/***************************************************************************** ppmtojpeg ****************************************************************************** This program is part of the Netpbm package. This program converts from the fundamental ppm format to the JFIF format which is based on JPEG. This program is by Bryan Henderson on 2000.03.06, but is derived with permission from the program cjpeg, which is in the Independent Jpeg Group's JPEG library package. Under the terms of that permission, redistribution of this software is restricted as described in the file README.JPEG. Copyright (C) 1991-1998, Thomas G. Lane. TODO: - Make it pnmtojpeg instead of ppmtojpeg. If input is PGM or PBM, produce JCS_GRAYSCALE output directly. *****************************************************************************/ #define _BSD_SOURCE 1 /* This makes sure strdup() is in string.h */ #include /* to declare isdigit(), etc. */ #include #include #include #include #include #include "ppm.h" #include "shhopt.h" #define EXIT_WARNING 2 /* Goes with EXIT_SUCCESS, EXIT_FAILURE in stdlib.h */ static const char * progname; /* program name for error messages */ enum restart_unit {RESTART_MCU, RESTART_ROW, RESTART_NONE}; struct cmdline_info { /* All the information the user supplied in the command line, in a form easy for the program to use. */ char *input_filename; int verbose; unsigned int quality; int force_baseline; int progressive; int arith_code; J_DCT_METHOD dct_method; int grayscale; long int max_memory_to_use; unsigned int trace_level; char *qslots; char *qtablefile; char *sample; char *scans; int smoothing_factor; int optimize; unsigned int restart_value; enum restart_unit restart_unit; char *restart; } cmdline; static void parse_command_line(const int argc, char ** argv, struct cmdline_info *cmdline_p); static void compute_rescaling_array(JSAMPLE ** const rescale_p, const pixval maxval, const struct jpeg_compress_struct cinfo); static void convert_scanlines(struct jpeg_compress_struct *cinfo_p, FILE *input_file, const pixval maxval, const int input_fmt, JSAMPLE xlate_table[]); static boolean read_quant_tables (j_compress_ptr cinfo, char * filename, int scale_factor, boolean force_baseline); static boolean read_scan_script (j_compress_ptr cinfo, char * filename); static boolean set_quant_slots (j_compress_ptr cinfo, char *arg); static boolean set_sample_factors (j_compress_ptr cinfo, char *arg); int main(int argc, char ** argv) { struct jpeg_compress_struct cinfo; struct jpeg_error_mgr jerr; FILE *input_file; FILE * output_file; int height; /* height of the input image in rows, as specified by its header */ int width; /* width of the input image in columns, as specified by its header */ pixval maxval; /* maximum value of an input pixel component, as specified by header */ int input_fmt; /* The input format, as determined by its header. */ JSAMPLE *rescale; /* => maxval-remapping array, or NULL */ /* This is an array that maps each possible pixval in the input to a new value such that while the range of the input values is 0 .. maxval, the range of the output values is 0 .. MAXJSAMPLE. */ int quality; int q_scale_factor; ppm_init(&argc, argv); progname = argv[0]; parse_command_line(argc, argv, &cmdline); /* Initialize the JPEG compression object with default error handling. */ cinfo.err = jpeg_std_error(&jerr); jpeg_create_compress(&cinfo); /* Initialize JPEG parameters. * Much of this may be overridden later. * In particular, we don't yet know the input file's color space, * but we need to provide some value for jpeg_set_defaults() to work. */ cinfo.in_color_space = JCS_RGB; /* arbitrary guess */ jpeg_set_defaults(&cinfo); /* Open the input file */ if (cmdline.input_filename == NULL) input_file = stdin; else { if ((input_file = fopen(cmdline.input_filename, "rb")) == NULL) pm_error("can't open %s. Errno=%s(%d).\n", cmdline.input_filename, strerror(errno), errno); free(cmdline.input_filename); } output_file = stdout; /* Open the ppm input */ ppm_readppminit(input_file, &width, &height, &maxval, &input_fmt); if (cmdline.verbose) { pm_message("Input file has format %c%c.