fix bug in MD5 sum printing
[flac.git] / src / metaflac / main.c
index ffedd3c..4f3b56a 100644 (file)
@@ -1,5 +1,5 @@
 /* metaflac - Command-line FLAC metadata editor
- * Copyright (C) 2001  Josh Coalson
+ * Copyright (C) 2001,2002  Josh Coalson
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  */
 
-/*
- * WATCHOUT - this is meant to be very lightweight an not even dependent
- * on libFLAC, so there are a couple places where FLAC__* variables are
- * duplicated here.  Look for 'DUPLICATE:' in comments.
- */
+/*@@@
+more powerful operations yet to add:
+       add a seektable, using same args as flac
+*/
 
+#if HAVE_CONFIG_H
+#  include <config.h>
+#endif
+
+#include "FLAC/assert.h"
+#include "FLAC/metadata.h"
 #include <ctype.h>
 #include <stdarg.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include "FLAC/all.h"
-
-static const char *sync_string_ = "fLaC"; /* DUPLICATE:FLAC__STREAM_SYNC_STRING */
-static const char *metadata_type_string_[] = { /* DUPLICATE:FLAC__MetaDataTypeString */
-       "STREAMINFO",
-       "PADDING",
-       "APPLICATION",
-       "SEEKTABLE"
+
+#if 0
+/*[JEC] was:#if HAVE_GETOPT_LONG*/
+/*[JEC] see flac/include/share/getopt.h as to why the change */
+#  include <getopt.h>
+#else
+#  include "share/getopt.h"
+#endif
+
+/*
+   FLAC__share__getopt format struct; note we don't use short options so we just
+   set the 'val' field to 0 everywhere to indicate a valid option.
+*/
+static struct FLAC__share__option long_options_[] = {
+       /* global options */
+    { "preserve-modtime", 0, 0, 0 },
+    { "with-filename", 0, 0, 0 },
+    { "no-filename", 0, 0, 0 },
+    { "dont-use-padding", 0, 0, 0 },
+       /* shorthand operations */
+    { "show-md5sum", 0, 0, 0 },
+    { "show-min-blocksize", 0, 0, 0 },
+    { "show-max-blocksize", 0, 0, 0 },
+    { "show-min-framesize", 0, 0, 0 },
+    { "show-max-framesize", 0, 0, 0 },
+    { "show-sample-rate", 0, 0, 0 },
+    { "show-channels", 0, 0, 0 },
+    { "show-bps", 0, 0, 0 },
+    { "show-total-samples", 0, 0, 0 },
+    { "show-vc-vendor", 0, 0, 0 },
+    { "show-vc-field", 1, 0, 0 },
+    { "remove-vc-all", 0, 0, 0 },
+    { "remove-vc-field", 1, 0, 0 },
+    { "remove-vc-firstfield", 1, 0, 0 },
+    { "set-vc-field", 1, 0, 0 },
+    { "add-padding", 1, 0, 0 },
+       /* major operations */
+    { "help", 0, 0, 0 },
+    { "list", 0, 0, 0 },
+    { "append", 0, 0, 0 },
+    { "remove", 0, 0, 0 },
+    { "remove-all", 0, 0, 0 },
+    { "merge-padding", 0, 0, 0 },
+    { "sort-padding", 0, 0, 0 },
+       /* major operation arguments */
+    { "block-number", 1, 0, 0 },
+    { "block-type", 1, 0, 0 },
+    { "except-block-type", 1, 0, 0 },
+    { "data-format", 1, 0, 0 },
+    { "application-data-format", 1, 0, 0 },
+    { "from-file", 1, 0, 0 },
+    {0, 0, 0, 0}
 };
-static const unsigned SEEKPOINT_LEN_ = 18; /* DUPLICATE:FLAC__STREAM_METADATA_SEEKPOINT_LEN */
 
-static int usage(const char *message, ...);
-static FLAC__bool list(FILE *f, FLAC__bool verbose);
-static FLAC__uint32 unpack_uint32(FLAC__byte *b, unsigned bytes);
-static FLAC__uint64 unpack_uint64(FLAC__byte *b, unsigned bytes);
-static void hexdump(const FLAC__byte *buf, unsigned bytes);
+typedef enum {
+       OP__SHOW_MD5SUM,
+       OP__SHOW_MIN_BLOCKSIZE,
+       OP__SHOW_MAX_BLOCKSIZE,
+       OP__SHOW_MIN_FRAMESIZE,
+       OP__SHOW_MAX_FRAMESIZE,
+       OP__SHOW_SAMPLE_RATE,
+       OP__SHOW_CHANNELS,
+       OP__SHOW_BPS,
+       OP__SHOW_TOTAL_SAMPLES,
+       OP__SHOW_VC_VENDOR,
+       OP__SHOW_VC_FIELD,
+       OP__REMOVE_VC_ALL,
+       OP__REMOVE_VC_FIELD,
+       OP__REMOVE_VC_FIRSTFIELD,
+       OP__SET_VC_FIELD,
+       OP__ADD_PADDING,
+       OP__LIST,
+       OP__APPEND,
+       OP__REMOVE,
+       OP__REMOVE_ALL,
+       OP__MERGE_PADDING,
+       OP__SORT_PADDING
+} OperationType;
+
+typedef enum {
+       ARG__BLOCK_NUMBER,
+       ARG__BLOCK_TYPE,
+       ARG__EXCEPT_BLOCK_TYPE,
+       ARG__DATA_FORMAT,
+       ARG__FROM_FILE
+} ArgumentType;
+
+typedef struct {
+       char *field_name;
+} Argument_VcFieldName;
+
+typedef struct {
+       char *field; /* the whole field as passed on the command line, i.e. "NAME=VALUE" */
+       char *field_name;
+       /* according to the vorbis spec, field values can contain \0 so simple C strings are not enough here */
+       unsigned field_value_length;
+       char *field_value;
+} Argument_VcField;
+
+typedef struct {
+       unsigned num_entries;
+       unsigned *entries;
+} Argument_BlockNumber;
+
+typedef struct {
+       FLAC__MetadataType type;
+       char application_id[4]; /* only relevant if type == FLAC__STREAM_METADATA_TYPE_APPLICATION */
+       FLAC__bool filter_application_by_id;
+} Argument_BlockTypeEntry;
+
+typedef struct {
+       unsigned num_entries;
+       Argument_BlockTypeEntry *entries;
+} Argument_BlockType;
+
+typedef struct {
+       FLAC__bool is_binary;
+} Argument_DataFormat;
+
+typedef struct {
+       char *file_name;
+} Argument_FromFile;
+
+typedef struct {
+       unsigned length;
+} Argument_AddPadding;
+
+typedef struct {
+       OperationType type;
+       union {
+               Argument_VcFieldName show_vc_field;
+               Argument_VcFieldName remove_vc_field;
+               Argument_VcFieldName remove_vc_firstfield;
+               Argument_VcField set_vc_field;
+               Argument_AddPadding add_padding;
+       } argument;
+} Operation;
+
+typedef struct {
+       ArgumentType type;
+       union {
+               Argument_BlockNumber block_number;
+               Argument_BlockType block_type;
+               Argument_DataFormat data_format;
+               Argument_FromFile from_file;
+       } value;
+} Argument;
+
+typedef struct {
+       FLAC__bool preserve_modtime;
+       FLAC__bool prefix_with_filename;
+       FLAC__bool use_padding;
+       FLAC__bool show_long_help;
+       FLAC__bool application_data_format_is_hexdump;
+       struct {
+               Operation *operations;
+               unsigned num_operations;
+               unsigned capacity;
+       } ops;
+       struct {
+               struct {
+                       unsigned num_shorthand_ops;
+                       unsigned num_major_ops;
+                       FLAC__bool has_block_type;
+                       FLAC__bool has_except_block_type;
+               } checks;
+               Argument *arguments;
+               unsigned num_arguments;
+               unsigned capacity;
+       } args;
+       unsigned num_files;
+       char **filenames;
+} CommandLineOptions;
+
+static void die(const char *message);
+static void init_options(CommandLineOptions *options);
+static FLAC__bool parse_options(int argc, char *argv[], CommandLineOptions *options);
+static FLAC__bool parse_option(int option_index, const char *option_argument, CommandLineOptions *options);
+static void free_options(CommandLineOptions *options);
+static void append_new_operation(CommandLineOptions *options, Operation operation);
+static void append_new_argument(CommandLineOptions *options, Argument argument);
+static Operation *append_major_operation(CommandLineOptions *options, OperationType type);
+static Operation *append_shorthand_operation(CommandLineOptions *options, OperationType type);
+static Argument *append_argument(CommandLineOptions *options, ArgumentType type);
+static int short_usage(const char *message, ...);
+static int long_usage(const char *message, ...);
+static char *local_strdup(const char *source);
+static FLAC__bool parse_vorbis_comment_field(const char *field_ref, char **field, char **name, char **value, unsigned *length);
+static FLAC__bool parse_add_padding(const char *in, unsigned *out);
+static FLAC__bool parse_block_number(const char *in, Argument_BlockNumber *out);
+static FLAC__bool parse_block_type(const char *in, Argument_BlockType *out);
+static FLAC__bool parse_data_format(const char *in, Argument_DataFormat *out);
+static FLAC__bool parse_application_data_format(const char *in, FLAC__bool *out);
+static FLAC__bool do_operations(const CommandLineOptions *options);
+static FLAC__bool do_major_operation(const CommandLineOptions *options);
+static FLAC__bool do_major_operation_on_file(const char *filename, const CommandLineOptions *options);
+static FLAC__bool do_major_operation__list(const char *filename, FLAC__Metadata_Chain *chain, const CommandLineOptions *options);
+static FLAC__bool do_major_operation__append(FLAC__Metadata_Chain *chain, const CommandLineOptions *options);
+static FLAC__bool do_major_operation__remove(FLAC__Metadata_Chain *chain, const CommandLineOptions *options);
+static FLAC__bool do_major_operation__remove_all(FLAC__Metadata_Chain *chain, const CommandLineOptions *options);
+static FLAC__bool do_shorthand_operations(const CommandLineOptions *options);
+static FLAC__bool do_shorthand_operations_on_file(const char *fielname, const CommandLineOptions *options);
+static FLAC__bool do_shorthand_operation(const char *filename, FLAC__Metadata_Chain *chain, const Operation *operation, FLAC__bool *needs_write);
+static FLAC__bool do_shorthand_operation__add_padding(FLAC__Metadata_Chain *chain, unsigned length, FLAC__bool *needs_write);
+static FLAC__bool do_shorthand_operation__streaminfo(const char *filename, FLAC__Metadata_Chain *chain, OperationType op);
+static FLAC__bool do_shorthand_operation__vorbis_comment(const char *filename, FLAC__Metadata_Chain *chain, const Operation *operation, FLAC__bool *needs_write);
+static FLAC__bool passes_filter(const CommandLineOptions *options, const FLAC__StreamMetadata *block, unsigned block_number);
+static void write_metadata(const char *filename, FLAC__StreamMetadata *block, unsigned block_number, FLAC__bool hexdump_application);
+static void write_vc_field(const char *filename, const FLAC__StreamMetadata_VorbisComment_Entry *entry);
+static void write_vc_fields(const char *filename, const char *field_name, const FLAC__StreamMetadata_VorbisComment_Entry entry[], unsigned num_entries);
+static FLAC__bool remove_vc_all(FLAC__StreamMetadata *block, FLAC__bool *needs_write);
+static FLAC__bool remove_vc_field(FLAC__StreamMetadata *block, const char *field_name, FLAC__bool *needs_write);
+static FLAC__bool remove_vc_firstfield(FLAC__StreamMetadata *block, const char *field_name, FLAC__bool *needs_write);
+static FLAC__bool set_vc_field(FLAC__StreamMetadata *block, const Argument_VcField *field, FLAC__bool *needs_write);
+static FLAC__bool field_name_matches_entry(const char *field_name, unsigned field_name_length, const FLAC__StreamMetadata_VorbisComment_Entry *entry);
+static void hexdump(const char *filename, const FLAC__byte *buf, unsigned bytes, const char *indent);
 
