/* pgmhist.c - print a histogram of the values in a PGM image ** ** Copyright (C) 1989 by Jef Poskanzer. ** ** Permission to use, copy, modify, and distribute this software and its ** documentation for any purpose and without fee is hereby granted, provided ** that the above copyright notice appear in all copies and that both that ** copyright notice and this permission notice appear in supporting ** documentation. This software is provided "as is" without express or ** implied warranty. */ #include #include #include "pm_c_util.h" #include "mallocvar.h" #include "shhopt.h" #include "pgm.h" struct CmdlineInfo { /* All the information the user supplied in the command line, in a form easy for the program to use. */ const char * inputFileName; /* Filename of input files */ unsigned int machine; unsigned int median; unsigned int quartile; unsigned int decile; unsigned int forensic; }; static void parseCommandLine(int argc, const char ** argv, struct CmdlineInfo * const cmdlineP) { /*---------------------------------------------------------------------------- Note that the file spec array we return is stored in the storage that was passed to us as the argv array. -----------------------------------------------------------------------------*/ optStruct3 opt; /* set by OPTENT3 */ optEntry * option_def; unsigned int option_def_index; MALLOCARRAY_NOFAIL(option_def, 100); option_def_index = 0; /* incremented by OPTENT3 */ OPTENT3(0, "machine", OPT_FLAG, NULL, &cmdlineP->machine, 0); OPTENT3(0, "median", OPT_FLAG, NULL, &cmdlineP->median, 0); OPTENT3(0, "quartile", OPT_FLAG, NULL, &cmdlineP->quartile, 0); OPTENT3(0, "decile", OPT_FLAG, NULL, &cmdlineP->decile, 0); OPTENT3(0, "forensic", OPT_FLAG, NULL, &cmdlineP->forensic, 0); opt.opt_table = option_def; opt.short_allowed = FALSE; /* We have no short (old-fashioned) options */ opt.allowNegNum = FALSE; /* We have no parms that are negative numbers */ pm_optParseOptions4(&argc, argv, opt, sizeof(opt), 0); /* Uses and sets argc, argv, and some of *cmdlineP and others. */ if (cmdlineP->median + cmdlineP->quartile + cmdlineP->decile > 1) pm_error("You may specify only one of -median, -quartile, " "and -decile"); if (argc-1 == 0) cmdlineP->inputFileName = "-"; else if (argc-1 != 1) pm_error("Program takes zero or one argument (filename). You " "specified %d", argc-1); else cmdlineP->inputFileName = argv[1]; free(option_def); } static gray universalMaxval(gray const maxval, int const format) { /*---------------------------------------------------------------------------- A maxval that makes it impossible for a pixel to be invalid in an image that states it maxval as 'maxval' and has format 'format'. E.g. in a one-byte-per-sample image, it's not possible to read a sample value greater than 255, so a maxval of 255 makes it impossible for a sample to be invalid. But: we never go above 65535, which means our maxval isn't entirely universal. If the image is plain PGM, it could contain a pixel that exceeds even that. -----------------------------------------------------------------------------*/ assert(0 < maxval && maxval < 65536); if (format == RPGM_FORMAT) { /* Raw PGM stream has either one or two bytes per pixel, depending upon its stated maxval. */ if (maxval > 255) return 65535; else return 255; } else if (format == RPBM_FORMAT) { /* A Raw PBM stream has one bit per pixel, which libnetpbm renders as 0 or 255 when we read it. */ assert(maxval == 255); return 255; } else { /* A plain PGM or PBM stream has essentially unlimited range in the tokens that are supposed to be sample values. We arbitrarily draw the line at 65535. */ return 65535; } } static void buildHistogram(FILE * const ifP, int const format, unsigned int const cols, unsigned int const rows, gray const mmaxval, unsigned long int ** const histP) { /*---------------------------------------------------------------------------- Compute the histogram of sample values in the input stream *ifP as *histP, in newly malloced storage. Assume the image maxval is 'mmaxval'. Assume *ifP is positioned to the start of the raster. -----------------------------------------------------------------------------*/ gray * grayrow; unsigned int row; unsigned int i; unsigned long int * hist; /* malloc'ed array */ grayrow = pgm_allocrow(cols); MALLOCARRAY(hist, mmaxval + 1); if (hist == NULL) pm_error("out of memory"); for (i = 0; i <= mmaxval; ++i) hist[i] = 0; for (row = 0; row < rows; ++row) { unsigned int col; pgm_readpgmrow(ifP, grayrow, cols, mmaxval, format); for (col = 0; col < cols; ++col) { /* Because total pixels in image is limited: */ assert (hist[grayrow[col]] < INT_MAX); ++hist[grayrow[col]]; } } pgm_freerow(grayrow); *histP = hist; } static void findQuantiles(unsigned int const n, unsigned long int const hist[], unsigned long int const totalCt, gray const mmaxval, gray * const quantile) { /*---------------------------------------------------------------------------- Find the order-n quantiles (e.g. n == 4 means quartiles) of the pixel sample values, given that hist[] is the histogram of them (hist[N] is the number of pixels that have sample value N). 