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ubinascii: b2a_base64: Optimize away a modulo operation.

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This commit is contained in:
Paul Sokolovsky 2015-07-04 12:36:46 +03:00
parent 616986a5f3
commit e284a95cc3
1 changed files with 8 additions and 3 deletions
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11
extmod/modubinascii.c
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@ -147,17 +147,20 @@ mp_obj_t mod_binascii_b2a_base64(mp_obj_t data) {
vstr_t vstr;
vstr_init_len(&vstr, ((bufinfo.len != 0) ? (((bufinfo.len - 1) / 3) + 1) * 4 : 0) + 1);
// First pass, we convert input buffer to numeric base 64 values
byte *in = bufinfo.buf, *out = (byte*)vstr.buf;
for (mp_uint_t i = bufinfo.len; i >= 3; i -= 3) {
mp_uint_t i;
for (i = bufinfo.len; i >= 3; i -= 3) {
*out++ = (in[0] & 0xFC) >> 2;
*out++ = (in[0] & 0x03) << 4 | (in[1] & 0xF0) >> 4;
*out++ = (in[1] & 0x0F) << 2 | (in[2] & 0xC0) >> 6;
*out++ = in[2] & 0x3F;
in += 3;
}
if (bufinfo.len % 3 != 0) {
if (i != 0) {
*out++ = (in[0] & 0xFC) >> 2;
if (bufinfo.len % 3 == 2) {
if (i == 2) {
*out++ = (in[0] & 0x03) << 4 | (in[1] & 0xF0) >> 4;
*out++ = (in[1] & 0x0F) << 2;
}
@ -167,6 +170,8 @@ mp_obj_t mod_binascii_b2a_base64(mp_obj_t data) {
}
*out++ = 64;
}
// Second pass, we convert number base 64 values to actual base64 ascii encoding
out = (byte*)vstr.buf;
for (mp_uint_t i = vstr.len - 1; i--;) {
if (*out < 26) {