From 269b2a2eb7c5d63bdfb7989a9c9626e8940aafd4 Mon Sep 17 00:00:00 2001
From: Guido van Rossum <guido@python.org>
Date: Tue, 8 Sep 1992 15:04:01 +0000
Subject: VFile: The Entry-Indigo trick doesn't work on 4.0.1 hosts. VFile:
 RandomVinFile can now write the cache to the file. Vinfo: use the cached
 index if present and print a message whether it's there.

---
 Demo/sgi/video/VFile.py | 71 ++++++++++++++++++++++++++++++++++++++++---------
 Demo/sgi/video/Vinfo.py | 15 ++++++++---
 2 files changed, 70 insertions(+), 16 deletions(-)

diff --git a/Demo/sgi/video/VFile.py b/Demo/sgi/video/VFile.py
index e5aea41..1516464 100755
--- a/Demo/sgi/video/VFile.py
+++ b/Demo/sgi/video/VFile.py
@@ -324,13 +324,14 @@ class Displayer(VideoParams):
 			gl.RGBcolor(200, 200, 200) # XXX rather light grey
 			gl.clear()
 			return
-		if self.format == 'rgb8' and is_entry_indigo():
-			gl.RGBmode()
-			gl.gconfig()
-			gl.RGBcolor(200, 200, 200) # XXX rather light grey
-			gl.clear()
-			gl.pixmode(GL.PM_SIZE, 8)
-			return
+## XXX Unfortunately this doesn't work on IRIX 4.0.1...
+##		if self.format == 'rgb8' and is_entry_indigo():
+##			gl.RGBmode()
+##			gl.gconfig()
+##			gl.RGBcolor(200, 200, 200) # XXX rather light grey
+##			gl.clear()
+##			gl.pixmode(GL.PM_SIZE, 8)
+##			return
 		gl.cmode()
 		gl.gconfig()
 		self.skipchrom = 0
@@ -756,7 +757,7 @@ class BasicVinFile(VideoParams):
 		self.framecount = self.framecount + 1
 
 
-# Derived class implementing random access
+# Derived class implementing random access and index cached in the file
 
 class RandomVinFile(BasicVinFile):
 
@@ -767,12 +768,58 @@ class RandomVinFile(BasicVinFile):
 
 	def warmcache(self):
 		if len(self.index) == 0:
-			self.rewind()
-			while 1:
-				try: dummy = self.skipnextframe()
-				except EOFError: break
+			try:
+				self.readcache()
+			except Error:
+				self.buildcache()
 		else:
 			print '[RandomVinFile.warmcache(): too late]'
+			self.rewind()
+
+	def buildcache(self):
+		self.index = []
+		self.rewind()
+		while 1:
+			try: dummy = self.skipnextframe()
+			except EOFError: break
+		self.rewind()
+
+	def writecache(self):
+		# Raises IOerror if the file is not seekable & writable!
+		import marshal
+		if len(self.index) == 0:
+			self.buildcache()
+			if len(self.index) == 0:
+				raise Error, self.filename + ': No frames'
+		self.fp.seek(0, 2)
+		self.fp.write('\n/////CMIF/////\n')
+		pos = self.fp.tell()
+		data = `pos`
+		data = '\n-*-*-CMIF-*-*-\n' + data + ' '*(15-len(data)) + '\n'
+		try:
+			marshal.dump(self.index, self.fp)
+			self.fp.write(data)
+			self.fp.flush()
+		finally:
+			self.rewind()
+
+	def readcache(self):
+		# Raises Error if there is no cache in the file
+		import marshal
+		if len(self.index) <> 0:
+			raise CallError
+		self.fp.seek(-32, 2)
+		data = self.fp.read()
+		if data[:16] <> '\n-*-*-CMIF-*-*-\n' or data[-1:] <> '\n':
+			self.rewind()
+			raise Error, self.filename + ': No cache'
+		pos = eval(data[16:-1])
+		self.fp.seek(pos)
+		try:
+			self.index = marshal.load(self.fp)
+		except TypeError:
+			self.rewind()
+			raise Error, self.filename + ': Bad cache'
 		self.rewind()
 
 	def getnextframeheader(self):
diff --git a/Demo/sgi/video/Vinfo.py b/Demo/sgi/video/Vinfo.py
index cfda32a..cf89a8d 100755
--- a/Demo/sgi/video/Vinfo.py
+++ b/Demo/sgi/video/Vinfo.py
@@ -54,7 +54,7 @@ def main():
 
 def process(filename):
 	try:
-		vin = VFile.VinFile().init(filename)
+		vin = VFile.RandomVinFile().init(filename)
 	except IOError, msg:
 		sys.stderr.write(filename + ': I/O error: ' + `msg` + '\n')
 		return 1
@@ -71,6 +71,12 @@ def process(filename):
 		vin.close()
 		return
 
+	try:
+		vin.readcache()
+		print '[Using cached index]'
+	except VFile.Error:
+		print '[Constructing index on the fly]'
+
 	if not short:
 		if delta:
 			print 'Frame time deltas:',
@@ -83,11 +89,12 @@ def process(filename):
 	datasize = 0
 	while 1:
 		try:
-			t, data, cdata = vin.getnextframe()
+			t, ds, cs = vin.getnextframeheader()
+			vin.skipnextframedata(ds, cs)
 		except EOFError:
 			break
-		datasize = datasize + len(data)
-		if cdata: datasize = datasize + len(cdata)
+		datasize = datasize + ds
+		if cs: datasize = datasize + cs
 		if not short:
 			if n%8 == 0:
 				sys.stdout.write('\n')
-- 
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