From 22de4815577a41785487beeb722dc09367fae4c6 Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Mon, 12 Jun 2017 19:41:59 -0400
Subject: [PATCH] Made an attempt to get .p/.80 checked and as far as the
 emulated machine.

---
 Storage/Data/ZX8081.cpp           | 44 +++++++++++++++++++++++++++++--
 Storage/Tape/Formats/ZX80O81P.cpp | 17 +++++++-----
 2 files changed, 53 insertions(+), 8 deletions(-)

diff --git a/Storage/Data/ZX8081.cpp b/Storage/Data/ZX8081.cpp
index 0bf6049d7..7df811cc6 100644
--- a/Storage/Data/ZX8081.cpp
+++ b/Storage/Data/ZX8081.cpp
@@ -45,8 +45,48 @@ static std::shared_ptr<File> ZX80FileFromData(const std::vector<uint8_t> &data)
 	return file;
 }
 
+static std::shared_ptr<File> ZX81FileFromData(const std::vector<uint8_t> &data) {
+	// Does this look like a ZX81 file?
+
+	// Look for a file name.
+	size_t data_pointer = 0;
+	int c = 11;
+	while(c--) {
+		if(data[data_pointer] & 0x80) break;
+		data_pointer++;
+	}
+	if(!c) return nullptr;
+	data_pointer++;
+
+	if(data.size() < data_pointer + 0x405e - 0x4009) return nullptr;
+
+	if(data[data_pointer]) return nullptr;
+
+	uint16_t vars = short_at(data_pointer + 0x4010 - 0x4009, data);
+	uint16_t end_of_file = short_at(data_pointer + 0x4014 - 0x4009, data);
+//	uint16_t display_address = short_at(0x400c - 0x4009, data);
+
+	// check that the end of file is contained within the supplied data
+	if(data_pointer + end_of_file - 0x4009 > data.size()) return nullptr;
+
+	// check for the proper ordering of buffers
+	if(vars > end_of_file) return nullptr;
+//	if(end_of_file > display_address) return nullptr;
+
+	// TODO: does it make sense to inspect the tokenised BASIC?
+	// It starts at 0x4028 and proceeds as [16-bit line number] [tokens] [0x76],
+	// but I'm as yet unable to find documentation of the tokens.
+
+	// TODO: check that the line numbers declared above exist (?)
+
+	std::shared_ptr<File> file(new File);
+	file->data = data;
+	file->isZX81 = true;
+	return file;
+}
+
 std::shared_ptr<File> Storage::Data::ZX8081::FileFromData(const std::vector<uint8_t> &data) {
 	std::shared_ptr<Storage::Data::ZX8081::File> result = ZX80FileFromData(data);
-
-	return result;
+	if(result) return result;
+	return ZX81FileFromData(data);
 }
diff --git a/Storage/Tape/Formats/ZX80O81P.cpp b/Storage/Tape/Formats/ZX80O81P.cpp
index 83fa6273f..53b64222b 100644
--- a/Storage/Tape/Formats/ZX80O81P.cpp
+++ b/Storage/Tape/Formats/ZX80O81P.cpp
@@ -14,14 +14,19 @@ using namespace Storage::Tape;
 ZX80O81P::ZX80O81P(const char *file_name) :
 	Storage::FileHolder(file_name) {
 
-	// Check that contents look like a ZX80 file
-	std::vector<uint8_t> whole_file((size_t)file_stats_.st_size);
-	fread(whole_file.data(), 1, (size_t)file_stats_.st_size, file_);
-	std::shared_ptr<::Storage::Data::ZX8081::File> file = Storage::Data::ZX8081::FileFromData(whole_file);
+	// Grab the actual file contents
+	data_.resize((size_t)file_stats_.st_size);
+	fread(data_.data(), 1, (size_t)file_stats_.st_size, file_);
 
-	if(!file || file->isZX81) throw ErrorNotZX80O81P;
+	// If it's a ZX81 file, prepend a file name.
+	char type = (char)tolower(file_name[strlen(file_name) - 1]);
+	if(type == 'p' || type == '1') {
+		// TODO, maybe: prefix a proper file name; this is leaving the file nameless.
+		data_.insert(data_.begin(), 0x80);
+	}
 
-	data_ = file->data;
+	std::shared_ptr<::Storage::Data::ZX8081::File> file = Storage::Data::ZX8081::FileFromData(data_);
+	if(!file) throw ErrorNotZX80O81P;
 
 	// then rewind and start again
 	virtual_reset();