/*
 * Assembly testing and benchmarking tool
 * Copyright (c) 2015 Henrik Gramner
 * Copyright (c) 2008 Loren Merritt
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * FFmpeg 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with FFmpeg; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "checkasm.h"
#include "libavutil/common.h"
#include "libavutil/cpu.h"
#include "libavutil/random_seed.h"

#if ARCH_X86
#include "libavutil/x86/cpu.h"
#endif

#if HAVE_SETCONSOLETEXTATTRIBUTE
#include <windows.h>
#define COLOR_RED    FOREGROUND_RED
#define COLOR_GREEN  FOREGROUND_GREEN
#define COLOR_YELLOW (FOREGROUND_RED|FOREGROUND_GREEN)
#else
#define COLOR_RED    1
#define COLOR_GREEN  2
#define COLOR_YELLOW 3
#endif

#if HAVE_UNISTD_H
#include <unistd.h>
#endif

#if !HAVE_ISATTY
#define isatty(fd) 1
#endif

/* List of tests to invoke */
static void (* const tests[])(void) = {
#if CONFIG_BSWAPDSP
    checkasm_check_bswapdsp,
#endif
#if CONFIG_H264PRED
    checkasm_check_h264pred,
#endif
#if CONFIG_H264QPEL
    checkasm_check_h264qpel,
#endif
    NULL
};

/* List of cpu flags to check */
static const struct {
    const char *name;
    const char *suffix;
    int flag;
} cpus[] = {
#if   ARCH_AARCH64
    { "ARMV8",    "armv8",    AV_CPU_FLAG_ARMV8 },
    { "NEON",     "neon",     AV_CPU_FLAG_NEON },
#elif ARCH_ARM
    { "ARMV5TE",  "armv5te",  AV_CPU_FLAG_ARMV5TE },
    { "ARMV6",    "armv6",    AV_CPU_FLAG_ARMV6 },
    { "ARMV6T2",  "armv6t2",  AV_CPU_FLAG_ARMV6T2 },
    { "VFP",      "vfp",      AV_CPU_FLAG_VFP },
    { "VFPV3",    "vfp3",     AV_CPU_FLAG_VFPV3 },
    { "NEON",     "neon",     AV_CPU_FLAG_NEON },
#elif ARCH_PPC
    { "ALTIVEC",  "altivec",  AV_CPU_FLAG_ALTIVEC },
    { "VSX",      "vsx",      AV_CPU_FLAG_VSX },
    { "POWER8",   "power8",   AV_CPU_FLAG_POWER8 },
#elif ARCH_X86
    { "MMX",      "mmx",      AV_CPU_FLAG_MMX|AV_CPU_FLAG_CMOV },
    { "MMXEXT",   "mmxext",   AV_CPU_FLAG_MMXEXT },
    { "3DNOW",    "3dnow",    AV_CPU_FLAG_3DNOW },
    { "3DNOWEXT", "3dnowext", AV_CPU_FLAG_3DNOWEXT },
    { "SSE",      "sse",      AV_CPU_FLAG_SSE },
    { "SSE2",     "sse2",     AV_CPU_FLAG_SSE2|AV_CPU_FLAG_SSE2SLOW },
    { "SSE3",     "sse3",     AV_CPU_FLAG_SSE3|AV_CPU_FLAG_SSE3SLOW },
    { "SSSE3",    "ssse3",    AV_CPU_FLAG_SSSE3|AV_CPU_FLAG_ATOM },
    { "SSE4.1",   "sse4",     AV_CPU_FLAG_SSE4 },
    { "SSE4.2",   "sse42",    AV_CPU_FLAG_SSE42 },
    { "AVX",      "avx",      AV_CPU_FLAG_AVX },
    { "XOP",      "xop",      AV_CPU_FLAG_XOP },
    { "FMA3",     "fma3",     AV_CPU_FLAG_FMA3 },
    { "FMA4",     "fma4",     AV_CPU_FLAG_FMA4 },
    { "AVX2",     "avx2",     AV_CPU_FLAG_AVX2 },
#endif
    { NULL }
};

typedef struct CheckasmFuncVersion {
    struct CheckasmFuncVersion *next;
    intptr_t (*func)();
    int ok;
    int cpu;
    int iterations;
    uint64_t cycles;
} CheckasmFuncVersion;

