add a flag when debugging to generate SIGFPE when signed integer overflow occurs. (this is UB)

this is definitely not all of them, a thorough rewrite must take place
to fix as many as we can.

include/endian.h

@@ -1,9 +1,45 @@
 /* Copyright (c) 2025 Quinn
  * Licensed under the MIT Licence. See LICENSE for details */
-#pragma once
 
-#if __has_include(<endian.h>)
-#include <endian.h>
+#ifndef PORTABLE_ENDIAN_H
+#define PORTABLE_ENDIAN_H
+
+#if defined(__GNUC__)
+
+/* test for the byteswap header */
+#if __has_include(<byteswap.h>)
+#include <byteswap.h>
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+#define le16toh(x) (x)
+#define le32toh(x) (x)
+#define le64toh(x) (x)
+#define htole16(x) (x)
+#define htole32(x) (x)
+#define htole64(x) (x)
+#define be16toh(x) __bswap16(x)
+#define be32toh(x) __bswap32(x)
+#define be64toh(x) __bswap64(x)
+#define htobe16(x) __bswap16(x)
+#define htobe32(x) __bswap32(x)
+#define htobe64(x) __bswap64(x)
+#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+#define le16toh(x) __bswap16(x)
+#define le32toh(x) __bswap32(x)
+#define le64toh(x) __bswap64(x)
+#define htole16(x) __bswap16(x)
+#define htole32(x) __bswap32(x)
+#define htole64(x) __bswap64(x)
+#define be16toh(x) (x)
+#define be32toh(x) (x)
+#define be64toh(x) (x)
+#define htobe16(x) (x)
+#define htobe32(x) (x)
+#define htobe64(x) (x)
+#else
+#error machine architecture unsupported! Expected either big-endian or little-endian, make sure to use a compiler which defines __BYTE_ORDER__ (like clang or gcc)
+#endif /* byte order */
+
+/* otherwise, utilise the compiler built-ins */
 #else
 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
 #define le16toh(x) __uint16_identity(x)
@@ -33,5 +69,12 @@
 #define htobe64(x) __uint64_identity(x)
 #else
 #error machine architecture unsupported! Expected either big-endian or little-endian, make sure to use a compiler which defines __BYTE_ORDER__ (like clang or gcc)
-#endif
-#endif
+#endif /* byte order */
+
+#endif /* has byteswap.h */
+
+#else
+#error GNU C is unavailable
+#endif /* __GNUC__ */
+
+#endif /* PORTABLE_ENDIAN_H */

makefile

@@ -14,7 +14,7 @@ MARCH   ?= $(shell uname -m)
 KERNEL  ?= $(shell uname -s | tr '[:upper:]' '[:lower:]')
 
 # compilation flags
-CFLAGS  += -c -std=gnu99 -Wall -Wextra -Wpedantic -MMD -MP
+CFLAGS  += -c -std=gnu99 -Wall -Wextra -Wpedantic -MMD -MP -Wno-pointer-arith
 LDFLAGS += -flto
 
 # architecture/OS detection
@@ -38,20 +38,20 @@ endif
 ifeq ($(DEBUG),1)
 PROF = dbg
 CFLAGS  += -UNDEBUG -Og -g -Wextra -Wpedantic
-CFLAGS  += $(if $(filter 1,$(ISWIN)),,-fsanitize=address,undefined)
-LDFLAGS += $(if $(filter 1,$(ISWIN)),,-fsanitize=address,undefined)
+CFLAGS  += $(if $(filter 1,$(ISWIN)),,-fsanitize=address,undefined) -ftrapv
+LDFLAGS += $(if $(filter 1,$(ISWIN)),,-fsanitize=address,undefined) -ftrapv
 # |--profile: testing
 else ifeq ($(DEBUG),test)
 PROF = test
 CFLAGS  += -UNDEBUG -O2 -g
-CFLAGS  += $(if $(filter 1,$(ISWIN)),,-fsanitize=address)
-LDFLAGS += $(if $(filter 1,$(ISWIN)),,-fsanitize=address)
+CFLAGS  += $(if $(filter 1,$(ISWIN)),,-fsanitize=address) -ftrapv
+LDFLAGS += $(if $(filter 1,$(ISWIN)),,-fsanitize=address) -ftrapv
 else
 PROF = rel
 CFLAGS += -DNDEBUG -O2
 endif
 
