Felix021

def fen_to_yuan(str_fen):
    fen = int(str_fen)
    return '%d.%02d' % (int(fen / 100) , fen % 100)

def fen_to_yuan(str_fen):
    fen = int(str_fen)
    sign, fen = fen < 0 and ('-', -fen) or ('', fen)
    return sign + '%d.%02d' % (int(fen / 100) , fen % 100)

#!/bin/bash

if [ -z "$1" -o -z "$2" ]; then
    echo "Usage: xgrep FilePattern WordPattern"
    exit
fi

filepat="$1"
greppat="$2"

shift
shift

set -x

find -name "$filepat" -exec grep {} -Hne "$greppat" $* \;

#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>
#include <sys/time.h>
#include <limits.h>

void *tester(void *arg)
{
    long *nloop = (long *)arg; //这里之前笔误写成int了。
    while ( (*nloop)-- );
    return NULL;
}

int driver(int nthread, int nloop, int npad)
{
    size_t size = npad + sizeof(long); //每个线程占用sizeof(long) + npad的空间
    char buff[size * nthread];
    pthread_t th[nthread];

    struct timeval s, e;
    gettimeofday(&s, NULL);

    for (int i = 0; i < nthread; i++) {
        int *arg = (int *)(buff + size * i);
        *arg = nloop;
        pthread_create(&th[i], NULL, tester, (void *)arg);
    }

    void *pret;
    for (int i = 0; i < nthread; i++)
        pthread_join(th[i], &pret);

    gettimeofday(&e, NULL);

    return (e.tv_sec - s.tv_sec) * 1000000 + e.tv_usec - s.tv_usec;
}

int main()
{
    int nloop = 1024 * 1024 * 128, nthread = 16, npad, best_padding = 0, best_usage = INT_MAX;
    printf("nloop = %d, nthread = %d\n\n", nloop, nthread);
    for (npad = 64; npad >= 0; npad -= 8) { //之所以步长为8是为了避免非8字节对齐long可能有的性能损失
        int i, usage = 0;;
        for (i = 0; i < 3; i++)
            usage += driver(nthread, nloop, npad);
        usage /= 3;
        if (usage < best_usage) {
            best_usage = usage;
            best_padding = npad;
        }
        printf("padding: %2d, time usage: %12d\n", npad, usage);
    }
    printf("\nbest padding: %2d, time usage: %12d\n", best_padding, best_usage);
    return 0;
}

size_t *n = (size_t *)args;
while ( (*n)-- );
return NULL;

#define NSMALLPOSINTS          257
#define NSMALLNEGINTS          5
/* References to small integers are saved in this array so that they
  can be shared.
  The integers that are saved are those in the range
  -NSMALLNEGINTS (inclusive) to NSMALLPOSINTS (not inclusive).
*/
static PyIntObject *small_ints[NSMALLNEGINTS + NSMALLPOSINTS];

PyObject *
PyInt_FromLong(long ival)
{
    register PyIntObject *v;
    //如果 -5 <= ival && ival < 257, 命中缓存~
    if (-NSMALLNEGINTS <= ival && ival < NSMALLPOSINTS) {
        v = small_ints[ival + NSMALLNEGINTS];
        Py_INCREF(v);
        return (PyObject *) v;
    }
    if (free_list == NULL) { //这个是另一个优化，相当于内存池，用链表实现
        if ((free_list = fill_free_list()) == NULL)
            return NULL;
    }
    /* Inline PyObject_New */
    v = free_list;
    free_list = (PyIntObject *)Py_TYPE(v);
    PyObject_INIT(v, &PyInt_Type);
    v->ob_ival = ival;
    return (PyObject *) v;
}