wasm: support more vendor libraries

Adds support for:
- box2d
- cgltf
- stb image
- stb rect pack

4 files changed, 106 insertions, 79 deletions

diff --git a/core/bytes/bytes.odin b/core/bytes/bytes.odin
index 45eb44307..c0d25bcce 100644
--- a/core/bytes/bytes.odin
+++ b/core/bytes/bytes.odin
@@ -334,7 +334,7 @@ Inputs:
 Returns:
 - index: The index of the byte `c`, or -1 if it was not found.
 */
-index_byte :: proc(s: []byte, c: byte) -> (index: int) #no_bounds_check {
+index_byte :: proc "contextless" (s: []byte, c: byte) -> (index: int) #no_bounds_check {
 	i, l := 0, len(s)
 
 	// Guard against small strings.  On modern systems, it is ALWAYS
@@ -469,7 +469,7 @@ Inputs:
 Returns:
 - index: The index of the byte `c`, or -1 if it was not found.
 */
-last_index_byte :: proc(s: []byte, c: byte) -> int #no_bounds_check {
+last_index_byte :: proc "contextless" (s: []byte, c: byte) -> int #no_bounds_check {
 	i := len(s)
 
 	// Guard against small strings.  On modern systems, it is ALWAYS
diff --git a/core/mem/allocators.odin b/core/mem/allocators.odin
index a5b93ad05..cbed5fbe3 100644
--- a/core/mem/allocators.odin
+++ b/core/mem/allocators.odin
@@ -1137,3 +1137,81 @@ buddy_allocator_proc :: proc(allocator_data: rawptr, mode: Allocator_Mode,
 
 	return nil, nil
 }
+
+// An allocator that keeps track of allocation sizes and passes it along to resizes.
+// This is useful if you are using a library that needs an equivalent of `realloc` but want to use
+// the Odin allocator interface.
+//
+// You want to wrap your allocator into this one if you are trying to use any allocator that relies
+// on the old size to work.
+//
+// The overhead of this allocator is an extra max(alignment, size_of(Header)) bytes allocated for each allocation, these bytes are
+// used to store the size and original pointer.
+Compat_Allocator :: struct {
+	parent: Allocator,
+}
+
+compat_allocator_init :: proc(rra: ^Compat_Allocator, allocator := context.allocator) {
+	rra.parent = allocator
+}
+
+compat_allocator :: proc(rra: ^Compat_Allocator) -> Allocator {
+	return Allocator{
+		data      = rra,
+		procedure = compat_allocator_proc,
+	}
+}
+
+compat_allocator_proc :: proc(allocator_data: rawptr, mode: Allocator_Mode,
+                             size, alignment: int,
+                             old_memory: rawptr, old_size: int,
+                             location := #caller_location) -> (data: []byte, err: Allocator_Error) {
+	size, old_size := size, old_size
+
+	Header :: struct {
+		size: int,
+		ptr:  rawptr,
+	}
+
+	rra := (^Compat_Allocator)(allocator_data)
+	switch mode {
+	case .Alloc, .Alloc_Non_Zeroed:
+		a    := max(alignment, size_of(Header))
+		size += a
+		assert(size >= 0, "overflow")
+
+		allocation := rra.parent.procedure(rra.parent.data, mode, size, alignment, old_memory, old_size, location) or_return
+		#no_bounds_check data = allocation[a:]
+
+		([^]Header)(raw_data(data))[-1] = {
+			size = size,
+			ptr  = raw_data(allocation),
+		}
+		return
+
+	case .Free:
+		header := ([^]Header)(old_memory)[-1]
+		return rra.parent.procedure(rra.parent.data, mode, size, alignment, header.ptr, header.size, location)
+
+	case .Resize, .Resize_Non_Zeroed:
+		header := ([^]Header)(old_memory)[-1]
+
+		a    := max(alignment, size_of(header))
+		size += a
+		assert(size >= 0, "overflow")
+
+		allocation := rra.parent.procedure(rra.parent.data, mode, size, alignment, header.ptr, header.size, location) or_return
+		#no_bounds_check data = allocation[a:]
+
+		([^]Header)(raw_data(data))[-1] = {
+			size = size,
+			ptr  = raw_data(allocation),
+		}
+		return
+
+	case .Free_All, .Query_Info, .Query_Features:
+		return rra.parent.procedure(rra.parent.data, mode, size, alignment, old_memory, old_size, location)
+
+	case: unreachable()
+	}
+}
diff --git a/core/os/os_js.odin b/core/os/os_js.odin
index eb434c727..02821c3e3 100644
--- a/core/os/os_js.odin
+++ b/core/os/os_js.odin
@@ -3,33 +3,38 @@ package os
 
 import "base:runtime"
 