-CFLAGS  += $(shell pkg-config --cflags glfw3 libarchive) -Ilib/glad/include
+CFLAGS  += $(shell pkg-config --cflags glfw3 libarchive) -Ilib/include -Ilib/glad/include
 LDFLAGS += $(shell pkg-config --libs glfw3 libarchive) -lm
 
 # get source files

src/dat/mcx.c

@@ -3,12 +3,12 @@
 #include "mcx.h"
 
 #include <assert.h>
+#include <endian.h>
 #include <stdint.h>
 #include <stdlib.h>
 #include <string.h>
 #include <time.h>
 
-#include "../util/compat/endian.h"
 #include "../util/intdef.h"
 
 #define TABLE  0x2000 // table byte size
@@ -16,10 +16,10 @@
 #define CHUNKS 0x400  // amount of chunks in a file
 
 /* Moves chunks `src_s` to `src_e` (inclusive) from `src`, back onto `dst`. */
-static void mvchunks(u8 *restrict buf, u8 *src, u8 *dst, int src_s, int src_e) {
+static void mvchunks(void *restrict buf, void *src, void *dst, int src_s, int src_e) {
 	assert(src > dst);
-	u32 *table = (u32 *)buf;
-	size_t len = src - dst; // acquire the amount of bytes that we shall move
+	u32 *table = (u32 *)buf; // BUG: strict aliasing
+	size_t len = src - dst;  // acquire the amount of bytes that we shall move
 	assert(!(len % SECTOR));
 
 	// count how many bytes we need to move, whilst updating location data
@@ -34,9 +34,9 @@ static void mvchunks(u8 *restrict buf, u8 *src, u8 *dst, int src_s, int src_e) {
 /* Deletes chunk `sidx` by moving chunks up to `eidx` back over `sidx` in `buf`.
  * `rmb` is an optional additional offset that can be applied, and signifies bytes already removed.
  * Returns the bytes removed by this function. */
-static size_t delchunk(u8 *restrict buf, size_t rmb, int sidx, int eidx) {
+static size_t delchunk(void *restrict buf, size_t rmb, int sidx, int eidx) {
 	// load the table data
-	u32 *table = (u32 *)buf;
+	u32 *table = (u32 *)buf; // BUG: strict aliasing
 	size_t slen, bidx, blen;
 	slen = be32toh(table[sidx]) & 0xFF;          // acquire the sector length of the chunk
 	bidx = (be32toh(table[sidx]) >> 8) * SECTOR; // acquire and compute the byte offset the chunk starts at
@@ -47,8 +47,8 @@ static size_t delchunk(u8 *restrict buf, size_t rmb, int sidx, int eidx) {
 	table[sidx + CHUNKS] = htobe32(time(NULL)); // assign the current time to the timestamp, for correctness  NOTE: might need to zero-out instead
 
 	// move the succeeding chunks over the deleted chunk
-	u8 *dst = buf + bidx - rmb;
-	u8 *src = buf + bidx + blen;
+	void *dst = buf + bidx - rmb;
+	void *src = buf + bidx + blen;
 	mvchunks(buf, src, dst, sidx, eidx - 1);
 	return blen;
 }
@@ -56,22 +56,22 @@ static size_t delchunk(u8 *restrict buf, size_t rmb, int sidx, int eidx) {
 /* Just call `delchunk` with the parameters and some defaults.
  * This is done instead of `delchunk` being globally linked, because
  * `delchunk` requests more specific parameters, which is confusing outside this module. */
-size_t mcx_delchunk(u8 *restrict buf, int chunk) {
+size_t mcx_delchunk(void *restrict buf, int chunk) {
 	return delchunk(buf, 0, chunk, CHUNKS);
 }
 