'mmaxval' is the highest index in hist[] (so its size is 'mmaxval' + 1, and there are no pixels greater than 'mmaxval' in the image). We return the ith quantile as quantile[i]. For example, for quartiles, quantile[3] is the least sample value for which at least 3/4 of the pixels are less than or equal to it. quantile[] must be allocated at least to size 'n'. 'n' must not be more than 100. -----------------------------------------------------------------------------*/ unsigned int quantSeq; /* 0 is first quantile, 1 is second quantile, etc. */ gray sampleVal; /* As we increment through all the possible sample values, this is the one we're considering now. */ unsigned int cumCt; /* The number of pixels that have sample value 'sampleVal' or less. */ assert(n > 1 && n <= 100); sampleVal = 0; /* initial value */ cumCt = hist[0]; /* initial value */ for (quantSeq = 1; quantSeq <= n; ++quantSeq) { unsigned long int const q = totalCt / n; unsigned long int const r = totalCt % n; unsigned long int const quantCt = q*quantSeq + (r*quantSeq + n - 1)/n; /* This is how many pixels are (ignoring quantization) in the quantile. E.g. for the 3rd quartile, it is 3/4 of the pixels in the image. This is equivalent to (float) totalCt * quantSeq / n rounded upwards. We use the int version in spite of complexities for preventing overflow for slight innacuracies in floating point arithmetic causes problems when used as loop counter and array index. */ assert(quantCt <= totalCt); /* at sampleVal == mmaxval, cumCt == totalCt, so because quantCt <= 'totalCt', 'sampleVal' cannot go above mmaxval. */ while (cumCt < quantCt) { ++sampleVal; cumCt += hist[sampleVal]; } assert(sampleVal <= mmaxval); /* 'sampleVal' is the lowest sample value for which at least 'quantCt' pixels have that sample value or less. 'cumCt' is the number of pixels that have sample value 'sampleVal' or less. */ quantile[quantSeq-1] = sampleVal; } } static void countCumulative(unsigned long int const hist[], gray const mmaxval, unsigned long int const totalPixelCt, unsigned long int ** const rcountP) { /*---------------------------------------------------------------------------- From the histogram hist[] (hist[N] is the number of pixels of sample value N), compute the cumulative distribution *rcountP ((*rcountP)[N] is the number of pixels of sample value N or higher). *rcountP is newly malloced memory. -----------------------------------------------------------------------------*/ unsigned long int * rcount; unsigned long int cumCount; int i; MALLOCARRAY(rcount, mmaxval + 1); if (rcount == NULL) pm_error("out of memory"); for (i = mmaxval, cumCount = 0; i >= 0; --i) { /* Because total pixels in image is limited: */ assert(ULONG_MAX - hist[i] >= cumCount); cumCount += hist[i]; rcount[i] = cumCount; } *rcountP = rcount; } static void reportHistHumanFriendly(unsigned long int const hist[], unsigned long int const rcount[], gray const maxval) { unsigned long int const totalPixelCt = rcount[0]; unsigned int cumCount; unsigned int i; printf("value count b%% w%% \n"); printf("----- ----- ------ ------\n"); for (i = 0, cumCount = 0; i <= maxval; ++i) { if (hist[i] > 0) { cumCount += hist[i]; printf( "%5d %5ld %5.3g%% %5.3g%%\n", i, hist[i], (float) cumCount * 100.0 / totalPixelCt, (float) rcount[i] * 100.0 / totalPixelCt); } } } static void reportHistForensicHumanFriendly(unsigned long int const hist[], unsigned long int const rcount[], gray const maxval, gray const mmaxval) { unsigned long int const totalPixelCt = rcount[0]; unsigned long int cumCount; unsigned int i; printf("value count b%% w%% \n"); printf("----- ----- ------ ------\n"); for (i = 0, cumCount = 0; i <= maxval; ++i) { if (hist[i] > 0) { cumCount += hist[i]; printf( "%5d %5ld %5.3g%% %5.3g%%\n", i, hist[i], (float) cumCount * 100.0 / totalPixelCt, (float) rcount[i] * 100.0 / totalPixelCt); } } if (totalPixelCt > cumCount) { printf("----- -----\n"); for (i = maxval; i <= mmaxval; ++i) { if (hist[i] > 