From 025065a9c63bb78dcacc544f115b10e081ee08e3 Mon Sep 17 00:00:00 2001
From: Stephan Bosch <stephan@rename-it.nl>
Date: Mon, 2 Aug 2010 14:59:06 +0200
Subject: [PATCH] Improved byte code encoding implementation of integers and
offsets.
---
src/lib-sieve/sieve-binary-code.c | 44 ++++++++++++++++++-------------
1 file changed, 25 insertions(+), 19 deletions(-)
diff --git a/src/lib-sieve/sieve-binary-code.c b/src/lib-sieve/sieve-binary-code.c
index c09532ce5..3cf40db17 100644
--- a/src/lib-sieve/sieve-binary-code.c
+++ b/src/lib-sieve/sieve-binary-code.c
@@ -85,10 +85,14 @@ sieve_size_t sieve_binary_emit_offset
int i;
sieve_size_t address = _sieve_binary_block_get_size(sblock);
+ uint8_t encoded[4];
+
for ( i = 3; i >= 0; i-- ) {
- uint8_t c = (uint8_t) (offset >> (i * 8));
- _sieve_binary_emit_data(sblock, &c, 1);
+ encoded[i] = (uint8_t) offset;
+ offset >>= 8;
}
+
+ _sieve_binary_emit_data(sblock, encoded, 4);
return address;
}
@@ -98,11 +102,14 @@ void sieve_binary_resolve_offset
{
int i;
sieve_offset_t offset = _sieve_binary_block_get_size(sblock) - address;
-
+ uint8_t encoded[4];
+
for ( i = 3; i >= 0; i-- ) {
- uint8_t c = (uint8_t) (offset >> (i * 8));
- _sieve_binary_update_data(sblock, address + 3 - i, &c, 1);
+ encoded[i] = (uint8_t) offset;
+ offset >>= 8;
}
+
+ _sieve_binary_update_data(sblock, address, encoded, 4);
}
/* Literal emission */
@@ -111,28 +118,24 @@ sieve_size_t sieve_binary_emit_integer
(struct sieve_binary_block *sblock, sieve_number_t integer)
{
sieve_size_t address = _sieve_binary_block_get_size(sblock);
- int i;
uint8_t buffer[sizeof(sieve_number_t) + 1];
- int bufpos = sizeof(buffer) - 1;
-
+ int bufpos = sizeof(buffer) - 1;
+
+ /* Encode last byte [0xxxxxxx]; msb == 0 marks the last byte */
buffer[bufpos] = integer & 0x7F;
bufpos--;
+
+ /* Encode first bytes [1xxxxxxx] */
integer >>= 7;
while ( integer > 0 ) {
- buffer[bufpos] = integer & 0x7F;
+ buffer[bufpos] = (integer & 0x7F) | 0x80;
bufpos--;
integer >>= 7;
}
- bufpos++;
- if ( (sizeof(buffer) - bufpos) > 1 ) {
- for ( i = bufpos; i < ((int) sizeof(buffer) - 1); i++) {
- buffer[i] |= 0x80;
- }
- }
-
- _sieve_binary_emit_data
- (sblock, buffer + bufpos, sizeof(buffer) - bufpos);
+ /* Emit encoded integer */
+ bufpos++;
+ _sieve_binary_emit_data(sblock, buffer + bufpos, sizeof(buffer) - bufpos);
return address;
}
@@ -286,12 +289,14 @@ bool sieve_binary_read_integer
if ( ADDR_BYTES_LEFT(address) == 0 )
return FALSE;
-
+
+ /* Read first integer bytes [1xxxxxxx] */
while ( (ADDR_DATA_AT(address) & 0x80) > 0 ) {
if ( ADDR_BYTES_LEFT(address) > 0 && bits > 0) {
*int_r |= ADDR_DATA_AT(address) & 0x7F;
ADDR_JUMP(address, 1);
+ /* Each byte encodes 7 bits of the integer */
*int_r <<= 7;
bits -= 7;
} else {
@@ -300,6 +305,7 @@ bool sieve_binary_read_integer
}
}
+ /* Read last byte [0xxxxxxx] */
*int_r |= ADDR_DATA_AT(address) & 0x7F;
ADDR_JUMP(address, 1);
--
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