Initialize state.
+    sp = 0;
+    init_tab();
+    int code_count = TABSIZE - 256;
+    in_buf_ptr     = in_buf;
+    in_len_rem     = in_len;
+    inflag         = 0;
+
+    // Main decompression loop.
+    int oldcode = get_code();
+    if(oldcode == -1)
+    {
+        *out_len = 0;
+        free(string_tab);
+        free(stack);
+        return 0;
+    }
+    int finchar = string_tab[oldcode].follower;
+
+    size_t out_pos = 0;
+    if(out_pos < *out_len) { out_buf[out_pos++] = finchar; }
+
+    int newcode;
+    while((newcode = get_code()) != -1)
+    {
+        int           code = newcode;
+        struct entry *ep   = &string_tab[code];
+
+        // Handle unknown codes and KwKwK case.
+        if(!ep->used)
+        {
+            code = oldcode;
+            ep   = &string_tab[code];
+            PUSH(finchar);
+        }
+        // Decode the string by traversing the table.
+        while(ep->predecessor != NO_PRED)
+        {
+            PUSH(ep->follower);
+            code = ep->predecessor;
+            ep   = &string_tab[code];
+        }
+        PUSH(finchar = ep->follower);
+
+        // Add the new string to the table if there's room.
+        if(code_count)
+        {
+            upd_tab(oldcode, finchar);
+            --code_count;
+        }
+        oldcode = newcode;
+
+        // Write the decoded string to the output buffer.
+        while(sp > 0)
+        {
+            int c = POP();
+            if(c == EMPTY) break;
+            if(out_pos < *out_len) { out_buf[out_pos++] = (unsigned char)c; }
+        }
+    }
+
+    // Clean up and return.
+    *out_len = out_pos;
+    free(string_tab);
+    free(stack);
+    return 0;
+}
+
+// Decompresses crunched data.
+AARU_EXPORT int AARU_CALL arc_decompress_crunch(const unsigned char *in_buf, size_t in_len, unsigned char *out_buf,
+                                                size_t *out_len)
+{
+    return arc_decompress_crunch_internal(in_buf, in_len, out_buf, out_len, 0);
+}
+
+// Decompresses crunched data with non-repeat packing.
+AARU_EXPORT int AARU_CALL arc_decompress_crunch_nrpack(const unsigned char *in_buf, size_t in_len,
+                                                       unsigned char *out_buf, size_t *out_len)
+{
+    // Allocate a temporary buffer for the intermediate decompressed data.
+    size_t         temp_len = *out_len * 2;  // Heuristic for temp buffer size.
+    unsigned char *temp_buf = malloc(temp_len);
+    if(!temp_buf) return -1;
+
+    // First, decompress the crunched data.
+    int result = arc_decompress_crunch_internal(in_buf, in_len, temp_buf, &temp_len, 0);
+    if(result == 0)
+    {
+        // Then, decompress the non-repeat packing.
+        result = arc_decompress_pack(temp_buf, temp_len, out_buf, out_len);
+    }
+
+    free(temp_buf);
+    return result;
+}
+
+// Decompresses crunched data with non-repeat packing and the new hash function.
+AARU_EXPORT int AARU_CALL arc_decompress_crunch_nrpack_new(const unsigned char *in_buf, size_t in_len,
+                                                           unsigned char *out_buf, size_t *out_len)
+{
+    // Allocate a temporary buffer.
+    size_t         temp_len = *out_len * 2;  // Heuristic.
+    unsigned char *temp_buf = malloc(temp_len);
+    if(!temp_buf) return -1;
+
+    // Decompress crunched data with the new hash.
+    int result = arc_decompress_crunch_internal(in_buf, in_len, temp_buf, &temp_len, 1);
+    if(result == 0)
+    {
+        // Decompress non-repeat packing.
+        result = arc_decompress_pack(temp_buf, temp_len, out_buf, out_len);
+    }
+
+    free(temp_buf);
+    return result;
+}