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Jump table packing/cracking improvements

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This commit is contained in:
whydoubt 2004-08-28 05:18:52 +00:00
parent 139752bf3a
commit f250fd507f
2 changed files with 41 additions and 10 deletions
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3
ChangeLog
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@ -1,3 +1,6 @@
Sat Aug 28 00:20:44 CDT 2004 Jeff Smith <whydoubt@yahoo.com>
* src/libmdb/write: Jump table packing/cracking improvements
Thu Aug 26 21:06:35 CDT 2004 Jeff Smith <whydoubt@yahoo.com>
* src/libmdb/write.c: Documentation fix
* src/sql/lexer.l: Add SQL quote escaping

48
src/libmdb/write.c
View File

@ -104,7 +104,7 @@ mdb_crack_row4(MdbTableDef *table, int row_start, int row_end, MdbField *fields)
unsigned int *var_col_offsets = NULL;
if (mdb_get_option(MDB_DEBUG_ROW)) {
buffer_dump(pg_buf, row_start, row_end+1);
buffer_dump(pg_buf, row_start, row_end);
}
row_cols = mdb_pg_get_int16(mdb, row_start);
@ -141,6 +141,8 @@ mdb_crack_row4(MdbTableDef *table, int row_start, int row_end, MdbField *fields)
fields[i].value = &pg_buf[row_start + col_start];
fields[i].siz = col->col_size;
fixed_cols_found++;
/* Use col->var_col_num because a deleted column is still
* present in the variable column offsets table for the row */
} else if ((!fields[i].is_fixed)
&& (col->var_col_num < row_var_cols)) {
col_start = var_col_offsets[col->var_col_num];
@ -190,11 +192,11 @@ mdb_crack_row3(MdbTableDef *table, int row_start, int row_end, MdbField *fields)
if (table->num_var_cols > 0) {
row_var_cols = pg_buf[row_end - bitmask_sz];
row_len = row_end - row_start + 1;
num_jumps = 0;
while (num_jumps < (row_len-bitmask_sz-row_var_cols-num_jumps-2)/256) {
num_jumps ++;
}
num_jumps = (row_len - 1) / 256;
col_ptr = row_end - bitmask_sz - num_jumps - 1;
/* If last jump is a dummy value, ignore it */
if ((col_ptr-row_start-row_var_cols)/256 < num_jumps)
num_jumps--;
var_col_offsets = (int *)g_malloc((row_var_cols+1)*sizeof(int));
jumps_used = 0;
@ -331,6 +333,11 @@ mdb_pack_row4(MdbTableDef *table, unsigned char *row_buffer, unsigned int num_fi
pos += fields[i].siz;
}
}
/* For tables without variable-length columns */
if (table->num_var_cols == 0) {
pos += mdb_pack_null_mask(&row_buffer[pos], num_fields, fields);
return pos;
}
/* Variable length columns */
for (i=0;i<num_fields;i++) {
if (!fields[i].is_fixed) {
@ -359,7 +366,6 @@ mdb_pack_row4(MdbTableDef *table, unsigned char *row_buffer, unsigned int num_fi
row_buffer[pos++] = (var_cols >> 8) & 0xff;
pos += mdb_pack_null_mask(&row_buffer[pos], num_fields, fields);
return pos;
}
@ -368,7 +374,8 @@ mdb_pack_row3(MdbTableDef *table, unsigned char *row_buffer, unsigned int num_fi
{
unsigned int pos = 0;
unsigned int var_cols = 0;
unsigned int i;
unsigned int i, j;
unsigned char *offset_high;
row_buffer[pos++] = num_fields;
@ -380,6 +387,11 @@ mdb_pack_row3(MdbTableDef *table, unsigned char *row_buffer, unsigned int num_fi
pos += fields[i].siz;
}
}
/* For tables without variable-length columns */
if (table->num_var_cols == 0) {
pos += mdb_pack_null_mask(&row_buffer[pos], num_fields, fields);
return pos;
}
/* Variable length columns */
for (i=0;i<num_fields;i++) {
if (!fields[i].is_fixed) {
@ -391,22 +403,38 @@ mdb_pack_row3(MdbTableDef *table, unsigned char *row_buffer, unsigned int num_fi
}
}
}
offset_high = (unsigned char *) g_malloc(var_cols+1);
offset_high[0] = (pos << 8) & 0xff;
j = 1;
/* EOD */
row_buffer[pos] = pos;
row_buffer[pos] = pos & 0xff;
pos++;
/* Variable length column offsets */
for (i=num_fields; i>0; i--) {
if (!fields[i-1].is_fixed) {
row_buffer[pos++] = fields[i-1].offset & 0xff;
offset_high[j++] = (fields[i-1].offset << 8) & 0xff;
}
}
/* FIXME: jump table goes here */
/* Dummy jump table entry */
if (offset_high[0] < (pos+(num_fields+7)/8-1)/255) {
row_buffer[pos++] = 0xff;
}
/* Jump table */
for (i=0; i<var_cols; i++) {
if (offset_high[i] > offset_high[i+1]) {
row_buffer[pos++] = var_cols-i;
}
}
g_free(offset_high);
row_buffer[pos++] = var_cols;
pos += mdb_pack_null_mask(&row_buffer[pos], num_fields, fields);
return pos;
}
int