 int main(int argc, char *argv[])
 {
-       int i;
-       FLAC__bool verbose = false, list_mode = true;
+       CommandLineOptions options;
+       int ret = 0;
 
-       if(argc <= 1)
-               return usage(0);
+       init_options(&options);
 
-       /* get the options */
-       for(i = 1; i < argc; i++) {
-               if(argv[i][0] != '-' || argv[i][1] == 0)
-                       break;
-               if(0 == strcmp(argv[i], "-l"))
-                       list_mode = true;
-               else if(0 == strcmp(argv[i], "-v"))
-                       verbose = true;
-               else if(0 == strcmp(argv[i], "-v-"))
-                       verbose = false;
-               else {
-                       return usage("ERROR: invalid option '%s'\n", argv[i]);
+       if(parse_options(argc, argv, &options))
+               ret = !do_operations(&options);
+
+       free_options(&options);
+
+       return ret;
+}
+
+void die(const char *message)
+{
+       FLAC__ASSERT(0 != message);
+       fprintf(stderr, "ERROR: %s\n", message);
+       exit(1);
+}
+
+void init_options(CommandLineOptions *options)
+{
+       options->preserve_modtime = false;
+
+       /* '2' is hack to mean "use default if not forced on command line" */
+       FLAC__ASSERT(true != 2);
+       options->prefix_with_filename = 2;
+
+       options->use_padding = true;
+       options->show_long_help = false;
+       options->application_data_format_is_hexdump = false;
+
+       options->ops.operations = 0;
+       options->ops.num_operations = 0;
+       options->ops.capacity = 0;
+
+       options->args.arguments = 0;
+       options->args.num_arguments = 0;
+       options->args.capacity = 0;
+
+       options->args.checks.num_shorthand_ops = 0;
+       options->args.checks.num_major_ops = 0;
+       options->args.checks.has_block_type = false;
+       options->args.checks.has_except_block_type = false;
+
+       options->num_files = 0;
+       options->filenames = 0;
+}
+
+FLAC__bool parse_options(int argc, char *argv[], CommandLineOptions *options)
+{
+    int ret;
+    int option_index = 1;
+       FLAC__bool had_error = false;
+
+    while ((ret = FLAC__share__getopt_long(argc, argv, "", long_options_, &option_index)) != -1) {
+        switch (ret) {
+            case 0:
+                               had_error |= !parse_option(option_index, FLAC__share__optarg, options);
+                break;
+                       case '?':
+                       case ':':
+                had_error = true;
+                break;
+            default:
+                               FLAC__ASSERT(0);
+                               break;
+        }
+    }
+
+       if(options->prefix_with_filename == 2)
+               options->prefix_with_filename = (argc - FLAC__share__optind > 1);
+
+       if(FLAC__share__optind >= argc && !options->show_long_help) {
+               fprintf(stderr,"ERROR: you must specify at least one FLAC file;\n");
+               fprintf(stderr,"       metaflac cannot be used as a pipe\n");
+               had_error = true;
+       }
+
+       options->num_files = argc - FLAC__share__optind;
+
+       if(options->num_files > 0) {
+               unsigned i = 0;
+               if(0 == (options->filenames = malloc(sizeof(char *) * options->num_files)))
+                       die("out of memory allocating space for file names list");
+               while(FLAC__share__optind < argc)
+                       options->filenames[i++] = local_strdup(argv[FLAC__share__optind++]);
+       }
+
+       if(options->args.checks.num_major_ops > 0) {
+               if(options->args.checks.num_major_ops > 1) {
+                       fprintf(stderr, "ERROR: you may only specify one major operation at a time\n");
+                       had_error = true;
+               }
+               else if(options->args.checks.num_shorthand_ops > 0) {
+                       fprintf(stderr, "ERROR: you may not mix shorthand and major operations\n");
+                       had_error = true;
                }
        }
-       if(i + (list_mode? 1:2) != argc)
-               return usage("ERROR: invalid arguments (more/less than %d filename%s?)\n", (list_mode? 1:2), (list_mode? "":"s"));
 
-       if(list_mode) {
-               FILE *f = fopen(argv[i], "r");
+       if(options->args.checks.has_block_type && options->args.checks.has_except_block_type) {
+               fprintf(stderr, "ERROR: you may not specify both '--block-type' and '--except-block-type'\n");
+               had_error = true;
+       }
+
+       if(had_error)
+               short_usage(0);
+
+       return !had_error;
+}
+
+FLAC__bool parse_option(int option_index, const char *option_argument, CommandLineOptions *options)
+{
+       const char *opt = long_options_[option_index].name;
+       Operation *op;
+       Argument *arg;
+       FLAC__bool ok = true;
 
