First steps to fix the scaling bug of CID-keyed CFF subfonts,
reported by Ding Li on 2008/03/28 on freetype-devel. * src/base/cff/cffparse.c (power_tens): New array. (cff_parse_real): Rewritten to introduce a fourth parameter which returns the `scaling' of the real number so that we have no precision loss. This is not used yet. Update all callers. (cff_parse_fixed_thousand): Replace with... (cff_parse_fixed_scaled): This function. Update all callers.
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ChangeLog
13
ChangeLog
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@ -1,3 +1,16 @@
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2008-05-04 Werner Lemberg <wl@gnu.org>
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First steps to fix the scaling bug of CID-keyed CFF subfonts,
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reported by Ding Li on 2008/03/28 on freetype-devel.
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* src/base/cff/cffparse.c (power_tens): New array.
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(cff_parse_real): Rewritten to introduce a fourth parameter which
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returns the `scaling' of the real number so that we have no
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precision loss. This is not used yet.
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Update all callers.
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(cff_parse_fixed_thousand): Replace with...
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(cff_parse_fixed_scaled): This function. Update all callers.
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2008-05-03 Werner Lemberg <wl@gnu.org>
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* src/base/ftobjs.c (FT_Load_Glyph): Call the auto-hinter without
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@ -136,24 +136,51 @@
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}
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static const FT_Long power_tens[] =
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{
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1L,
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10L,
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100L,
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1000L,
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10000L,
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100000L,
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1000000L,
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10000000L,
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100000000L,
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1000000000L
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};
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/* read a real */
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static FT_Fixed
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cff_parse_real( FT_Byte* start,
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FT_Byte* limit,
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FT_Int power_ten )
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FT_Int power_ten,
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FT_Int* scaling )
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{
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FT_Byte* p = start;
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FT_Long num, divider, result, exponent;
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FT_Int sign = 0, exponent_sign = 0;
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FT_Byte* p = start;
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FT_UInt nib;
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FT_UInt phase;
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FT_Long result, number, rest, exponent;
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FT_Int sign = 0, exponent_sign = 0;
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FT_Int exponent_add, integer_length, fraction_length;
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result = 0;
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num = 0;
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divider = 1;
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/* first of all, read the integer part */
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if ( scaling )
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*scaling = 0;
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result = 0;
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number = 0;
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rest = 0;
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exponent = 0;
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exponent_add = 0;
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integer_length = 0;
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fraction_length = 0;
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/* First of all, read the integer part. */
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phase = 4;
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for (;;)
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@ -166,7 +193,7 @@
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/* Make sure we don't read past the end. */
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if ( p >= limit )
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goto Bad;
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goto Exit;
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}
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/* Get the nibble. */
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@ -178,10 +205,20 @@
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else if ( nib > 9 )
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break;
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else
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result = result * 10 + nib;
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{
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/* Increase exponent if we can't add the digit. */
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if ( number >= 0xCCCCCCCL )
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exponent_add++;
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/* Skip leading zeros. */
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else if ( nib || number )
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{
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integer_length++;
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number = number * 10 + nib;
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}
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}
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}
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/* read decimal part, if any */
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/* Read fraction part, if any. */
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if ( nib == 0xa )
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for (;;)
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{
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@ -193,7 +230,7 @@
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/* Make sure we don't read past the end. */
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if ( p >= limit )
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goto Bad;
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goto Exit;
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}
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/* Get the nibble. */
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@ -202,24 +239,18 @@
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if ( nib >= 10 )
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break;
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/* Increase precision if the integer part is zero */
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/* and we have to scale the real number. */
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if ( !result && power_ten )
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/* Skip leading zeros if possible. */
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if ( !nib && !number )
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exponent_add--;
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/* Only add digit if we don't overflow. */
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else if ( number < 0xCCCCCCCL )
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{
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power_ten--;
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num = num * 10 + nib;
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}
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else
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{
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if ( divider < 10000000L )
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{
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num = num * 10 + nib;
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divider *= 10;
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}
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fraction_length++;
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number = number * 10 + nib;
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}
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}
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/* read exponent, if any */
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/* Read exponent, if any. */
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if ( nib == 12 )
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{
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exponent_sign = 1;
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if ( nib == 11 )
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{
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exponent = 0;
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for (;;)
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{
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/* If we entered this iteration with phase == 4, we need */
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/* to read a new byte. */
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/* If we entered this iteration with phase == 4, */
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/* we need to read a new byte. */
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if ( phase )
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{
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p++;
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/* Make sure we don't read past the end. */
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if ( p >= limit )
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goto Bad;
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goto Exit;
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}
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/* Get the nibble. */
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break;
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exponent = exponent * 10 + nib;
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/* Arbitrarily limit exponent. */
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if ( exponent > 1000 )
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goto Exit;
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}
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if ( exponent_sign )
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exponent = -exponent;
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power_ten += (FT_Int)exponent;
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}
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/* Move the integer part into the higher 16 bits. */
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result <<= 16;
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/* We don't check `power_ten' and `exponent_add'. */
