string.cpp

一个小型C语言编译器

#include <assert.h>
#include <stddef.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>

#include "self_def.h"



#define NELEMS(a) ((int)(sizeof (a)/sizeof ((a)[0])))





static struct string {
	char *str;
	int len;
	struct string *link;
} *buckets[1024];
static int scatter[] = {	/* map characters to random values */
	2078917053, 143302914,   1027100827, 1953210302, 755253631,
	2002600785, 1405390230,  45248011,   1099951567, 433832350,
	2018585307, 438263339,   813528929,  1703199216, 618906479,
	573714703,  766270699,   275680090,  1510320440, 1583583926,
	1723401032, 1965443329,  1098183682, 1636505764, 980071615,
	1011597961, 643279273,   1315461275, 157584038,  1069844923,
	471560540,  89017443,    1213147837, 1498661368, 2042227746,
	1968401469, 1353778505,  1300134328, 2013649480, 306246424,
	1733966678, 1884751139,  744509763,  400011959,  1440466707,
	1363416242, 973726663,   59253759,   1639096332, 336563455,
	1642837685, 1215013716,  154523136,  593537720,  704035832,
	1134594751, 1605135681,  1347315106, 302572379,  1762719719,
	269676381,  774132919,   1851737163, 1482824219, 125310639,
	1746481261, 1303742040,  1479089144, 899131941,  1169907872,
	1785335569, 485614972,   907175364,  382361684,  885626931,
	200158423,  1745777927,  1859353594, 259412182,  1237390611,
	48433401,   1902249868,  304920680,  202956538,  348303940,
	1008956512, 1337551289,  1953439621, 208787970,  1640123668,
	1568675693, 478464352,   266772940,  1272929208, 1961288571,
	392083579,  871926821,   1117546963, 1871172724, 1771058762,
	139971187,  1509024645,  109190086,  1047146551, 1891386329,
	994817018,  1247304975,  1489680608, 706686964,  1506717157,
	579587572,  755120366,   1261483377, 884508252,  958076904,
	1609787317, 1893464764,  148144545,  1415743291, 2102252735,
	1788268214, 836935336,   433233439,  2055041154, 2109864544,
	247038362,  299641085,   834307717,  1364585325, 23330161,
	457882831,  1504556512,  1532354806, 567072918,  404219416,
	1276257488, 1561889936,  1651524391, 618454448,  121093252,
	1010757900, 1198042020,  876213618,  124757630,  2082550272,
	1834290522, 1734544947,  1828531389, 1982435068, 1002804590,
	1783300476, 1623219634,  1839739926, 69050267,   1530777140,
	1802120822, 316088629,   1830418225, 488944891,  1680673954,
	1853748387, 946827723,   1037746818, 1238619545, 1513900641,
	1441966234, 367393385,   928306929,  946006977,  985847834,
	1049400181, 1956764878,  36406206,   1925613800, 2081522508,
	2118956479, 1612420674,  1668583807, 1800004220, 1447372094,
	523904750,  1435821048,  923108080,  216161028,  1504871315,
	306401572,  2018281851,  1820959944, 2136819798, 359743094,
	1354150250, 1843084537,  1306570817, 244413420,  934220434,
	672987810,  1686379655,  1301613820, 1601294739, 484902984,
	139978006,  503211273,   294184214,  176384212,  281341425,
	228223074,  147857043,   1893762099, 1896806882, 1947861263,
	1193650546, 273227984,   1236198663, 2116758626, 489389012,
	593586330,  275676551,   360187215,  267062626,  265012701,
	719930310,  1621212876,  2108097238, 2026501127, 1865626297,
	894834024,  552005290,   1404522304, 48964196,   5816381,
	1889425288, 188942202,   509027654,  36125855,   365326415,
	790369079,  264348929,   513183458,  536647531,  13672163,
	313561074,  1730298077,  286900147,  1549759737, 1699573055,
	776289160,  2143346068,  1975249606, 1136476375, 262925046,
	92778659,   1856406685,  1884137923, 53392249,   1735424165,
	1602280572
};






char *string(char* str);
char *stringd(int n); 
char *stringn(char* str, int len);




char *string(char* str)
{
	char *s;

	for (s = str; *s; s++)
		;
	return stringn(str, s - str);
}


char *stringd(int n)
{
	char str[25], *s = str + sizeof (str);
	unsigned m;

	if (n == INT_MIN)
		m = (unsigned)INT_MAX + 1;
	else if (n < 0)
		m = -n;
	else
		m = n;
	do
		*--s = m%10 + '0';
	while ((m /= 10) != 0);
	if (n < 0)
		*--s = '-';
	return stringn(s, str + sizeof (str) - s);
}
char *stringn(char* str, int len)
{
    //
    char* string_ = NULL;

    string_ = (char*)malloc(len+1);
    if(string_ == NULL){
        printf("mem process faile\r\n");
        exit(1);
    }
    memcpy(string_, str, len);
    string_[len] = '\0';
    return string_;
    //


    /*
	int i;
	unsigned int h;
	char *end;
	struct string *p;

	assert(str);
	for (h = 0, i = len, end = str; i > 0; i--)
		h = (h<<1) + scatter[*(unsigned char *)end++];
	h &= NELEMS(buckets)-1;
	for (p = buckets[h]; p; p = p->link)
		if (len == p->len) {
			char *s1 = str, *s2 = p->str;
			do {
				if (s1 == end)
					return p->str;
			} while (*s1++ == *s2++);
		}
	{
		static char *next, *strlimit;
		if (len + 1 >= strlimit - next) {
			int n = len + 4*1024;
			next = allocate(n, PERM);
			strlimit = next + n;
		}
		NEW(p, PERM);
		p->len = len;
		for (p->str = next; str < end; )
			*next++ = *str++;
		*next++ = 0;
		p->link = buckets[h];
		buckets[h] = p;
		return p->str;
	}
    */

    //return NULL;
}