apps/plugins/mpegplayer/mpeg_misc.h

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id$
   9  *
  10  * Miscellaneous helper API declarations
  11  *
  12  * Copyright (c) 2007 Michael Sevakis
  13  *
  14  * This program is free software; you can redistribute it and/or
  15  * modify it under the terms of the GNU General Public License
  16  * as published by the Free Software Foundation; either version 2
  17  * of the License, or (at your option) any later version.
  18  *
  19  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  20  * KIND, either express or implied.
  21  *
  22  ****************************************************************************/
  23 #ifndef MPEG_MISC_H
  24 #define MPEG_MISC_H
  25
  26 /* Miscellaneous helpers */
  27 #ifndef ALIGNED_ATTR
  28 #define ALIGNED_ATTR(x) __attribute__((aligned(x)))
  29 #endif
  30
  31 /* Generic states for when things are too simple to care about naming them */
  32 enum state_enum
  33 {
  34     state0 = 0,
  35     state1,
  36     state2,
  37     state3,
  38     state4,
  39     state5,
  40     state6,
  41     state7,
  42     state8,
  43     state9,
  44 };
  45
  46 /* Macros for comparing memory bytes to a series of constant bytes in an
  47    efficient manner - evaluate to true if corresponding bytes match */
  48 #if defined (CPU_ARM)
  49 /* ARM must load 32-bit values at addres % 4 == 0 offsets but this data
  50    isn't aligned nescessarily, so just byte compare */
  51 #define CMP_3_CONST(_a, _b) \
  52     ({  int _x;                             \
  53         asm volatile (                      \
  54             "ldrb   %[x], [%[a], #0]  \n"   \
  55             "eors   %[x], %[x], %[b0] \n"   \
  56             "ldreqb %[x], [%[a], #1]  \n"   \
  57             "eoreqs %[x], %[x], %[b1] \n"   \
  58             "ldreqb %[x], [%[a], #2]  \n"   \
  59             "eoreqs %[x], %[x], %[b2] \n"   \
  60             : [x]"=&r"(_x)                  \
  61             : [a]"r"(_a),                   \
  62               [b0]"i"(((_b) >> 24) & 0xff), \
  63               [b1]"i"(((_b) >> 16) & 0xff), \
  64               [b2]"i"(((_b) >>  8) & 0xff)  \
  65         );                                  \
  66         _x == 0; })
  67
  68 #define CMP_4_CONST(_a, _b) \
  69     ({  int _x;                             \
  70         asm volatile (                      \
  71             "ldrb   %[x], [%[a], #0]  \n"   \
  72             "eors   %[x], %[x], %[b0] \n"   \
  73             "ldreqb %[x], [%[a], #1]  \n"   \
  74             "eoreqs %[x], %[x], %[b1] \n"   \
  75             "ldreqb %[x], [%[a], #2]  \n"   \
  76             "eoreqs %[x], %[x], %[b2] \n"   \
  77             "ldreqb %[x], [%[a], #3]  \n"   \
  78             "eoreqs %[x], %[x], %[b3] \n"   \
  79             : [x]"=&r"(_x)                  \
  80             : [a]"r"(_a),                   \
  81               [b0]"i"(((_b) >> 24) & 0xff), \
  82               [b1]"i"(((_b) >> 16) & 0xff), \
  83               [b2]"i"(((_b) >>  8) & 0xff), \
  84               [b3]"i"(((_b)      ) & 0xff)  \
  85         );                                  \
  86         _x == 0; })
  87
  88 #elif defined (CPU_COLDFIRE)
  89 /* Coldfire can just load a 32 bit value at any offset but ASM is not the
  90    best way to integrate this with the C code */
  91 #define CMP_3_CONST(a, b) \
  92     (((*(uint32_t *)(a) >> 8) == ((uint32_t)(b) >> 8)))
  93
  94 #define CMP_4_CONST(a, b) \
  95     ((*(uint32_t *)(a) == (b)))
  96
  97 #else
