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Shrink struct datastream by borrowing the user buffer

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YAMAMOTO Takashi 2021-04-23 13:40:10 +09:00
parent ed455904f3
commit 21b7581b04
1 changed files with 13 additions and 1 deletions
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14
lib/decode.c
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@ -399,7 +399,7 @@ static quirc_decode_error_t correct_format(uint16_t *f_ret)
*/ */
struct datastream { struct datastream {
uint8_t raw[QUIRC_MAX_PAYLOAD]; uint8_t *raw;
int data_bits; int data_bits;
int ptr; int ptr;
@ -905,11 +905,23 @@ quirc_decode_error_t quirc_decode(const struct quirc_code *code,
if (err) if (err)
return err; return err;
/*
* Borrow data->payload to store the raw bits.
* It's only used during read_data + coddestream_ecc below.
*
* This trick saves the size of struct datastream, which we allocate
* on the stack.
*/
ds.raw = data->payload;
read_data(code, data, &ds); read_data(code, data, &ds);
err = codestream_ecc(data, &ds); err = codestream_ecc(data, &ds);
if (err) if (err)
return err; return err;
ds.raw = NULL; /* We've done with this buffer. */
err = decode_payload(data, &ds); err = decode_payload(data, &ds);
if (err) if (err)
return err; return err;