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exponent += power_ten + exponent_add;
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/* Place the decimal part into the lower 16 bits. */
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if ( num )
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result |= FT_DivFix( num, divider );
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/* apply power of 10 if needed */
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if ( power_ten > 0 )
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if ( scaling )
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{
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divider = 10; /* actually, this will be used as multiplier here */
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while ( --power_ten > 0 )
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divider = divider * 10;
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/* Only use `fraction_length'. */
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fraction_length += integer_length;
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exponent += integer_length;
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result = FT_MulFix( divider << 16, result );
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if ( fraction_length <= 5 )
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{
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if ( number > 0x7FFFL )
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{
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result = FT_DivFix( number, 10 );
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*scaling = exponent - fraction_length + 1;
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}
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else
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{
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if ( exponent > 0 )
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{
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FT_Int new_fraction_length, shift;
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/* Make `scaling' as small as possible. */
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new_fraction_length = FT_MIN( exponent, 5 );
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exponent -= new_fraction_length;
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shift = new_fraction_length - fraction_length;
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number *= power_tens[shift];
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if ( number > 0x7FFFL )
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{
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number /= 10;
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exponent += 1;
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}
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}
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else
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exponent -= fraction_length;
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result = number << 16;
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*scaling = exponent;
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}
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}
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else
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{
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if ( ( number / power_tens[fraction_length - 5] ) > 0x7FFFL )
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{
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result = FT_DivFix( number, power_tens[fraction_length - 4] );
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*scaling = exponent - 4;
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}
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else
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{
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result = FT_DivFix( number, power_tens[fraction_length - 5] );
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*scaling = exponent - 5;
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}
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}
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}
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else if ( power_ten < 0 )
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else
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{
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divider = 10;
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while ( ++power_ten < 0 )
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divider = divider * 10;
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integer_length += exponent;
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fraction_length -= exponent;
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result = FT_DivFix( result, divider << 16 );
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/* Check for overflow and underflow. */
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if ( FT_ABS( integer_length ) > 5 )
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goto Exit;
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/* Convert into 16.16 format. */
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if ( fraction_length > 0 )
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{
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if ( ( number / power_tens[fraction_length] ) > 0x7FFFL )
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goto Exit;
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result = FT_DivFix( number, power_tens[fraction_length] );
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}
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else
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{
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number *= power_tens[-fraction_length];
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if ( number > 0x7FFFL )
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goto Exit;
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result = number << 16;
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}
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}
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if ( sign )
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Exit:
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return result;
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Bad:
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result = 0;
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goto Exit;
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}
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static FT_Long
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cff_parse_num( FT_Byte** d )
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{
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return ( **d == 30 ? ( cff_parse_real ( d[0], d[1], 0 ) >> 16 )
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: cff_parse_integer( d[0], d[1] ) );
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return **d == 30 ? ( cff_parse_real( d[0], d[1], 0, NULL ) >> 16 )
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: cff_parse_integer( d[0], d[1] );
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}
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static FT_Fixed
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cff_parse_fixed( FT_Byte** d )
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{
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return ( **d == 30 ? cff_parse_real ( d[0], d[1], 0 )
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: cff_parse_integer( d[0], d[1] ) << 16 );
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return **d == 30 ? cff_parse_real( d[0], d[1], 0, NULL )
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: cff_parse_integer( d[0], d[1] ) << 16;
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}
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/* read a floating point number, either integer or real, */
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/* but return 1000 times the number read in. */
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/* but return `10^scaling' times the number read in */
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static FT_Fixed
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cff_parse_fixed_thousand( FT_Byte** d )
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cff_parse_fixed_scaled( FT_Byte** d,
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FT_Int scaling )
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{
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return **d ==
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30 ? cff_parse_real ( d[0], d[1], 3 )
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: (FT_Fixed)FT_MulFix( cff_parse_integer( d[0], d[1] ) << 16, 1000 );
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30 ? cff_parse_real( d[0], d[1], scaling, NULL )
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: (FT_Fixed)FT_MulFix( cff_parse_integer( d[0], d[1] ) << 16,
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power_tens[scaling] );
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}
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static FT_Error
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cff_parse_font_matrix( CFF_Parser parser )
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{
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FT_Vector* offset = &dict->font_offset;
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FT_UShort* upm = &dict->units_per_em;
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FT_Byte** data = parser->stack;
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FT_Error error;
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FT_Error error = CFF_Err_Stack_Underflow;
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FT_Fixed temp;
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error = CFF_Err_Stack_Underflow;
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if ( parser->top >= parser->stack + 6 )
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{
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matrix->xx = cff_parse_fixed_thousand( data++ );
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matrix->yx = cff_parse_fixed_thousand( data++ );
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matrix->xy = cff_parse_fixed_thousand( data++ );
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matrix->yy = cff_parse_fixed_thousand( data++ );
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offset->x = cff_parse_fixed_thousand( data++ );
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offset->y = cff_parse_fixed_thousand( data );
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matrix->xx = cff_parse_fixed_scaled( data++, 3 );
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matrix->yx = cff_parse_fixed_scaled( data++, 3 );
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matrix->xy = cff_parse_fixed_scaled( data++, 3 );
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matrix->yy = cff_parse_fixed_scaled( data++, 3 );
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offset->x = cff_parse_fixed_scaled( data++, 3 );
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offset->y = cff_parse_fixed_scaled( data, 3 );
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temp = FT_ABS( matrix->yy );
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goto Store_Number;
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case cff_kind_fixed_thousand:
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val = cff_parse_fixed_thousand( parser->stack );
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val = cff_parse_fixed_scaled( parser->stack, 3 );
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Store_Number:
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switch ( field->size )
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