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engines/glk/adrift/scutils.cpp

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+/* ScummVM - Graphic Adventure Engine
+ *
+ * ScummVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * 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 3 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, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include "glk/adrift/scare.h"
+#include "glk/adrift/scprotos.h"
+#include "glk/glk.h"
+#include "glk/events.h"
+#include "common/debug.h"
+#include "common/str.h"
+#include "common/textconsole.h"
+
+namespace Glk {
+namespace Adrift {
+
+/*
+ * Module notes:
+ *
+ * o Implement smarter selective module tracing.
+ */
+
+/*
+ * sc_trace()
+ *
+ * Debugging trace function; printf wrapper that writes to stderr.
+ */
+void sc_trace(const sc_char *format, ...) {
+	va_list ap;
+	assert(format);
+
+	va_start(ap, format);
+	Common::String s = Common::String::format(format, ap);
+	va_end(ap);
+	debug("%s", s.c_str());
+}
+
+
+/*
+ * sc_error()
+ * sc_fatal()
+ *
+ * Error reporting functions.  sc_error() prints a message and continues.
+ * sc_fatal() prints a message, then calls abort().
+ */
+void sc_error(const sc_char *format, ...) {
+	va_list ap;
+	assert(format);
+
+	va_start(ap, format);
+	Common::String s = Common::String::vformat(format, ap);
+	va_end(ap);
+	warning("%s", s.c_str());
+}
+
+void sc_fatal(const sc_char *format, ...) {
+	va_list ap;
+	assert(format);
+
+	va_start(ap, format);
+	Common::String s = Common::String::format(format, ap);
+	va_end(ap);
+	error("%s", s.c_str());
+}
+
+
+/* Unique non-heap address for zero size malloc() and realloc() requests. */
+static void *sc_zero_allocation = &sc_zero_allocation;
+
+/*
+ * sc_malloc()
+ * sc_realloc()
+ * sc_free()
+ *
+ * Non-failing wrappers around malloc functions.  Newly allocated memory is
+ * cleared to zero.  In ANSI/ISO C, zero byte allocations are implementation-
+ * defined, so we have to take special care to get predictable behavior.
+ */
+void *sc_malloc(size_t size) {
+	void *allocated;
+
+	if (size == 0)
+		return sc_zero_allocation;
+
+	allocated = malloc(size);
+	if (!allocated)
+		sc_fatal("sc_malloc: requested %lu bytes\n", (sc_uint) size);
+	else if (allocated == sc_zero_allocation)
+		sc_fatal("sc_malloc: zero-byte allocation address returned\n");
+
+	memset(allocated, 0, size);
+	return allocated;
+}
+
+void *sc_realloc(void *pointer, size_t size) {
+	void *allocated;
+
+	if (size == 0) {
+		sc_free(pointer);
+		return sc_zero_allocation;
+	}
+
+	if (pointer == sc_zero_allocation)
+		pointer = nullptr;
+
+	allocated = realloc(pointer, size);
+	if (!allocated)
+		sc_fatal("sc_realloc: requested %lu bytes\n", (sc_uint) size);
+	else if (allocated == sc_zero_allocation)
+		sc_fatal("sc_realloc: zero-byte allocation address returned\n");
+
+	if (!pointer)
+		memset(allocated, 0, size);
+	return allocated;
+}
+
+void sc_free(void *pointer) {
+	if (sc_zero_allocation != &sc_zero_allocation)
+		sc_fatal("sc_free: write to zero-byte allocation address detected\n");
+
+	if (pointer && pointer != sc_zero_allocation)
+		free(pointer);
+}
+
+
+/*
+ * sc_strncasecmp()
+ * sc_strcasecmp()
+ *
+ * Strncasecmp and strcasecmp are not ANSI functions, so here are local
+ * definitions to do the same jobs.
