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don't use sprintf for rendering numbers

This commit is contained in:
psyc://psyced.org/~lynX 2011-04-25 16:11:47 +02:00
parent 97d40c09bd
commit f4791db17c
4 changed files with 100 additions and 5 deletions

View file

@ -15,4 +15,8 @@
void * memmem(const void *l, size_t l_len, const void *s, size_t s_len);
#endif
#if !defined(_GNU_SOURCE) && !defined(__FBSDID)
int itoa(int number, char* out, int base);
#endif
#endif // PSYC_LIB_H

View file

@ -2,8 +2,8 @@ CFLAGS=-I../include -DDEBUG=2 -DPSYC_COMPILE_LIBRARY -g -O0 -Wall
CC=cc
# CC=clang
S=psyc.c parser.c match.c render.c memmem.c variable.c
O=psyc.o parser.o match.o render.o memmem.o variable.o
S=psyc.c parser.c match.c render.c memmem.c itoa.c variable.c
O=psyc.o parser.o match.o render.o memmem.o itoa.o variable.o
default:
@/bin/echo -e "Usage:\n\tmake diet - compile with diet libc\n\tmake lib - compile with normal gnu libc"
@ -19,6 +19,9 @@ lib: $S
match: match.c
${CC} -o $@ -DDEBUG=4 -DCMDTOOL -DTEST $<
itoa: itoa.c
${CC} -o $@ -DDEBUG=4 -DCMDTOOL -DTEST -O0 $<
it: match
clean:

85
src/itoa.c Normal file
View file

@ -0,0 +1,85 @@
#define ALPHANUMS "zyxwvutsrqponmlkjihgfedcba9876543210123456789abcdefghijklmnopqrstuvwxyz"
/** converts an integer to a string, using a base of 10 by default.
*
* if you NULL out the output buffer it will return the expected
* output string length anyway.
*/
int itoa(int number, char* out, int base) {
int t, count;
char *p, *q;
char c;
p = q = out;
if (base < 2 || base > 36) base = 10;
do {
t = number;
number /= base;
if (out) *p = ALPHANUMS[t+35 - number*base];
p++;
} while (number);
if (t < 0) {
if (out) *p = '-';
p++;
}
count = p-out;
if (out) {
*p-- = '\0';
while(q < p) {
c = *p;
*p-- = *q;
*q++ = c;
}
}
return count;
}
/* This little test program shows that itoa() is roughly 3 times faster
* than sprintf --lynX
*/
#ifdef CMDTOOL
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int main(int argc, char **argv) {
char out[4404];
int in[44];
int c, i, j;
if (argc < 3 || argc > sizeof(in)) {
printf("Usage: %s <times> <numbers>+\n\nExample: %s 999999 123 234 345 -49 -21892\n", argv[0], argv[0]);
return -1;
}
for (j=argc-1; j; j--) {
// printf("Looking at arg #%d: %s\n", j, argv[j]);
in[j] = atoi(argv[j]);
// printf("Got %d: %d\n", j, in[j]);
}
for (i=in[1]; i; i--) {
c = 0;
for (j=argc-1; j>1; j--) {
# if 0
// use good old sprintf
c += sprintf(&out[c], " %d", in[j]);
# else
# if 1
// use the itoa implementation
out[c++] = ' ';
c += itoa(in[j], &out[c], 10);
# else
// just count the needed space
c += itoa(in[j], NULL, 10) + 1;
# endif
# endif
}
}
printf("%d times, %d count, buffer len: %d, buffer: %s\n",
in[1], c, strlen(out), "<omitted>"); // out
return 0;
}
#endif

View file

@ -11,7 +11,8 @@ inline int PSYC_renderModifier(PSYC_Modifier *m, char *buffer)
if (m->flag == PSYC_MODIFIER_NEED_LENGTH)
{
buffer[cur++] = ' ';
cur += sprintf(buffer + cur, "%ld", m->value.length);
// cur += sprintf(buffer + cur, "%ld", m->value.length);
cur += itoa(m->value.length, buffer + cur, 10);
}
memcpy(buffer + cur, m->value.ptr, m->value.length);
cur += m->value.length;
@ -30,8 +31,10 @@ PSYC_RenderRC PSYC_render(PSYC_Packet *packet, char *buffer, size_t buflen)
for (i = 0; i < packet->routing.lines; i++)
cur += PSYC_renderModifier(packet->routing.modifiers[i], buffer + cur);
if (packet->flag == PSYC_PACKET_NEED_LENGTH)
cur += sprintf(buffer + cur, "%ld", packet->contentLength);
if (packet->flag == PSYC_PACKET_NEED_LENGTH) {
// cur += sprintf(buffer + cur, "%ld", packet->contentLength);
cur += itoa(packet->contentLength, buffer + cur, 10);
}
buffer[cur++] = '\n';