Refactor getSearchRange()
diff --git a/Lib/fontTools/ttLib/__init__.py b/Lib/fontTools/ttLib/__init__.py
index 1286765..546b327 100644
--- a/Lib/fontTools/ttLib/__init__.py
+++ b/Lib/fontTools/ttLib/__init__.py
@@ -966,3 +966,25 @@
for tag in sortedTagList(tables, tableOrder):
writer[tag] = reader[tag]
writer.close()
+
+
+def maxPowerOfTwo(x):
+ """Return the highest exponent of two, so that
+ (2 ** exponent) <= x. Return 0 if x is 0.
+ """
+ exponent = 0
+ while x:
+ x = x >> 1
+ exponent = exponent + 1
+ return max(exponent - 1, 0)
+
+
+def getSearchRange(n, itemSize):
+ """Calculate searchRange, entrySelector, rangeShift.
+ """
+ # This stuff needs to be stored in the file, because?
+ exponent = maxPowerOfTwo(n)
+ searchRange = (2 ** exponent) * itemSize
+ entrySelector = exponent
+ rangeShift = max(0, n * itemSize - searchRange)
+ return searchRange, entrySelector, rangeShift
diff --git a/Lib/fontTools/ttLib/sfnt.py b/Lib/fontTools/ttLib/sfnt.py
index 95679e9..c65fd28 100644
--- a/Lib/fontTools/ttLib/sfnt.py
+++ b/Lib/fontTools/ttLib/sfnt.py
@@ -15,6 +15,7 @@
from __future__ import print_function, division, absolute_import
from fontTools.misc.py23 import *
from fontTools.misc import sstruct
+from fontTools.ttLib import getSearchRange
import struct
@@ -116,7 +117,7 @@
self.directorySize = sfntDirectorySize
self.DirectoryEntry = SFNTDirectoryEntry
- self.searchRange, self.entrySelector, self.rangeShift = getSearchRange(numTables)
+ self.searchRange, self.entrySelector, self.rangeShift = getSearchRange(numTables, 16)
self.nextTableOffset = self.directorySize + numTables * self.DirectoryEntry.formatSize
# clear out directory area
@@ -242,7 +243,7 @@
# Haven't debugged.
if self.DirectoryEntry != SFNTDirectoryEntry:
# Create a SFNT directory for checksum calculation purposes
- self.searchRange, self.entrySelector, self.rangeShift = getSearchRange(self.numTables)
+ self.searchRange, self.entrySelector, self.rangeShift = getSearchRange(self.numTables, 16)
directory = sstruct.pack(sfntDirectoryFormat, self)
tables = sorted(self.tables.items())
for tag, entry in tables:
@@ -464,29 +465,6 @@
return value
-def maxPowerOfTwo(x):
- """Return the highest exponent of two, so that
- (2 ** exponent) <= x
- """
- exponent = 0
- while x:
- x = x >> 1
- exponent = exponent + 1
- return max(exponent - 1, 0)
-
-
-def getSearchRange(n):
- """Calculate searchRange, entrySelector, rangeShift for the
- sfnt directory. 'n' is the number of tables.
- """
- # This stuff needs to be stored in the file, because?
- exponent = maxPowerOfTwo(n)
- searchRange = (2 ** exponent) * 16
- entrySelector = exponent
- rangeShift = max(0, n * 16 - searchRange)
- return searchRange, entrySelector, rangeShift
-
-
if __name__ == "__main__":
import doctest
doctest.testmod()
diff --git a/Lib/fontTools/ttLib/tables/_c_m_a_p.py b/Lib/fontTools/ttLib/tables/_c_m_a_p.py
index a3fb6cc..0519e78 100644
--- a/Lib/fontTools/ttLib/tables/_c_m_a_p.py
+++ b/Lib/fontTools/ttLib/tables/_c_m_a_p.py
@@ -1,6 +1,7 @@
from __future__ import print_function, division, absolute_import
from fontTools.misc.py23 import *
from fontTools.misc.textTools import safeEval, readHex
+from fontTools.ttLib import getSearchRange
from fontTools.unicode import Unicode
from . import DefaultTable
import sys
@@ -699,8 +700,6 @@
def compile(self, ttFont):
if self.data:
return struct.pack(">HHH", self.format, self.length, self.language) + self.data
-
- from fontTools.ttLib.sfnt import maxPowerOfTwo
charCodes = list(self.cmap.keys())
lenCharCodes = len(charCodes)
@@ -775,13 +774,10 @@
idDelta.append(1) # 0xffff + 1 == (tadaa!) 0. So this end code maps to .notdef
idRangeOffset.append(0)
- # Insane.
+ # Insane.
segCount = len(endCode)
segCountX2 = segCount * 2
- maxExponent = maxPowerOfTwo(segCount)
- searchRange = 2 * (2 ** maxExponent)
- entrySelector = maxExponent
- rangeShift = max(0, 2 * segCount - searchRange)
+ searchRange, entrySelector, rangeShift = getSearchRange(segCount, 2)
charCodeArray = array.array("H", endCode + [0] + startCode)
idDeltaArray = array.array("H", idDelta)
diff --git a/Lib/fontTools/ttLib/tables/_k_e_r_n.py b/Lib/fontTools/ttLib/tables/_k_e_r_n.py
index b8e60d3..928298b 100644
--- a/Lib/fontTools/ttLib/tables/_k_e_r_n.py
+++ b/Lib/fontTools/ttLib/tables/_k_e_r_n.py
@@ -1,6 +1,6 @@
from __future__ import print_function, division, absolute_import
from fontTools.misc.py23 import *
-from fontTools.ttLib import sfnt
+from fontTools.ttLib import getSearchRange
from fontTools.misc.textTools import safeEval, readHex
from fontTools.misc.fixedTools import fixedToFloat as fi2fl, floatToFixed as fl2fi
from . import DefaultTable
@@ -116,9 +116,7 @@
def compile(self, ttFont):
nPairs = len(self.kernTable)
- entrySelector = sfnt.maxPowerOfTwo(nPairs)
- searchRange = (2 ** entrySelector) * 6
- rangeShift = max(0, (nPairs - (2 ** entrySelector)) * 6)
+ searchRange, entrySelector, rangeShift = getSearchRange(nPairs, 6)
data = struct.pack(">HHHH", nPairs, searchRange, entrySelector, rangeShift)
# yeehee! (I mean, turn names into indices)