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Diffstat (limited to 'third_party/libpng/arm/arm_init.c')
| -rw-r--r-- | third_party/libpng/arm/arm_init.c | 221 |
1 files changed, 221 insertions, 0 deletions
diff --git a/third_party/libpng/arm/arm_init.c b/third_party/libpng/arm/arm_init.c new file mode 100644 index 0000000..15f5162 --- /dev/null +++ b/third_party/libpng/arm/arm_init.c @@ -0,0 +1,221 @@ + +/* arm_init.c - NEON optimised filter functions + * + * Copyright (c) 2013 Glenn Randers-Pehrson + * Written by Mans Rullgard, 2011. + * Last changed in libpng 1.5.17 [July 18, 2013] + * + * This code is released under the libpng license. + * For conditions of distribution and use, see the disclaimer + * and license in png.h + */ +/* Below, after checking __linux__, various non-C90 POSIX 1003.1 functions are + * called. + */ +#define _POSIX_SOURCE 1 + +#include "../pngpriv.h" + +#ifdef PNG_READ_SUPPORTED +#if PNG_ARM_NEON_OPT > 0 +#ifdef PNG_ARM_NEON_CHECK_SUPPORTED /* Do run-time checks */ +#include <signal.h> /* for sig_atomic_t */ + +#ifdef __ANDROID__ +/* Linux provides access to information about CPU capabilites via + * /proc/self/auxv, however Android blocks this while still claiming to be + * Linux. The Andoid NDK, however, provides appropriate support. + * + * Documentation: http://www.kandroid.org/ndk/docs/CPU-ARM-NEON.html + */ +#include <cpu-features.h> + +static int +png_have_neon(png_structp png_ptr) +{ + /* This is a whole lot easier than the mess below, however it is probably + * implemented as below, therefore it is better to cache the result (these + * function calls may be slow!) + */ + PNG_UNUSED(png_ptr) + return android_getCpuFamily() == ANDROID_CPU_FAMILY_ARM && + (android_getCpuFeatures() & ANDROID_CPU_ARM_FEATURE_NEON) != 0; +} +#elif defined(__linux__) +/* The generic __linux__ implementation requires reading /proc/self/auxv and + * looking at each element for one that records NEON capabilities. + */ +#include <unistd.h> /* for POSIX 1003.1 */ +#include <errno.h> /* for EINTR */ + +#include <sys/types.h> +#include <sys/stat.h> +#include <fcntl.h> +#include <elf.h> +#include <asm/hwcap.h> + +/* A read call may be interrupted, in which case it returns -1 and sets errno to + * EINTR if nothing was done, otherwise (if something was done) a partial read + * may result. + */ +static size_t +safe_read(png_structp png_ptr, int fd, void *buffer_in, size_t nbytes) +{ + size_t ntotal = 0; + char *buffer = png_voidcast(char*, buffer_in); + + while (nbytes > 0) + { + unsigned int nread; + int iread; + + /* Passing nread > INT_MAX to read is implementation defined in POSIX + * 1003.1, therefore despite the unsigned argument portable code must + * limit the value to INT_MAX! + */ + if (nbytes > INT_MAX) + nread = INT_MAX; + + else + nread = (unsigned int)/*SAFE*/nbytes; + + iread = read(fd, buffer, nread); + + if (iread == -1) + { + /* This is the devil in the details, a read can terminate early with 0 + * bytes read because of EINTR, yet it still returns -1 otherwise end + * of file cannot be distinguished. + */ + if (errno != EINTR) + { + png_warning(png_ptr, "/proc read failed"); + return 0; /* I.e. a permanent failure */ + } + } + + else if (iread < 0) + { + /* Not a valid 'read' result: */ + png_warning(png_ptr, "OS /proc read bug"); + return 0; + } + + else if (iread > 0) + { + /* Continue reading until a permanent failure, or EOF */ + buffer += iread; + nbytes -= (unsigned int)/*SAFE*/iread; + ntotal += (unsigned int)/*SAFE*/iread; + } + + else + return ntotal; + } + + return ntotal; /* nbytes == 0 */ +} + +static int +png_have_neon(png_structp png_ptr) +{ + int fd = open("/proc/self/auxv", O_RDONLY); + Elf32_auxv_t aux; + + /* Failsafe: failure to open means no NEON */ + if (fd == -1) + { + png_warning(png_ptr, "/proc/self/auxv open failed"); + return 0; + } + + while (safe_read(png_ptr, fd, &aux, sizeof aux) == sizeof aux) + { + if (aux.a_type == AT_HWCAP && (aux.a_un.a_val & HWCAP_NEON) != 0) + { + close(fd); + return 1; + } + } + + close(fd); + return 0; +} +#else + /* We don't know how to do a run-time check on this system */ +# error "no support for run-time ARM NEON checks" +#endif /* OS checks */ +#endif /* PNG_ARM_NEON_CHECK_SUPPORTED */ + +#ifndef PNG_ALIGNED_MEMORY_SUPPORTED +# error "ALIGNED_MEMORY is required; set: -DPNG_ALIGNED_MEMORY_SUPPORTED" +#endif + +void +png_init_filter_functions_neon(png_structp pp, unsigned int bpp) +{ +#ifdef PNG_ARM_NEON_API_SUPPORTED + switch ((pp->options >> PNG_ARM_NEON) & 3) + { + case PNG_OPTION_UNSET: + /* Allow the run-time check to execute if it has been enabled - + * thus both API and CHECK can be turned on. If it isn't supported + * this case will fall through to the 'default' below, which just + * returns. + */ +#endif /* PNG_ARM_NEON_API_SUPPORTED */ +#ifdef PNG_ARM_NEON_CHECK_SUPPORTED + { + static volatile sig_atomic_t no_neon = -1; /* not checked */ + + if (no_neon < 0) + no_neon = !png_have_neon(pp); + + if (no_neon) + return; + } +#ifdef PNG_ARM_NEON_API_SUPPORTED + break; +#endif +#endif /* PNG_ARM_NEON_CHECK_SUPPORTED */ +#ifdef PNG_ARM_NEON_API_SUPPORTED + case PNG_OPTION_ON: + /* Option turned on */ + break; + + default: /* OFF or INVALID */ + return; + } +#endif + + /* IMPORTANT: any new external functions used here must be declared using + * PNG_INTERNAL_FUNCTION in ../pngpriv.h. This is required so that the + * 'prefix' option to configure works: + * + * ./configure --with-libpng-prefix=foobar_ + * + * Verify you have got this right by running the above command, doing a build + * and examining pngprefix.h; it must contain a #define for every external + * function you add. (Notice that this happens automatically for the + * initialization function.) + */ + pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up_neon; + + if (bpp == 3) + { + pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub3_neon; + pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg3_neon; + pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = + png_read_filter_row_paeth3_neon; + } + + else if (bpp == 4) + { + pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub4_neon; + pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg4_neon; + pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = + png_read_filter_row_paeth4_neon; + } +} +#endif /* PNG_ARM_NEON_OPT > 0 */ +#endif /* PNG_READ_SUPPORTED */ |