mirror of
https://github.com/mdbtools/mdbtools.git
synced 2025-09-20 19:27:53 +08:00
more gmdb2 work, reorged mdbhandle
This commit is contained in:
brianb
@@ -26,11 +26,57 @@
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typedef struct {
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void *value;
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int siz;
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int start;
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unsigned char is_null;
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unsigned char is_fixed;
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int colnum;
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int offset;
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} MdbField;
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void
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_mdb_put_int16(unsigned char *buf, guint32 offset, guint32 value)
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{
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buf[offset] = value % 256;
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value /= 256;
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buf[offset+1] = value % 256;
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}
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void
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_mdb_put_int32(unsigned char *buf, guint32 offset, guint32 value)
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{
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buf[offset] = value % 256;
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value /= 256;
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buf[offset+1] = value % 256;
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value /= 256;
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buf[offset+2] = value % 256;
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value /= 256;
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buf[offset+3] = value % 256;
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}
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size_t
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mdb_write_pg(MdbHandle *mdb, unsigned long pg)
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{
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size_t len;
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struct stat status;
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off_t offset = pg * mdb->fmt->pg_size;
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fstat(mdb->f->fd, &status);
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/* is page beyond current size + 1 ? */
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if (status.st_size < offset + mdb->fmt->pg_size) {
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fprintf(stderr,"offset %lu is beyond EOF\n",offset);
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return 0;
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}
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lseek(mdb->f->fd, offset, SEEK_SET);
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len = write(mdb->f->fd,mdb->pg_buf,mdb->fmt->pg_size);
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if (len==-1) {
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perror("write");
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return 0;
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} else if (len<mdb->fmt->pg_size) {
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/* fprintf(stderr,"EOF reached %d bytes returned.\n",len, mdb->pg_size); */
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return 0;
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}
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mdb->cur_pos = 0;
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return len;
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}
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static int
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mdb_is_col_indexed(MdbTableDef *table, int colnum)
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{
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@@ -51,15 +97,16 @@ mdb_crack_row(MdbTableDef *table, int row_start, int row_end, MdbField *fields)
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MdbCatalogEntry *entry = table->entry;
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MdbHandle *mdb = entry->mdb;
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MdbColumn *col;
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int var_cols, fixed_cols, num_cols, i, totcols;
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int i, j;
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int var_cols, fixed_cols, num_cols, totcols;
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int var_cols_found, fixed_cols_found, var_entry_pos;
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int col_start, next_col;
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unsigned char *nullmask;
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int bitmask_sz;
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int byte_num, bit_num;
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int eod, len; /* end of data */
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printf("field 0 %s\n", fields[0].value);
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if (mdb->jet_version==MDB_VER_JET4) {
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if (IS_JET4(mdb)) {
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num_cols = mdb_get_int16(mdb, row_start);
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} else {
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num_cols = mdb->pg_buf[row_start];
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@@ -72,17 +119,17 @@ int byte_num, bit_num;
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col = g_ptr_array_index (table->columns, i);
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if (mdb_is_fixed_col(col)) {
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fixed_cols++;
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fields[totcols++].colnum = i;
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fields[totcols].colnum = i;
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fields[totcols].siz = col->col_size;
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fields[totcols].is_fixed = 1;
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fields[totcols++].is_fixed = 1;
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}
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}
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for (i = 0; i < table->num_cols; i++) {
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col = g_ptr_array_index (table->columns, i);
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if (!mdb_is_fixed_col(col)) {
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var_cols++;
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fields[totcols++].colnum = i;
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fields[totcols].is_fixed = 0;
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fields[totcols].colnum = i;
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fields[totcols++].is_fixed = 0;
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}
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}
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@@ -97,25 +144,142 @@ int byte_num, bit_num;
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printf("col %d is %s\n", i, fields[i].is_null ? "null" : "not null");
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}
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/* find the end of data pointer */
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if (IS_JET4(mdb)) {
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eod = mdb_get_int16(mdb, row_end - 3 - var_cols*2 - bitmask_sz);
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} else {
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eod = mdb->pg_buf[row_end-1-var_cols-bitmask_sz];
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}
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printf("eod is %d\n", eod);
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if (IS_JET4(mdb)) {
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col_start = 2;
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} else {
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/* data starts at 1 */
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col_start = 1;
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}
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/* actual cols on this row */
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fixed_cols_found = 0;
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var_cols_found = 0;
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totcols = 0;
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/* loop through fixed columns and add values to fields[] */
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for (j=0;j<table->num_cols;j++) {
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col = g_ptr_array_index(table->columns,j);