-               if(0 == f) {
-                       fprintf(stderr, "ERROR opening %s\n", argv[i]);
-                       return 1;
+    if(0 == strcmp(opt, "preserve-modtime")) {
+               options->preserve_modtime = true;
+       }
+    else if(0 == strcmp(opt, "with-filename")) {
+               options->prefix_with_filename = true;
+       }
+    else if(0 == strcmp(opt, "no-filename")) {
+               options->prefix_with_filename = false;
+       }
+    else if(0 == strcmp(opt, "dont-use-padding")) {
+               options->use_padding = false;
+       }
+    else if(0 == strcmp(opt, "show-md5sum")) {
+               (void) append_shorthand_operation(options, OP__SHOW_MD5SUM);
+       }
+    else if(0 == strcmp(opt, "show-min-blocksize")) {
+               (void) append_shorthand_operation(options, OP__SHOW_MIN_BLOCKSIZE);
+       }
+    else if(0 == strcmp(opt, "show-max-blocksize")) {
+               (void) append_shorthand_operation(options, OP__SHOW_MAX_BLOCKSIZE);
+       }
+    else if(0 == strcmp(opt, "show-min-framesize")) {
+               (void) append_shorthand_operation(options, OP__SHOW_MIN_FRAMESIZE);
+       }
+    else if(0 == strcmp(opt, "show-max-framesize")) {
+               (void) append_shorthand_operation(options, OP__SHOW_MAX_FRAMESIZE);
+       }
+    else if(0 == strcmp(opt, "show-sample-rate")) {
+               (void) append_shorthand_operation(options, OP__SHOW_SAMPLE_RATE);
+       }
+    else if(0 == strcmp(opt, "show-channels")) {
+               (void) append_shorthand_operation(options, OP__SHOW_CHANNELS);
+       }
+    else if(0 == strcmp(opt, "show-bps")) {
+               (void) append_shorthand_operation(options, OP__SHOW_BPS);
+       }
+    else if(0 == strcmp(opt, "show-total-samples")) {
+               (void) append_shorthand_operation(options, OP__SHOW_TOTAL_SAMPLES);
+       }
+    else if(0 == strcmp(opt, "show-vc-vendor")) {
+               (void) append_shorthand_operation(options, OP__SHOW_VC_VENDOR);
+       }
+    else if(0 == strcmp(opt, "show-vc-field")) {
+               op = append_shorthand_operation(options, OP__SHOW_VC_FIELD);
+               FLAC__ASSERT(0 != option_argument);
+               op->argument.show_vc_field.field_name = local_strdup(option_argument);
+       }
+    else if(0 == strcmp(opt, "remove-vc-all")) {
+               (void) append_shorthand_operation(options, OP__REMOVE_VC_ALL);
+       }
+    else if(0 == strcmp(opt, "remove-vc-field")) {
+               op = append_shorthand_operation(options, OP__REMOVE_VC_FIELD);
+               FLAC__ASSERT(0 != option_argument);
+               op->argument.remove_vc_field.field_name = local_strdup(option_argument);
+       }
+    else if(0 == strcmp(opt, "remove-vc-firstfield")) {
+               op = append_shorthand_operation(options, OP__REMOVE_VC_FIRSTFIELD);
+               FLAC__ASSERT(0 != option_argument);
+               op->argument.remove_vc_firstfield.field_name = local_strdup(option_argument);
+       }
+    else if(0 == strcmp(opt, "set-vc-field")) {
+               op = append_shorthand_operation(options, OP__SET_VC_FIELD);
+               FLAC__ASSERT(0 != option_argument);
+               if(!parse_vorbis_comment_field(option_argument, &(op->argument.set_vc_field.field), &(op->argument.set_vc_field.field_name), &(op->argument.set_vc_field.field_value), &(op->argument.set_vc_field.field_value_length))) {
+                       fprintf(stderr, "ERROR: malformed vorbis comment field \"%s\"\n", option_argument);
+                       ok = false;
+               }
+       }
+    else if(0 == strcmp(opt, "add-padding")) {
+               op = append_shorthand_operation(options, OP__ADD_PADDING);
+               FLAC__ASSERT(0 != option_argument);
+               if(!parse_add_padding(option_argument, &(op->argument.add_padding.length))) {
+                       fprintf(stderr, "ERROR: illegal length \"%s\", length must be >= 0 and < 2^%u\n", option_argument, FLAC__STREAM_METADATA_LENGTH_LEN);
+                       ok = false;
+               }
+       }
+    else if(0 == strcmp(opt, "help")) {
+               options->show_long_help = true;
+       }
+    else if(0 == strcmp(opt, "list")) {
+               (void) append_major_operation(options, OP__LIST);
+       }
+    else if(0 == strcmp(opt, "append")) {
+               (void) append_major_operation(options, OP__APPEND);
+       }
+    else if(0 == strcmp(opt, "remove")) {
+               (void) append_major_operation(options, OP__REMOVE);
+       }
+    else if(0 == strcmp(opt, "remove-all")) {
+               (void) append_major_operation(options, OP__REMOVE_ALL);
+       }
+    else if(0 == strcmp(opt, "merge-padding")) {
+               (void) append_major_operation(options, OP__MERGE_PADDING);
+       }
+    else if(0 == strcmp(opt, "sort-padding")) {
+               (void) append_major_operation(options, OP__SORT_PADDING);
+       }
+    else if(0 == strcmp(opt, "block-number")) {
+               arg = append_argument(options, ARG__BLOCK_NUMBER);
+               FLAC__ASSERT(0 != option_argument);
+               if(!parse_block_number(option_argument, &(arg->value.block_number))) {
+                       fprintf(stderr, "ERROR: malformed block number specification \"%s\"\n", option_argument);
+                       ok = false;
+               }
+       }
+    else if(0 == strcmp(opt, "block-type")) {
+               arg = append_argument(options, ARG__BLOCK_TYPE);
+               FLAC__ASSERT(0 != option_argument);
+               if(!parse_block_type(option_argument, &(arg->value.block_type))) {
+                       fprintf(stderr, "ERROR: malformed block type specification \"%s\"\n", option_argument);
+                       ok = false;
+               }
+               options->args.checks.has_block_type = true;
+       }
+    else if(0 == strcmp(opt, "except-block-type")) {
+               arg = append_argument(options, ARG__EXCEPT_BLOCK_TYPE);
+               FLAC__ASSERT(0 != option_argument);
+               if(!parse_block_type(option_argument, &(arg->value.block_type))) {
+                       fprintf(stderr, "ERROR: malformed block type specification \"%s\"\n", option_argument);
+                       ok = false;
+               }
+               options->args.checks.has_except_block_type = true;
+       }
+    else if(0 == strcmp(opt, "data-format")) {
+               arg = append_argument(options, ARG__DATA_FORMAT);
+               FLAC__ASSERT(0 != option_argument);
+               if(!parse_data_format(option_argument, &(arg->value.data_format))) {
+                       fprintf(stderr, "ERROR: illegal data format \"%s\"\n", option_argument);
+                       ok = false;
+               }
+       }
+    else if(0 == strcmp(opt, "application-data-format")) {
+               FLAC__ASSERT(0 != option_argument);
+               if(!parse_application_data_format(option_argument, &(options->application_data_format_is_hexdump))) {
+                       fprintf(stderr, "ERROR: illegal application data format \"%s\"\n", option_argument);
+                       ok = false;
                }
+       }
+    else if(0 == strcmp(opt, "from-file")) {
+               arg = append_argument(options, ARG__FROM_FILE);
+               FLAC__ASSERT(0 != option_argument);
+               arg->value.from_file.file_name = local_strdup(option_argument);
+       }
+       else {
+               FLAC__ASSERT(0);
+       }
+
+       return ok;
+}
+
+void free_options(CommandLineOptions *options)
+{
+       unsigned i;
+       Operation *op;
+       Argument *arg;
 
-               if(!list(f, verbose))
-                       return 1;
+       FLAC__ASSERT(0 == options->ops.operations || options->ops.num_operations > 0);
+       FLAC__ASSERT(0 == options->args.arguments || options->args.num_arguments > 0);
 
-               fclose(f);
+       for(i = 0, op = options->ops.operations; i < options->ops.num_operations; i++, op++) {
+               switch(op->type) {
+                       case OP__SHOW_VC_FIELD:
+                       case OP__REMOVE_VC_FIELD:
+                       case OP__REMOVE_VC_FIRSTFIELD:
+                               if(0 != op->argument.show_vc_field.field_name)
+                                       free(op->argument.show_vc_field.field_name);
+                               break;
+                       case OP__SET_VC_FIELD:
+                               if(0 != op->argument.set_vc_field.field)
+                                       free(op->argument.set_vc_field.field);
+                               if(0 != op->argument.set_vc_field.field_name)
+                                       free(op->argument.set_vc_field.field_name);
+                               if(0 != op->argument.set_vc_field.field_value)
+                                       free(op->argument.set_vc_field.field_value);
+                               break;
+                       default:
+                               break;
+               }
        }
 
-       return 0;
+       for(i = 0, arg = options->args.arguments; i < options->args.num_arguments; i++, arg++) {
+               switch(arg->type) {
+                       case ARG__BLOCK_NUMBER:
+                               if(0 != arg->value.block_number.entries)
+                                       free(arg->value.block_number.entries);
+                               break;
+                       case ARG__BLOCK_TYPE:
+                       case ARG__EXCEPT_BLOCK_TYPE:
+                               if(0 != arg->value.block_type.entries)
+                                       free(arg->value.block_type.entries);
+                               break;
+                       case ARG__FROM_FILE:
+                               if(0 != arg->value.from_file.file_name)
+                                       free(arg->value.from_file.file_name);
+                               break;
+                       default:
+                               break;
+               }
+       }
+
+       if(0 != options->ops.operations)
+               free(options->ops.operations);
+
+       if(0 != options->args.arguments)
+               free(options->args.arguments);
+
+       if(0 != options->filenames)
+               free(options->filenames);
+}
+
+void append_new_operation(CommandLineOptions *options, Operation operation)
+{
+       if(options->ops.capacity == 0) {
+               options->ops.capacity = 50;
+               if(0 == (options->ops.operations = malloc(sizeof(Operation) * options->ops.capacity)))
+                       die("out of memory allocating space for option list");
+               memset(options->ops.operations, 0, sizeof(Operation) * options->ops.capacity);
+       }
+       if(options->ops.capacity <= options->ops.num_operations) {
+               unsigned original_capacity = options->ops.capacity;
+               options->ops.capacity *= 4;
+               if(0 == (options->ops.operations = realloc(options->ops.operations, sizeof(Operation) * options->ops.capacity)))
+                       die("out of memory allocating space for option list");
+               memset(options->ops.operations + original_capacity, 0, sizeof(Operation) * (options->ops.capacity - original_capacity));
+       }
+
+       options->ops.operations[options->ops.num_operations++] = operation;
+}
+
+void append_new_argument(CommandLineOptions *options, Argument argument)
+{
+       if(options->args.capacity == 0) {
+               options->args.capacity = 50;
+               if(0 == (options->args.arguments = malloc(sizeof(Argument) * options->args.capacity)))
+                       die("out of memory allocating space for option list");
+               memset(options->args.arguments, 0, sizeof(Argument) * options->args.capacity);
+       }
+       if(options->args.capacity <= options->args.num_arguments) {
+               unsigned original_capacity = options->args.capacity;
+               options->args.capacity *= 4;
+               if(0 == (options->args.arguments = realloc(options->args.arguments, sizeof(Argument) * options->args.capacity)))
+                       die("out of memory allocating space for option list");
+               memset(options->args.arguments + original_capacity, 0, sizeof(Argument) * (options->args.capacity - original_capacity));
+       }
+
+       options->args.arguments[options->args.num_arguments++] = argument;
+}
+
+Operation *append_major_operation(CommandLineOptions *options, OperationType type)
+{
+       Operation op;
+       memset(&op, 0, sizeof(op));
+       op.type = type;
+       append_new_operation(options, op);
+       options->args.checks.num_major_ops++;
+       return options->ops.operations + (options->ops.num_operations - 1);
+}
+
+Operation *append_shorthand_operation(CommandLineOptions *options, OperationType type)
+{
+       Operation op;
+       memset(&op, 0, sizeof(op));
+       op.type = type;
+       append_new_operation(options, op);
+       options->args.checks.num_shorthand_ops++;
+       return options->ops.operations + (options->ops.num_operations - 1);
+}
+
+Argument *append_argument(CommandLineOptions *options, ArgumentType type)
+{
+       Argument arg;
+       memset(&arg, 0, sizeof(arg));
+       arg.type = type;
+       append_new_argument(options, arg);
+       return options->args.arguments + (options->args.num_arguments - 1);
+}
+
+static void usage_header(FILE *out)
+{
+       fprintf(out, "==============================================================================\n");
+       fprintf(out, "metaflac - Command-line FLAC metadata editor version %s\n", FLAC__VERSION_STRING);
+       fprintf(out, "Copyright (C) 2001,2002  Josh Coalson\n");
+       fprintf(out, "\n");
+       fprintf(out, "This program is free software; you can redistribute it and/or\n");
+       fprintf(out, "modify it under the terms of the GNU General Public License\n");
+       fprintf(out, "as published by the Free Software Foundation; either version 2\n");
+       fprintf(out, "of the License, or (at your option) any later version.\n");
+       fprintf(out, "\n");
+       fprintf(out, "This program is distributed in the hope that it will be useful,\n");
+       fprintf(out, "but WITHOUT ANY WARRANTY; without even the implied warranty of\n");
+       fprintf(out, "MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the\n");
+       fprintf(out, "GNU General Public License for more details.\n");
+       fprintf(out, "\n");
+       fprintf(out, "You should have received a copy of the GNU General Public License\n");
+       fprintf(out, "along with this program; if not, write to the Free Software\n");
+       fprintf(out, "Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.\n");
+       fprintf(out, "==============================================================================\n");
+}
+
+static void usage_summary(FILE *out)
+{
+    fprintf(out, "Usage:\n");
+    fprintf(out, "  metaflac [options] [operations] FLACfile [FLACfile ...]\n");
+    fprintf(out, "\n");
+    fprintf(out, "Use metaflac to list, add, remove, or edit metadata in one or more FLAC files.\n");
+    fprintf(out, "You may perform one major operation, or many shorthand operations at a time.\n");
+    fprintf(out, "\n");
+    fprintf(out, "Options:\n");
+    fprintf(out, "--preserve-modtime    Preserve the original modification time in spite of edits\n");
+    fprintf(out, "--with-filename       Prefix each output line with the FLAC file name\n");
+    fprintf(out, "                      (the default if more than one FLAC file is specified)\n");
+    fprintf(out, "--no-filename         Do not prefix each output line with the FLAC file name\n");
+    fprintf(out, "                      (the default if only one FLAC file is specified)\n");
+    fprintf(out, "--dont-use-padding    By default metaflac tries to use padding where possible\n");
+    fprintf(out, "                      to avoid rewriting the entire file if the metadata size\n");
+    fprintf(out, "                      changes.  Use this option to tell metaflac to not take\n");
+    fprintf(out, "                      advantage of padding this way.\n");
 }
 
