1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/media/libpng/arm/linux.c Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,159 @@
1.4 +/* contrib/arm-neon/linux.c
1.5 + *
1.6 + * Copyright (c) 2014 Glenn Randers-Pehrson
1.7 + * Written by John Bowler, 2014.
1.8 + * Last changed in libpng 1.6.10 [March 6, 2014]
1.9 + *
1.10 + * This code is released under the libpng license.
1.11 + * For conditions of distribution and use, see the disclaimer
1.12 + * and license in png.h
1.13 + *
1.14 + * SEE contrib/arm-neon/README before reporting bugs
1.15 + *
1.16 + * STATUS: SUPPORTED
1.17 + * BUG REPORTS: png-mng-implement@sourceforge.net
1.18 + *
1.19 + * png_have_neon implemented for Linux by reading the widely available
1.20 + * pseudo-file /proc/cpuinfo.
1.21 + *
1.22 + * This code is strict ANSI-C and is probably moderately portable, it does
1.23 + * however use <stdio.h> and assumes that /proc/cpuinfo is never localized.
1.24 + */
1.25 +#include <stdio.h>
1.26 +
1.27 +static int
1.28 +png_have_neon(png_structp png_ptr)
1.29 +{
1.30 + FILE *f = fopen("/proc/cpuinfo", "rb");
1.31 +
1.32 + if (f != NULL)
1.33 + {
1.34 + /* This is a simple state machine which reads the input byte-by-byte until
1.35 + * it gets a match on the 'neon' feature or reaches the end of the stream.
1.36 + */
1.37 + static const char ch_feature[] = { 70, 69, 65, 84, 85, 82, 69, 83 };
1.38 + static const char ch_neon[] = { 78, 69, 79, 78 };
1.39 +
1.40 + enum
1.41 + {
1.42 + StartLine, Feature, Colon, StartTag, Neon, HaveNeon, SkipTag, SkipLine
1.43 + } state;
1.44 + int counter;
1.45 +
1.46 + for (state=StartLine, counter=0;;)
1.47 + {
1.48 + int ch = fgetc(f);
1.49 +
1.50 + if (ch == EOF)
1.51 + {
1.52 + /* EOF means error or end-of-file, return false; neon at EOF is
1.53 + * assumed to be a mistake.
1.54 + */
1.55 + fclose(f);
1.56 + return 0;
1.57 + }
1.58 +
1.59 + switch (state)
1.60 + {
1.61 + case StartLine:
1.62 + /* Match spaces at the start of line */
1.63 + if (ch <= 32) /* skip control characters and space */
1.64 + break;
1.65 +
1.66 + counter=0;
1.67 + state = Feature;
1.68 + /* FALL THROUGH */
1.69 +
1.70 + case Feature:
1.71 + /* Match 'FEATURE', ASCII case insensitive. */
1.72 + if ((ch & ~0x20) == ch_feature[counter])
1.73 + {
1.74 + if (++counter == (sizeof ch_feature))
1.75 + state = Colon;
1.76 + break;
1.77 + }
1.78 +
1.79 + /* did not match 'feature' */
1.80 + state = SkipLine;
1.81 + /* FALL THROUGH */
1.82 +
1.83 + case SkipLine:
1.84 + skipLine:
1.85 + /* Skip everything until we see linefeed or carriage return */
1.86 + if (ch != 10 && ch != 13)
1.87 + break;
1.88 +
1.89 + state = StartLine;
1.90 + break;
1.91 +
1.92 + case Colon:
1.93 + /* Match any number of space or tab followed by ':' */
1.94 + if (ch == 32 || ch == 9)
1.95 + break;
1.96 +
1.97 + if (ch == 58) /* i.e. ':' */
1.98 + {
1.99 + state = StartTag;
1.100 + break;
1.101 + }
1.102 +
1.103 + /* Either a bad line format or a 'feature' prefix followed by
1.104 + * other characters.
1.105 + */
1.106 + state = SkipLine;
1.107 + goto skipLine;
1.108 +
1.109 + case StartTag:
1.110 + /* Skip space characters before a tag */
1.111 + if (ch == 32 || ch == 9)
1.112 + break;
1.113 +
1.114 + state = Neon;
1.115 + counter = 0;
1.116 + /* FALL THROUGH */
1.117 +
1.118 + case Neon:
1.119 + /* Look for 'neon' tag */
1.120 + if ((ch & ~0x20) == ch_neon[counter])
1.121 + {
1.122 + if (++counter == (sizeof ch_neon))
1.123 + state = HaveNeon;
1.124 + break;
1.125 + }
1.126 +
1.127 + state = SkipTag;
1.128 + /* FALL THROUGH */
1.129 +
1.130 + case SkipTag:
1.131 + /* Skip non-space characters */
1.132 + if (ch == 10 || ch == 13)
1.133 + state = StartLine;
1.134 +
1.135 + else if (ch == 32 || ch == 9)
1.136 + state = StartTag;
1.137 + break;
1.138 +
1.139 + case HaveNeon:
1.140 + /* Have seen a 'neon' prefix, but there must be a space or new
1.141 + * line character to terminate it.
1.142 + */
1.143 + if (ch == 10 || ch == 13 || ch == 32 || ch == 9)
1.144 + {
1.145 + fclose(f);
1.146 + return 1;
1.147 + }
1.148 +
1.149 + state = SkipTag;
1.150 + break;
1.151 +
1.152 + default:
1.153 + png_error(png_ptr, "png_have_neon: internal error (bug)");
1.154 + }
1.155 + }
1.156 + }
1.157 +
1.158 + else
1.159 + png_warning(png_ptr, "/proc/cpuinfo open failed");
1.160 +
1.161 + return 0;
1.162 +}
