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Diffstat (limited to '')
-rw-r--r-- | src/lib/ffmpeg7/rational.pas | 170 |
1 files changed, 170 insertions, 0 deletions
diff --git a/src/lib/ffmpeg7/rational.pas b/src/lib/ffmpeg7/rational.pas new file mode 100644 index 00000000..45ca8b87 --- /dev/null +++ b/src/lib/ffmpeg7/rational.pas @@ -0,0 +1,170 @@ +(* + * rational numbers + * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at> + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + * + * This is a part of Pascal porting of ffmpeg. + * - Originally by Victor Zinetz for Delphi and Free Pascal on Windows. + * - For Mac OS X, some modifications were made by The Creative CAT, denoted as CAT + * in the source codes. + * - Changes and updates by the UltraStar Deluxe Team + * + * Conversion of libavutil/rational.h + * avutil version 50.43.0 + * + *) + +unit rational; + +{$IFDEF FPC} + {$MODE DELPHI} + {$PACKENUM 4} (* use 4-byte enums *) + {$PACKRECORDS C} (* C/C++-compatible record packing *) +{$ELSE} + {$MINENUMSIZE 4} (* use 4-byte enums *) +{$ENDIF} + +{$I switches.inc} + +interface + +uses + ctypes, + UConfig; + +type + (* + * rational number numerator/denominator + *) + PAVRational = ^TAVRational; + TAVRational = record + num: cint; ///< numerator + den: cint; ///< denominator + end; + + TAVRationalArray = array[0 .. (MaxInt div SizeOf(TAVRational))-1] of TAVRational; + PAVRationalArray = ^TAVRationalArray; + +(** + * Compare two rationals. + * @param a first rational + * @param b second rational + * @return 0 if a==b, 1 if a>b and -1 if a<b + *) +function av_cmp_q(a: TAVRational; b: TAVRational): cint; {$IFDEF HasInline}inline;{$ENDIF} + +(** + * Convert rational to double. + * @param a rational to convert + * @return (double) a + *) +function av_q2d(a: TAVRational): cdouble; {$IFDEF HasInline}inline;{$ENDIF} + +(** + * Reduce a fraction. + * This is useful for framerate calculations. + * @param dst_num destination numerator + * @param dst_den destination denominator + * @param num source numerator + * @param den source denominator + * @param max the maximum allowed for dst_num & dst_den + * @return 1 if exact, 0 otherwise + *) +function av_reduce(dst_num: PCint; dst_den: PCint; num: cint64; den: cint64; max: cint64): cint; + cdecl; external av__util; + +(** + * Multiply two rationals. + * @param b first rational + * @param c second rational + * @return b*c + *) +function av_mul_q(b: TAVRational; c: TAVRational): TAVRational; + cdecl; external av__util; {av_const} + +(** + * Divide one rational by another. + * @param b first rational + * @param c second rational + * @return b/c + *) +function av_div_q(b: TAVRational; c: TAVRational): TAVRational; + cdecl; external av__util; {av_const} + +(** + * Add two rationals. + * @param b first rational + * @param c second rational + * @return b+c + *) +function av_add_q(b: TAVRational; c: TAVRational): TAVRational; + cdecl; external av__util; {av_const} + +(** + * Subtract one rational from another. + * @param b first rational + * @param c second rational + * @return b-c + *) +function av_sub_q(b: TAVRational; c: TAVRational): TAVRational; + cdecl; external av__util; {av_const} + +(** + * Convert a double precision floating point number to a rational. + * inf is expressed as {1,0} or {-1,0} depending on the sign. + * + * @param d double to convert + * @param max the maximum allowed numerator and denominator + * @return (AVRational) d + *) +function av_d2q(d: cdouble; max: cint): TAVRational; + cdecl; external av__util; {av_const} + +(** + * @return 1 if q1 is nearer to q than q2, -1 if q2 is nearer + * than q1, 0 if they have the same distance. + *) +function av_nearer_q(q, q1, q2: TAVRational): cint; + cdecl; external av__util; + +(** + * Find the nearest value in q_list to q. + * @param q_list an array of rationals terminated by {0, 0} + * @return the index of the nearest value found in the array + *) +function av_find_nearest_q_idx(q: TAVRational; q_list: {const} PAVRationalArray): cint; + cdecl; external av__util; + +implementation + +function av_cmp_q (a: TAVRational; b: TAVRational): cint; +var + tmp: cint64; +begin + tmp := a.num * cint64(b.den) - b.num * cint64(a.den); + + if (tmp <> 0) then + Result := (tmp shr 63) or 1 + else + Result := 0 +end; + +function av_q2d(a: TAVRational): cdouble; +begin + Result := a.num / a.den; +end; + +end. |