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if (mdb_is_fixed_col(col) && ++fixed_cols_found <= fixed_cols) {
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fields[totcols].start = row_start + col_start;
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fields[totcols++].value = &mdb->pg_buf[row_start + col_start];
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if (col->col_type != MDB_BOOL)
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col_start += col->col_size;
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}
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}
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for (j=0;j<table->num_cols;j++) {
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col = g_ptr_array_index(table->columns,j);
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if (!mdb_is_fixed_col(col) && ++var_cols_found <= var_cols) {
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if (var_cols_found==var_cols) {
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len=eod - col_start;
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printf("len = %d eod %d col_start %d\n",len, eod, col_start);
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} else {
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if (IS_JET4(mdb)) {
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/* position of the var table
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* entry for this column */
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var_entry_pos =
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row_end -
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bitmask_sz -
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var_cols_found * 2 - 2 - 1;
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next_col = mdb_get_int16(mdb, var_entry_pos);
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len = next_col - col_start;
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} else {
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var_entry_pos =
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row_end -
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bitmask_sz -
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var_cols_found - 1;
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len=mdb->pg_buf[var_entry_pos] - mdb->pg_buf[var_entry_pos+1];
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printf("%d %d %d %d\n", mdb->pg_buf[var_entry_pos-1],mdb->pg_buf[var_entry_pos],len, col_start);
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}
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} /* if found==var_cols */
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if (len<0) len+=256;
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fields[totcols].start = row_start + col_start;
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fields[totcols].value = &mdb->pg_buf[row_start +col_start];
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fields[totcols++].siz = len;
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col_start += len;
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} /* if !fixed */
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} /* for */
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return num_cols;
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}
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/* fields must be ordered with fixed columns first, then vars, subsorted by
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* column number */
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int
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mdb_pack_row(MdbTableDef *table, unsigned char *row_buffer, MdbField *fields)
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mdb_pack_row(MdbTableDef *table, unsigned char *row_buffer, int num_fields, MdbField *fields)
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{
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int pos = 0;
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int var_cols = 0;
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unsigned char bit, byte;
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int i;
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row_buffer[pos++] = num_fields;
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for (i=0;i<num_fields;i++) {
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if (fields[i].is_fixed) {
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fields[i].offset = pos;
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memcpy(&row_buffer[pos], fields[i].value, fields[i].siz);
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pos += fields[i].siz;
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}
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}
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for (i=0;i<num_fields;i++) {
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if (!fields[i].is_fixed) {
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var_cols++;
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fields[i].offset = pos;
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memcpy(&row_buffer[pos], fields[i].value, fields[i].siz);
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pos += fields[i].siz;
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}
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}
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/* EOD */
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row_buffer[pos++] = pos;
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for (i=num_fields-1;i>=num_fields - var_cols;i--) {
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row_buffer[pos++] = fields[i].offset % 256;
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}
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row_buffer[pos++] = var_cols;
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byte = 0;
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bit = 0;
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for (i=0;i<num_fields;i++) {
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/* column is null is bit is clear (0) */
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if (!fields[i].is_null) {
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byte |= 1 << bit;
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printf("%d %d %d %d\n", i, bit, 1 << bit, byte);
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}
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bit++;
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if (bit==8) {
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row_buffer[pos++] = byte;
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bit=0;
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byte = 0;
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}
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}
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/* if we've written any bits to the current byte, flush it*/
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if (bit)
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row_buffer[pos++] = byte;
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return pos;
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}
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int
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mdb_pg_get_freespace(MdbHandle *mdb)
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{
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MdbFormatConstants *fmt = mdb->fmt;
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int rows, free_start, free_end;
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rows = mdb_get_int16(mdb, mdb->row_count_offset);
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free_start = mdb->row_count_offset + 2 + (rows * 2);
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free_end = mdb_get_int16(mdb, (mdb->row_count_offset + rows * 2)) -1;
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rows = mdb_get_int16(mdb, fmt->row_count_offset);
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free_start = fmt->row_count_offset + 2 + (rows * 2);
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free_end = mdb_get_int16(mdb, (fmt->row_count_offset + rows * 2)) -1;
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#if MDB_DEBUG_WRITE
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printf("free space left on page = %d\n", free_end - free_start);
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#endif
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return (free_end - free_start);
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return (free_end - free_start + 1);
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}
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int
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mdb_update_row(MdbTableDef *table)
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@@ -125,18 +289,26 @@ int i;
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MdbColumn *col;
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MdbCatalogEntry *entry = table->entry;
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MdbHandle *mdb = entry->mdb;
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MdbFormatConstants *fmt = mdb->fmt;
