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Diffstat (limited to 'libpng/contrib/libtests/tarith.c')
| -rw-r--r-- | libpng/contrib/libtests/tarith.c | 999 |
1 files changed, 999 insertions, 0 deletions
diff --git a/libpng/contrib/libtests/tarith.c b/libpng/contrib/libtests/tarith.c new file mode 100644 index 00000000..cb17ffa7 --- /dev/null +++ b/libpng/contrib/libtests/tarith.c @@ -0,0 +1,999 @@ + +/* tarith.c + * + * Copyright (c) 2011-2013 John Cunningham Bowler + * + * Last changed in libpng 1.6.0 [February 14, 2013] + * + * This code is released under the libpng license. + * For conditions of distribution and use, see the disclaimer + * and license in png.h + * + * Test internal arithmetic functions of libpng. + * + * This code must be linked against a math library (-lm), but does not require + * libpng or zlib to work. Because it includes the complete source of 'png.c' + * it tests the code with whatever compiler options are used to build it. + * Changing these options can substantially change the errors in the + * calculations that the compiler chooses! + */ +#define _POSIX_SOURCE 1 +#define _ISOC99_SOURCE 1 + +/* Obtain a copy of the code to be tested (plus other things), disabling + * stuff that is not required. + */ +#include <math.h> +#include <stdlib.h> +#include <ctype.h> +#include <string.h> +#include <assert.h> + +#include "../../pngpriv.h" + +#define png_error png_warning + +void png_warning(png_const_structrp png_ptr, png_const_charp msg) +{ + fprintf(stderr, "validation: %s\n", msg); +} + +#define png_fixed_error png_fixed_warning + +void png_fixed_warning(png_const_structrp png_ptr, png_const_charp msg) +{ + fprintf(stderr, "overflow in: %s\n", msg); +} + +#define png_set_error_fn(pp, ep, efp, wfp) ((void)0) +#define png_malloc(pp, s) malloc(s) +#define png_malloc_warn(pp, s) malloc(s) +#define png_malloc_base(pp, s) malloc(s) +#define png_calloc(pp, s) calloc(1, (s)) +#define png_free(pp, s) free(s) + +#define png_safecat(b, sb, pos, str) (pos) +#define png_format_number(start, end, format, number) (start) + +#define crc32(crc, pp, s) (crc) +#define inflateReset(zs) Z_OK + +#define png_create_struct(type) (0) +#define png_destroy_struct(pp) ((void)0) +#define png_create_struct_2(type, m, mm) (0) +#define png_destroy_struct_2(pp, f, mm) ((void)0) + +#undef PNG_SIMPLIFIED_READ_SUPPORTED +#undef PNG_SIMPLIFIED_WRITE_SUPPORTED +#undef PNG_USER_MEM_SUPPORTED + +#include "../../png.c" + +/* Validate ASCII to fp routines. */ +static int verbose = 0; + +int validation_ascii_to_fp(int count, int argc, char **argv) +{ + int showall = 0; + double max_error=2; /* As a percentage error-in-last-digit/.5 */ + double max_error_abs=17; /* Used when precision is DBL_DIG */ + double max = 0; + double max_abs = 0; + double test = 0; /* Important to test this. */ + int precision = 5; + int nonfinite = 0; + int finite = 0; + int ok = 0; + int failcount = 0; + int minorarith = 0; + + while (--argc > 0) + if (strcmp(*++argv, "-a") == 0) + showall = 1; + else if (strcmp(*argv, "-e") == 0 && argc > 0) + { + --argc; + max_error = atof(*++argv); + } + else if (strcmp(*argv, "-E") == 0 && argc > 0) + { + --argc; + max_error_abs = atof(*++argv); + } + else + { + fprintf(stderr, "unknown argument %s\n", *argv); + return 1; + } + + do + { + png_size_t index; + int state, failed = 0; + char buffer[64]; + + if (isfinite(test)) + ++finite; + else + ++nonfinite; + + if (verbose) + fprintf(stderr, "%.