-int usage(const char *message, ...)
+int short_usage(const char *message, ...)
 {
        va_list args;
 
@@ -98,192 +700,959 @@ int usage(const char *message, ...)
                va_end(args);
 
        }
-       printf("==============================================================================\n");
-       printf("metaflac - Command-line FLAC metadata editor version %s\n", FLAC__VERSION_STRING);
-       printf("Copyright (C) 2001  Josh Coalson\n");
-       printf("\n");
-       printf("This program is free software; you can redistribute it and/or\n");
-       printf("modify it under the terms of the GNU General Public License\n");
-       printf("as published by the Free Software Foundation; either version 2\n");
-       printf("of the License, or (at your option) any later version.\n");
-       printf("\n");
-       printf("This program is distributed in the hope that it will be useful,\n");
-       printf("but WITHOUT ANY WARRANTY; without even the implied warranty of\n");
-       printf("MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the\n");
-       printf("GNU General Public License for more details.\n");
-       printf("\n");
-       printf("You should have received a copy of the GNU General Public License\n");
-       printf("along with this program; if not, write to the Free Software\n");
-       printf("Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.\n");
-       printf("==============================================================================\n");
-       printf("Usage:\n");
-       printf("  metaflac [options] infile [outfile]\n");
-       printf("\n");
-       printf("options:\n");
-       printf("  -l : list metadata blocks\n");
-       printf("  -v : verbose\n");
+       usage_header(stderr);
+       fprintf(stderr, "\n");
+       fprintf(stderr, "This is the short help; for full help use 'metaflac --help'\n");
+       fprintf(stderr, "\n");
+       usage_summary(stderr);
+
+       return message? 1 : 0;
+}
+
+int long_usage(const char *message, ...)
+{
+       FILE *out = (message? stderr : stdout);
+       va_list args;
+
+       if(message) {
+               va_start(args, message);
+
+               (void) vfprintf(stderr, message, args);
+
+               va_end(args);
+
+       }
+       usage_header(out);
+    fprintf(out, "\n");
+       usage_summary(out);
+    fprintf(out, "\n");
+    fprintf(out, "Shorthand operations:\n");
+    fprintf(out, "--show-md5sum         Show the MD5 signature from the STREAMINFO block.\n");
+    fprintf(out, "--show-min-blocksize  Show the minimum block size from the STREAMINFO block.\n");
+    fprintf(out, "--show-max-blocksize  Show the maximum block size from the STREAMINFO block.\n");
+    fprintf(out, "--show-min-framesize  Show the minimum frame size from the STREAMINFO block.\n");
+    fprintf(out, "--show-max-framesize  Show the maximum frame size from the STREAMINFO block.\n");
+    fprintf(out, "--show-sample-rate    Show the sample rate from the STREAMINFO block.\n");
+    fprintf(out, "--show-channels       Show the number of channels from the STREAMINFO block.\n");
+    fprintf(out, "--show-bps            Show the # of bits per sample from the STREAMINFO block.\n");
+    fprintf(out, "--show-total-samples  Show the total # of samples from the STREAMINFO block.\n");
+    fprintf(out, "\n");
+    fprintf(out, "--show-vc-vendor      Show the vendor string from the VORBIS_COMMENT block.\n");
+    fprintf(out, "--show-vc-field=name  Show all Vorbis comment fields where the the field name\n");
+    fprintf(out, "                      matches 'name'.\n");
+    fprintf(out, "--remove-vc-field=name\n");
+    fprintf(out, "                      Remove all Vorbis comment fields whose field name is\n");
+    fprintf(out, "                      'name'.\n");
+    fprintf(out, "--remove-vc-firstfield=name\n");
+    fprintf(out, "                      Remove first Vorbis comment field whose field name is\n");
+    fprintf(out, "                      'name'.\n");
+    fprintf(out, "--remove-vc-all       Remove all Vorbis comment fields, leaving only the\n");
+    fprintf(out, "                      vendor string in the VORBIS_COMMENT block.\n");
+    fprintf(out, "--set-vc-field=field  Add a Vorbis comment field.  The field must comply with\n");
+    fprintf(out, "                      the Vorbis comment spec, of the form \"NAME=VALUE\".  If\n");
+    fprintf(out, "                      there is currently no VORBIS_COMMENT block, one will be\n");
+    fprintf(out, "                      created.\n");
+    fprintf(out, "--add-padding=length  Add a padding block of the given length (in bytes).\n");
+    fprintf(out, "                      The overall length of the new block will be 4 + length;\n");
+    fprintf(out, "                      the extra 4 bytes is for the metadata block header.\n");
+    fprintf(out, "\n");
+    fprintf(out, "Major operations:\n");
+    fprintf(out, "--list\n");
+    fprintf(out, "    List the contents of one or more metadata blocks to stdout.  By default,\n");
+    fprintf(out, "    all metadata blocks are listed in text format.  Use the following options\n");
+    fprintf(out, "    to change this behavior:\n");
+    fprintf(out, "\n");
+    fprintf(out, "    --block-number=#[,#[...]]\n");
+    fprintf(out, "    An optional comma-separated list of block numbers to display.  The first\n");
+    fprintf(out, "    block, the STREAMINFO block, is block 0.\n");
+    fprintf(out, "\n");
+    fprintf(out, "    --block-type=type[,type[...]]\n");
+    fprintf(out, "    --except-block-type=type[,type[...]]\n");
+    fprintf(out, "    An optional comma-separated list of block types to included or ignored\n");
+    fprintf(out, "    with this option.  Use only one of --block-type or --except-block-type.\n");
+    fprintf(out, "    The valid block types are: STREAMINFO, PADDING, APPLICATION, SEEKTABLE,\n");
+    fprintf(out, "    VORBIS_COMMENT.  You may narrow down the types of APPLICATION blocks\n");
+    fprintf(out, "    displayed as follows:\n");
+    fprintf(out, "        APPLICATION:abcd        The APPLICATION block(s) whose textual repre-\n");
+    fprintf(out, "                                sentation of the 4-byte ID is \"abcd\"\n");
+    fprintf(out, "        APPLICATION:0xXXXXXXXX  The APPLICATION block(s) whose hexadecimal big-\n");
+    fprintf(out, "                                endian representation of the 4-byte ID is\n");
+    fprintf(out, "                                \"0xXXXXXXXX\".  For the example \"abcd\" above the\n");
+    fprintf(out, "                                hexadecimal equivalalent is 0x61626364\n");
+    fprintf(out, "\n");
+    fprintf(out, "    NOTE: if both --block-number and --[except-]block-type are specified,\n");
+    fprintf(out, "          the result is the logical AND of both arguments.\n");
+    fprintf(out, "\n");
+#if 0
+       /*@@@ not implemented yet */
+    fprintf(out, "    --data-format=binary|text\n");
+    fprintf(out, "    By default a human-readable text representation of the data is displayed.\n");
+    fprintf(out, "    You may specify --data-format=binary to dump the raw binary form of each\n");
+    fprintf(out, "    metadata block.  The output can be read in using a subsequent call to\n");
+    fprintf(out, "    "metaflac --append --from-file=..."\n");
+    fprintf(out, "\n");
+#endif
+    fprintf(out, "    --application-data-format=hexdump|text\n");
+    fprintf(out, "    If the application block you are displaying contains binary data but your\n");
+    fprintf(out, "    --data-format=text, you can display a hex dump of the application data\n");
+    fprintf(out, "    contents instead using --application-data-format=hexdump\n");
+    fprintf(out, "\n");
+#if 0
+       /*@@@ not implemented yet */
+    fprintf(out, "--append\n");
+    fprintf(out, "    Insert a metadata block from a file.  The input file must be in the same\n");
+    fprintf(out, "    format as generated with --list.\n");
+    fprintf(out, "\n");
+    fprintf(out, "    --block-number=#\n");
+    fprintf(out, "    Specify the insertion point (defaults to last block).  The new block will\n");
+    fprintf(out, "    be added after the given block number.  This prevents the illegal insertion\n");
+    fprintf(out, "    of a block before the first STREAMINFO block.  You may not --append another\n");
+    fprintf(out, "    STREAMINFO block.\n");
+    fprintf(out, "\n");
+    fprintf(out, "    --from-file=filename\n");
+    fprintf(out, "    Mandatory 'option' to specify the input file containing the block contents.\n");
+    fprintf(out, "\n");
+    fprintf(out, "    --data-format=binary|text\n");
+    fprintf(out, "    By default the block contents are assumed to be in binary format.  You can\n");
+    fprintf(out, "    override this by specifying --data-format=text\n");
+    fprintf(out, "\n");
+#endif
+    fprintf(out, "--remove\n");
+    fprintf(out, "    Remove one or more metadata blocks from the metadata.  Unless\n");
+    fprintf(out, "    --dont-use-padding is specified, the blocks will be replaced with padding.\n");
+    fprintf(out, "    You may not remove the STREAMINFO block.\n");
+    fprintf(out, "\n");
+    fprintf(out, "    --block-number=#[,#[...]]\n");
+    fprintf(out, "    --block-type=type[,type[...]]\n");
+    fprintf(out, "    --except-block-type=type[,type[...]]\n");
+    fprintf(out, "    See --list above for usage.\n");
+    fprintf(out, "\n");
+    fprintf(out, "    NOTE: if both --block-number and --[except-]block-type are specified,\n");
+    fprintf(out, "          the result is the logical AND of both arguments.\n");
+    fprintf(out, "\n");
+    fprintf(out, "--remove-all\n");
+    fprintf(out, "    Remove all metadata blocks (except the STREAMINFO block) from the\n");
+    fprintf(out, "    metadata.  Unless --dont-use-padding is specified, the blocks will be\n");
+    fprintf(out, "    replaced with padding.\n");
+    fprintf(out, "\n");
+    fprintf(out, "--merge-padding\n");
+    fprintf(out, "    Merge adjacent PADDING blocks into single blocks.\n");
+    fprintf(out, "\n");
+    fprintf(out, "--sort-padding\n");
+    fprintf(out, "    Move all PADDING blocks to the end of the metadata and merge them into a\n");
+    fprintf(out, "    single block.\n");
 
