ceph/src/isa-l/igzip/generate_constant_block_header.c

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  29
  30 #include <stdint.h>
  31 #include <stdio.h>
  32 #include "huff_codes.h"
  33 #include "bitbuf2.h"
  34
  35 #define MAX_HEADER_SIZE 350
  36 #define BLOCK_SIZE 16*1024
  37
  38 void fprint_header(FILE * outfile, uint8_t * header, uint64_t bit_count)
  39 {
  40         int i;
  41         fprintf(outfile, "unsigned char data[] = {");
  42         for (i = 0; i < bit_count / 8; i++) {
  43                 if ((i & 7) == 0)
  44                         fprintf(outfile, "\n\t");
  45                 else
  46                         fprintf(outfile, " ");
  47                 fprintf(outfile, "0x%02x,", header[i]);
  48         }
  49
  50         if ((i & 7) == 0)
  51                 fprintf(outfile, "\n\t");
  52         else
  53                 fprintf(outfile, " ");
  54         fprintf(outfile, "0x%02x", header[i]);
  55         fprintf(outfile, "\t};\n\n");
  56
  57 }
  58
  59 int main(int argc, char **argv)
  60 {
  61         /* Generates a header for a constant block, along with some manual
  62          * twiddling to create a header with the desired properties*/
  63         uint8_t stream[BLOCK_SIZE];
  64         struct isal_huff_histogram histogram;
  65         uint64_t *lit_histogram = histogram.lit_len_histogram;
  66         uint64_t *dist_histogram = histogram.dist_histogram;
  67         uint8_t header[MAX_HEADER_SIZE];
  68         struct huff_tree lit_tree, dist_tree;
  69         struct huff_tree lit_tree_array[2 * LIT_LEN - 1], dist_tree_array[2 * DIST_LEN - 1];
  70         struct huff_code lit_huff_table[LIT_LEN], dist_huff_table[DIST_LEN];
  71         uint64_t bit_count;
  72
  73         uint8_t repeated_char = 0x00;
  74
  75         memset(header, 0, sizeof(header));
  76         memset(&histogram, 0, sizeof(histogram));       /* Initialize histograms. */
  77         memset(stream, repeated_char, sizeof(stream));
  78         memset(lit_tree_array, 0, sizeof(lit_tree_array));
  79         memset(dist_tree_array, 0, sizeof(dist_tree_array));
  80         memset(lit_huff_table, 0, sizeof(lit_huff_table));
  81         memset(dist_huff_table, 0, sizeof(dist_huff_table));
  82
  83         isal_update_histogram(stream, sizeof(stream), &histogram);
  84
  85         /* These are set to manually change the histogram to create a header with the
  86          * desired properties. In this case, the header is modified so that it is byte
  87          * unaligned by 6 bits, so that 0 is a 2 bit code, so that the header plus the
  88          * encoding of one 0 is byte aligned*/
  89         lit_histogram[repeated_char] = 20;
  90         lit_histogram[280] = 2;
  91         lit_histogram[264] = 5;
  92         lit_histogram[282] = 0;
  93
  94         lit_tree = create_symbol_subset_huff_tree(lit_tree_array, lit_histogram, LIT_LEN);
  95         dist_tree = create_symbol_subset_huff_tree(dist_tree_array, dist_histogram, DIST_LEN);
  96         if (create_huff_lookup(lit_huff_table, LIT_LEN, lit_tree, 15) > 0) {
  97                 printf("Error, code with invalid length for Deflate standard.\n");
  98                 return 1;
  99         }
 100
 101         if (create_huff_lookup(dist_huff_table, DIST_LEN, dist_tree, 15) > 0) {
 102                 printf("Error, code with invalid length for Deflate standard.\n");
 103                 return 1;
 104         }
 105
 106         /* Remove litral symbol corresponding to the unoptimal look back
 107          * distance of 258 found by gen_histogram*/
 108         dist_huff_table[16].length = 0;
 109
 110         bit_count = create_header(header, sizeof(header), lit_huff_table, dist_huff_table, 1);
 111         printf("Header for %x\n", repeated_char);
 112         fprintf(stdout, "Complete Bytes: %lu\n", bit_count / 8);
 113         fprintf(stdout, "Byte Offset:    %lu\n\n", (bit_count) & 7);
 114         fprint_header(stdout, header, bit_count);
 115         printf("\n");
 116
 117         return 0;
 118 }