/* Binary search tree node */
typedef struct CheckasmFunc {
    struct CheckasmFunc *child[2];
    CheckasmFuncVersion versions;
    char name[1];
} CheckasmFunc;

/* Internal state */
static struct {
    CheckasmFunc *funcs;
    CheckasmFunc *current_func;
    CheckasmFuncVersion *current_func_ver;
    const char *bench_pattern;
    int bench_pattern_len;
    int num_checked;
    int num_failed;
    int nop_time;
    int cpu_flag;
    const char *cpu_flag_name;
} state;

/* PRNG state */
AVLFG checkasm_lfg;

/* Print colored text to stderr if the terminal supports it */
static void color_printf(int color, const char *fmt, ...)
{
    static int use_color = -1;
    va_list arg;

#if HAVE_SETCONSOLETEXTATTRIBUTE
    static HANDLE con;
    static WORD org_attributes;

    if (use_color < 0) {
        CONSOLE_SCREEN_BUFFER_INFO con_info;
        con = GetStdHandle(STD_ERROR_HANDLE);
        if (con && con != INVALID_HANDLE_VALUE && GetConsoleScreenBufferInfo(con, &con_info)) {
            org_attributes = con_info.wAttributes;
            use_color = 1;
        } else
            use_color = 0;
    }
    if (use_color)
        SetConsoleTextAttribute(con, (org_attributes & 0xfff0) | (color & 0x0f));
#else
    if (use_color < 0) {
        const char *term = getenv("TERM");
        use_color = term && strcmp(term, "dumb") && isatty(2);
    }
    if (use_color)
        fprintf(stderr, "\x1b[%d;3%dm", (color & 0x08) >> 3, color & 0x07);
#endif

    va_start(arg, fmt);
    vfprintf(stderr, fmt, arg);
    va_end(arg);

    if (use_color) {
#if HAVE_SETCONSOLETEXTATTRIBUTE
        SetConsoleTextAttribute(con, org_attributes);
#else
        fprintf(stderr, "\x1b[0m");
#endif
    }
}

/* Deallocate a tree */
static void destroy_func_tree(CheckasmFunc *f)
{
    if (f) {
        CheckasmFuncVersion *v = f->versions.next;
        while (v) {
            CheckasmFuncVersion *next = v->next;
            free(v);
            v = next;
        }

        destroy_func_tree(f->child[0]);
        destroy_func_tree(f->child[1]);
        free(f);
    }
}

/* Allocate a zero-initialized block, clean up and exit on failure */
static void *checkasm_malloc(size_t size)
{
    void *ptr = calloc(1, size);
    if (!ptr) {
        fprintf(stderr, "checkasm: malloc failed\n");
        destroy_func_tree(state.funcs);
        exit(1);
    }
    return ptr;
}

/* Get the suffix of the specified cpu flag */
static const char *cpu_suffix(int cpu)
{
    int i = FF_ARRAY_ELEMS(cpus);

    while (--i >= 0)
        if (cpu & cpus[i].flag)
            return cpus[i].suffix;

    return "c";
}

#ifdef AV_READ_TIME
static int cmp_nop(const void *a, const void *b)
{
    return *(const uint16_t*)a - *(const uint16_t*)b;
}

/* Measure the overhead of the timing code (in decicycles) */
static int measure_nop_time(void)
{
    uint16_t nops[10000];
    int i, nop_sum = 0;

    for (i = 0; i < 10000; i++) {
        uint64_t t = AV_READ_TIME();
        nops[i] = AV_READ_TIME() - t;
    }

    qsort(nops, 10000, sizeof(uint16_t), cmp_nop);
    for (i = 2500; i < 7500; i++)
        nop_sum += nops[i];

    return nop_sum / 500;
}

/* Print benchmark results */
static void print_benchs(CheckasmFunc *f)
{
    if (f) {
        print_benchs(f->child[0]);

