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by brian
clean slate |
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/**********************************************************************
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Utilities for converting data from the database file
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to the machine format.
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(c) 1995 Innobase Oy
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Created 11/28/1995 Heikki Tuuri
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***********************************************************************/
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#include "mach0data.h" |
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#ifdef UNIV_NONINL
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#include "mach0data.ic" |
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#endif
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/*************************************************************
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Reads a ulint in a compressed form if the log record fully contains it. */
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byte* |
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mach_parse_compressed( |
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/*==================*/
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/* out: pointer to end of the stored field, NULL if
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not complete */
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byte* ptr, /* in: pointer to buffer from where to read */ |
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byte* end_ptr,/* in: pointer to end of the buffer */ |
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ulint* val) /* out: read value (< 2^32) */ |
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{
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ulint flag; |
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ut_ad(ptr && end_ptr && val); |
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if (ptr >= end_ptr) { |
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return(NULL); |
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}
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flag = mach_read_from_1(ptr); |
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if (flag < 0x80UL) { |
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*val = flag; |
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return(ptr + 1); |
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} else if (flag < 0xC0UL) { |
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if (end_ptr < ptr + 2) { |
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return(NULL); |
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}
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*val = mach_read_from_2(ptr) & 0x7FFFUL; |
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return(ptr + 2); |
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} else if (flag < 0xE0UL) { |
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if (end_ptr < ptr + 3) { |
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return(NULL); |
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}
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*val = mach_read_from_3(ptr) & 0x3FFFFFUL; |
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return(ptr + 3); |
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} else if (flag < 0xF0UL) { |
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if (end_ptr < ptr + 4) { |
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return(NULL); |
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}
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*val = mach_read_from_4(ptr) & 0x1FFFFFFFUL; |
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return(ptr + 4); |
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} else { |
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ut_ad(flag == 0xF0UL); |
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if (end_ptr < ptr + 5) { |
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return(NULL); |
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}
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*val = mach_read_from_4(ptr + 1); |
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return(ptr + 5); |
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}
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}
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/*************************************************************
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Reads a dulint in a compressed form if the log record fully contains it. */
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byte* |
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mach_dulint_parse_compressed( |
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/*=========================*/
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/* out: pointer to end of the stored field, NULL if
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not complete */
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byte* ptr, /* in: pointer to buffer from where to read */ |
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byte* end_ptr,/* in: pointer to end of the buffer */ |
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dulint* val) /* out: read value */ |
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{
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ulint high; |
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ulint low; |
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ulint size; |
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ut_ad(ptr && end_ptr && val); |
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if (end_ptr < ptr + 5) { |
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return(NULL); |
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}
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high = mach_read_compressed(ptr); |
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size = mach_get_compressed_size(high); |
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ptr += size; |
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if (end_ptr < ptr + 4) { |
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return(NULL); |
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}
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low = mach_read_from_4(ptr); |
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*val = ut_dulint_create(high, low); |
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return(ptr + 4); |
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}
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