+ */
+sc_int sc_strncasecmp(const sc_char *s1, const sc_char *s2, sc_int n) {
+	sc_int index_;
+	assert(s1 && s2);
+
+	for (index_ = 0; index_ < n; index_++) {
+		sc_int diff;
+
+		diff = sc_tolower(s1[index_]) - sc_tolower(s2[index_]);
+		if (diff < 0 || diff > 0)
+			return diff < 0 ? -1 : 1;
+	}
+
+	return 0;
+}
+
+sc_int sc_strcasecmp(const sc_char *s1, const sc_char *s2) {
+	sc_int s1len, s2len, result;
+	assert(s1 && s2);
+
+	s1len = strlen(s1);
+	s2len = strlen(s2);
+
+	result = sc_strncasecmp(s1, s2, s1len < s2len ? s1len : s2len);
+	if (result < 0 || result > 0)
+		return result;
+	else
+		return s1len < s2len ? -1 : s1len > s2len ? 1 : 0;
+}
+
+
+/*
+ * sc_platform_rand()
+ * sc_congruential_rand()
+ * sc_set_random_handler()
+ *
+ * Internal random number generation functions.  We offer two: one is a self-
+ * seeding wrapper around the platform's rand(), which should generate good
+ * random numbers but with a sequence that is platform-dependent; the other
+ * is a linear congruential generator with a long period that is guaranteed
+ * to return the same sequence for all platforms.  The default is the first,
+ * with the latter intended for predictability of game actions.
+ */
+static sc_int sc_platform_rand(sc_uint new_seed) {
+	static sc_bool is_seeded = FALSE;
+
+	/* If reseeding, seed with the value supplied, note seeded, and return 0. */
+	if (new_seed > 0) {
+		g_vm->setRandomNumberSeed(new_seed);
+		is_seeded = TRUE;
+		return 0;
+	} else {
+		/* If not explicitly seeded yet, generate a seed from time(). */
+		if (!is_seeded) {
+			//srand ((sc_uint) time (NULL));
+			is_seeded = TRUE;
+		}
+
+		/* Return the next rand() number in the sequence. */
+		return g_vm->getRandomNumber(0xffffff);
+	}
+}
+
+static sc_int sc_congruential_rand(sc_uint new_seed) {
+	static sc_bool is_seeded = FALSE;
+	static sc_uint rand_state = 1;
+
+	/* If reseeding, seed with the value supplied, and note seeded. */
+	if (new_seed > 0) {
+		rand_state = new_seed;
+		is_seeded = TRUE;
+		return 0;
+	} else {
+		/* If not explicitly seeded yet, generate a seed from time(). */
+		if (!is_seeded) {
+			rand_state = (sc_uint)g_vm->_events->getTotalPlayTicks();
+			is_seeded = TRUE;
+		}
+
+		/*
+		 * Advance random state, using constants from Park & Miller (1988).
+		 * To keep the values the same for both 32 and 64 bit longs, mask out
+		 * any bits above the bottom 32.
+		 */
+		rand_state = (rand_state * 16807 + 2147483647) & 0xffffffff;
+
+		/*
+		 * Discard the lowest bit as a way to map 32-bits unsigned to a 32-bit
+		 * positive signed.
+		 */
+		return rand_state >> 1;
+	}
+}
+
+
+/* Function pointer for the actual random number generator in use. */
+static sc_int(*sc_rand_function)(sc_uint) = sc_platform_rand;
+
+/*
+ * sc_set_congruential_random()
+ * sc_set_platform_random()
+ * sc_is_congruential_random()
+ * sc_seed_random()
+ * sc_rand()
+ * sc_randomint()
+ *
+ * Public interface to random functions; control and reseed the random
+ * handler in use, generate a random number, and a convenience function to
+ * generate a random value within a given range.