-       return 1;
+       return message? 1 : 0;
 }
 
-FLAC__bool list(FILE *f, FLAC__bool verbose)
+char *local_strdup(const char *source)
 {
-       FLAC__byte buf[65536];
-       FLAC__byte *b = buf;
-       FLAC__StreamMetaData metadata;
-       unsigned blocknum = 0, byte_offset = 0, i;
+       char *ret;
+       FLAC__ASSERT(0 != source);
+       if(0 == (ret = strdup(source)))
+               die("out of memory during strdup()");
+       return ret;
+}
+
+FLAC__bool parse_vorbis_comment_field(const char *field_ref, char **field, char **name, char **value, unsigned *length)
+{
+       char *p, *s;
+
+       if(0 != field)
+               *field = local_strdup(field_ref);
+
+       s = local_strdup(field_ref);
 
-       /* read the stream sync code */
-       if(fread(buf, 1, 4, f) < 4 || memcmp(buf, sync_string_, 4)) {
-               fprintf(stderr, "ERROR: not a FLAC file (no '%s' header)\n", sync_string_);
+       if(0 == (p = strchr(s, '='))) {
+               free(s);
                return false;
        }
-       byte_offset += 4;
+       *p++ = '\0';
+       *name = local_strdup(s);
+       *value = local_strdup(p);
+       *length = strlen(p);
 
-       /* read the metadata blocks */
-       do {
-               /* read the metadata block header */
-               if(fread(buf, 1, 4, f) < 4) {
-                       fprintf(stderr, "ERROR: short count reading metadata block header\n");
+       free(s);
+       return true;
+}
+
+FLAC__bool parse_add_padding(const char *in, unsigned *out)
+{
+       *out = (unsigned)strtoul(in, 0, 10);
+       return *out < (1u << FLAC__STREAM_METADATA_LENGTH_LEN);
+}
+
+FLAC__bool parse_block_number(const char *in, Argument_BlockNumber *out)
+{
+       char *p, *q, *s, *end;
+       long i;
+       unsigned entry;
+
+       if(*in == '\0')
+               return false;
+
+       s = local_strdup(in);
+
+       /* first count the entries */
+       for(out->num_entries = 1, p = strchr(s, ','); p; out->num_entries++, p = strchr(++p, ','))
+               ;
+
+       /* make space */
+       FLAC__ASSERT(out->num_entries > 0);
+       if(0 == (out->entries = malloc(sizeof(unsigned) * out->num_entries)))
+               die("out of memory allocating space for option list");
+
+       /* load 'em up */
+       entry = 0;
+       q = s;
+       while(q) {
+               FLAC__ASSERT(entry < out->num_entries);
+               if(0 != (p = strchr(q, ',')))
+                       *p++ = '\0';
+               if(!isdigit((int)(*q)) || (i = strtol(q, &end, 10)) < 0 || *end) {
+                       free(s);
                        return false;
                }
-               metadata.is_last = (buf[0] & 0x80)? true:false;
-               metadata.type = (FLAC__MetaDataType)(buf[0] & 0x7f);
-               metadata.length = unpack_uint32(buf+1, 3);
-
-               /* print header */
-               printf("METADATA block #%u\n", blocknum);
-               printf("byte offset: %u\n", byte_offset);
-               printf("type: %u (%s)\n", (unsigned)metadata.type, metadata.type<=FLAC__METADATA_TYPE_SEEKTABLE? metadata_type_string_[metadata.type] : "UNKNOWN");
-               printf("is last: %s\n", metadata.is_last? "true":"false");
-               printf("length: %u\n", metadata.length);
-
-               if(metadata.length > sizeof(buf)) {
-                       printf("SKIPPING large block\n\n");
-                       continue;
-               }
+               out->entries[entry++] = (unsigned)i;
+               q = p;
+       }
+       FLAC__ASSERT(entry == out->num_entries);
+
+       free(s);
+       return true;
+}
+
+FLAC__bool parse_block_type(const char *in, Argument_BlockType *out)
+{
+       char *p, *q, *r, *s;
+       unsigned entry;
 
-               /* read the metadata block data */
-               if(fread(buf, 1, metadata.length, f) < metadata.length) {
-                       fprintf(stderr, "ERROR: short count reading metadata block data\n\n");
+       if(*in == '\0')
+               return false;
+
+       s = local_strdup(in);
+
+       /* first count the entries */
+       for(out->num_entries = 1, p = strchr(s, ','); p; out->num_entries++, p = strchr(++p, ','))
+               ;
+
+       /* make space */
+       FLAC__ASSERT(out->num_entries > 0);
+       if(0 == (out->entries = malloc(sizeof(Argument_BlockTypeEntry) * out->num_entries)))
+               die("out of memory allocating space for option list");
+
+       /* load 'em up */
+       entry = 0;
+       q = s;
+       while(q) {
+               FLAC__ASSERT(entry < out->num_entries);
+               if(0 != (p = strchr(q, ',')))
+                       *p++ = 0;
+               r = strchr(q, ':');
+               if(r)
+                       *r++ = '\0';
+               if(0 != r && 0 != strcmp(q, "APPLICATION")) {
+                       free(s);
                        return false;
                }
-               switch(metadata.type) {
-                       case FLAC__METADATA_TYPE_STREAMINFO:
-                               b = buf;
-                               metadata.data.stream_info.min_blocksize = unpack_uint32(b, 2); b += 2;
-                               metadata.data.stream_info.max_blocksize = unpack_uint32(b, 2); b += 2;
-                               metadata.data.stream_info.min_framesize = unpack_uint32(b, 3); b += 3;
-                               metadata.data.stream_info.max_framesize = unpack_uint32(b, 3); b += 3;
-                               metadata.data.stream_info.sample_rate = (unpack_uint32(b, 2) << 4) | ((unsigned)(b[2] & 0xf0) >> 4);
-                               metadata.data.stream_info.channels = (unsigned)((b[2] & 0x0e) >> 1) + 1;
-                               metadata.data.stream_info.bits_per_sample = ((((unsigned)(b[2] & 0x01)) << 1) | (((unsigned)(b[3] & 0xf0)) >> 4)) + 1;
-                               metadata.data.stream_info.total_samples = (((FLAC__uint64)(b[3] & 0x0f)) << 32) | unpack_uint64(b+4, 4);
-                               memcpy(metadata.data.stream_info.md5sum, b+8, 16);
-                               break;
-                       case FLAC__METADATA_TYPE_PADDING:
-                               if(verbose) {
-                                       /* dump contents */
-                               }
-                               break;
-                       case FLAC__METADATA_TYPE_APPLICATION:
-                               memcpy(buf, metadata.data.application.id, 4);
-                               metadata.data.application.data = buf+4;
-                               break;
-                       case FLAC__METADATA_TYPE_SEEKTABLE:
-                               metadata.data.seek_table.num_points = metadata.length / SEEKPOINT_LEN_;
-                               b = buf; /* we leave the points in buf for printing later */
-                               break;
-                       default:
-                               printf("SKIPPING block of unknown type\n\n");
-                               continue;
+               if(0 == strcmp(q, "STREAMINFO")) {
+                       out->entries[entry++].type = FLAC__METADATA_TYPE_STREAMINFO;
                }
-
-               /* print data */
-               switch(metadata.type) {
-                       case FLAC__METADATA_TYPE_STREAMINFO:
-                               printf("minumum blocksize: %u samples\n", metadata.data.stream_info.min_blocksize);
-                               printf("maximum blocksize: %u samples\n", metadata.data.stream_info.max_blocksize);
-                               printf("minimum framesize: %u bytes\n", metadata.data.stream_info.min_framesize);
-                               printf("maximum framesize: %u bytes\n", metadata.data.stream_info.max_framesize);
-                               printf("sample_rate: %u Hz\n", metadata.data.stream_info.sample_rate);
-                               printf("channels: %u\n", metadata.data.stream_info.channels);
-                               printf("bits-per-sample: %u\n", metadata.data.stream_info.bits_per_sample);
-                               printf("total samples: %llu\n", metadata.data.stream_info.total_samples);
-                               printf("MD5 signature: ");
-                               for(i = 0; i < 16; i++)
-                                       printf("%02x", metadata.data.stream_info.md5sum[i]);
-                               printf("\n");
-                               break;
-                       case FLAC__METADATA_TYPE_PADDING:
-                               if(verbose) {
-                                       printf("pad contents:\n");
-                                       hexdump(buf, metadata.length);
+               else if(0 == strcmp(q, "PADDING")) {
+                       out->entries[entry++].type = FLAC__METADATA_TYPE_PADDING;
+               }
+               else if(0 == strcmp(q, "APPLICATION")) {
+                       out->entries[entry].type = FLAC__METADATA_TYPE_APPLICATION;
+                       out->entries[entry].filter_application_by_id = (0 != r);
+                       if(0 != r) {
+                               if(strlen(r) == 4) {
+                                       strcpy(out->entries[entry].application_id, r);
                                }
-                               break;
-                       case FLAC__METADATA_TYPE_APPLICATION:
-                               printf("Application ID: ");
-                               for(i = 0; i < 4; i++)
-                                       printf("%02x", metadata.data.application.id[i]);
-                               printf("\n");
-                               if(verbose) {
-                                       printf("data contents:\n");
-                                       hexdump(metadata.data.application.data, metadata.length);
+                               else if(strlen(r) == 10 && strncmp(r, "0x", 2) == 0 && strspn(r+2, "0123456789ABCDEFabcdef") == 8) {
+                                       FLAC__uint32 x = strtoul(r+2, 0, 16);
+                                       out->entries[entry].application_id[3] = (FLAC__byte)(x & 0xff);
+                                       out->entries[entry].application_id[2] = (FLAC__byte)((x>>=8) & 0xff);
+                                       out->entries[entry].application_id[1] = (FLAC__byte)((x>>=8) & 0xff);
+                                       out->entries[entry].application_id[0] = (FLAC__byte)((x>>=8) & 0xff);
                                }
-                               break;
-                       case FLAC__METADATA_TYPE_SEEKTABLE:
-                               printf("seek points: %u\n", metadata.data.seek_table.num_points);
-                               for(i = 0; i < metadata.data.seek_table.num_points; i++, b += SEEKPOINT_LEN_) {
-                                       printf("\tpoint %d: sample_number=%llu, stream_offset=%llu, frame_samples=%u\n", i, unpack_uint64(b, 8), unpack_uint64(b+8, 8), unpack_uint32(b+16, 2));
+                               else {
+                                       free(s);
+                                       return false;
                                }
-                               break;
-                       default:
-                               FLAC__ASSERT(0);
+                       }
+                       entry++;
                }
+               else if(0 == strcmp(q, "SEEKTABLE")) {
+                       out->entries[entry++].type = FLAC__METADATA_TYPE_SEEKTABLE;
+               }
+               else if(0 == strcmp(q, "VORBIS_COMMENT")) {
+                       out->entries[entry++].type = FLAC__METADATA_TYPE_VORBIS_COMMENT;
+               }
+               else {
+                       free(s);
+                       return false;
+               }
+               q = p;
+       }
+       FLAC__ASSERT(entry == out->num_entries);
 