  98 /* Don't know what this is - use bytewise comparisons */
  99 #define CMP_3_CONST(a, b) \
 100     (( ((a)[0] ^ (((b) >> 24) & 0xff)) | \
 101        ((a)[1] ^ (((b) >> 16) & 0xff)) | \
 102        ((a)[2] ^ (((b) >>  8) & 0xff)) ) == 0)
 103
 104 #define CMP_4_CONST(a, b) \
 105     (( ((a)[0] ^ (((b) >> 24) & 0xff)) | \
 106        ((a)[1] ^ (((b) >> 16) & 0xff)) | \
 107        ((a)[2] ^ (((b) >>  8) & 0xff)) | \
 108        ((a)[3] ^ (((b)      ) & 0xff)) ) == 0)
 109 #endif /* CPU_* */
 110
 111
 112 /** Streams **/
 113
 114 /* Convert PTS/DTS ticks to our clock ticks */
 115 #define TS_TO_TICKS(pts) ((uint64_t)CLOCK_RATE*(pts) / TS_SECOND)
 116 /* Convert our clock ticks to PTS/DTS ticks */
 117 #define TICKS_TO_TS(ts)  ((uint64_t)TS_SECOND*(ts) / CLOCK_RATE)
 118 /* Convert timecode ticks to our clock ticks */
 119 #define TC_TO_TICKS(stamp) ((uint64_t)CLOCK_RATE*(stamp) / TC_SECOND)
 120 /* Convert our clock ticks to timecode ticks */
 121 #define TICKS_TO_TC(stamp) ((uint64_t)TC_SECOND*(stamp) / CLOCK_RATE)
 122 /* Convert timecode ticks to timestamp ticks */
 123 #define TC_TO_TS(stamp) ((stamp) / 600)
 124
 125 /*
 126  * S = start position, E = end position
 127  *
 128  * pos:
 129  *     initialize to search start position (S)
 130  *
 131  * len:
 132  *     initialize to = ABS(S-E)
 133  *     scanning = remaining bytes in scan direction
 134  *
 135  * dir:
 136  *     scan direction; >= 0 == forward, < 0 == reverse
 137  *
 138  * margin:
 139  *     amount of data to right of cursor - initialize by stream_scan_normalize
 140  *
 141  * data:
 142  *     Extra data used/returned by the function implemented
 143  *
 144  * Forward scan:
 145  *     S      pos         E
 146  *     |       *<-margin->| dir->
 147  *     |       |<--len--->|
 148  *
 149  * Reverse scan:
 150  *     E      pos         S
 151  *     |<-len->*<-margin->| <-dir
 152  *     |       |          |
 153  */
 154 struct stream_scan
 155 {
 156     off_t   pos;    /* Initial scan position (file offset) */
 157     ssize_t len;    /* Maximum length of scan */
 158     off_t   dir;    /* Direction - >= 0; forward, < 0 backward */
 159     ssize_t margin; /* Used by function to track margin between position and data end */
 160     intptr_t data;  /* */
 161 };
 162
 163 #define SSCAN_REVERSE (-1)
 164 #define SSCAN_FORWARD 1
 165
 166 /* Ensures direction is -1 or 1 and margin is properly initialized */
 167 void stream_scan_normalize(struct stream_scan *sk);
 168
 169 /* Moves a scan cursor. If amount is positive, the increment is in the scan
 170  * direction, otherwise opposite the scan direction */
 171 void stream_scan_offset(struct stream_scan *sk, off_t by);
 172
 173 /** Time helpers **/
 174 struct hms
 175 {
 176     unsigned int hrs;
 177     unsigned int min;
 178     unsigned int sec;
 179     unsigned int frac;
 180 };
 181
 182 void ts_to_hms(uint32_t ts, struct hms *hms);
 183 void hms_format(char *buf, size_t bufsize, struct hms *hms);
 184
 185 /** Maths **/
 186
 187 /* Moving average */
 188 #define AVERAGE(var, x, count) \
 189     ({ typeof (count) _c = (count);   \
 190        ((var) * (_c-1) + (x)) / (_c); })
 191
 192 /* Multiply two unsigned 32-bit integers yielding a 64-bit result and
 193  * divide by another unsigned 32-bit integer to yield a 32-bit result.
 194  * Rounds to nearest with saturation. */
 195 uint32_t muldiv_uint32(uint32_t multiplicand,
 196                        uint32_t multiplier,
 197                        uint32_t divisor);
 198
 199 #endif /* MPEG_MISC_H */