Revise file size handling in file breakpoints.

After changing the variable names to better reflect their actual usage and removing unnecessary conditional branches and intransparent additions, the code becomes a lot clearer.

Most notably though, this fixes a bug in patch configurations that have both a replacement file bigger than the original and a .jdiff patch on top: Previously, patchhooks_run() would have only received the size of the game's original file, cutting off the replacement file in the process.
Thanks to Gamer251's Mima patch for creating such a configuration and revealing this flaw.

thcrap/src/bp_file.c

@@ -10,10 +10,12 @@
 #include "thcrap.h"
 #include "bp_file.h"
 
+#define POST_JSON_SIZE(fr) (fr)->pre_json_size + (fr)->patch_size
+
 static int file_rep_hooks_run(file_rep_t *fr)
 {
 	return patchhooks_run(
-		fr->hooks, fr->game_buffer, fr->rep_size, fr->game_size, fr->patch
+		fr->hooks, fr->game_buffer, POST_JSON_SIZE(fr), fr->pre_json_size, fr->patch
 	);
 }
 
@@ -25,8 +27,8 @@ int file_rep_clear(file_rep_t *fr)
 	SAFE_FREE(fr->rep_buffer);
 	fr->patch = json_decref_safe(fr->patch);
 	fr->hooks = json_decref_safe(fr->hooks);
-	fr->rep_size = 0;
-	fr->game_size = 0;
+	fr->patch_size = 0;
+	fr->pre_json_size = 0;
 	fr->object = NULL;
 	SAFE_FREE(fr->name);
 	return 0;
@@ -81,7 +83,7 @@ int BP_file_name(x86_reg_t *regs, json_t *bp_info)
 	}
 	fn_len = strlen(*file_name) + 1;
 	fr->name = EnsureUTF8(*file_name, fn_len);
-	fr->rep_buffer = stack_game_file_resolve(fr->name, &fr->rep_size);
+	fr->rep_buffer = stack_game_file_resolve(fr->name, &fr->pre_json_size);
 	fr->hooks = patchhooks_build(fr->name);
 	if(fr->hooks) {
 		size_t diff_fn_len = fn_len + strlen(".jdiff") + 1;
@@ -93,7 +95,7 @@ int BP_file_name(x86_reg_t *regs, json_t *bp_info)
 			fr->patch = stack_game_json_resolve(diff_fn, &diff_size);
 			VLA_FREE(diff_fn);
 		}
-		fr->rep_size += diff_size;
+		fr->patch_size += diff_size;
 	}
 	return 1;
 }
@@ -107,30 +109,15 @@ int BP_file_size(x86_reg_t *regs, json_t *bp_info)
 	size_t *file_size = json_object_get_register(bp_info, regs, "file_size");
 	int set_patch_size = !(json_is_false(json_object_get(bp_info, "set_patch_size")));
 	// ----------
-
 	// Other breakpoints
 	// -----------------
 	BP_file_name(regs, bp_info);
 	// -----------------
-
-	if(!file_size) {
-		return 1;
+	if(file_size && !fr->pre_json_size) {
+		fr->pre_json_size = *file_size;
 	}
-
-	fr->game_size = *file_size;
-
-	if(fr->patch) {
-		// If we only have a patch and no replacement file, the replacement size
-		// doesn't yet include the actual base file part
-		if(!fr->rep_buffer) {
-			fr->rep_size += fr->game_size;
-		}
-		if(set_patch_size) {
-			*file_size = fr->rep_size;
-		}
-	} else if(fr->rep_buffer && fr->rep_size) {
-		// Set size of replacement file
-		*file_size = fr->rep_size;
+	if(set_patch_size) {
+		BP_file_size_patch(regs, bp_info);
 	}
 	return 1;
 }
@@ -143,8 +130,11 @@ int BP_file_size_patch(x86_reg_t *regs, json_t *bp_info)
 	// ----------
 	size_t *file_size = json_object_get_register(bp_info, regs, "file_size");
 	// ----------
-	if(file_size && fr->rep_size && fr->game_size != fr->rep_size) {
-		*file_size = fr->rep_size;
+	size_t post_json_size = POST_JSON_SIZE(fr);
+	// Yes, these checks are necessary because th08 needs to place this
+	// breakpoint on a generic memory allocation call.
+	if(file_size && fr->pre_json_size && fr->pre_json_size != post_json_size) {
+		*file_size = post_json_size;
 	}
 	return 1;
 }
@@ -179,12 +169,12 @@ int BP_file_load(x86_reg_t *regs, json_t *bp_info)
 	BP_file_buffer(regs, bp_info);
 	// -----------------
 
-	if(!fr->game_buffer || !fr->rep_buffer || !fr->rep_size) {
+	if(!fr->game_buffer || !fr->rep_buffer || !fr->pre_json_size) {
 		return 1;
 	}
 
 	// Let's do it
-	memcpy(fr->game_buffer, fr->rep_buffer, fr->rep_size);
+	memcpy(fr->game_buffer, fr->rep_buffer, fr->pre_json_size);
 
 	file_rep_hooks_run(fr);
 
@@ -217,7 +207,7 @@ int DumpDatFile(const char *dir, const file_rep_t *fr)
 		sprintf(fn, "%s/%s", dir, fr->name);
 
 		if(!PathFileExists(fn)) {
-			file_write(fn, fr->game_buffer, fr->game_size);
+			file_write(fn, fr->game_buffer, fr->pre_json_size);
 		}
 		VLA_FREE(fn);
 	}

thcrap/src/bp_file.h

@@ -17,20 +17,21 @@
 
 // File replacement state
 typedef struct {
-	// Combined JSON patch that will be applied to the file
+	// Combined JSON patch to be applied to the file, and its maximum size
 	json_t *patch;
+	size_t patch_size;
 	// JSON array of hook functions to be run on this file
 	json_t *hooks;
 
 	// File name. Enforced to be in UTF-8
 	char *name;
 
-	// Size of the thing we're replacing the game's file with
-	size_t rep_size;
-	// Size of the game's own file in the game's own memory
-	size_t game_size;
-
+	// Potential replacement file, applied before the JSON patch
 	void *rep_buffer;
+	// Size of [rep_buffer] if we have one; otherwise, size of the original
+	// game file. [game_buffer] is guaranteed to be at least this large.
+	size_t pre_json_size;
+
 	void *game_buffer;
 
 	// Pointer to an object of the game's file class.
@@ -76,8 +77,7 @@ int BP_file_name(x86_reg_t *regs, json_t *bp_info);
   *		Type: register
   *
   *	[set_patch_size]
-  *		Set to false to not write the size of the patched file
-  *		to the [file_size] register.
+  *		Set to false to skip the call to BP_file_size().
   *		Type: bool
   *
   * Other breakpoints called
@@ -87,10 +87,10 @@ int BP_file_name(x86_reg_t *regs, json_t *bp_info);
 int BP_file_size(x86_reg_t *regs, json_t *bp_info);
 
 /**
-  * If we define a larger buffer in [BP_file_size], the game's decompression
-  * algorithm may produce bogus data after the end of the original file.
-  * This breakpoint can be used to write the actual size of the completely
-  * patched file separately from [BP_file_size].
+  * Writes the post-JSON file size to the game's memory. This is a separate
+  * breakpoint because th08's archive decompression algorithm produces bogus
+  * data after the end of the original file in case a larger than expected
+  * file size is written at BP_file_size().
   *
   * Own JSON parameters
   * -------------------