-               if(!metadata.is_last)
-                       printf("\n");
+       free(s);
+       return true;
+}
 
-               blocknum++;
-               byte_offset += (4 + metadata.length);
-       } while (!metadata.is_last);
+FLAC__bool parse_data_format(const char *in, Argument_DataFormat *out)
+{
+       if(0 == strcmp(in, "binary"))
+               out->is_binary = true;
+       else if(0 == strcmp(in, "text"))
+               out->is_binary = false;
+       else
+               return false;
+       return true;
+}
 
+FLAC__bool parse_application_data_format(const char *in, FLAC__bool *out)
+{
+       if(0 == strcmp(in, "hexdump"))
+               *out = true;
+       else if(0 == strcmp(in, "text"))
+               *out = false;
+       else
+               return false;
        return true;
 }
 
-FLAC__uint32 unpack_uint32(FLAC__byte *b, unsigned bytes)
+FLAC__bool do_operations(const CommandLineOptions *options)
+{
+       FLAC__bool ok = true;
+
+       if(options->show_long_help) {
+               long_usage(0);
+       }
+       else if(options->args.checks.num_major_ops > 0) {
+               FLAC__ASSERT(options->args.checks.num_shorthand_ops == 0);
+               FLAC__ASSERT(options->args.checks.num_major_ops == 1);
+               FLAC__ASSERT(options->args.checks.num_major_ops == options->ops.num_operations);
+               ok = do_major_operation(options);
+       }
+       else if(options->args.checks.num_shorthand_ops > 0) {
+               FLAC__ASSERT(options->args.checks.num_shorthand_ops == options->ops.num_operations);
+               ok = do_shorthand_operations(options);
+       }
+
+       return ok;
+}
+
+FLAC__bool do_major_operation(const CommandLineOptions *options)
 {
-       FLAC__uint32 ret = 0;
        unsigned i;
+       FLAC__bool ok = true;
 
-       for(i = 0; i < bytes; i++)
-               ret = (ret << 8) | (FLAC__uint32)(*b++);
+       /*@@@ to die after first error,  v---  add '&& ok' here */
+       for(i = 0; i < options->num_files; i++)
+               ok &= do_major_operation_on_file(options->filenames[i], options);
 
-       return ret;
+       return ok;
+}
+
+FLAC__bool do_major_operation_on_file(const char *filename, const CommandLineOptions *options)
+{
+       FLAC__bool ok = true, needs_write = false;
+       FLAC__Metadata_Chain *chain = FLAC__metadata_chain_new();
+
+       if(0 == chain)
+               die("out of memory allocating chain");
+
+       if(!FLAC__metadata_chain_read(chain, filename)) {
+               fprintf(stderr, "ERROR: reading metadata, status = \"%s\"\n", FLAC__Metadata_ChainStatusString[FLAC__metadata_chain_status(chain)]);
+               return false;
+       }
+
+       switch(options->ops.operations[0].type) {
+               case OP__LIST:
+                       ok = do_major_operation__list(options->prefix_with_filename? filename : 0, chain, options);
+                       break;
+               case OP__APPEND:
+                       ok = do_major_operation__append(chain, options);
+                       needs_write = true;
+                       break;
+               case OP__REMOVE:
+                       ok = do_major_operation__remove(chain, options);
+                       needs_write = true;
+                       break;
+               case OP__REMOVE_ALL:
+                       ok = do_major_operation__remove_all(chain, options);
+                       needs_write = true;
+                       break;
+               case OP__MERGE_PADDING:
+                       FLAC__metadata_chain_merge_padding(chain);
+                       needs_write = true;
+                       break;
+               case OP__SORT_PADDING:
+                       FLAC__metadata_chain_sort_padding(chain);
+                       needs_write = true;
+                       break;
+               default:
+                       FLAC__ASSERT(0);
+                       return false;
+       }
+
+       if(ok && needs_write) {
+               if(options->use_padding)
+                       FLAC__metadata_chain_sort_padding(chain);
+               ok = FLAC__metadata_chain_write(chain, options->use_padding, options->preserve_modtime);
+               if(!ok)
+                       fprintf(stderr, "ERROR: writing FLAC file %s, error = %s\n", filename, FLAC__Metadata_ChainStatusString[FLAC__metadata_chain_status(chain)]);
+       }
+
+       FLAC__metadata_chain_delete(chain);
+
+       return ok;
+}
+
+FLAC__bool do_major_operation__list(const char *filename, FLAC__Metadata_Chain *chain, const CommandLineOptions *options)
+{
+       FLAC__Metadata_Iterator *iterator = FLAC__metadata_iterator_new();
+       FLAC__StreamMetadata *block;
+       FLAC__bool ok = true;
+       unsigned block_number;
+
+       if(0 == iterator)
+               die("out of memory allocating iterator");
+
+       FLAC__metadata_iterator_init(iterator, chain);
+
+       block_number = 0;
+       do {
+               block = FLAC__metadata_iterator_get_block(iterator);
+               ok &= (0 != block);
+               if(!ok)
+                       fprintf(stderr, "ERROR: couldn't get block from chain\n");
+               else if(passes_filter(options, FLAC__metadata_iterator_get_block(iterator), block_number))
+                       write_metadata(filename, block, block_number, options->application_data_format_is_hexdump);
+               block_number++;
+       } while(ok && FLAC__metadata_iterator_next(iterator));
+
+       FLAC__metadata_iterator_delete(iterator);
+
+       return ok;
+}
+
+FLAC__bool do_major_operation__append(FLAC__Metadata_Chain *chain, const CommandLineOptions *options)
+{
+       (void) chain, (void) options;
+       fprintf(stderr, "ERROR: --append not implemented yet\n"); /*@@@*/
+       return false;
+}
+
+FLAC__bool do_major_operation__remove(FLAC__Metadata_Chain *chain, const CommandLineOptions *options)
+{
+       FLAC__Metadata_Iterator *iterator = FLAC__metadata_iterator_new();
+       FLAC__bool ok = true;
+       unsigned block_number;
+
+       if(0 == iterator)
+               die("out of memory allocating iterator");
+
+       FLAC__metadata_iterator_init(iterator, chain);
+
+       block_number = 0;
+       while(ok && FLAC__metadata_iterator_next(iterator)) {
+               block_number++;
+               if(passes_filter(options, FLAC__metadata_iterator_get_block(iterator), block_number)) {
+                       ok &= FLAC__metadata_iterator_delete_block(iterator, options->use_padding);
+                       if(options->use_padding)
+                               ok &= FLAC__metadata_iterator_next(iterator);
+               }
+       }
+
+       FLAC__metadata_iterator_delete(iterator);
+
+       return ok;
 }
 
-FLAC__uint64 unpack_uint64(FLAC__byte *b, unsigned bytes)
+FLAC__bool do_major_operation__remove_all(FLAC__Metadata_Chain *chain, const CommandLineOptions *options)
+{
+       FLAC__Metadata_Iterator *iterator = FLAC__metadata_iterator_new();
+       FLAC__bool ok = true;
+
+       if(0 == iterator)
+               die("out of memory allocating iterator");
+
+       FLAC__metadata_iterator_init(iterator, chain);
+
+       while(ok && FLAC__metadata_iterator_next(iterator)) {
+               ok &= FLAC__metadata_iterator_delete_block(iterator, options->use_padding);
+               if(options->use_padding)
+                       ok &= FLAC__metadata_iterator_next(iterator);
+       }
+
+       FLAC__metadata_iterator_delete(iterator);
+
+       return ok;
+}
+
+FLAC__bool do_shorthand_operations(const CommandLineOptions *options)
 {
-       FLAC__uint64 ret = 0;
        unsigned i;
+       FLAC__bool ok = true;
 
-       for(i = 0; i < bytes; i++)
-               ret = (ret << 8) | (FLAC__uint64)(*b++);
+       /*@@@ to die after first error,  v---  add '&& ok' here */
+       for(i = 0; i < options->num_files; i++)
+               ok &= do_shorthand_operations_on_file(options->filenames[i], options);
 
