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#include <stdio.h> |
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#include <stdlib.h> |
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#include <math.h> |
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|
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#define BUFSZ (1 << 22) |
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|
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#ifdef WIN32 |
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// whatever |
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static |
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double drand48() { |
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double r = rand() / (double)RAND_MAX; |
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return r; |
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} |
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long lrand48() { |
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long l = 0; |
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int i; |
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for (i = 0; i < 32; i++) { |
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l = l ^ (l << 2) ^ (l << 1) ^ rand(); |
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} |
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return l; |
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} |
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#endif |
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|
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#ifdef _WIN32 |
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#define XD3_WIN32 1 |
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#else |
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#define XD3_POSIX 1 |
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#endif |
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#define XD3_MAIN 1 |
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#define main notmain |
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#define EXTERNAL_COMPRESSION 0 |
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#define XD3_USE_LARGEFILE64 1 |
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#include "xdelta3.c" |
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#undef main |
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|
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|
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double error_prob = 0.0001; |
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usize_t mean_change = 100; |
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xoff_t total_change = 0; |
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xoff_t total_size = 0; |
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usize_t max_change = 0; |
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usize_t num_change = 0; |
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|
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|
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static usize_t |
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edist (usize_t mean, usize_t max) |
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{ |
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double mean_d = mean; |
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double erand = log (1.0 / drand48 ()); |
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usize_t x = (usize_t) (mean_d * erand + 0.5); |
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|
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return (x < max) ? (x > 0 ? x : 1) : max; |
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} |
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|
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void modify (char *buf, usize_t size) |
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{ |
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usize_t bufpos = 0, j; |
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usize_t last_end = 0; |
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|
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for (;; /* bufpos and j are incremented in the inner loop */) |
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{ |
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/* The size of the next modification. */ |
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usize_t next_size = edist (mean_change, 1 << 31); |
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/* The expected interval of such a change. */ |
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double expect_interval = ((double) next_size * (1.0 - error_prob)) / error_prob; |
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/* The number of bytes until the next modification. */ |
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usize_t next_mod = edist ((usize_t)expect_interval, 1 << 31); |
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|
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if (next_size + next_mod + bufpos > size) { break; } |
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|
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if (max_change < next_size) { max_change = next_size; } |
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|
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bufpos += next_mod; |
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|
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fprintf (stderr, "COPY: %I64u-%I64u (%u)\n", |
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total_size + (xoff_t)last_end, |
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total_size + (xoff_t)bufpos, |
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bufpos - last_end); |
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fprintf (stderr, "ADD: %I64u-%I64u (%u) is change %u\n", |
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total_size + (xoff_t)bufpos, |
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total_size + (xoff_t)(bufpos + next_size), |
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next_size, num_change); |
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|
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total_change += next_size; |
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num_change += 1; |
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|
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for (j = 0; j < next_size; j += 1, bufpos += 1) |
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{ |
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buf[bufpos] = (char)(lrand48 () >> 3); |
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} |
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|
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last_end = bufpos; |
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} |
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|
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fprintf (stderr, "COPY: %I64u-%I64u (%u)\n", |
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total_size + last_end, |
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total_size + size, size - last_end); |
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|
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total_size += size; |
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} |
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|
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int main(int argc, char **argv) |
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{ |
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main_file inp, out; |
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char *buf = malloc(BUFSZ); |
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int c, ret; |
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main_file_init(&inp); |
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main_file_init(&out); |
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option_force = 1; |
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if (argc > 5) |
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{ |
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fprintf (stderr, "usage: badcopy [byte_error_prob [mean_error_size]]\n"); |
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return 1; |
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} |
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|
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if (argc > 4) { mean_change = atoi (argv[4]); } |
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if (argc > 3) { error_prob = atof (argv[3]); } |
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fprintf (stderr, "mean change = %u; error_prob = %0.10f\n", mean_change, error_prob); |
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|
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if ((ret = main_file_open (&inp, argv[1], XO_READ)) != 0) { |
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return 1; |
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} |
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if ((ret = main_file_open (&out, argv[2], XO_WRITE)) != 0) { |
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return 1; |
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} |
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|
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if (error_prob < 0.0 || error_prob > 1.0) |
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{ |
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fprintf (stderr, "warning: error probability out of range\n"); |
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return 1; |
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} |
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|
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do |
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{ |
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if ((ret = main_file_read (&inp, buf, BUFSZ, &c, "read failed")) != 0) { |
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return 1; |
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} |
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|
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if (c == 0) { break; } |
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|
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modify (buf, c); |
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|
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if ((ret = main_file_write (&out, buf, c, "write failed")) != 0) { |
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return 1; |
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} |
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} |
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while (c == BUFSZ); |
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|
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if ((ret = main_file_close (&out))) |
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{ |
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return 1; |
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} |
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|
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fprintf (stderr, "add_prob %f; %u adds; total_change %u of %u bytes; add percentage %f; max add size %u\n", |
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error_prob, num_change, total_change, total_size, (double) total_change / (double) total_size, max_change); |
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|
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return 0; |
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} |