        /* Only print functions with at least one assembly version */
        if (f->versions.cpu || f->versions.next) {
            CheckasmFuncVersion *v = &f->versions;
            do {
                if (v->iterations) {
                    int decicycles = (10*v->cycles/v->iterations - state.nop_time) / 4;
                    printf("%s_%s: %d.%d\n", f->name, cpu_suffix(v->cpu), decicycles/10, decicycles%10);
                }
            } while ((v = v->next));
        }

        print_benchs(f->child[1]);
    }
}
#endif

/* ASCIIbetical sort except preserving natural order for numbers */
static int cmp_func_names(const char *a, const char *b)
{
    int ascii_diff, digit_diff;

    for (; !(ascii_diff = *a - *b) && *a; a++, b++);
    for (; av_isdigit(*a) && av_isdigit(*b); a++, b++);

    return (digit_diff = av_isdigit(*a) - av_isdigit(*b)) ? digit_diff : ascii_diff;
}

/* Get a node with the specified name, creating it if it doesn't exist */
static CheckasmFunc *get_func(const char *name, int length)
{
    CheckasmFunc *f, **f_ptr = &state.funcs;

    /* Search the tree for a matching node */
    while ((f = *f_ptr)) {
        int cmp = cmp_func_names(name, f->name);
        if (!cmp)
            return f;

        f_ptr = &f->child[(cmp > 0)];
    }

    /* Allocate and insert a new node into the tree */
    f = *f_ptr = checkasm_malloc(sizeof(CheckasmFunc) + length);
    memcpy(f->name, name, length+1);

    return f;
}

/* Perform tests and benchmarks for the specified cpu flag if supported by the host */
static void check_cpu_flag(const char *name, int flag)
{
    int old_cpu_flag = state.cpu_flag;

    flag |= old_cpu_flag;
    av_set_cpu_flags_mask(flag);
    state.cpu_flag = av_get_cpu_flags();

    if (!flag || state.cpu_flag != old_cpu_flag) {
        int i;

        state.cpu_flag_name = name;
        for (i = 0; tests[i]; i++)
            tests[i]();
    }
}

/* Print the name of the current CPU flag, but only do it once */
static void print_cpu_name(void)
{
    if (state.cpu_flag_name) {
        color_printf(COLOR_YELLOW, "%s:\n", state.cpu_flag_name);
        state.cpu_flag_name = NULL;
    }
}

int main(int argc, char *argv[])
{
    int i, seed, ret = 0;

    if (!tests[0] || !cpus[0].flag) {
        fprintf(stderr, "checkasm: no tests to perform\n");
        return 0;
    }

    if (argc > 1 && !strncmp(argv[1], "--bench", 7)) {
#ifndef AV_READ_TIME
        fprintf(stderr, "checkasm: --bench is not supported on your system\n");
        return 1;
#endif
        if (argv[1][7] == '=') {
            state.bench_pattern = argv[1] + 8;
            state.bench_pattern_len = strlen(state.bench_pattern);
        } else
            state.bench_pattern = "";

        argc--;
        argv++;
    }

    seed = (argc > 1) ? atoi(argv[1]) : av_get_random_seed();
    fprintf(stderr, "checkasm: using random seed %u\n", seed);
    av_lfg_init(&checkasm_lfg, seed);

    check_cpu_flag(NULL, 0);
    for (i = 0; cpus[i].flag; i++)
        check_cpu_flag(cpus[i].name, cpus[i].flag);