-       return ret;
+       return ok;
+}
+
+FLAC__bool do_shorthand_operations_on_file(const char *filename, const CommandLineOptions *options)
+{
+       unsigned i;
+       FLAC__bool ok = true, needs_write = false;
+       FLAC__Metadata_Chain *chain = FLAC__metadata_chain_new();
+
+       if(0 == chain)
+               die("out of memory allocating chain");
+
+       if(!FLAC__metadata_chain_read(chain, filename)) {
+               fprintf(stderr, "ERROR: reading metadata, status = \"%s\"\n", FLAC__Metadata_ChainStatusString[FLAC__metadata_chain_status(chain)]);
+               return false;
+       }
+
+       for(i = 0; i < options->ops.num_operations && ok; i++)
+               ok &= do_shorthand_operation(options->prefix_with_filename? filename : 0, chain, &options->ops.operations[i], &needs_write);
+
+       if(ok) {
+               if(options->use_padding)
+                       FLAC__metadata_chain_sort_padding(chain);
+               ok = FLAC__metadata_chain_write(chain, options->use_padding, options->preserve_modtime);
+               if(!ok)
+                       fprintf(stderr, "ERROR: writing FLAC file %s, error = %s\n", filename, FLAC__Metadata_ChainStatusString[FLAC__metadata_chain_status(chain)]);
+       }
+
+       FLAC__metadata_chain_delete(chain);
+
+       return ok;
+}
+
+FLAC__bool do_shorthand_operation(const char *filename, FLAC__Metadata_Chain *chain, const Operation *operation, FLAC__bool *needs_write)
+{
+       FLAC__bool ok = true;
+
+       switch(operation->type) {
+               case OP__SHOW_MD5SUM:
+               case OP__SHOW_MIN_BLOCKSIZE:
+               case OP__SHOW_MAX_BLOCKSIZE:
+               case OP__SHOW_MIN_FRAMESIZE:
+               case OP__SHOW_MAX_FRAMESIZE:
+               case OP__SHOW_SAMPLE_RATE:
+               case OP__SHOW_CHANNELS:
+               case OP__SHOW_BPS:
+               case OP__SHOW_TOTAL_SAMPLES:
+                       ok = do_shorthand_operation__streaminfo(filename, chain, operation->type);
+                       break;
+               case OP__SHOW_VC_VENDOR:
+               case OP__SHOW_VC_FIELD:
+               case OP__REMOVE_VC_ALL:
+               case OP__REMOVE_VC_FIELD:
+               case OP__REMOVE_VC_FIRSTFIELD:
+               case OP__SET_VC_FIELD:
+                       ok = do_shorthand_operation__vorbis_comment(filename, chain, operation, needs_write);
+                       break;
+               case OP__ADD_PADDING:
+                       ok = do_shorthand_operation__add_padding(chain, operation->argument.add_padding.length, needs_write);
+                       break;
+               default:
+                       ok = false;
+                       FLAC__ASSERT(0);
+                       break;
+       };
+
+       return ok;
+}
+
+FLAC__bool do_shorthand_operation__add_padding(FLAC__Metadata_Chain *chain, unsigned length, FLAC__bool *needs_write)
+{
+       FLAC__StreamMetadata *padding = 0;
+       FLAC__Metadata_Iterator *iterator = FLAC__metadata_iterator_new();
+
+       if(0 == iterator)
+               die("out of memory allocating iterator");
+
+       FLAC__metadata_iterator_init(iterator, chain);
+
+       while(FLAC__metadata_iterator_next(iterator))
+               ;
+
+       padding = FLAC__metadata_object_new(FLAC__METADATA_TYPE_PADDING);
+       if(0 == padding)
+               die("out of memory allocating PADDING block");
+
+       padding->length = length;
+
+       if(!FLAC__metadata_iterator_insert_block_after(iterator, padding)) {
+               fprintf(stderr, "ERROR: adding new PADDING block to metadata, status =\"%s\"\n", FLAC__Metadata_ChainStatusString[FLAC__metadata_chain_status(chain)]);
+               FLAC__metadata_object_delete(padding);
+               return false;
+       }
+
+       *needs_write = true;
+       return true;
+}
+
+FLAC__bool do_shorthand_operation__streaminfo(const char *filename, FLAC__Metadata_Chain *chain, OperationType op)
+{
+       unsigned i;
+       FLAC__bool ok = true;
+       FLAC__StreamMetadata *block;
+       FLAC__Metadata_Iterator *iterator = FLAC__metadata_iterator_new();
+
+       if(0 == iterator)
+               die("out of memory allocating iterator");
+
+       FLAC__metadata_iterator_init(iterator, chain);
+
+       block = FLAC__metadata_iterator_get_block(iterator);
+
+       FLAC__ASSERT(0 != block);
+       FLAC__ASSERT(block->type == FLAC__METADATA_TYPE_STREAMINFO);
+
+       if(0 != filename)
+               printf("%s:", filename);
+
+       switch(op) {
+               case OP__SHOW_MD5SUM:
+                       for(i = 0; i < 16; i++)
+                               printf("%02x", block->data.stream_info.md5sum[i]);
+                       printf("\n");
+                       break;
+               case OP__SHOW_MIN_BLOCKSIZE:
+                       printf("%u\n", block->data.stream_info.min_blocksize);
+                       break;
+               case OP__SHOW_MAX_BLOCKSIZE:
+                       printf("%u\n", block->data.stream_info.max_blocksize);
+                       break;
+               case OP__SHOW_MIN_FRAMESIZE:
+                       printf("%u\n", block->data.stream_info.min_framesize);
+                       break;
+               case OP__SHOW_MAX_FRAMESIZE:
+                       printf("%u\n", block->data.stream_info.max_framesize);
+                       break;
+               case OP__SHOW_SAMPLE_RATE:
+                       printf("%u\n", block->data.stream_info.sample_rate);
+                       break;
+               case OP__SHOW_CHANNELS:
+                       printf("%u\n", block->data.stream_info.channels);
+                       break;
+               case OP__SHOW_BPS:
+                       printf("%u\n", block->data.stream_info.bits_per_sample);
+                       break;
+               case OP__SHOW_TOTAL_SAMPLES:
+                       printf("%llu\n", block->data.stream_info.total_samples);
+                       break;
+               default:
+                       ok = false;
+                       FLAC__ASSERT(0);
+                       break;
+       };
+
+       FLAC__metadata_iterator_delete(iterator);
+
+       return ok;
+}
+
+FLAC__bool do_shorthand_operation__vorbis_comment(const char *filename, FLAC__Metadata_Chain *chain, const Operation *operation, FLAC__bool *needs_write)
+{
+       FLAC__bool ok = true, found_vc_block = false;
+       FLAC__StreamMetadata *block = 0;
+       FLAC__Metadata_Iterator *iterator = FLAC__metadata_iterator_new();
+
+       if(0 == iterator)
+               die("out of memory allocating iterator");
+
+       FLAC__metadata_iterator_init(iterator, chain);
+
+       do {
+               block = FLAC__metadata_iterator_get_block(iterator);
+               if(block->type == FLAC__METADATA_TYPE_VORBIS_COMMENT)
+                       found_vc_block = true;
+       } while(!found_vc_block && FLAC__metadata_iterator_next(iterator));
+
+       /* create a new block if necessary */
+       if(!found_vc_block && operation->type == OP__SET_VC_FIELD) {
+               block = FLAC__metadata_object_new(FLAC__METADATA_TYPE_VORBIS_COMMENT);
+               if(0 == block)
+                       die("out of memory allocating VORBIS_COMMENT block");
+               while(FLAC__metadata_iterator_next(iterator))
+                       ;
+               if(!FLAC__metadata_iterator_insert_block_after(iterator, block)) {
+                       fprintf(stderr, "ERROR: adding new VORBIS_COMMENT block to metadata, status =\"%s\"\n", FLAC__Metadata_ChainStatusString[FLAC__metadata_chain_status(chain)]);
+                       return false;
+               }
+               /* iterator is left pointing to new block */
+               FLAC__ASSERT(FLAC__metadata_iterator_get_block(iterator) == block);
+       }
+
+       FLAC__ASSERT(0 != block);
+       FLAC__ASSERT(block->type == FLAC__METADATA_TYPE_VORBIS_COMMENT);
+
+       switch(operation->type) {
+               case OP__SHOW_VC_VENDOR:
+                       write_vc_field(filename, &block->data.vorbis_comment.vendor_string);
+                       break;
+               case OP__SHOW_VC_FIELD:
+                       write_vc_fields(filename, operation->argument.show_vc_field.field_name, block->data.vorbis_comment.comments, block->data.vorbis_comment.num_comments);
+                       break;
+               case OP__REMOVE_VC_ALL:
+                       ok = remove_vc_all(block, needs_write);
+                       break;
+               case OP__REMOVE_VC_FIELD:
+                       ok = remove_vc_field(block, operation->argument.remove_vc_field.field_name, needs_write);
+                       break;
+               case OP__REMOVE_VC_FIRSTFIELD:
+                       ok = remove_vc_firstfield(block, operation->argument.remove_vc_firstfield.field_name, needs_write);
+                       break;
+               case OP__SET_VC_FIELD:
+                       ok = set_vc_field(block, &operation->argument.set_vc_field, needs_write);
+                       break;
+               default:
+                       ok = false;
+                       FLAC__ASSERT(0);
+                       break;
+       };
+
+       return ok;
+}
+
+FLAC__bool passes_filter(const CommandLineOptions *options, const FLAC__StreamMetadata *block, unsigned block_number)
+{
+       unsigned i, j;
+       FLAC__bool matches_number = false, matches_type = false;
+       FLAC__bool has_block_number_arg = false;
+
+       for(i = 0; i < options->args.num_arguments; i++) {
+               if(options->args.arguments[i].type == ARG__BLOCK_TYPE || options->args.arguments[i].type == ARG__EXCEPT_BLOCK_TYPE) {
+                       for(j = 0; j < options->args.arguments[i].value.block_type.num_entries; j++) {
+                               if(options->args.arguments[i].value.block_type.entries[j].type == block->type) {
+                                       if(block->type != FLAC__METADATA_TYPE_APPLICATION || !options->args.arguments[i].value.block_type.entries[j].filter_application_by_id || 0 == memcmp(options->args.arguments[i].value.block_type.entries[j].application_id, block->data.application.id, FLAC__STREAM_METADATA_APPLICATION_ID_LEN/8))
+                                               matches_type = true;
+                               }
+                       }
+               }
+               else if(options->args.arguments[i].type == ARG__BLOCK_NUMBER) {