\n" "It has %d rows of %d columns of pixels " "with max sample value of %d.", (char) (input_fmt/256), (char) (input_fmt % 256), height, width, maxval); } cinfo.data_precision = BITS_IN_JSAMPLE; /* we always rescale data to this */ cinfo.image_width = (unsigned int) width; cinfo.image_height = (unsigned int) height; /* For the pnm version, we need to change these based on PBM/PGM/PPM */ cinfo.in_color_space = JCS_RGB; /* format of input to compressor */ cinfo.input_components = 3; compute_rescaling_array(&rescale, maxval, cinfo); cinfo.arith_code = cmdline.arith_code; cinfo.dct_method = cmdline.dct_method; if (cmdline.trace_level == 0 && cmdline.verbose) cinfo.err->trace_level = 1; else cinfo.err->trace_level = cmdline.trace_level; if (cmdline.grayscale) jpeg_set_colorspace(&cinfo, JCS_GRAYSCALE); else /* This default will be based on the in_color_space set above */ jpeg_default_colorspace(&cinfo); if (cmdline.max_memory_to_use != -1) cinfo.mem->max_memory_to_use = cmdline.max_memory_to_use; cinfo.optimize_coding = cmdline.optimize; if (cmdline.quality == -1) { quality = 75; q_scale_factor = 100; } else { quality = cmdline.quality; q_scale_factor = jpeg_quality_scaling(cmdline.quality); } if (cmdline.smoothing_factor != -1) cinfo.smoothing_factor = cmdline.smoothing_factor; /* Set quantization tables for selected quality. */ /* Some or all may be overridden if user specified --qtables. */ jpeg_set_quality(&cinfo, quality, cmdline.force_baseline); if (cmdline.qtablefile != NULL) { if (! read_quant_tables(&cinfo, cmdline.qtablefile, q_scale_factor, cmdline.force_baseline)) pm_error("Can't use quantization table file '%s'.", cmdline.qtablefile); } if (cmdline.qslots != NULL) { if (! set_quant_slots(&cinfo, cmdline.qslots)) pm_error("Bad quantization-table-selectors parameter string '%s'.", cmdline.qslots); } if (cmdline.sample != NULL) { if (! set_sample_factors(&cinfo, cmdline.sample)) pm_error("Bad sample-factors parameters string '%s'.", cmdline.sample); } if (cmdline.progressive) jpeg_simple_progression(&cinfo); if (cmdline.scans != NULL) { if (! read_scan_script(&cinfo, cmdline.scans)) { pm_message("Error in scan script '%s'.", cmdline.scans); } } /* Specify data destination for compression */ jpeg_stdio_dest(&cinfo, output_file); /* Start compressor */ jpeg_start_compress(&cinfo, TRUE); /* Translate and copy over the actual scanlines */ convert_scanlines(&cinfo, input_file, maxval, input_fmt, rescale); /* Finish compression and release memory */ jpeg_finish_compress(&cinfo); jpeg_destroy_compress(&cinfo); /* Close files, if we opened them */ if (input_file != stdin) fclose(input_file); /* Program may have exited with non-zero completion code vie various function calls above. */ exit((jerr.num_warnings > 0) ? EXIT_WARNING : EXIT_SUCCESS); } static void interpret_restart(const char * const restart, unsigned int * const restart_value_p, enum restart_unit * const restart_unit_p) { /*---------------------------------------------------------------------------- Interpret the restart command line option. Return values suitable for plugging into a jpeg_compress_struct to control compression. -----------------------------------------------------------------------------*/ if (restart == NULL) { /* No --restart option. Set default */ *restart_unit_p = RESTART_NONE; } else { /* Restart interval in MCU rows (or in MCUs with 'b'). */ long lval; char ch; unsigned int matches; matches= sscanf(restart, "%ld%c", &lval, &ch); if (matches == 0) pm_error("Invalid value for the --restart option : '%s'.", restart); else { if (lval < 0 || lval > 65535L) { pm_error("--restart value %ld is out of range.", lval); exit(EXIT_FAILURE); } else { if (matches == 1) { *restart_value_p = lval; *restart_unit_p = RESTART_ROW; } else { if (ch == 'b' || ch == 'B') { *restart_value_p = lval; *restart_unit_p = RESTART_MCU; } else pm_error("Invalid --restart value '%s'.", restart); } } } } } static void interpret_maxmemory (const char * const maxmemory, long int * const max_memory_to_use_p) { long int lval; char ch; if (maxmemory == NULL) { *max_memory_to_use_p = -1; /* unspecified */ } else if (sscanf(maxmemory, "%ld%c", &lval, &ch) < 1) { pm_error("Invalid value for --maxmemory option: '%s'.", maxmemory); exit(EXIT_FAILURE); } else { if (ch == 'm' || ch == 'M') lval *= 1000L; *max_memory_to_use_p = lval * 1000L; } } static void parse_command_line(const int argc, char ** argv, struct cmdline_info *cmdline_p) { /*---------------------------------------------------------------------------- Note that many of the strings that this function returns in the *cmdline_p structure are actually in the supplied argv array. And sometimes, one of these strings is actually just a suffix of an entry in argv! On the other hand, unlike other option processing functions, we do not change argv at all. -----------------------------------------------------------------------------*/ int i; /* local loop variable */ char *dctval; char *maxmemory; char *restart; optStruct *option_def = malloc(100*sizeof(optStruct)); /* Instructions to OptParseOptions on how to parse our options. */ unsigned int option_def_index; int argc_parse; /* argc, except we modify it as we parse */ char ** const argv_parse = malloc(argc*sizeof(char *)); /* argv, except we modify it as we parse */ option_def_index = 0; /* incremented by OPTENTRY */ OPTENTRY(0, "verbose", OPT_FLAG, &cmdline_p->verbose, 0); OPTENTRY(0, "quality", OPT_UINT, &cmdline_p->quality, 0); OPTENTRY(0, "baseline", OPT_FLAG, &cmdline_p->force_baseline, 0); OPTENTRY(0, "progressive", OPT_FLAG, &cmdline_p->progressive, 0); OPTENTRY(0, "arithmetic", OPT_FLAG, &cmdline_p->arith_code, 0); OPTENTRY(0, "dct", OPT_STRING, &dctval, 0); OPTENTRY(0, "grayscale", OPT_FLAG, &cmdline_p->grayscale, 0); OPTENTRY(0, "greyscale", OPT_FLAG, &cmdline_p->grayscale, 0); OPTENTRY(0, "maxmemory", OPT_STRING, &maxmemory, 0); OPTENTRY(0, "tracelevel", OPT_UINT, &cmdline_p->trace_level, 0); OPTENTRY(0, "qslots", OPT_STRING, &cmdline_p->qslots, 0); OPTENTRY(0, "qtables", OPT_STRING, &cmdline_p->qtablefile, 0); OPTENTRY(0, "sample", OPT_STRING, &cmdline_p->sample, 0); OPTENTRY(0, "scans", OPT_STRING, &cmdline_p->scans, 0); OPTENTRY(0, "smooth", OPT_UINT, &cmdline_p->smoothing_factor, 0); OPTENTRY(0, "optimize", OPT_FLAG, &cmdline_p->optimize, 0); OPTENTRY(0, "optimise", OPT_FLAG, &cmdline_p->optimize, 0); OPTENTRY(0, "restart", OPT_STRING, &restart, 0); /* Set the defaults */ cmdline_p->verbose = FALSE; cmdline_p->quality = -1; /* unspecified */ cmdline_p->force_baseline = FALSE; cmdline_p->progressive = FALSE; cmdline_p->arith_code = FALSE; dctval = NULL; cmdline_p->grayscale = FALSE; maxmemory = NULL; cmdline_p->trace_level = 0; cmdline_p->qslots = NULL; cmdline_p->qtablefile = NULL; cmdline_p->sample = NULL; cmdline_p->scans = NULL; cmdline_p->smoothing_factor = -1; cmdline_p->optimize = FALSE; restart = NULL; /* Make private copy of arguments for optParseOptions to corrupt */ argc_parse = argc; for (i=0; i < argc; i++) argv_parse[i] = argv[i]; pm_optParseOptions(&argc_parse, argv_parse, option_def, 0); /* Uses and sets argc_parse, argv_parse and all of *cmdline_p. */ if (argc_parse - 1 == 0) cmdline_p->input_filename = NULL; /* he wants stdin */ else if (argc_parse - 1 == 1) cmdline_p->input_filename = strdup(argv_parse[1]); else pm_error("Too many arguments. The only argument accepted" "is the input file specification."); if (dctval == NULL) cmdline_p->dct_method = JDCT_DEFAULT; else { if (strcmp(dctval, "int") == 0) cmdline_p->dct_method = JDCT_ISLOW; else if (strcmp(dctval, "fast") == 0) cmdline_p->dct_method = JDCT_IFAST; else if (strcmp(dctval, "float") == 0) cmdline_p->dct_method = JDCT_FLOAT; else pm_error("Invalid value for the --dct option: '%s'.", dctval); } interpret_maxmemory(maxmemory, &cmdline_p->max_memory_to_use); interpret_restart(restart, &cmdline_p->restart_value, &cmdline_p->restart_unit); if (cmdline_p->smoothing_factor > 100) pm_error("Smoothing factor %d is greater than 100 (%%).", cmdline_p->smoothing_factor); free(argv_parse); } static void compute_rescaling_array(JSAMPLE ** const rescale_p, const pixval maxval, const struct