-size_t mcx_delchunk_range(u8 *restrict buf, int start, int end) {
+size_t mcx_delchunk_range(void *restrict buf, int start, int end) {
 	assert(start < end && end < CHUNKS);
-	u32 *table = (u32 *)buf;
-	u8 *dst = buf + (be32toh(table[start]) >> 8) * SECTOR;
-	u8 *src = buf + (be32toh(table[end]) >> 8) * SECTOR;
+	u32 *table = (u32 *)buf; // BUG: strict aliasing
+	void *dst = buf + (be32toh(table[start]) >> 8) * SECTOR;
+	void *src = buf + (be32toh(table[end]) >> 8) * SECTOR;
 	src += (be32toh(table[end]) & 0xFF) * SECTOR;
 
 	// zeroes-out the chunk data within this range. (and set the timestamp)
 	u32 ts = htobe32(time(NULL));
 	for (int i = start; i <= end; i++) {
-		table[i] = 0;
-		table[i + CHUNKS] = ts;
+		table[i] = 0;           // BUG: strict aliasing
+		table[i + CHUNKS] = ts; // BUG: strict aliasing
 	}
 
 	// move the remaining chunks down
@@ -89,7 +89,7 @@ static int cmp_chunkids(const void *restrict x, const void *restrict y) {
 
 /* Sorts the chunks marked for deletion from smallest to greatest index.
  * Then performs the deletion in this order. Making sure to only update the chunks up to the next. */
-size_t mcx_delchunk_bulk(u8 *restrict buf, const u16 *restrict chunks, int chunkc) {
+size_t mcx_delchunk_bulk(void *restrict buf, const u16 *restrict chunks, int chunkc) {
 	// ensure the chunks ids we're working on are sorted from least to greatest
 	u16 chunkids[chunkc + 1];
 	memcpy(chunkids, chunks, chunkc);
@@ -104,9 +104,9 @@ size_t mcx_delchunk_bulk(u8 *restrict buf, const u16 *restrict chunks, int chunk
 
 /* Sum together the 4th byte in each location integer to compute the sector size of all chunks.
  * Multiplying by `SECTOR`, and adding the size of the table itself. */
-size_t mcx_calcsize(const u8 *restrict buf) {
+size_t mcx_calcsize(const void *restrict buf) {
 	size_t size = 0;
 	for (uint i = 0; i < CHUNKS; i++)
-		size += *(buf + (i * 4) + 3);
+		size += *(u8 *)(buf + (i * 4) + 3);
 	return (size * CHUNKS) + TABLE;
 }

src/dat/mcx.h

@@ -18,20 +18,20 @@ struct mcx_chunk {
  * The chunk's location data shall become `0`, and timestamp data the current time.
  * All succeeding chunks shall be moved back, freeing space.
  * Returns the amount of bytes removed. */
-size_t mcx_delchunk(u8 *restrict buf, int chunk) NONNULL((1));
+size_t mcx_delchunk(void *restrict buf, int chunk) NONNULL((1));
 
 /* Deletes the range defined by `start`—`end` (inclusive) of chunks out of `buf`.
  * The chunk's location data shall become `0`, and timestamp data the current time.
  * All succeeding chunks shall be moved back, freeing space.
  * Returns the amount of bytes removed */
-size_t mcx_delchunk_range(u8 *restrict buf, int start, int end) NONNULL((1));
+size_t mcx_delchunk_range(void *restrict buf, int start, int end) NONNULL((1));
 