*g %d\n", DBL_DIG, test, precision); + + /* Check for overflow in the buffer by setting a marker. */ + memset(buffer, 71, sizeof buffer); + + png_ascii_from_fp(0, buffer, precision+10, test, precision); + + /* Allow for a three digit exponent, this stuff will fail if + * the exponent is bigger than this! + */ + if (buffer[precision+7] != 71) + { + fprintf(stderr, "%g[%d] -> '%s'[%lu] buffer overflow\n", test, + precision, buffer, (unsigned long)strlen(buffer)); + failed = 1; + } + + /* Following are used for the number parser below and must be + * initialized to zero. + */ + state = 0; + index = 0; + if (!isfinite(test)) + { + /* Expect 'inf' */ + if (test >= 0 && strcmp(buffer, "inf") || + test < 0 && strcmp(buffer, "-inf")) + { + fprintf(stderr, "%g[%d] -> '%s' but expected 'inf'\n", test, + precision, buffer); + failed = 1; + } + } + else if (!png_check_fp_number(buffer, precision+10, &state, &index) || + buffer[index] != 0) + { + fprintf(stderr, "%g[%d] -> '%s' but has bad format ('%c')\n", test, + precision, buffer, buffer[index]); + failed = 1; + } + else if (PNG_FP_IS_NEGATIVE(state) && !(test < 0)) + { + fprintf(stderr, "%g[%d] -> '%s' but negative value not so reported\n", + test, precision, buffer); + failed = 1; + assert(!PNG_FP_IS_ZERO(state)); + assert(!PNG_FP_IS_POSITIVE(state)); + } + else if (PNG_FP_IS_ZERO(state) && !(test == 0)) + { + fprintf(stderr, "%g[%d] -> '%s' but zero value not so reported\n", + test, precision, buffer); + failed = 1; + assert(!PNG_FP_IS_NEGATIVE(state)); + assert(!PNG_FP_IS_POSITIVE(state)); + } + else if (PNG_FP_IS_POSITIVE(state) && !(test > 0)) + { + fprintf(stderr, "%g[%d] -> '%s' but postive value not so reported\n", + test, precision, buffer); + failed = 1; + assert(!PNG_FP_IS_NEGATIVE(state)); + assert(!PNG_FP_IS_ZERO(state)); + } + else + { + /* Check the result against the original. */ + double out = atof(buffer); + double change = fabs((out - test)/test); + double allow = .5/pow(10, + (precision >= DBL_DIG) ? DBL_DIG-1 : precision-1); + + /* NOTE: if you hit this error case are you compiling with gcc + * and -O0? Try -O2 - the errors can accumulate if the FP + * code above is not optimized and may drift outside the .5 in + * DBL_DIG allowed. In any case a small number of errors may + * occur (very small ones - 1 or 2%) because of rounding in the + * calculations, either in the conversion API or in atof. + */ + if (change >= allow && (isfinite(out) || + fabs(test/DBL_MAX) <= 1-allow)) + { + double percent = (precision >= DBL_DIG) ? max_error_abs : max_error; + double allowp = (change-allow)*100/allow; + + if (precision >= DBL_DIG) + { + if (max_abs < allowp) max_abs = allowp; + } + + else + { + if (max < allowp) max = allowp; + } + + if (showall || allowp >= percent) + { + fprintf(stderr, + "%.*g[%d] -> '%s' -> %.*g number changed (%g > %g (%d%%))\n", + DBL_DIG, test, precision, buffer, DBL_DIG, out, change, allow, + (int)round(allowp)); + failed = 1; + } + else + ++minorarith; + } + } + + if (failed) + ++failcount; + else + ++ok; + +skip: + /* Generate a new number and precision. */ + precision = rand(); + if (precision & 1) test = -test; + precision >>= 1; + + /* Generate random numbers. */ + if (test == 0 || !isfinite(test)) + test = precision+1; + else + { + /* Derive the exponent from the previous rand() value. */ + int exponent = precision % (DBL_MAX_EXP - DBL_MIN_EXP) + DBL_MIN_EXP; + int tmp; + test = frexp(test * rand(), &tmp); + test = ldexp(test, exponent); + precision >>= 8; /* arbitrary */ + } + + /* This limits the precision to 32 digits, enough for standard + * IEEE implementations which have at most 15 digits. + */ + precision = (precision & 0x1f) + 1; + } + while (--count); + + printf("Tested %d