+foreign import "odin_env"
+
 @(require_results)
 is_path_separator :: proc(c: byte) -> bool {
 	return c == '/' || c == '\\'
 }
 
+Handle :: distinct u32
+
+stdout: Handle = 1
+stderr: Handle = 2
+
 @(require_results)
 open :: proc(path: string, mode: int = O_RDONLY, perm: int = 0) -> (Handle, Error) {
 	unimplemented("core:os procedure not supported on JS target")
 }
 
 close :: proc(fd: Handle) -> Error {
-	unimplemented("core:os procedure not supported on JS target")
+	return nil
 }
 
 flush :: proc(fd: Handle) -> (err: Error) {
-	unimplemented("core:os procedure not supported on JS target")
+	return nil
 }
 
-
-
 write :: proc(fd: Handle, data: []byte) -> (int, Error) {
-	unimplemented("core:os procedure not supported on JS target")
-}
-
-@(private="file")
-read_console :: proc(handle: Handle, b: []byte) -> (n: int, err: Error) {
-	unimplemented("core:os procedure not supported on JS target")
+	foreign odin_env {
+		@(link_name="write")
+		_write :: proc "contextless" (fd: Handle, p: []byte) ---
+	}
+	_write(fd, data)
+	return len(data), nil
 }
 
 read :: proc(fd: Handle, data: []byte) -> (int, Error) {
@@ -45,19 +50,6 @@ file_size :: proc(fd: Handle) -> (i64, Error) {
 	unimplemented("core:os procedure not supported on JS target")
 }
 
-
-@(private)
-MAX_RW :: 1<<30
-
-@(private)
-pread :: proc(fd: Handle, data: []byte, offset: i64) -> (int, Error) {
-	unimplemented("core:os procedure not supported on JS target")
-}
-@(private)
-pwrite :: proc(fd: Handle, data: []byte, offset: i64) -> (int, Error) {
-	unimplemented("core:os procedure not supported on JS target")
-}
-
 read_at :: proc(fd: Handle, data: []byte, offset: i64) -> (n: int, err: Error) {
 	unimplemented("core:os procedure not supported on JS target")
 }
@@ -65,16 +57,6 @@ write_at :: proc(fd: Handle, data: []byte, offset: i64) -> (n: int, err: Error)
 	unimplemented("core:os procedure not supported on JS target")
 }
 
-stdout: Handle = 1
-stderr: Handle = 2
-
-@(require_results)
-get_std_handle :: proc "contextless" (h: uint) -> Handle {
-	context = runtime.default_context()
-	unimplemented("core:os procedure not supported on JS target")
-}
-
-
 @(require_results)
 exists :: proc(path: string) -> bool {
 	unimplemented("core:os procedure not supported on JS target")
@@ -90,9 +72,6 @@ is_dir :: proc(path: string) -> bool {
 	unimplemented("core:os procedure not supported on JS target")
 }
 
-// NOTE(tetra): GetCurrentDirectory is not thread safe with SetCurrentDirectory and GetFullPathName
-//@private cwd_lock := win32.SRWLOCK{} // zero is initialized
-
 @(require_results)
 get_current_directory :: proc(allocator := context.allocator) -> string {
 	unimplemented("core:os procedure not supported on JS target")
@@ -118,18 +97,6 @@ remove_directory :: proc(path: string) -> (err: Error) {
 }
 
 
-
-@(private, require_results)
-is_abs :: proc(path: string) -> bool {
-	unimplemented("core:os procedure not supported on JS target")
-}
-
-@(private, require_results)
-fix_long_path :: proc(path: string) -> string {
-	unimplemented("core:os procedure not supported on JS target")
-}
-
-
 link :: proc(old_name, new_name: string) -> (err: Error) {
 	unimplemented("core:os procedure not supported on JS target")
 }
@@ -169,7 +136,6 @@ read_dir :: proc(fd: Handle, n: int, allocator := context.allocator) -> (fi: []F
 	unimplemented("core:os procedure not supported on JS target")
 }
 