 /* Deletes a `chunkc` chunks from `chunks` out of `buf`.
  * If the `chunks` indices are known to be sequential, i.e. have a constant difference of `1`, `mcx_delchunk_range` should be preferred.
  * The chunk's location data shall become `0`, and timestamp data the current time.
  * All succeeding chunks shall be moved back, freeing space.
  * Returns the amount of bytes removed */
-size_t mcx_delchunk_bulk(u8 *restrict buf, const u16 *restrict chunks, int chunkc) NONNULL((1, 2));
+size_t mcx_delchunk_bulk(void *restrict buf, const u16 *restrict chunks, int chunkc) NONNULL((1, 2));
 
 /* Computes the byte size of the `*.mcX` file in `buf` and returns it. */
-size_t mcx_calcsize(const u8 *restrict buf) NONNULL((1)) PURE;
+size_t mcx_calcsize(const void *restrict buf) NONNULL((1)) PURE;

src/dat/nbt.c

@@ -3,11 +3,11 @@
 #include "nbt.h"
 
 #include <assert.h>
+#include <endian.h>
 #include <stddef.h>
 #include <stdlib.h>
 #include <string.h>
 
-#include "../util/compat/endian.h"
 #include "../util/intdef.h"
 
 #define MAX_DEPTH 512
@@ -15,7 +15,7 @@
 /* Processes the incoming array data in `buf`. Which contains `nmem` items of `size`.
  * The data shall be converted to little-endian on little-endian systems
  * Outputs the allocated data to `out`, returns where the next pointer would be. */
-static const u8 *procarr(const u8 *restrict buf, i32 nmem, uint size, struct nbt_array *restrict *restrict out) {
+static const void *procarr(const void *restrict buf, i32 nmem, uint size, struct nbt_array *restrict *restrict out) {
 	size_t len = nmem * size;
 	*out = malloc(sizeof(struct nbt_array) + len);
 	if (!*out) return buf + len;
@@ -30,6 +30,7 @@ static const u8 *procarr(const u8 *restrict buf, i32 nmem, uint size, struct nbt
 	if (size == 1) return buf;
 	size_t i = 0;
 	while (i < len) {
+		// BUG: strict aliasing
 		switch (size) {
 		case 2:  *(u16 *)((*out)->dat + i) = be16toh(*(u16 *)((*out)->dat + i)); break;
 		case 4:  *(u32 *)((*out)->dat + i) = be32toh(*(u32 *)((*out)->dat + i)); break;
@@ -43,12 +44,12 @@ static const u8 *procarr(const u8 *restrict buf, i32 nmem, uint size, struct nbt
 }
 
 /* calls `procarr` for the simple types available. */
-static const u8 *proclist(const u8 *restrict buf, struct nbt_array *restrict *restrict out) {
+static const void *proclist(const void *restrict buf, struct nbt_array *restrict *restrict out) {
 	uint size;
 
 	*out = NULL;
 
-	switch (*buf) {
+	switch (*(u8 *)buf) {
 	case NBT_I8:  size = 1; break;
 	case NBT_I16: size = 2; break;
 	case NBT_I32: // fall through
@@ -59,20 +60,21 @@ static const u8 *proclist(const u8 *restrict buf, struct nbt_array *restrict *re
 	}
 
 	buf++;
-	i32 len = (i32)be32toh(*(u32 *)buf);
+	i32 len = (i32)be32toh(*(u32 *)buf); // BUG: strict aliasing
 	buf += 4;
 	return procarr(buf, len, size, out);
 }
 
-const u8 *nbt_proctag(const u8 *restrict buf, u16 slen, void *restrict out) {
-	const u8 *ptr, *tmp;
+const void *nbt_proctag(const void *restrict buf, u16 slen, void *restrict out) {
+	const void *ptr, *tmp;
 	ptr = buf + 3 + slen;
 
 	i32 nmem;
 	uint size;
 