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MdbField fields[256];
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unsigned char row_buffer[4096];
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int old_row_size, new_row_size, delta, num_fields;
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fields[0].value = "hello";
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row_start = mdb_get_int16(mdb, (mdb->row_count_offset + 2) + (table->cur_row*2));
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row_end = mdb_find_end_of_row(mdb, table->cur_row);
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if (!mdb->f->writable) {
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fprintf(stderr, "File is not open for writing\n");
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return 0;
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}
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row_start = mdb_get_int16(mdb, (fmt->row_count_offset + 2) + ((table->cur_row-1)*2));
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row_end = mdb_find_end_of_row(mdb, table->cur_row-1);
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old_row_size = row_end - row_start;
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row_start &= 0x0FFF; /* remove flags */
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#if MDB_DEBUG_WRITE
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printf("page %lu row %d start %d end %d\n", table->cur_phys_pg, table->cur_row-1, row_start, row_end);
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buffer_dump(mdb->pg_buf, row_start, row_end);
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#endif
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for (i=0;i<table->num_cols;i++) {
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col = g_ptr_array_index(table->columns,i);
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if (col->bind_ptr && mdb_is_col_indexed(table,i)) {
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@@ -148,13 +320,95 @@ int old_row_size, new_row_size, delta, num_fields;
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#if MDB_DEBUG_WRITE
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for (i=0;i<num_fields;i++) {
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printf("col %d %d start %d siz %d\n", i, fields[i].colnum, fields[i].start, fields[i].siz);
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}
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#endif
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for (i=0;i<table->num_cols;i++) {
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col = g_ptr_array_index(table->columns,i);
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if (col->bind_ptr) {
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printf("yes\n");
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fields[i].value = col->bind_ptr;
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fields[i].siz = *(col->len_ptr);
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}
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}
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new_row_size = mdb_pack_row(table, row_buffer, &fields);
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new_row_size = mdb_pack_row(table, row_buffer, num_fields, &fields);
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#if MDB_DEBUG_WRITE
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buffer_dump(row_buffer, 0, new_row_size-1);
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#endif
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delta = new_row_size - old_row_size;
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if ((mdb_pg_get_freespace(mdb) - delta) < 0) {
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fprintf(stderr, "No space left on this page, update will not occur\n");
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return 0;
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}
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/* do it! */
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mdb_replace_row(table, table->cur_row-1, row_buffer, new_row_size);
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}
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int
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mdb_replace_row(MdbTableDef *table, int row, unsigned char *new_row, int new_row_size)
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{
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MdbCatalogEntry *entry = table->entry;
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MdbHandle *mdb = entry->mdb;
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MdbFormatConstants *fmt = mdb->fmt;
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unsigned char *new_pg;
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guint16 num_rows;
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int row_start, row_end, row_size;
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int i, pos;
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#if MDB_DEBUG_WRITE
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buffer_dump(mdb->pg_buf, 0, 39);
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buffer_dump(mdb->pg_buf, fmt->pg_size - 160, fmt->pg_size-1);
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printf("updating row %d on page %lu\n", row, table->cur_phys_pg);
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#endif
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new_pg = (unsigned char *) g_malloc0(fmt->pg_size);
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g_free(new_pg);
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new_pg[0]=0x01;
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new_pg[1]=0x01;
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_mdb_put_int32(new_pg, 4, entry->table_pg);
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num_rows = mdb_get_int16(mdb, fmt->row_count_offset);
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_mdb_put_int16(new_pg, fmt->row_count_offset, num_rows);
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pos = mdb->fmt->pg_size;
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/* rows before */
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for (i=0;i<row;i++) {
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row_start = mdb_get_int16(mdb, (fmt->row_count_offset + 2) + (i*2));
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row_end = mdb_find_end_of_row(mdb, i);
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row_size = row_end - row_start + 1;
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pos -= row_size;
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memcpy(&new_pg[pos], &mdb->pg_buf[row_start], row_size);
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_mdb_put_int16(new_pg, (fmt->row_count_offset + 2) + (i*2), pos);
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}
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/* our row */
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pos -= new_row_size;
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memcpy(&new_pg[pos], new_row, new_row_size);
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_mdb_put_int16(new_pg, (fmt->row_count_offset + 2) + (row*2), pos);
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/* rows after */
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for (i=row+1;i<num_rows;i++) {
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row_start = mdb_get_int16(mdb, (fmt->row_count_offset + 2) + (i*2));
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row_end = mdb_find_end_of_row(mdb, i);
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row_size = row_end - row_start + 1;
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pos -= row_size;
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memcpy(&new_pg[pos], &mdb->pg_buf[row_start], row_size);
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_mdb_put_int16(new_pg, (fmt->row_count_offset + 2) + (i*2), pos);
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}
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/* almost done, copy page over current */
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memcpy(mdb->pg_buf, new_pg, fmt->pg_size);
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_mdb_put_int16(mdb->pg_buf, 2, mdb_pg_get_freespace(mdb));
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#if MDB_DEBUG_WRITE
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buffer_dump(mdb->pg_buf, 0, 39);
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buffer_dump(mdb->pg_buf, fmt->pg_size - 160, fmt->pg_size-1);
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#endif
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/* drum roll, please */
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if (!mdb_write_pg(mdb, table->cur_phys_pg)) {
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fprintf(stderr, "write failed! exiting...\n");
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exit(1);
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}
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}
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