-Handle    :: distinct uintptr
 File_Time :: distinct u64
 
 _Platform_Error :: enum i32 {
@@ -254,12 +220,7 @@ WSAECONNRESET             :: Platform_Error.WSAECONNRESET
 ERROR_FILE_IS_PIPE        :: General_Error.File_Is_Pipe
 ERROR_FILE_IS_NOT_DIR     :: General_Error.Not_Dir
 
-// "Argv" arguments converted to Odin strings
-args := _alloc_command_line_arguments()
-
-
-
-
+args: []string
 
 @(require_results)
 last_write_time :: proc(fd: Handle) -> (File_Time, Error) {
@@ -279,26 +240,14 @@ get_page_size :: proc() -> int {
 
 @(private, require_results)
 _processor_core_count :: proc() -> int {
-	unimplemented("core:os procedure not supported on JS target")
+	return 1
 }
 
 exit :: proc "contextless" (code: int) -> ! {
-	context = runtime.default_context()
-	unimplemented("core:os procedure not supported on JS target")
+	unimplemented_contextless("core:os procedure not supported on JS target")
 }
 
-
-
 @(require_results)
 current_thread_id :: proc "contextless" () -> int {
-	context = runtime.default_context()
-	unimplemented("core:os procedure not supported on JS target")
+	return 0
 }
-
-
-
-@(require_results)
-_alloc_command_line_arguments :: proc() -> []string {
-	return nil
-}
-
diff --git a/core/strings/strings.odin b/core/strings/strings.odin
index b69c4a0e0..dbc84f8b7 100644
--- a/core/strings/strings.odin
+++ b/core/strings/strings.odin
@@ -93,7 +93,7 @@ Inputs:
 Returns:
 - res: A string created from the null-terminated byte pointer and length
 */
-string_from_null_terminated_ptr :: proc(ptr: [^]byte, len: int) -> (res: string) {
+string_from_null_terminated_ptr :: proc "contextless" (ptr: [^]byte, len: int) -> (res: string) {
 	s := string(ptr[:len])
 	s = truncate_to_byte(s, 0)
 	return s
@@ -139,7 +139,7 @@ NOTE: Failure to find the byte results in returning the entire string.
 Returns:
 - res: The truncated string
 */
-truncate_to_byte :: proc(str: string, b: byte) -> (res: string) {
+truncate_to_byte :: proc "contextless" (str: string, b: byte) -> (res: string) {
 	n := index_byte(str, b)
 	if n < 0 {
 		n = len(str)
@@ -261,7 +261,7 @@ Inputs:
 Returns:
 - result: `-1` if `lhs` comes first, `1` if `rhs` comes first, or `0` if they are equal
 */
-compare :: proc(lhs, rhs: string) -> (result: int) {
+compare :: proc "contextless" (lhs, rhs: string) -> (result: int) {
 	return mem.compare(transmute([]byte)lhs, transmute([]byte)rhs)
 }
 /*
@@ -1447,7 +1447,7 @@ Output:
 	-1
 
 */
-index_byte :: proc(s: string, c: byte) -> (res: int) {
+index_byte :: proc "contextless" (s: string, c: byte) -> (res: int) {
 	return #force_inline bytes.index_byte(transmute([]u8)s, c)
 }
 /*
@@ -1482,7 +1482,7 @@ Output:
 	-1
 
 */
-last_index_byte :: proc(s: string, c: byte) -> (res: int) {
+last_index_byte :: proc "contextless" (s: string, c: byte) -> (res: int) {
 	return #force_inline bytes.last_index_byte(transmute([]u8)s, c)
 }
 /*
@@ -1576,8 +1576,8 @@ Output:
 	-1
 
 */
-index :: proc(s, substr: string) -> (res: int) {
-	hash_str_rabin_karp :: proc(s: string) -> (hash: u32 = 0, pow: u32 = 1) {
+index :: proc "contextless" (s, substr: string) -> (res: int) {
+	hash_str_rabin_karp :: proc "contextless" (s: string) -> (hash: u32 = 0, pow: u32 = 1) {
 		for i := 0; i < len(s); i += 1 {
 			hash = hash*PRIME_RABIN_KARP + u32(s[i])
 		}