jpeg_compress_struct cinfo) { /*---------------------------------------------------------------------------- Compute the rescaling array for a maximum pixval of 'maxval'. Allocate the memory for it too. -----------------------------------------------------------------------------*/ const long half_maxval = maxval / 2; long val; *rescale_p = (JSAMPLE *) (cinfo.mem->alloc_small) ((j_common_ptr) &cinfo, JPOOL_IMAGE, (size_t) (((long) maxval + 1L) * sizeof(JSAMPLE))); for (val = 0; val <= maxval; val++) { /* The multiplication here must be done in 32 bits to avoid overflow */ (*rescale_p)[val] = (JSAMPLE) ((val*MAXJSAMPLE + half_maxval)/maxval); } } static void translate_row(const pixel ppm_buffer[], JSAMPLE jpeg_buffer[], const int width, const JSAMPLE translate[]) { /*---------------------------------------------------------------------------- Convert the input row, in ppm format, to an output row in JPEG compressor input format. This is a byte for byte copy, translated through the array 'translate'. -----------------------------------------------------------------------------*/ unsigned int column; /* I'm not sure why the JPEG library data structures don't have some kind of pixel data structure (such that a row buffer is an array of pixels, rather than an array of samples). But because of this, we have to index jpeg_buffer the old fashioned way. */ for (column = 0; column < width; column++) { jpeg_buffer[column*3+0] = translate[(int)PPM_GETR(ppm_buffer[column])]; jpeg_buffer[column*3+1] = translate[(int)PPM_GETG(ppm_buffer[column])]; jpeg_buffer[column*3+2] = translate[(int)PPM_GETB(ppm_buffer[column])]; } } static void translate_row(const pixel ppm_buffer[], JSAMPLE jpeg_buffer[], const int width, const JSAMPLE translate[]); static void convert_scanlines(struct jpeg_compress_struct *cinfo_p, FILE *input_file, const pixval maxval, const int input_fmt, JSAMPLE xlate_table[]){ /*---------------------------------------------------------------------------- Read scan lines from the input file, which is already opened in the netpbm library sense and ready for reading, and write them to the output JPEG object. Translate the ppm sample values to JPEG sample values through the thable xlate_table[]. -----------------------------------------------------------------------------*/ pixel* ppm_buffer; /* contains the row of the input image currently being processed, in ppm_readrow format */ JSAMPARRAY buffer; /* Row 0 of this array contains the row of the output image currently being processed, in JPEG compressor input format. The array only has that one row. */ /* Allocate the libppm output and compressor input buffers */ buffer = (*cinfo_p->mem->alloc_sarray) ((j_common_ptr) cinfo_p, JPOOL_IMAGE, (unsigned int) cinfo_p->image_width * cinfo_p->input_components, (unsigned int) 1); ppm_buffer = ppm_allocrow(cinfo_p->image_width); while (cinfo_p->next_scanline < cinfo_p->image_height) { if (cinfo_p->err->trace_level > 1) pm_message("Converting Row %d...", cinfo_p->next_scanline); ppm_readppmrow(input_file, ppm_buffer, cinfo_p->image_width, maxval, input_fmt); translate_row(ppm_buffer, buffer[0], cinfo_p->image_width, xlate_table); jpeg_write_scanlines(cinfo_p, buffer, 1); if (cinfo_p->err->trace_level > 1) pm_message("Done."); } ppm_freerow(ppm_buffer); /* Dont' worry about the compressor input buffer; it gets freed automatically */ } /*---------------------------------------------------------------------------- The functions below here are essentially the file rdswitch.c from the JPEG library. They perform the functions specifed by the following ppmtojpeg options: -qtables file Read quantization tables from text file -scans file Read scan script from text file -qslots N[,N,...] Set component quantization table selectors -sample HxV[,HxV,...] Set component sampling factors -----------------------------------------------------------------------------*/ static int text_getc (FILE * file) /* Read next char, skipping over any comments (# to end of line) */ /* A comment/newline sequence is returned as a newline */ { register int ch; ch = getc(file); if (ch == '#') { do { ch = getc(file); } while (ch != '\n' && ch != EOF); } return ch; } static boolean read_text_integer (FILE * file, long * result, int * termchar) /* Read an unsigned decimal integer from a file, store it in result */ /* Reads one trailing character after the integer; returns it in termchar */ { register int ch; register long val; /* Skip any leading whitespace, detect EOF */ do { ch = text_getc(file); if (ch == EOF) { *termchar = ch; return FALSE; } } while (isspace(ch)); if (! isdigit(ch)) { *termchar = ch; return FALSE; } val = ch - '0'; while ((ch = text_getc(file)) != EOF) { if (! isdigit(ch)) break; val *= 10; val += ch - '0'; } *result = val; *termchar = ch; return TRUE; } static boolean read_quant_tables (j_compress_ptr cinfo, char * filename, int scale_factor, boolean force_baseline) /* Read a set of quantization tables from the specified file. * The file is plain ASCII text: decimal numbers with whitespace between. * Comments preceded by '#' may be included in the file. * There may be one to NUM_QUANT_TBLS tables in the file, each of 64 values. * The tables are implicitly numbered 0,1,etc. * NOTE: does not affect the qslots mapping, which will default to selecting * table 0 for luminance (or primary) components, 1 for chrominance components. * You must use -qslots if you want a different component->table mapping. */ { FILE * fp; int tblno, i, termchar; long val; unsigned int table[DCTSIZE2]; if ((fp = fopen(filename, "rb")) == NULL) { fprintf(stderr, "%s: Can't open table file %s\n", progname, filename); return FALSE; } tblno = 0; while (read_text_integer(fp, &val, &termchar)) { /* read 1st element of table */ if (tblno >= NUM_QUANT_TBLS) { fprintf(stderr, "%s: Too many tables in file %s\n", progname, filename); fclose(fp); return FALSE; } table[0] = (unsigned int) val; for (i = 1; i < DCTSIZE2; i++) { if (! read_text_integer(fp, &val, &termchar)) { fprintf(stderr, "%s: Invalid table data in file %s\n", progname, filename); fclose(fp); return FALSE; } table[i] = (unsigned int) val; } jpeg_add_quant_table(cinfo, tblno, table, scale_factor, force_baseline); tblno++; } if (termchar != EOF) { fprintf(stderr, "%s: Non-numeric data in file %s\n", progname, filename); fclose(fp); return FALSE; } fclose(fp); return TRUE; } static boolean read_scan_integer (FILE * file, long * result, int * termchar) /* Variant of read_text_integer that always looks for a non-space termchar; * this simplifies parsing of punctuation in scan scripts. */ { register int ch; if (! read_text_integer(file, result, termchar)) return FALSE; ch = *termchar; while (ch != EOF && isspace(ch)) ch = text_getc(file); if (isdigit(ch)) { /* oops, put it back */ if (ungetc(ch, file) == EOF) return FALSE; ch = ' '; } else { /* Any separators other than ';' and ':' are ignored; * this allows user to insert commas, etc, if desired. */ if (ch != EOF && ch != ';' && ch != ':') ch = ' '; } *termchar = ch; return TRUE; } boolean read_scan_script (j_compress_ptr cinfo, char * filename) /* Read a scan script from the specified text file. * Each entry in the file defines one scan to be emitted. * Entries are separated by semicolons ';'. * An entry contains one to four component indexes, * optionally followed by a colon ':' and four progressive-JPEG parameters. * The component indexes denote which component(s) are to be transmitted * in the current scan. The first component has index 0. * Sequential JPEG is used if the progressive-JPEG parameters are omitted. * The file is free format text: any whitespace may appear between numbers * and the ':' and ';' punctuation marks. Also, other punctuation (such * as commas or dashes) can be placed between numbers if desired. * Comments preceded by '#' may be included in the file. * Note: we do very little validity checking here; * jcmaster.c will validate the script parameters. */ { FILE * fp; int scanno, ncomps, termchar; long val; jpeg_scan_info * scanptr; #define MAX_SCANS 100 /* quite arbitrary limit */ jpeg_scan_info scans[MAX_SCANS]; if ((fp = fopen(filename, "r")) == NULL) { fprintf(stderr, "%s: Can't open scan definition file %s\n", progname, filename); return FALSE; } scanptr = scans; scanno = 0; while (read_scan_integer(fp, &val, &termchar)) { if (scanno >= MAX_SCANS) { fprintf(stderr, "%s: Too many scans defined in file %s\n", progname, filename); fclose(fp); return FALSE; } scanptr->component_index[0] = (int) val; ncomps = 1; while (termchar == ' ') { if (ncomps >= MAX_COMPS_IN_SCAN) { fprintf(stderr, "%s: Too many components in one scan in file %s\n", progname, filename); fclose(fp); return FALSE; } if (! read_scan_integer(fp, &val, &termchar)) goto bogus; scanptr->component_index[ncomps] = (int) val; ncomps++; } scanptr->comps_in_scan = ncomps; if (termchar == ':') { if (! read_scan_integer(fp, &val, &termchar) || termchar != ' ') goto bogus; scanptr->Ss = (int) val; if (! read_scan_integer(fp, &val, &termchar) || termchar != ' ') goto bogus; scanptr->Se = (int) val; if (! read_scan_integer(fp, &val, &termchar) || termchar != ' ') goto bogus; scanptr->Ah = (int) val; if (! read_scan_integer(fp, &val, &termchar)) goto bogus; scanptr->Al = (int) val; } else { /* set non-progressive parameters */ scanptr->Ss = 0; scanptr->Se = DCTSIZE2-1; scanptr->Ah = 0; scanptr->Al = 0; } if (termchar != ';' && termchar != EOF) { bogus: fprintf(stderr, "%s: Invalid scan entry format in file %s\n", progname, filename); fclose(fp); return FALSE; } scanptr++, scanno++; } if (termchar != EOF) { fprintf(stderr, "%s: Non-numeric data in file %s\n", progname, filename); fclose(fp); return FALSE; } if (scanno > 0) { /* Stash completed scan list in cinfo structure. * NOTE: for cjpeg's use, JPOOL_IMAGE is the right lifetime for this data, * but if you want to compress multiple images you'd want JPOOL_PERMANENT. */ scanptr = (jpeg_scan_info *) (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, scanno * sizeof(jpeg_scan_info)); memcpy(scanptr, scans, sizeof(jpeg_scan_info)); cinfo->scan_info = scanptr; cinfo->num_scans = scanno; } fclose(fp); return TRUE; } static boolean set_quant_slots (j_compress_ptr cinfo, char *arg) /* Process a quantization-table-selectors parameter string, of the form * N[,N,...] * If there are more components than parameters, the last value is replicated. */ { int val = 0; /* default table # */ int ci; char ch; for (ci = 0; ci < MAX_COMPONENTS; ci++) { if (*arg) { ch = ','; /* if not set by sscanf, will be ',' */ if (sscanf(arg, "%d%c", &val, &ch) < 1) return FALSE; if (ch != ',') /* syntax check */ return FALSE; if (val < 0 || val >= NUM_QUANT_TBLS) { fprintf(stderr, "%s: Invalid quantization table number: %d. " "JPEG quantization tables are numbered 0..%d\n", progname, val, NUM_QUANT_TBLS - 1); return FALSE; } cinfo->comp_info[ci].quant_tbl_no = val; while (*arg && *arg++ != ',') /* advance to next segment of arg string */ ; } else { /* reached end of parameter, set remaining components to last table */ cinfo->comp_info[ci].quant_tbl_no = val; } } return TRUE; } static boolean set_sample_factors (j_compress_ptr cinfo, char *arg) /* Process a sample-factors parameter string, of the form * HxV[,HxV,...] * If there are more components than parameters, "1x1" is assumed for the rest. */ { int ci, val1, val2; char ch1, ch2; for (ci = 0; ci < MAX_COMPONENTS; ci++) { if (*arg) { ch2 = ','; /* if not set by sscanf, will be ',' */ if (sscanf(arg, "%d%c%d%c", &val1, &ch1, &val2, &ch2) < 3) return FALSE; if ((ch1 != 'x' && ch1 != 'X') || ch2 != ',') /* syntax check */ return FALSE; if (val1 <= 0 || val1 > 4) { fprintf(stderr, "%s: Invalid sampling factor: %d. " "JPEG sampling factors must be 1..4\n", progname, val1); return FALSE; } if (val2 <= 0 || val2 > 4) { fprintf(stderr, "%s: Invalid sampling factor: %d. " "JPEG sampling factors must be 1..4\n", progname, val2); return FALSE; } cinfo->comp_info[ci].h_samp_factor = val1; cinfo->comp_info[ci].v_samp_factor = val2; while (*arg && *arg++ != ',') /* advance to next segment of arg string */ ; } else { /* reached end of parameter, set remaining components to 1x1 sampling */ cinfo->comp_info[ci].h_samp_factor = 1; cinfo->comp_info[ci].v_samp_factor = 1; } } return TRUE; }