3 files changed, 24 insertions, 19 deletions

diff --git a/include/mupdf/fitz/context.h b/include/mupdf/fitz/context.h
index 7f5e15c8..c2b08898 100644
--- a/include/mupdf/fitz/context.h
+++ b/include/mupdf/fitz/context.h
@@ -10,6 +10,7 @@
 
 typedef struct fz_alloc_context_s fz_alloc_context;
 typedef struct fz_error_context_s fz_error_context;
+typedef struct fz_error_stack_slot_s fz_error_stack_slot;
 typedef struct fz_id_context_s fz_id_context;
 typedef struct fz_warn_context_s fz_warn_context;
 typedef struct fz_font_context_s fz_font_context;
@@ -30,13 +31,16 @@ struct fz_alloc_context_s
 	void (*free)(void *, void *);
 };
 
+struct fz_error_stack_slot_s
+{
+	int code;
+	fz_jmp_buf buffer;
+};
+
 struct fz_error_context_s
 {
-	int top;
-	struct {
-		int code;
-		fz_jmp_buf buffer;
-	} stack[256];
+	fz_error_stack_slot *top;
+	fz_error_stack_slot stack[256];
 	int errcode;
 	char message[256];
 };
@@ -50,24 +54,24 @@ void fz_var_imp(void *);
 */
 
 #define fz_try(ctx) \
-	{{{ fz_push_try(ctx); \
-	if (fz_setjmp(ctx->error->stack[ctx->error->top].buffer) == 0)\
+	{{{ \
+	if (fz_setjmp(fz_push_try(ctx)->buffer) == 0)\
 	{ do {
 
 #define fz_always(ctx) \
 		} while (0); \
 	} \
-	if (ctx->error->stack[ctx->error->top].code < 3) \
+	if (ctx->error->top->code < 3) \
 	{ \
-		ctx->error->stack[ctx->error->top].code++; \
+		ctx->error->top->code++; \
 		do { \
 
 #define fz_catch(ctx) \
 		} while(0); \
 	} }}} \
-	if (ctx->error->stack[ctx->error->top--].code > 1)
+	if ((ctx->error->top--)->code > 1)
 
-void fz_push_try(fz_context *ctx);
+fz_error_stack_slot *fz_push_try(fz_context *ctx);
 FZ_NORETURN void fz_throw(fz_context *ctx, int errcode, const char *, ...) __printflike(3, 4);
 FZ_NORETURN void fz_rethrow(fz_context *ctx);
 FZ_NORETURN void fz_rethrow_message(fz_context *ctx, const char *fmt, ...)  __printflike(2, 3);
diff --git a/source/fitz/context.c b/source/fitz/context.c
index 5d3373c2..52c225e9 100644
--- a/source/fitz/context.c
+++ b/source/fitz/context.c
@@ -100,7 +100,7 @@ fz_drop_context(fz_context *ctx)
 
 	if (ctx->error)
 	{
-		assert(ctx->error->top == -1);
+		assert(ctx->error->top == ctx->error->stack - 1);
 		fz_free(ctx, ctx->error);
 	}
 
@@ -129,7 +129,7 @@ new_context_phase1(const fz_alloc_context *alloc, const fz_locks_context *locks)
 	ctx->error = Memento_label(fz_malloc_no_throw(ctx, sizeof(fz_error_context)), "fz_error_context");
 	if (!ctx->error)
 		goto cleanup;
-	ctx->error->top = -1;
+	ctx->error->top = ctx->error->stack - 1;
 	ctx->error->errcode = FZ_ERROR_NONE;
 	ctx->error->message[0] = 0;
 
diff --git a/source/fitz/error.c b/source/fitz/error.c
index a34e5b79..724fd078 100644
--- a/source/fitz/error.c
+++ b/source/fitz/error.c
@@ -82,10 +82,10 @@ void fz_warn(fz_context *ctx, const char *fmt, ...)
 
 FZ_NORETURN static void throw(fz_context *ctx)
 {
-	if (ctx->error->top >= 0)
+	if (ctx->error->top >= ctx->error->stack)
 	{
-		ctx->error->stack[ctx->error->top].code += 2;
-		fz_longjmp(ctx->error->stack[ctx->error->top].buffer, ctx->error->stack[ctx->error->top].code);
+		ctx->error->top->code += 2;
+		fz_longjmp(ctx->error->top->buffer, 1);
 	}
 	else
 	{
@@ -100,15 +100,16 @@ FZ_NORETURN static void throw(fz_context *ctx)
 	}
 }
 
-void fz_push_try(fz_context *ctx)
+fz_error_stack_slot *fz_push_try(fz_context *ctx)
 {
 	/* If we would overflow the exception stack, throw an exception instead
 	 * of entering the try block. */
-	if (ctx->error->top + 1 >= nelem(ctx->error->stack))
+	if (ctx->error->top + 1 >= ctx->error->stack + nelem(ctx->error->stack))
 		fz_throw(ctx, FZ_ERROR_GENERIC, "exception stack overflow!");
 
 	ctx->error->top++;
-	ctx->error->stack[ctx->error->top].code = 0;
+	ctx->error->top->code = 0;
+	return ctx->error->top;
 }
 
 int fz_caught(fz_context *ctx)