    if (state.num_failed) {
        fprintf(stderr, "checkasm: %d of %d tests have failed\n", state.num_failed, state.num_checked);
        ret = 1;
    } else {
        fprintf(stderr, "checkasm: all %d tests passed\n", state.num_checked);
#ifdef AV_READ_TIME
        if (state.bench_pattern) {
            state.nop_time = measure_nop_time();
            printf("nop: %d.%d\n", state.nop_time/10, state.nop_time%10);
            print_benchs(state.funcs);
        }
#endif
    }

    destroy_func_tree(state.funcs);
    return ret;
}

/* Decide whether or not the specified function needs to be tested and
 * allocate/initialize data structures if needed. Returns a pointer to a
 * reference function if the function should be tested, otherwise NULL */
intptr_t (*checkasm_check_func(intptr_t (*func)(), const char *name, ...))()
{
    char name_buf[256];
    intptr_t (*ref)() = func;
    CheckasmFuncVersion *v;
    int name_length;
    va_list arg;

    va_start(arg, name);
    name_length = vsnprintf(name_buf, sizeof(name_buf), name, arg);
    va_end(arg);

    if (!func || name_length <= 0 || name_length >= sizeof(name_buf))
        return NULL;

    state.current_func = get_func(name_buf, name_length);
    v = &state.current_func->versions;

    if (v->func) {
        CheckasmFuncVersion *prev;
        do {
            /* Only test functions that haven't already been tested */
            if (v->func == func)
                return NULL;

            if (v->ok)
                ref = v->func;

            prev = v;
        } while ((v = v->next));

        v = prev->next = checkasm_malloc(sizeof(CheckasmFuncVersion));
    }

    v->func = func;
    v->ok = 1;
    v->cpu = state.cpu_flag;
    state.current_func_ver = v;

    if (state.cpu_flag)
        state.num_checked++;

    return ref;
}

/* Decide whether or not the current function needs to be benchmarked */
int checkasm_bench_func(void)
{
    return !state.num_failed && state.bench_pattern &&
           !strncmp(state.current_func->name, state.bench_pattern, state.bench_pattern_len);
}

/* Indicate that the current test has failed */
void checkasm_fail_func(const char *msg, ...)
{
    if (state.current_func_ver->cpu && state.current_func_ver->ok) {
        va_list arg;

        print_cpu_name();
        fprintf(stderr, "   %s_%s (", state.current_func->name, cpu_suffix(state.current_func_ver->cpu));
        va_start(arg, msg);
        vfprintf(stderr, msg, arg);
        va_end(arg);
        fprintf(stderr, ")\n");

        state.current_func_ver->ok = 0;
        state.num_failed++;
    }
}

/* Update benchmark results of the current function */
void checkasm_update_bench(int iterations, uint64_t cycles)
{
    state.current_func_ver->iterations += iterations;
    state.current_func_ver->cycles += cycles;
}

/* Print the outcome of all tests performed since the last time this function was called */
void checkasm_report(const char *name, ...)
{
    static int prev_checked, prev_failed, max_length;

    if (state.num_checked > prev_checked) {
        print_cpu_name();

        if (*name) {
            int pad_length = max_length;
            va_list arg;

            fprintf(stderr, " - ");
            va_start(arg, name);
            pad_length -= vfprintf(stderr, name, arg);
            va_end(arg);
            fprintf(stderr, "%*c", FFMAX(pad_length, 0) + 2, '[');
        } else
            fprintf(stderr, " - %-*s [", max_length, state.current_func->name);

        if (state.num_failed == prev_failed)
            color_printf(COLOR_GREEN, "OK");
        else
            color_printf(COLOR_RED, "FAILED");
        fprintf(stderr, "]\n");

        prev_checked = state.num_checked;
        prev_failed  = state.num_failed;
    } else if (!state.cpu_flag) {
        int length;

        /* Calculate the amount of padding required to make the output vertically aligned */
        if (*name) {
            va_list arg;
            va_start(arg, name);
            length = vsnprintf(NULL, 0, name, arg);
            va_end(arg);
        } else
            length = strlen(state.current_func->name);

        if (length > max_length)
            max_length = length;
    }
}