A parser of the Android Gesture file format that outputs giv files for each character

GestureParse.py

#!/usr/bin/python

######################################################################
# A python parser for the file format in the Android Gesture builder.
# Each character is output in a giv (http://giv.sourceforge.net/giv/)
# file format.
#
# MIT License
# 
# Copyright (c) 2017 Dov Grobgeld
# 
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
# 
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
# 
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.
#
# Dov Grobgeld
######################################################################

import sys,struct

def readShort(fh):
  return struct.unpack('>h',fh.read(2))[0]

def readUShort(fh):
  return struct.unpack('>H',fh.read(2))[0]

def readInt(fh):
  return struct.unpack('>i',fh.read(4))[0]

def readFloat(fh):
  return struct.unpack('>f',fh.read(4))[0]

def readLong(fh):
  hl = struct.unpack('>2I',fh.read(8))
  return (hl[0]<<32) + hl[1]

# From stack overflow

# build a table mapping lead byte to expected follow-byte count
# bytes 00-BF have 0 follow bytes, F5-FF is not legal UTF8
# C0-DF: 1, E0-EF: 2 and F0-F4: 3 follow bytes.
# leave F5-FF set to 0 to minimize reading broken data.
_lead_byte_to_count = []
for i in range(256):
    _lead_byte_to_count.append(
        1 + (i >= 0xe0) + (i >= 0xf0) if 0xbf < i < 0xf5 else 0)

def readUTF8(f, count):
    """Read `count` UTF-8 bytes from file `f`, return as unicode"""
    # Assumes UTF-8 data is valid; leaves it up to the `.decode()` call to validate
    res = []
    while count:
        count -= 1
        lead = f.read(1)
        res.append(lead)
        readcount = _lead_byte_to_count[ord(lead)]
        if readcount:
            res.append(f.read(readcount))
    return (''.join(res)).decode('utf8')
  
def readString(fh):
  stringLen = readUShort(fh)
  return readUTF8(fh, stringLen)

class Gesture:
  def __init__(self,
               name,
               points):
    self.name = name
    self.points = points
    

def ReadGesturesFile(filename):
  fh = open(filename, 'rb')
  #    Header
  #                2 bytes     short       File format version number
  #                4 bytes     int         Number of entries
  version = readShort(fh)
  numEntries = readInt(fh)

  entries = []

  # assume unistroke
  for entryId in range(numEntries):
    #    Entry
    #                X bytes     UTF String  Entry name
    #                4 bytes     int         Number of gestures
    name = readString(fh)
    numGestures = readInt(fh)
    for gestureId in range(numGestures):
      #    Gesture
      #                8 bytes     long        Gesture ID
      #                4 bytes     int         Number of strokes
      id = readLong(fh)
      numStrokes = readInt(fh)
      giv = open('gesture-'+name+'-%d.giv'%gestureId,'w')
      giv.write('$marks fcircle\n')
      for strokeId in range(numStrokes):
        #    Stroke
        #                4 bytes     int         Number of points
        numPoints = readInt(fh)
        points = []
        for pointId in range(numPoints):
          #    Point
          #                4 bytes     float       X coordinate of the point
          #                4 bytes     float       Y coordinate of the point
          #                8 bytes     long        Time stamp
    
          x,y = readFloat(fh),readFloat(fh)
          points += [(x,y)]
          timeStamp = readLong(fh)
          giv.write('%f %f\n'%(x,y))
      giv.close()
      entries += [Gesture(name, points)]
  return entries


if __name__=='__main__':
  if len(sys.argv)<1:
    print 'Need name of gesture file!'
    exit(-1)
  Filename = sys.argv[1]
  ReadGesturesFile(Filename)