1# -*- coding: utf-8 -*-
2#
3# (c) Copyright 2001-2015 HP Development Company, L.P.
4#
5# This program is free software; you can redistribute it and/or modify
6# it under the terms of the GNU General Public License as published by
7# the Free Software Foundation; either version 2 of the License, or
8# (at your option) any later version.
9#
10# This program is distributed in the hope that it will be useful,
11# but WITHOUT ANY WARRANTY; without even the implied warranty of
12# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13# GNU General Public License for more details.
14#
15# You should have received a copy of the GNU General Public License
16# along with this program; if not, write to the Free Software
17# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
18#
19# Author: Don Welch
20
21#
22# Ported from Perl's Image::Size module by Randy J. Ray
23#
24
25# Std Lib
26import os
27import os.path
28import re
29import struct
30
31# Re patterns
32xbm_pat = re.compile(r'^\#define\s*\S*\s*(\d+)\s*\n\#define\s*\S*\s*(\d+)', re.IGNORECASE)
33xpm_pat = re.compile(r'"\s*(\d+)\s+(\d+)(\s+\d+\s+\d+){1,2}\s*"', re.IGNORECASE)
34ppm_pat1 = re.compile(r'^\#.*', re.IGNORECASE | re.MULTILINE)
35ppm_pat2 = re.compile(r'^(P[1-6])\s+(\d+)\s+(\d+)', re.IGNORECASE)
36ppm_pat3 = re.compile(r'IMGINFO:(\d+)x(\d+)', re.IGNORECASE)
37tiff_endian_pat = re.compile(r'II\x2a\x00')
38
39
40def readin(stream, length, offset=0):
41    if offset != 0:
42        stream.seek(offset, 0)
43
44    return stream.read(length)
45
46
47def xbmsize(stream):
48    width, height = -1, -1
49    match = xbm_pat.match(readin(stream,1024))
50
51    try:
52        width = int(match.group(1))
53        height = int(match.group(2))
54    except:
55        pass
56
57    return width, height
58
59
60def xpmsize(stream):
61    width, height = -1, -1
62    match = re.search(xpm_pat, readin(stream, 1024))
63    try:
64        width = int(match.group(1))
65        height = int(match.group(2))
66    except:
67        pass
68
69    return width, height
70
71
72def pngsize(stream): # also does MNG
73    width, height = -1, -1
74
75    if readin(stream, 4, 12) in ('IHDR', 'MHDR'):
76        height, width = struct.unpack("!II", stream.read(8))
77
78    return width,height
79
80
81def jpegsize(stream):
82    width, height = -1, -1
83    stream.seek(2)
84    while True:
85        length = 4
86        buffer = readin(stream, length)
87        try:
88            marker, code, length = struct.unpack("!c c h", buffer)
89        except:
90            break
91
92        if marker != '\xff':
93            break
94
95        if 0xc0 <= ord(code) <= 0xc3:
96            length = 5
97            height, width = struct.unpack("!xhh", readin(stream, length))
98
99        else:
100            readin(stream, length-2)
101
102    return width, height
103
104
105def ppmsize(stream):
106    width, height = -1, -1
107    header = re.sub(ppm_pat1, '', readin(stream, 1024))
108    match = ppm_pat2.match(header)
109    typ = ''
110    try:
111        typ = match.group(1)
112        width = int(match.group(2))
113        height = int(match.group(3))
114    except:
115        pass
116
117    if typ == 'P7':
118        match = ppm_pat3.match(header)
119
120        try:
121            width = int(match.group(1))
122            height = int(match.group(2))
123        except:
124            pass
125
126    return width, height
127
128
129def tiffsize(stream):
130    header = readin(stream, 4)
131    endian = ">"
132    match = tiff_endian_pat.match(header)
133
134    if match is not None:
135        endian = "<"
136
137    input = readin(stream, 4, 4)
138    offset = struct.unpack('%si' % endian, input)[0]
139    num_dirent = struct.unpack('%sH' % endian, readin(stream, 2, offset))[0]
140    offset += 2
141    num_dirent = offset+(num_dirent*12)
142    width, height = -1, -1
143
144    while True:
145        ifd = readin(stream, 12, offset)
146
147        if ifd == '' or offset > num_dirent:
148            break
149
150        offset += 12
151        tag = struct.unpack('%sH'% endian, ifd[0:2])[0]
152        type = struct.unpack('%sH' % endian, ifd[2:4])[0]
153
154        if tag == 0x0100:
155            width = struct.unpack("%si" % endian, ifd[8:12])[0]
156
157        elif tag == 0x0101:
158            height = struct.unpack("%si" % endian, ifd[8:12])[0]
159
160    return width, height
161
162
163def bmpsize(stream):
164    width, height = struct.unpack("<II", readin(stream, 8, 18))
165    return width, height
166
167
168def gifsize(stream):
169    # since we only care about the printed size of the image
170    # we only need to get the logical screen sizes, which are
171    # the maximum extents of the image. This code is much simpler
172    # than the code from Image::Size
173    #width, height = -1, -1
174    buf = readin(stream, 7, 6) # LSx, GCTF, etc
175    height, width, flags, bci, par = struct.unpack('<HHBBB', buf)
176
177    return width, height
178
179
180
181
182TYPE_MAP = {re.compile('^GIF8[7,9]a')              : ('image/gif', gifsize),
183             re.compile("^\xFF\xD8")                : ('image/jpeg', jpegsize),
184             re.compile("^\x89PNG\x0d\x0a\x1a\x0a") : ('image/png', pngsize),
185             re.compile("^P[1-7]")                  : ('image/x-portable-pixmap', ppmsize),
186             re.compile('\#define\s+\S+\s+\d+')     : ('image/x-xbitmap', xbmsize),
187             re.compile('\/\* XPM \*\/')            : ('image/x-xpixmap', xpmsize),
188             re.compile('^MM\x00\x2a')              : ('image/tiff', tiffsize),
189             re.compile('^II\*\x00')                : ('image/tiff', tiffsize),
190             re.compile('^BM')                      : ('image/x-bitmap', bmpsize),
191             re.compile("^\x8aMNG\x0d\x0a\x1a\x0a") : ('image/png', pngsize),
192           }
193
194
195def imagesize(filename, mime_type=''):
196    width, height = -1, -1
197
198    f = open(filename, 'r')
199    buffer = f.read(4096)
200
201    if not mime_type:
202        for t in TYPE_MAP:
203            match = t.search(buffer)
204            if match is not None:
205                mime_type, func = TYPE_MAP[t]
206                break
207
208    if mime_type and func:
209        f.seek(0)
210        width, height = func(f)
211    else:
212        width, height = -1, -1
213
214    f.close()
215
216    return height, width, mime_type
217
218