+                       has_block_number_arg = true;
+                       for(j = 0; j < options->args.arguments[i].value.block_number.num_entries; j++) {
+                               if(options->args.arguments[i].value.block_number.entries[j] == block_number)
+                                       matches_number = true;
+                       }
+               }
+       }
+
+       if(!has_block_number_arg)
+               matches_number = true;
+
+       if(options->args.checks.has_block_type) {
+               FLAC__ASSERT(!options->args.checks.has_except_block_type);
+       }
+       else if(options->args.checks.has_except_block_type)
+               matches_type = !matches_type;
+       else
+               matches_type = true;
+
+       return matches_number && matches_type;
+}
+
+void write_metadata(const char *filename, FLAC__StreamMetadata *block, unsigned block_number, FLAC__bool hexdump_application)
+{
+       unsigned i;
+
+/*@@@ yuck, should do this with a varargs function or something: */
+#define PPR if(filename)printf("%s:",filename);
+       PPR; printf("METADATA block #%u\n", block_number);
+       PPR; printf("  type: %u (%s)\n", (unsigned)block->type, block->type<=FLAC__METADATA_TYPE_VORBIS_COMMENT? FLAC__MetadataTypeString[block->type] : "UNKNOWN");
+       PPR; printf("  is last: %s\n", block->is_last? "true":"false");
+       PPR; printf("  length: %u\n", block->length);
+
+       switch(block->type) {
+               case FLAC__METADATA_TYPE_STREAMINFO:
+                       PPR; printf("  minumum blocksize: %u samples\n", block->data.stream_info.min_blocksize);
+                       PPR; printf("  maximum blocksize: %u samples\n", block->data.stream_info.max_blocksize);
+                       PPR; printf("  minimum framesize: %u bytes\n", block->data.stream_info.min_framesize);
+                       PPR; printf("  maximum framesize: %u bytes\n", block->data.stream_info.max_framesize);
+                       PPR; printf("  sample_rate: %u Hz\n", block->data.stream_info.sample_rate);
+                       PPR; printf("  channels: %u\n", block->data.stream_info.channels);
+                       PPR; printf("  bits-per-sample: %u\n", block->data.stream_info.bits_per_sample);
+                       PPR; printf("  total samples: %llu\n", block->data.stream_info.total_samples);
+                       PPR; printf("  MD5 signature: ");
+                       for(i = 0; i < 16; i++) {
+                               printf("%02x", (unsigned)block->data.stream_info.md5sum[i]);
+                       }
+                       printf("\n");
+                       break;
+               case FLAC__METADATA_TYPE_PADDING:
+                       /* nothing to print */
+                       break;
+               case FLAC__METADATA_TYPE_APPLICATION:
+                       PPR; printf("  application ID: ");
+                       for(i = 0; i < 4; i++) {
+                               PPR; printf("%02x", block->data.application.id[i]);
+                       }
+                       PPR; printf("\n");
+                       PPR; printf("  data contents:\n");
+                       if(0 != block->data.application.data) {
+                               if(hexdump_application)
+                                       hexdump(filename, block->data.application.data, block->length - FLAC__STREAM_METADATA_HEADER_LENGTH, "    ");
+                               else
+                                       (void) fwrite(block->data.application.data, 1, block->length - FLAC__STREAM_METADATA_HEADER_LENGTH, stdout);
+                       }
+                       break;
+               case FLAC__METADATA_TYPE_SEEKTABLE:
+                       PPR; printf("  seek points: %u\n", block->data.seek_table.num_points);
+                       for(i = 0; i < block->data.seek_table.num_points; i++) {
+                               if(block->data.seek_table.points[i].sample_number != FLAC__STREAM_METADATA_SEEKPOINT_PLACEHOLDER) {
+                                       PPR; printf("    point %d: sample_number=%llu, stream_offset=%llu, frame_samples=%u\n", i, block->data.seek_table.points[i].sample_number, block->data.seek_table.points[i].stream_offset, block->data.seek_table.points[i].frame_samples);
+                               }
+                               else {
+                                       PPR; printf("    point %d: PLACEHOLDER\n", i);
+                               }
+                       }
+                       break;
+               case FLAC__METADATA_TYPE_VORBIS_COMMENT:
+                       PPR; printf("  vendor string: ");
+                       fwrite(block->data.vorbis_comment.vendor_string.entry, 1, block->data.vorbis_comment.vendor_string.length, stdout);
+                       printf("\n");
+                       PPR; printf("  comments: %u\n", block->data.vorbis_comment.num_comments);
+                       for(i = 0; i < block->data.vorbis_comment.num_comments; i++) {
+                               PPR; printf("    comment[%u]: ", i);
+                               fwrite(block->data.vorbis_comment.comments[i].entry, 1, block->data.vorbis_comment.comments[i].length, stdout);
+                               printf("\n");
+                       }
+                       break;
+               default:
+                       PPR; printf("SKIPPING block of unknown type\n");
+                       break;
+       }
+#undef PPR
+}
+
+void write_vc_field(const char *filename, const FLAC__StreamMetadata_VorbisComment_Entry *entry)
+{
+       if(filename)
+               printf("%s:", filename);
+       (void) fwrite(entry->entry, 1, entry->length, stdout);
+       printf("\n");
+}
+
+void write_vc_fields(const char *filename, const char *field_name, const FLAC__StreamMetadata_VorbisComment_Entry entry[], unsigned num_entries)
+{
+       unsigned i;
+       const unsigned field_name_length = strlen(field_name);
+
+       for(i = 0; i < num_entries; i++) {
+               if(field_name_matches_entry(field_name, field_name_length, entry + i))
+                       write_vc_field(filename, entry + i);
+       }
+}
+
+FLAC__bool remove_vc_all(FLAC__StreamMetadata *block, FLAC__bool *needs_write)
+{
+       FLAC__ASSERT(0 != block);
+       FLAC__ASSERT(block->type == FLAC__METADATA_TYPE_VORBIS_COMMENT);
+       FLAC__ASSERT(0 != needs_write);
+
+       if(0 != block->data.vorbis_comment.comments) {
+               FLAC__ASSERT(block->data.vorbis_comment.num_comments > 0);
+               if(!FLAC__metadata_object_vorbiscomment_resize_comments(block, 0))
+                       return false;
+               *needs_write = true;
+       }
+       else {
+               FLAC__ASSERT(block->data.vorbis_comment.num_comments == 0);
+       }
+
+       return true;
+}
+
+FLAC__bool remove_vc_field(FLAC__StreamMetadata *block, const char *field_name, FLAC__bool *needs_write)
+{
+       FLAC__bool ok = true;
+       const unsigned field_name_length = strlen(field_name);
+       int i;
+
+       FLAC__ASSERT(0 != block);
+       FLAC__ASSERT(block->type == FLAC__METADATA_TYPE_VORBIS_COMMENT);
+       FLAC__ASSERT(0 != needs_write);
+
+       /* must delete from end to start otherwise it will interfere with our iteration */
+       for(i = (int)block->data.vorbis_comment.num_comments - 1; ok && i >= 0; i--) {
+               if(field_name_matches_entry(field_name, field_name_length, block->data.vorbis_comment.comments + i)) {
+                       ok &= FLAC__metadata_object_vorbiscomment_delete_comment(block, (unsigned)i);
+                       if(ok)
+                               *needs_write = true;
+               }
+       }
+
+       return ok;
+}
+
+FLAC__bool remove_vc_firstfield(FLAC__StreamMetadata *block, const char *field_name, FLAC__bool *needs_write)
+{
+       const unsigned field_name_length = strlen(field_name);
+       unsigned i;
+
+       FLAC__ASSERT(0 != block);
+       FLAC__ASSERT(block->type == FLAC__METADATA_TYPE_VORBIS_COMMENT);
+       FLAC__ASSERT(0 != needs_write);
+
+       for(i = 0; i < block->data.vorbis_comment.num_comments; i++) {
+               if(field_name_matches_entry(field_name, field_name_length, block->data.vorbis_comment.comments + i)) {
+                       if(!FLAC__metadata_object_vorbiscomment_delete_comment(block, (unsigned)i))
+                               return false;
+                       else
+                               *needs_write = true;
+                       break;
+               }
+       }
+
+       return true;
+}
+
+FLAC__bool set_vc_field(FLAC__StreamMetadata *block, const Argument_VcField *field, FLAC__bool *needs_write)
+{
+       FLAC__StreamMetadata_VorbisComment_Entry entry;
+       FLAC__ASSERT(0 != block);
+       FLAC__ASSERT(block->type == FLAC__METADATA_TYPE_VORBIS_COMMENT);
+       FLAC__ASSERT(0 != field);
+       FLAC__ASSERT(0 != needs_write);
+
+       entry.length = strlen(field->field);
+       entry.entry = field->field;
+
+       if(!FLAC__metadata_object_vorbiscomment_insert_comment(block, block->data.vorbis_comment.num_comments, entry, /*copy=*/true)) {
+               return false;
+       }
+       else {
+               *needs_write = true;
+               return true;
+       }
+}
+
+FLAC__bool field_name_matches_entry(const char *field_name, unsigned field_name_length, const FLAC__StreamMetadata_VorbisComment_Entry *entry)
+{
+       return (0 != memchr(entry->entry, '=', entry->length) && 0 == strncmp(field_name, entry->entry, field_name_length));
 }
 
-void hexdump(const FLAC__byte *buf, unsigned bytes)
+void hexdump(const char *filename, const FLAC__byte *buf, unsigned bytes, const char *indent)
 {
        unsigned i, left = bytes;
        const FLAC__byte *b = buf;
 
        for(i = 0; i < bytes; i += 16) {
-               printf("%08X: "
+               printf("%s%s%s%08X: "
                        "%02X %02X %02X %02X %02X %02X %02X %02X "
                        "%02X %02X %02X %02X %02X %02X %02X %02X "
                        "%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c\n",
-                       i,
+                       filename? filename:"", filename? ":":"",
+                       indent, i,
                        left >  0? (unsigned char)b[ 0] : 0,
                        left >  1? (unsigned char)b[ 1] : 0,
                        left >  2? (unsigned char)b[ 2] : 0,