-	switch (*buf) {
-	case NBT_I8:  *(u8 *)out = *ptr; return ptr + 1;
+	// BUG: strict aliasing
+	switch (*(u8 *)buf) {
+	case NBT_I8:  *(u8 *)out = *(u8 *)ptr; return ptr + 1;
 	case NBT_I16: *(u16 *)out = be16toh(*(u16 *)ptr); return ptr + 2;
 	case NBT_I32: // fall through
 	case NBT_F32: *(u32 *)out = be16toh(*(u32 *)ptr); return ptr + 4;
@@ -99,10 +101,11 @@ const u8 *nbt_proctag(const u8 *restrict buf, u16 slen, void *restrict out) {
  * `ptr` is assumed to be the start of the `NBT_LIST` data, e.i. The list's ID, followed by the list's length.
  * If `ID` is `NBT_I8`, `NBT_I16`, `NBT_I32`, `NBT_I64`, `NBT_F32`, or `NBT_F64`, the entire list length is computed and returned.
  * For other types this won't be possible, and thus will add `1` to `dpt`, and write the list data to `lens` and `tags` at this new `dpt`. */
-static const u8 *nexttag_list(const u8 *restrict ptr, uint *restrict const dpt, i32 *restrict const lens, u8 *restrict const tags) {
-	const u8 *tag = ptr;
+static const void *nexttag_list(const void *restrict ptr, uint *restrict const dpt, i32 *restrict const lens, u8 *restrict const tags) {
+	const void *tag = ptr;
 	ptr++;
-	switch (*tag) {
+	// BUG: strict aliasing
+	switch (*(u8 *)tag) {
 	case NBT_END: break;
 	case NBT_I8:  ptr += (i32)be32toh(*(u32 *)ptr) * 1; break;
 	case NBT_I16: ptr += (i32)be32toh(*(u32 *)ptr) * 2; break;
@@ -113,8 +116,8 @@ static const u8 *nexttag_list(const u8 *restrict ptr, uint *restrict const dpt,
 	default:
 		// TODO: handle out of bounds... Might not be required if we use flexible array member
 		(*dpt)++;
-		tags[*dpt] = *tag;
-		lens[*dpt] = (i32)be32toh(*(u32 *)ptr);
+		tags[*dpt] = *(u8 *)tag;
+		lens[*dpt] = (i32)be32toh(*(u32 *)ptr); // BUG: strict aliasing
 		break;
 	}
 	ptr += 4;
@@ -127,18 +130,19 @@ static const u8 *nexttag_list(const u8 *restrict ptr, uint *restrict const dpt,
  * - `lens` shall contain `MAX_DEPTH` of items representing the list length, if the current item is non-zero we shall assume we're in a list.
  *     Where the value is decremented until we reach `0`.
  * - `tags` shall contain `MAX_DEPTH` of items representing the list's stored type. */
-static const u8 *nexttag(const u8 *restrict tag, uint *restrict const dpt, i32 *restrict const lens, u8 *restrict const tags) {
+static const void *nexttag(const void *restrict tag, uint *restrict const dpt, i32 *restrict const lens, u8 *restrict const tags) {
 	u8 type;
-	const u8 *ptr = tag;
+	const void *ptr = tag;
 	if (lens[*dpt]) {
 		type = tags[*dpt];
 		lens[*dpt]--;
 		*dpt -= !lens[*dpt];
 	} else {
-		type = *tag;
-		ptr += be16toh(*(u16 *)(tag + 1)) + 3;
+		type = *(u8 *)tag;
+		ptr += be16toh(*(u16 *)(tag + 1)) + 3; // BUG: strict aliasing
 	}
 
+	// BUG: strict aliasing
 	switch (type) {
 	case NBT_I8:  ptr += 1; break;
 	case NBT_I16: ptr += 2; break;
@@ -169,8 +173,8 @@ static const u8 *nexttag(const u8 *restrict tag, uint *restrict const dpt, i32 *
  * - compound:list:int32
  * - string
  */
-const u8 *nbt_nexttag(const u8 *restrict buf) {
-	const u8 *tag;
+const void *nbt_nexttag(const void *restrict buf) {
+	const void *tag;
 	u8 tags[MAX_DEPTH] = {0};
 	i32 lens[MAX_DEPTH] = {0};
 	uint dpt = 0;

src/dat/nbt.h

@@ -3,11 +3,11 @@
 #pragma once
 
 #include <assert.h>
+#include <endian.h>
 #include <stdbool.h>
 #include <stdlib.h>
 