0) { cumCount += hist[i]; printf( "%5d %5ld %5.3g%% %5.3g%%\n", i, hist[i], (float) cumCount * 100.0 / totalPixelCt, (float) rcount[i] * 100.0 / totalPixelCt); } } } } static void reportHistMachineFriendly(unsigned long int const hist[], gray const maxval) { unsigned int i; for (i = 0; i <= maxval; ++i) { printf("%u %lu\n", i, hist[i]); } } static void reportQuantilesMachineFriendly(gray const quantile[], unsigned int const n) { unsigned int i; for (i = 0; i < n; ++i) printf("%u\n", quantile[i]); } static void reportMedianHumanFriendly(gray const median) { printf("Median: %5u\n", median); } static void reportQuartilesHumanFriendly(gray const quartile[]) { unsigned int i; printf("Quartiles:\n"); printf("Q Value\n"); printf("---- -----\n"); for (i = 1; i <= 4; ++i) printf("%3u%% %5u\n", 25*i, quartile[i-1]); } static void reportDecilesHumanFriendly(gray const decile[]) { unsigned int i; printf("Deciles:\n"); printf("Q Value\n"); printf("--- -----\n"); for (i = 1; i <= 10; ++i) printf("%3u%% %5u\n", 10*i, decile[i-1]); } static void summarizeInvalidPixels(unsigned long int const hist[], unsigned long int const rcount[], gray const mmaxval, gray const maxval) { /*---------------------------------------------------------------------------- Print total count of valid and invalid pixels, if there are any invalid ones. -----------------------------------------------------------------------------*/ unsigned long int const invalidPixelCt = mmaxval > maxval ? rcount[maxval+1] : 0; if (invalidPixelCt > 0) { unsigned long int const totalPixelCt = rcount[0]; unsigned long int const validPixelCt = totalPixelCt - invalidPixelCt; printf("\n"); printf("** Image stream contains invalid sample values " "(above maxval %u)\n", maxval); printf("Valid sample values: %lu (%5.4g%%)\n", validPixelCt, (float)validPixelCt / totalPixelCt * 100.0); printf("Invalid sample values: %lu (%5.4g%%)\n", invalidPixelCt, (float)invalidPixelCt / totalPixelCt * 100.0); } } static void reportFromHistogram(const unsigned long int * const hist, gray const mmaxval, gray const maxval, unsigned long int const totalPixelCt, struct CmdlineInfo const cmdline) { /*---------------------------------------------------------------------------- Analyze histogram 'hist', which has 'mmaxval' buckets, and report what we find. 'maxval' is the maxval that the image states (but note that we tolerate invalid sample values greater than maxval, which could be as high as 'mmaxval'). 'cmdline' tells what kind of reporting to do. -----------------------------------------------------------------------------*/ if (cmdline.median) { gray median[2]; findQuantiles(2, hist, totalPixelCt, mmaxval, median); if (cmdline.machine) reportQuantilesMachineFriendly(median, 1); else reportMedianHumanFriendly(median[0]); } else if (cmdline.quartile) { gray quartile[4]; findQuantiles(4, hist, totalPixelCt, mmaxval, quartile); if (cmdline.machine) reportQuantilesMachineFriendly(quartile, 4); else reportQuartilesHumanFriendly(quartile); } else if (cmdline.decile) { gray decile[10]; findQuantiles(10, hist, totalPixelCt, mmaxval, decile); if (cmdline.machine) reportQuantilesMachineFriendly(decile, 10); else reportDecilesHumanFriendly(decile); } else { if (cmdline.machine) reportHistMachineFriendly(hist, mmaxval); else { unsigned long int * rcount; /* malloc'ed array */ countCumulative(hist, mmaxval, totalPixelCt, &rcount); if (cmdline.forensic) reportHistForensicHumanFriendly(hist, rcount, maxval, mmaxval); else reportHistHumanFriendly(hist, rcount, maxval); summarizeInvalidPixels(hist, rcount, mmaxval, maxval); free(rcount); } } } int main(int argc, const char ** argv) { struct CmdlineInfo cmdline; FILE * ifP; int rows, cols; int format; gray maxval; /* Stated maxval of the image */ gray mmaxval; /* Maxval we assume, which may be greater than the stated maxval so that we can process invalid pixels in the image that exceed the maxval. */ unsigned long int totalPixelCt; unsigned long int * hist; /* malloc'ed array */ pm_proginit(&argc, argv); parseCommandLine(argc, argv, &cmdline); ifP = pm_openr(cmdline.inputFileName); pgm_readpgminit(ifP, &cols, &rows, &maxval, &format); if (ULONG_MAX / cols < rows) pm_error("Too many pixels (%u x %u) in image. " "Maximum computable is %lu", cols, rows, ULONG_MAX); totalPixelCt = cols * rows; mmaxval = cmdline.forensic ? universalMaxval(maxval, format) : maxval; buildHistogram(ifP, format, cols, rows, mmaxval, &hist); reportFromHistogram(hist, mmaxval, maxval, totalPixelCt, cmdline); free(hist); pm_close(ifP); return 0; }