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base64: encode without using snprintf

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For speed. In some tests, this approch is 29 times faster!

Closes #10026
This commit is contained in:
Daniel Stenberg 2022-12-04 00:34:09 +01:00
parent fa467a2fa9
commit fc02a78081
No known key found for this signature in database
GPG Key ID: 5CC908FDB71E12C2
1 changed files with 25 additions and 50 deletions
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75
lib/base64.c
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@ -37,8 +37,7 @@
#include "warnless.h"
#include "curl_base64.h"
/* The last 3 #include files should be in this order */
#include "curl_printf.h"
/* The last 2 #include files should be in this order */
#include "curl_memory.h"
#include "memdebug.h"
@ -172,20 +171,16 @@ static CURLcode base64_encode(const char *table64,
const char *inputbuff, size_t insize,
char **outptr, size_t *outlen)
{
unsigned char ibuf[3];
unsigned char obuf[4];
int i;
int inputparts;
char *output;
char *base64data;
const char *indata = inputbuff;
const unsigned char *in = (unsigned char *)inputbuff;
const char *padstr = &table64[64]; /* Point to padding string. */
*outptr = NULL;
*outlen = 0;
if(!insize)
insize = strlen(indata);
insize = strlen(inputbuff);
#if SIZEOF_SIZE_T == 4
if(insize > UINT_MAX/4)
@ -196,51 +191,31 @@ static CURLcode base64_encode(const char *table64,
if(!output)
return CURLE_OUT_OF_MEMORY;
while(insize > 0) {
for(i = inputparts = 0; i < 3; i++) {
if(insize > 0) {
inputparts++;
ibuf[i] = (unsigned char) *indata;
indata++;
insize--;
while(insize >= 3) {
*output++ = table64[ in[0] >> 2 ];
*output++ = table64[ ((in[0] & 0x03) << 4) | (in[1] >> 4) ];
*output++ = table64[ ((in[1] & 0x0F) << 2) | ((in[2] & 0xC0) >> 6) ];
*output++ = table64[ in[2] & 0x3F ];
insize -= 3;
in += 3;
}
if(insize) {
/* this is only one or two bytes now */
*output++ = table64[ in[0] >> 2 ];
if(insize == 1) {
*output++ = table64[ ((in[0] & 0x03) << 4) ];
if(*padstr) {
*output++ = *padstr;
*output++ = *padstr;
}
else
ibuf[i] = 0;
}
obuf[0] = (unsigned char) ((ibuf[0] & 0xFC) >> 2);
obuf[1] = (unsigned char) (((ibuf[0] & 0x03) << 4) | \
((ibuf[1] & 0xF0) >> 4));
obuf[2] = (unsigned char) (((ibuf[1] & 0x0F) << 2) | \
((ibuf[2] & 0xC0) >> 6));
obuf[3] = (unsigned char) (ibuf[2] & 0x3F);
switch(inputparts) {
case 1: /* only one byte read */
i = msnprintf(output, 5, "%c%c%s%s",
table64[obuf[0]],
table64[obuf[1]],
padstr,
padstr);
break;
case 2: /* two bytes read */
i = msnprintf(output, 5, "%c%c%c%s",
table64[obuf[0]],
table64[obuf[1]],
table64[obuf[2]],
padstr);
break;
default:
i = msnprintf(output, 5, "%c%c%c%c",
table64[obuf[0]],
table64[obuf[1]],
table64[obuf[2]],
table64[obuf[3]]);
break;
else {
/* insize == 2 */
*output++ = table64[ ((in[0] & 0x03) << 4) | ((in[1] & 0xF0) >> 4) ];
*output++ = table64[ ((in[1] & 0x0F) << 2) ];
if(*padstr)
*output++ = *padstr;
}
output += i;
}
/* Zero terminate */