finite values, %d non-finite, %d OK (%d failed) %d minor " + "arithmetic errors\n", finite, nonfinite, ok, failcount, minorarith); + printf(" Error with >=%d digit precision %.2f%%\n", DBL_DIG, max_abs); + printf(" Error with < %d digit precision %.2f%%\n", DBL_DIG, max); + + return 0; +} + +/* Observe that valid FP numbers have the forms listed in the PNG extensions + * specification: + * + * [+,-]{integer,integer.fraction,.fraction}[{e,E}[+,-]integer] + * + * Test each of these in turn, including invalid cases. + */ +typedef enum checkfp_state +{ + start, fraction, exponent, states +} checkfp_state; + +/* The characters (other than digits) that characterize the states: */ +static const char none[] = ""; +static const char hexdigits[16] = "0123456789ABCDEF"; + +static const struct +{ + const char *start; /* Characters valid at the start */ + const char *end; /* Valid characters that end the state */ + const char *tests; /* Characters to test after 2 digits seen */ +} +state_characters[states] = +{ + /* start: */ { "+-.", ".eE", "+-.e*0369" }, + /* fraction: */ { none, "eE", "+-.E#0147" }, + /* exponent: */ { "+-", none, "+-.eE^0258" } +}; + +typedef struct +{ + char number[1024]; /* Buffer for number being tested */ + int limit; /* Command line limit */ + int verbose; /* Shadows global variable */ + int ctimes; /* Number of numbers tested */ + int cmillions; /* Count of millions of numbers */ + int cinvalid; /* Invalid strings checked */ + int cnoaccept; /* Characters not accepted */ +} +checkfp_command; + +typedef struct +{ + int cnumber; /* Index into number string */ + checkfp_state check_state; /* Current number state */ + int at_start; /* At start (first character) of state */ + int cdigits_in_state; /* Digits seen in that state */ + int limit; /* Limit on same for checking all chars */ + int state; /* Current parser state */ + int is_negative; /* Number is negative */ + int is_zero; /* Number is (still) zero */ + int number_was_valid; /* Previous character validity */ +} +checkfp_control; + +static int check_all_characters(checkfp_command *co, checkfp_control c); + +static int check_some_characters(checkfp_command *co, checkfp_control c, + const char *tests); + +static int check_one_character(checkfp_command *co, checkfp_control c, int ch) +{ + /* Test this character (ch) to ensure the parser does the correct thing. + */ + png_size_t index = 0; + const char test = (char)ch; + const int number_is_valid = png_check_fp_number(&test, 1, &c.state, &index); + const int character_accepted = (index == 1); + + if (c.check_state != exponent && isdigit(ch) && ch != '0') + c.is_zero = 0; + + if (c.check_state == start && c.at_start && ch == '-') + c.is_negative = 1; + + if (isprint(ch)) + co->number[c.cnumber++] = (char)ch; + else + { + co->number[c.cnumber++] = '<'; + co->number[c.cnumber++] = hexdigits[(ch >> 4) & 0xf]; + co->number[c.cnumber++] = hexdigits[ch & 0xf]; + co->number[c.cnumber++] = '>'; + } + co->number[c.cnumber] = 0; + + if (co->verbose > 1) + fprintf(stderr, "%s\n", co->number); + + if (++(co->ctimes) == 1000000) + { + if (co->verbose == 1) + fputc('.', stderr); + co->ctimes = 0; + ++(co->cmillions); + } + + if (!number_is_valid) + ++(co->cinvalid); + + if (!character_accepted) + ++(co->cnoaccept); + + /* This should never fail (it's a serious bug if it does): */ + if (index != 0 && index != 1) + { + fprintf(stderr, "%s: read beyond end of string (%lu)\n", co->number, + (unsigned long)index); + return 0; + } + + /* Validate the new state, note that the PNG_FP_IS_ macros all return + * false unless the number is