Support Sin .sin pak files

Apparently the only differences to Q2 paks are the header being "SPAK"
instead of "PACK" and directory entry's names being 120chars long
instead of 56, see:
https://github.com/id-Software/RTCW-SP/blob/master/src/bspc/l_qfiles.h#L71

This even seems to work.
Refactored a bit to easily support Q2, DK and Sin (and maybe more?) paks
and rewrote mktree() in a shorter, more elegant way without malloc() :)

README

@@ -29,6 +29,8 @@ following order:
    in bytes. Since every directory entry is 64 bytes 
    long this value modulo 64 must be 0: 
      (dir_length % 64) == 0;
+   Also this means that the number of directory entries
+   can be calculated with dir_length / 64
 
 The directory can be anywere in the file but most times
 it's written to the end. In consists of datablocks, 
@@ -41,6 +43,21 @@ in the following order:
  - A 4 byte integer giving the length of the file
    in bytes.
 
+------------------------------------------------------
+
+            The Sin Pak File Format (.sin)
+            ------------------------------
+
+It's very similar to the Quake II format, there are only
+small differences:
+ - The header on the start of the file starts with "SPAK"
+   instead of "PACK"
+ - The filename in the directory entry is 120 bytes long
+   => a directory entry is 128 bytes long instead of 64
+   => the number of directory entries is dir_length / 128
+      instead of dir_length / 64
+
+
 -------------------------------------------------------
 
             The Daikatana Pak File Format
@@ -51,7 +68,7 @@ additionally supports compressing files within the pak.
 Daikatana only did that for .tga .bmp .wal .pcx and .bsp files and might
 expect other files to be uncompressed (in case you want to write a compressor).
 
-In Daikatana directory entries are 72 bytes long, because they have to
+In Daikatana directory entries are 72 bytes long, because they have two
 additional 4byte integer fields at the end:
  - A 4 byte integer giving the compressed length of the file in bytes,
    if it is compressed.

pakextract.c

@@ -1,6 +1,6 @@
 /*-
  * Copyright (c) 2012-2016 Yamagi Burmeister
- *               2015-2016 Daniel Gibson
+ *               2015-2017 Daniel Gibson
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -31,14 +31,38 @@
 #include <string.h>
 
 #include <unistd.h> // chdir()
-#include <sys/stat.h>
+#include <sys/stat.h> // mkdir()
 
 
 #include <assert.h>
 
+
 enum {
-	HDR_DIR_LEN_Q2 = 64,
+	PAK_MODE_Q2, // standard Quake/Quake2 pak
-	HDR_DIR_LEN_DK = 72
+	PAK_MODE_SIN,
+	PAK_MODE_DK,
+	
+	_NUM_PAK_MODES
+};
+
+static int pak_mode = PAK_MODE_Q2;
+
+static const char* PAK_MODE_NAMES[_NUM_PAK_MODES] = {
+	"Quake(2)",  // PAK_MODE_Q2
+	"Sin",       // PAK_MODE_SIN
+	"Daikatana", // PAK_MODE_DK
+};
+
+static const int HDR_LEN[_NUM_PAK_MODES] = {
+	64,  // PAK_MODE_Q2
+	128, // PAK_MODE_SIN
+	72,  // PAK_MODE_DK
+};
+
+static const int DIR_FILENAME_LEN[_NUM_PAK_MODES] = {
+	56,  // PAK_MODE_Q2
+	120, // PAK_MODE_SIN
+	56,  // PAK_MODE_DK
 };
 
 /* Holds the pak header */
@@ -49,12 +73,11 @@ struct
 	int dir_length;
 } header;
 
-int dk_pak_mode = 0;
 
 /* A directory entry */
 typedef struct
 {
-	char file_name[56];
+	char file_name[120];
 	int file_pos;
 	int file_length; // in case of is_compressed: size after decompression
 
@@ -72,34 +95,24 @@ typedef struct
  *        ommitted
  */
 static void
-mktree(char *s)
+mktree(const char *s)
 {
-	char *dir;
+	char dir[128] = {0};
-	char *elements[28];
+	int i;
-	char *path;
+	int sLen = strlen(s);
-	char *token;
-	int i, j;
 
-	path = calloc(56, sizeof(char));
+	strncpy(dir, s, sizeof(dir)-1);
-	dir = malloc(sizeof(char) * 56);
 	
-	strncpy(dir, s, sizeof(char) * 56);
+	for(i=1; i<sLen; ++i)
-
-	for (i = 0; (token = strsep(&dir, "/")) != NULL; i++)
 	{
-		elements[i] = token;
+		if(dir[i] == '/')
-	}
-
-	for (j = 0; j < i - 1; j++)
 		{
-		strcat(path, elements[j]);
+			dir[i] = '\0'; // this ends the string at this point and allows creating the directory up to here
-		strcat(path, "/");
+			mkdir(dir, 0700);
 			
-		mkdir(path, 0700);
+			dir[i] = '/'; // restore the / so we can can go on to create next directory
+		}
 	}
-
-	free(path);
-	free(dir);
 }
 
 /*
@@ -133,21 +146,25 @@ read_header(FILE *fd)
 