 #include "../util/atrb.h"
-#include "../util/compat/endian.h"
 #include "../util/intdef.h"
 
 /* NBT (named binary tag) is a tree data structure. Tags have a numeric type ID, name and a payload.
@@ -49,8 +49,8 @@ struct nbt_array {
  * if `buf` points to `NBT_I8`, `NBT_I16`, `NBT_I32`, `NBT_I64`, `NBT_F32`, or `NBT_F64`, `*out` is assumed
  * to have the available byte width for one of these types. In the case of `NBT_ARR*` and `NBT_LIST`
  * it must point to a `struct nbt_array*`. Where in the case of `NBT_LIST`, it must be one of the previous static-width types. */
-const u8 *nbt_proctag(const u8 *restrict buf, u16 slen, void *restrict out) NONNULL((1, 3));
+const void *nbt_proctag(const void *restrict buf, u16 slen, void *restrict out) NONNULL((1, 3));
 
 /* searches for the end of a named tag without processing data, the final pointer is returned.
  * `NULL` is returned upon failure, the otherwise returned pointer is not guaranteed to be valid. */
-const u8 *nbt_nexttag(const u8 *restrict buf) NONNULL((1)) PURE;
+const void *nbt_nexttag(const void *restrict buf) NONNULL((1)) PURE;

src/main.c

@@ -31,13 +31,15 @@ static inline int init(void) {
 	return 0;
 }
 
-static inline void quit(void) {
+static void quit(void) {
 	glfwTerminate();
 }
 
+
 int main(int argc, char **argv) {
 	(void)argc, (void)argv;
 	printf("debug: [DBG], info: [INF], warning: [WAR], error: [ERR], fatal: [FAT]\n");
+	atexit(quit);
 	if (init()) fatal("failed to initialize!");
 
 	window_loop();

src/util/colour32.h

@@ -1,27 +0,0 @@
-/* Copyright (c) 2025 Quinn
- * Licensed under the MIT Licence. See LICENSE for details */
-#pragma once
-#include <stdint.h>
-
-#include "vec.h"
-
-#define COLOUR32_BLACK   ((u8vec4){0x00, 0x00, 0x00, 0xFF})
-#define COLOUR32_RED     ((u8vec4){0xFF, 0x00, 0x00, 0xFF})
-#define COLOUR32_YELLOW  ((u8vec4){0xFF, 0xFF, 0x00, 0xFF})
-#define COLOUR32_ORANGE  ((u8vec4){0xFF, 0x6D, 0x00, 0xFF})
-#define COLOUR32_GREEN   ((u8vec4){0x00, 0xFF, 0x00, 0xFF})
-#define COLOUR32_CYAN    ((u8vec4){0x00, 0xFF, 0xFF, 0xFF})
-#define COLOUR32_BLUE    ((u8vec4){0x00, 0x00, 0xFF, 0xFF})
-#define COLOUR32_MAGENTA ((u8vec4){0xFF, 0x00, 0xFF, 0xFF})
-#define COLOUR32_WHITE   ((u8vec4){0xFF, 0xFF, 0xFF, 0xFF})
-
-// american macros:
-#define COLOR32_BLACK   COLOUR32_BLACK
-#define COLOR32_RED     COLOUR32_RED
-#define COLOR32_YELLOW  COLOUR32_YELLOW
-#define COLOR32_ORANGE  COLOUR32_ORANGE
-#define COLOR32_GREEN   COLOUR32_GREEN
-#define COLOR32_CYAN    COLOUR32_CYAN
-#define COLOR32_BLUE    COLOUR32_BLUE
-#define COLOR32_MAGENTA COLOUR32_MAGENTA
-#define COLOR32_WHITE   COLOUR32_WHITE