+ */
+void sc_set_congruential_random(void) {
+	sc_rand_function = sc_congruential_rand;
+}
+
+void sc_set_platform_random(void) {
+	sc_rand_function = sc_platform_rand;
+}
+
+sc_bool sc_is_congruential_random(void) {
+	return sc_rand_function == sc_congruential_rand;
+}
+
+void sc_seed_random(sc_uint new_seed) {
+	/* Ignore zero values of new_seed by simply using 1 instead. */
+	sc_rand_function(new_seed > 0 ? new_seed : 1);
+}
+
+sc_int sc_rand(void) {
+	sc_int retval;
+
+	/* Passing zero indicates this is not a seed operation. */
+	retval = sc_rand_function(0);
+	return retval;
+}
+
+sc_int sc_randomint(sc_int low, sc_int high) {
+	/*
+	 * If the range is invalid, just return the low value given.  This mimics
+	 * Adrift under the same conditions, and also guards against division by
+	 * zero in the mod operation.
+	 */
+	return (high < low) ? low : low + sc_rand() % (high - low + 1);
+}
+
+
+/* Miscellaneous general ascii constants. */
+static const sc_char NUL = '\0';
+static const sc_char SPACE = ' ';
+
+/*
+ * sc_strempty()
+ *
+ * Return TRUE if a string is either zero-length or contains only whitespace.
+ */
+sc_bool sc_strempty(const sc_char *string) {
+	sc_int index_;
+	assert(string);
+
+	/* Scan for any non-space character. */
+	for (index_ = 0; string[index_] != NUL; index_++) {
+		if (!sc_isspace(string[index_]))
+			return FALSE;
+	}
+
+	/* None found, so string is empty. */
+	return TRUE;
+}
+
+
+/*
+ * sc_trim_string()
+ *
+ * Trim leading and trailing whitespace from a string.  Modifies the string
+ * in place, and returns the string address for convenience.
+ */
+sc_char *sc_trim_string(sc_char *string) {
+	sc_int index_;
+	assert(string);
+
+	for (index_ = strlen(string) - 1;
+	        index_ >= 0 && sc_isspace(string[index_]); index_--)
+		string[index_] = NUL;
+
+	for (index_ = 0; sc_isspace(string[index_]);)
+		index_++;
+	memmove(string, string + index_, strlen(string) - index_ + 1);
+
+	return string;
+}
+
+
+/*
+ * sc_normalize_string()
+ *
+ * Trim a string, and set all runs of whitespace to a single space character.
+ * Modifies the string in place, and returns the string address for
+ * convenience.
+ */
+sc_char *sc_normalize_string(sc_char *string) {
+	sc_int index_;
+	assert(string);
+
+	/* Trim all leading and trailing spaces. */
+	string = sc_trim_string(string);
+
+	/* Compress multiple whitespace runs into a single space character. */
+	for (index_ = 0; string[index_] != NUL; index_++) {
+		if (sc_isspace(string[index_])) {
+			sc_int cursor;
+
+			string[index_] = SPACE;
+			for (cursor = index_ + 1; sc_isspace(string[cursor]);)
+				cursor++;
+			memmove(string + index_ + 1,
+			        string + cursor, strlen(string + cursor) + 1);
+		}
+	}
+
+	return string;
+}
+
+
+/*
+ * sc_compare_word()
+ *
+ * Return TRUE if the first word in the string is word, case insensitive.
+ */
+sc_bool sc_compare_word(const sc_char *string, const sc_char *word, sc_int length) {
+	assert(string && word);
+
+	/* Return TRUE if string starts with word, then space or string end. */
+	return sc_strncasecmp(string, word, length) == 0
+	       && (string[length] == NUL || sc_isspace(string[length]));
+}
+
+
+/*
+ * sc_hash()
+ *
+ * Hash a string, hashpjw algorithm, from 'Compilers, principles, techniques,
+ * and tools', page 436, unmodulo'ed and somewhat restyled.
+ */
+sc_uint sc_hash(const sc_char *string) {
+	sc_int index_;
+	sc_uint hash;
+	assert(string);
+
+	hash = 0;
+	for (index_ = 0; string[index_] != NUL; index_++) {
+		sc_uint temp;
+
+		hash = (hash << 4) + string[index_];
+		temp = hash & 0xf0000000;
+		if (temp != 0) {
+			hash = hash ^ (temp >> 24);
+			hash = hash ^ temp;
+		}
+	}
+
+	return hash;
+}
+
+} // End of namespace Adrift
+} // End of namespace Glk