valid. + */ + if (PNG_FP_IS_NEGATIVE(c.state) != + (number_is_valid && !c.is_zero && c.is_negative)) + { + fprintf(stderr, "%s: negative when it is not\n", co->number); + return 0; + } + + if (PNG_FP_IS_ZERO(c.state) != (number_is_valid && c.is_zero)) + { + fprintf(stderr, "%s: zero when it is not\n", co->number); + return 0; + } + + if (PNG_FP_IS_POSITIVE(c.state) != + (number_is_valid && !c.is_zero && !c.is_negative)) + { + fprintf(stderr, "%s: positive when it is not\n", co->number); + return 0; + } + + /* Testing a digit */ + if (isdigit(ch)) + { + if (!character_accepted) + { + fprintf(stderr, "%s: digit '%c' not accepted\n", co->number, ch); + return 0; + } + + if (!number_is_valid) + { + fprintf(stderr, "%s: saw a digit (%c) but number not valid\n", + co->number, ch); + return 0; + } + + ++c.cdigits_in_state; + c.at_start = 0; + c.number_was_valid = 1; + + /* Continue testing characters in this state. Either test all of + * them or, if we have already seen one digit in this state, just test a + * limited set. + */ + if (c.cdigits_in_state < 1) + return check_all_characters(co, c); + + else + return check_some_characters(co, c, + state_characters[c.check_state].tests); + } + + /* A non-digit; is it allowed here? */ + else if (((ch == '+' || ch == '-') && c.check_state != fraction && + c.at_start) || + (ch == '.' && c.check_state == start) || + ((ch == 'e' || ch == 'E') && c.number_was_valid && + c.check_state != exponent)) + { + if (!character_accepted) + { + fprintf(stderr, "%s: character '%c' not accepted\n", co->number, ch); + return 0; + } + + /* The number remains valid after start of fraction but nowhere else. */ + if (number_is_valid && (c.check_state != start || ch != '.')) + { + fprintf(stderr, "%s: saw a non-digit (%c) but number valid\n", + co->number, ch); + return 0; + } + + c.number_was_valid = number_is_valid; + + /* Check for a state change. When changing to 'fraction' if the number + * is valid at this point set the at_start to false to allow an exponent + * 'e' to come next. + */ + if (c.check_state == start && ch == '.') + { + c.check_state = fraction; + c.at_start = !number_is_valid; + c.cdigits_in_state = 0; + c.limit = co->limit; + return check_all_characters(co, c); + } + + else if (c.check_state < exponent && (ch == 'e' || ch == 'E')) + { + c.check_state = exponent; + c.at_start = 1; + c.cdigits_in_state = 0; + c.limit = co->limit; + return check_all_characters(co, c); + } + + /* Else it was a sign, and the state doesn't change. */ + else + { + if (ch != '-' && ch != '+') + { + fprintf(stderr, "checkfp: internal error (1)\n"); + return 0; + } + + c.at_start = 0; + return check_all_characters(co, c); + } + } + + /* Testing an invalid character */ + else + { + if (character_accepted) + { + fprintf(stderr, "%s: character '%c' [0x%.2x] accepted\n", co->number, + ch, ch); + return 0; + } + + if (number_is_valid != c.number_was_valid) + { + fprintf(stderr, + "%s: character '%c' [0x%.2x] changed number validity\n", co->number, + ch, ch); + return 0; + } + + /* Do nothing - the parser has stuck; return success and keep going with + * the next character. + */ + } + + /* Successful return (the caller will try the next character.) */ + return 1; +} + +static int check_all_characters(checkfp_command *co, checkfp_control c) +{ + int ch; + + if (c.cnumber+4 < sizeof co->number) for (ch=0; ch<256; ++ch) + { + if (!check_one_character(co, c, ch)) + return 0; + } + + return 1; +} + +static int check_some_characters(checkfp_command *co, checkfp_control c, + const char *tests) +{ + int i; + + --(c.limit); + + if (c.cnumber+4 < sizeof co->number && c.limit >= 0) + { + if (c.limit > 0) for (i=0; tests[i]; ++i) + { + if (!check_one_character(co, c, tests[i])) + return 0; + } + + /* At the end check all the characters. */ + else + return check_all_characters(co, c); + } + + return 1; +} + +int validation_checkfp(int count, int argc, char **argv) +{ + int result; + checkfp_command command; + checkfp_control control; + + command.number[0] = 0; + command.limit = 3; + command.verbose = verbose; + command.ctimes = 0; + command.cmillions = 0; + command.cinvalid = 0; + command.cnoaccept = 0; + + while (--argc > 0) + { + ++argv; + if (argc > 1 && strcmp(*argv, "-l") == 0) + { + --argc; + command.limit = atoi(*++argv); + } + + else + { + fprintf(stderr, "unknown argument %s\n", *argv); + return 1; + } + } + + control.cnumber = 0; + control.check_state = start; + control.at_start = 1; + control.cdigits_in_state = 0; + control.limit = command.limit; + control.state = 0; + control.is_negative = 0; + control.is_zero = 1; + control.number_was_valid = 0; + + result = check_all_characters(&command, control); + + printf("checkfp: %s: checked %d,%.3d,%.3d,%.3d strings (%d invalid)\n", + result ? "pass" : "FAIL", command.cmillions / 1000, + command.cmillions % 1000, command.ctimes / 1000, command.ctimes % 1000, + command.cinvalid); + + return result; +} + +int validation_muldiv(int count, int argc, char **argv) +{ + int tested = 0; + int overflow = 0; + int error = 0; + int error64 = 0; + int passed = 0; + int randbits = 0; + png_uint_32 randbuffer; + png_fixed_point a; + png_int_32 times, div; + + while (--argc > 0) + { + fprintf(stderr, "unknown argument %s\n", *++argv); + return 1; + } + + /* Find out about the random number generator. */ + randbuffer = RAND_MAX; + while (randbuffer != 0) ++randbits, randbuffer >>= 1; + printf("Using random number generator that makes %d bits\n", randbits); + for (div=0; div<32; div += randbits) + randbuffer = (randbuffer << randbits) ^ rand(); + + a = 0; + times = div = 0; + do + { + png_fixed_point result; + /* NOTE: your mileage may vary, a type is required below that can + * hold 64 bits or more, if floating point is used a 64-bit or + * better mantissa is required. + */ + long long int fp, fpround; + unsigned long hi, lo; + int ok; + + /* Check the values, png_64bit_product can only handle positive + * numbers, so correct for that here. + */ + { + long u1, u2; + int n = 0; + if (a < 0) u1 = -a, n = 1; else u1 = a; + if (times < 0) u2 = -times, n = !n; else u2 = times; + png_64bit_product(u1, u2, &hi, &lo); + if (n) + { + /* -x = ~x+1 */ + lo = ((~lo) + 1) & 0xffffffff; + hi = ~hi; + if (lo == 0) ++hi; + } + } + + fp = a; + fp *= times; + if ((fp & 0xffffffff) != lo || ((fp >> 32) & 0xffffffff) != hi) + { + fprintf(stderr, "png_64bit_product %d * %d -> %lx|%.8lx not %llx\n", + a, times, hi, lo, fp); + ++error64; + } + + if (div != 0) + { + /* Round - this is C round to zero. */ + if ((fp < 0) != (div < 0)) + fp -= div/2; + else + fp += div/2; + + fp /= div; + fpround = fp; + /* Assume 2's complement here: */ + ok = fpround <= PNG_UINT_31_MAX && + fpround >= -1-(long long int)PNG_UINT_31_MAX; + if (!ok) ++overflow; + } + else + ok = 0, ++overflow, fpround = fp/*misleading*/; + + if (verbose) + fprintf(stderr, "TEST %d * %d / %d -> %lld (%s)\n", a, times, div, + fp, ok ? "ok" : "overflow"); + + ++tested; + if (png_muldiv(&result, a, times, div) != ok) + { + ++error; + if (ok) + fprintf(stderr, "%d * %d / %d -> overflow (expected %lld)\n", a, + times, div, fp); + else + fprintf(stderr, "%d * %d / %d -> %d (expected overflow %lld)\n", a, + times, div, result, fp); + } + else if (ok && result != fpround) + { + ++error; + fprintf(stderr, "%d * %d / %d -> %d not %lld\n", a, times, div, result, + fp); + } + else + ++passed; + + /* Generate three new values, this uses rand() and rand() only returns + * up to RAND_MAX. + */ + /* CRUDE */ + a += times; + times += div; + div = randbuffer; + randbuffer = (randbuffer << randbits) ^ rand(); + } + while (--count > 0); + + printf("%d tests including %d overflows, %d passed, %d failed (%d 64-bit " + "errors)\n", tested, overflow, passed, error, error64); + return 0; +} + +/* When FP is on this just becomes a speed test - compile without FP to get real + * validation. + */ +#ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED +#define LN2 .000010576586617430806112933839 /* log(2)/65536 */ +#define L2INV 94548.46219969910586572651 /* 65536/log(2) */ + +/* For speed testing, need the internal functions too: */ +static png_uint_32 png_log8bit(unsigned x) +{ + if (x > 0) + return (png_uint_32)floor(.5-log(x/255.)*L2INV); + + return 0xffffffff; +} + +static png_uint_32 png_log16bit(png_uint_32 x) +{ + if (x > 0) + return (png_uint_32)floor(.5-log(x/65535.)*L2INV); + + return 0xffffffff; +} + +static png_uint_32 png_exp(png_uint_32 x) +{ + return (png_uint_32)floor(.5 + exp(x * -LN2) * 0xffffffffU); +} + +static png_byte png_exp8bit(png_uint_32 log) +{ + return (png_byte)floor(.5 + exp(log * -LN2) * 255); +} + +static png_uint_16 png_exp16bit(png_uint_32 log) +{ + return (png_uint_16)floor(.5 + exp(log * -LN2) * 65535); +} +#endif /* FLOATING_ARITHMETIC */ + +int validation_gamma(int argc, char **argv) +{ + double gamma[9] = { 2.2, 1.8, 1.52, 1.45, 1., 1/1.45, 1/1.52, 1/1.8, 1/2.2 }; + double maxerr; + int i, silent=0, onlygamma=0; + + /* Silence the output with -s, just test the gamma functions with -g: */ + while (--argc > 0) + if (strcmp(*++argv, "-s") == 0) + silent = 1; + else if (strcmp(*argv, "-g") == 0) + onlygamma = 1; + else + { + fprintf(stderr, "unknown argument %s\n", *argv); + return 1; + } + + if (!onlygamma) + { + /* First validate the log functions: */ + maxerr = 0; + for (i=0; i<256; ++i) + { + double correct = -log(i/255.)/log(2.)*65536; + double error = png_log8bit(i) - correct; + + if (i != 0 && fabs(error) > maxerr) + maxerr = fabs(error); + + if (i == 0 && png_log8bit(i) != 0xffffffff || + i != 0 && png_log8bit(i) != floor(correct+.5)) + { + fprintf(stderr, "8-bit log error: %d: got %u, expected %f\n", + i, png_log8bit(i), correct); + } + } + + if (!silent) + printf("maximum 8-bit log error = %f\n", maxerr); + + maxerr = 0; + for (i=0; i<65536; ++i) + { + double correct = -log(i/65535.)/log(2.)*65536; + double error = png_log16bit(i) - correct; + + if (i != 0 && fabs(error) > maxerr) + maxerr = fabs(error); + + if (i == 0 && png_log16bit(i) != 0xffffffff || + i != 0 && png_log16bit(i) != floor(correct+.5)) + { + if (error > .68) /* By experiment error is less than .68 */ + { + fprintf(stderr, "16-bit log error: %d: got %u, expected %f" + " error: %f\n", i, png_log16bit(i), correct, error); + } + } + } + + if (!silent) + printf("maximum 16-bit log error = %f\n", maxerr); + + /* Now exponentiations. */ + maxerr = 0; + for (i=0; i<=0xfffff; ++i) + { + double correct = exp(-i/65536. * log(2.)) * (65536. * 65536); + double error = png_exp(i) - correct; + + if (fabs(error) > maxerr) + maxerr = fabs(error); + if (fabs(error) > 1883) /* By experiment. */ + { + fprintf(stderr, "32-bit exp error: %d: got %u, expected %f" + " error: %f\n", i, png_exp(i), correct, error); + } + } + + if (!silent) + printf("maximum 