 	// TODO: we could convert the ints to platform endianess now
 
-	if (strncmp(header.signature, "PACK", 4) != 0)
+	if (strncmp(header.signature, "SPAK", 4) == 0)
+	{
+		pak_mode = PAK_MODE_SIN;
+	}
+	else if (strncmp(header.signature, "PACK", 4) != 0)
 	{
 		fprintf(stderr, "Not a pak file\n");
 		return 0;
 	}
 
-	int direntry_len = dk_pak_mode ? HDR_DIR_LEN_DK : HDR_DIR_LEN_Q2;
+	int direntry_len = HDR_LEN[pak_mode];
 
 	// Note that this check is not reliable, it could pass and it could still be the wrong kind of pak!
 	if ((header.dir_length % direntry_len) != 0)
 	{
-		const char* curmode = dk_pak_mode ? "Daikatana" : "Quake(2)";
+		const char* curmode = PAK_MODE_NAMES[pak_mode];
-		const char* othermode = (!dk_pak_mode) ? "Daikatana" : "Quake(2)";
+		const char* othermode = (pak_mode != PAK_MODE_DK) ? "Daikatana" : "Quake(2)";
 		fprintf(stderr, "Corrupt pak file - maybe it's not %s format but %s format?\n", curmode, othermode);
-		if(!dk_pak_mode)
+		if(pak_mode != PAK_MODE_DK)
 			fprintf(stderr, "If this is a Daikatana .pak file, try adding '-dk' to command-line!\n");
 		else
 			fprintf(stderr, "Are you sure this is a Daikatana .pak file? Try removing '-dk' from command-line!\n");
@@ -161,11 +178,11 @@ read_header(FILE *fd)
 static int
 read_dir_entry(directory* entry, FILE* fd)
 {
-	if(fread(entry->file_name, 56, 1, fd) != 1) return 0;
+	if(fread(entry->file_name, DIR_FILENAME_LEN[pak_mode], 1, fd) != 1) return 0;
 	if(fread(&(entry->file_pos), 4, 1, fd) != 1) return 0;
 	if(fread(&(entry->file_length), 4, 1, fd) != 1) return 0;
 
-	if(dk_pak_mode)
+	if(pak_mode == PAK_MODE_DK)
 	{
 		if(fread(&(entry->compressed_length), 4, 1, fd) != 1) return 0;
 		if(fread(&(entry->is_compressed), 4, 1, fd) != 1) return 0;
@@ -193,7 +210,7 @@ static directory *
 read_directory(FILE *fd, int listOnly, int* num_entries)
 {
 	int i;
-	int direntry_len = dk_pak_mode ? HDR_DIR_LEN_DK : HDR_DIR_LEN_Q2;
+	int direntry_len = HDR_LEN[pak_mode];
 	int num_dir_entries = header.dir_length / direntry_len;
 	directory* dir = calloc(num_dir_entries, sizeof(directory));
 
@@ -222,7 +239,7 @@ read_directory(FILE *fd, int listOnly, int* num_entries)
 		{
 			printf("%s (%d bytes", cur->file_name, cur->file_length);
 			
-			if(dk_pak_mode && cur->is_compressed)
+			if((pak_mode == PAK_MODE_DK) && cur->is_compressed)
 				printf(", %d compressed", cur->compressed_length);
 			
 			printf(")\n");
@@ -368,7 +385,7 @@ extract_files(FILE *fd, directory *dirs, int num_entries)
 
 		if(d->is_compressed)
 		{
-			assert(dk_pak_mode != 0 && "Only Daikatana paks contain compressed files!");
+			assert((pak_mode == PAK_MODE_DK) && "Only Daikatana paks contain compressed files!");
 			extract_compressed(fd, d);
 		}
 		else
@@ -382,19 +399,14 @@ static void
 printUsage(const char* argv0)
 {
 
-	fprintf(stderr, "Extractor for Quake/Quake2 (and compatible) and Daikatana .pak files\n");
+	fprintf(stderr, "Extractor for Quake/Quake2 (and compatible) and Daikatana .pak and Sin .sin files\n");
 
 	fprintf(stderr, "Usage: %s [-l] [-dk] [-o output dir] pakfile\n", argv0);
 	fprintf(stderr, "       -l     don't extract, just list contents\n");
-	fprintf(stderr, "       -dk    Daikatana pak format (Quake is default)\n");
+	fprintf(stderr, "       -dk    Daikatana pak format (Quake is default, Sin is detected automatically)\n");
 	fprintf(stderr, "       -o     directory to extract to\n");
 }
 
-/*
- * A small programm to extract a Quake II pak file.
- * The pak file is given as the first an only 
- * argument.
- */
 int
 main(int argc, char *argv[])
 {
@@ -418,7 +430,7 @@ main(int argc, char *argv[])
 	{
 		const char* arg = argv[i];
 		if(strcmp(arg, "-l") == 0) list_only = 1;
-		else if(strcmp(arg, "-dk") == 0) dk_pak_mode = 1;
+		else if(strcmp(arg, "-dk") == 0) pak_mode = PAK_MODE_DK;
 		else if(strcmp(arg, "-o") == 0)
 		{
 			++i; // go to next argument (should be out_dir)