32-bit exp error = %f\n", maxerr); + + maxerr = 0; + for (i=0; i<=0xfffff; ++i) + { + double correct = exp(-i/65536. * log(2.)) * 255; + double error = png_exp8bit(i) - correct; + + if (fabs(error) > maxerr) + maxerr = fabs(error); + if (fabs(error) > .50002) /* By experiment */ + { + fprintf(stderr, "8-bit exp error: %d: got %u, expected %f" + " error: %f\n", i, png_exp8bit(i), correct, error); + } + } + + if (!silent) + printf("maximum 8-bit exp error = %f\n", maxerr); + + maxerr = 0; + for (i=0; i<=0xfffff; ++i) + { + double correct = exp(-i/65536. * log(2.)) * 65535; + double error = png_exp16bit(i) - correct; + + if (fabs(error) > maxerr) + maxerr = fabs(error); + if (fabs(error) > .524) /* By experiment */ + { + fprintf(stderr, "16-bit exp error: %d: got %u, expected %f" + " error: %f\n", i, png_exp16bit(i), correct, error); + } + } + + if (!silent) + printf("maximum 16-bit exp error = %f\n", maxerr); + } /* !onlygamma */ + + /* Test the overall gamma correction. */ + for (i=0; i<9; ++i) + { + unsigned j; + double g = gamma[i]; + png_fixed_point gfp = floor(g * PNG_FP_1 + .5); + + if (!silent) + printf("Test gamma %f\n", g); + + maxerr = 0; + for (j=0; j<256; ++j) + { + double correct = pow(j/255., g) * 255; + png_byte out = png_gamma_8bit_correct(j, gfp); + double error = out - correct; + + if (fabs(error) > maxerr) + maxerr = fabs(error); + if (out != floor(correct+.5)) + { + fprintf(stderr, "8bit %d ^ %f: got %d expected %f error %f\n", + j, g, out, correct, error); + } + } + + if (!silent) + printf("gamma %f: maximum 8-bit error %f\n", g, maxerr); + + maxerr = 0; + for (j=0; j<65536; ++j) + { + double correct = pow(j/65535., g) * 65535; + png_uint_16 out = png_gamma_16bit_correct(j, gfp); + double error = out - correct; + + if (fabs(error) > maxerr) + maxerr = fabs(error); + if (fabs(error) > 1.62) + { + fprintf(stderr, "16bit %d ^ %f: got %d expected %f error %f\n", + j, g, out, correct, error); + } + } + + if (!silent) + printf("gamma %f: maximum 16-bit error %f\n", g, maxerr); + } + + return 0; +} + +/**************************** VALIDATION TESTS ********************************/ +/* Various validation routines are included herein, they require some + * definition for png_warning and png_error, seetings of VALIDATION: + * + * 1: validates the ASCII to floating point conversions + * 2: validates png_muldiv + * 3: accuracy test of fixed point gamma tables + */ + +/* The following COUNT (10^8) takes about 1 hour on a 1GHz Pentium IV + * processor. + */ +#define COUNT 1000000000 + +int main(int argc, char **argv) +{ + int count = COUNT; + + while (argc > 1) + { + if (argc > 2 && strcmp(argv[1], "-c") == 0) + { + count = atoi(argv[2]); + argc -= 2; + argv += 2; + } + + else if (strcmp(argv[1], "-v") == 0) + { + ++verbose; + --argc; + ++argv; + } + + else + break; + } + + if (count > 0 && argc > 1) + { + if (strcmp(argv[1], "ascii") == 0) + return validation_ascii_to_fp(count, argc-1, argv+1); + else if (strcmp(argv[1], "checkfp") == 0) + return validation_checkfp(count, argc-1, argv+1); + else if (strcmp(argv[1], "muldiv") == 0) + return validation_muldiv(count, argc-1, argv+1); + else if (strcmp(argv[1], "gamma") == 0) + return validation_gamma(argc-1, argv+1); + } + + /* Bad argument: */ + fprintf(stderr, + "usage: tarith [-v] [-c count] {ascii,muldiv,gamma} [args]\n"); + fprintf(stderr, " arguments: ascii [-a (all results)] [-e error%%]\n"); + fprintf(stderr, " checkfp [-l max-number-chars]\n"); + fprintf(stderr, " muldiv\n"); + fprintf(stderr, " gamma -s (silent) -g (only gamma; no log)\n"); + return 1; +} |