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#include "track_remove_parser.h"
#include <stdio.h>
typedef enum {
TR_TOK_RANGE,
TR_TOK_END_OF_FILE,
TR_TOK_INVALID
} TrackRemoveToken;
typedef struct {
const char *str;
size_t size;
size_t offset;
Range range;
} TrackRemoveTokenizer;
static int is_number(char c) {
return c >= '0' && c <= '9';
}
/* Returns non-0 value on overflow */
static int string_to_num_unchecked(const char *str, size_t size, int *number) {
int result = 0;
for(size_t i = 0; i < size; ++i) {
const int result_before = result;
result *= 10;
result += (str[i] - '0');
/* overflow */
if(result <= result_before)
return 1;
}
*number = result;
return 0;
}
static void track_remover_tokenizer_init(TrackRemoveTokenizer *self, const char *str, size_t size) {
self->str = str;
self->size = size;
self->offset = 0;
self->range.start = 0;
self->range.end = 0;
}
static int track_remover_tokenizer_get_char(TrackRemoveTokenizer *self) {
if(self->offset < self->size)
return self->str[self->offset];
else
return '\0';
}
static TrackRemoveToken track_remover_tokenizer_next(TrackRemoveTokenizer *self) {
char c;
for(;;) {
c = track_remover_tokenizer_get_char(self);
if(c != ' ' && c != '\t')
break;
++self->offset;
}
if(c >= '1' && c <= '9') {
size_t number_start = self->offset;
++self->offset;
for(;;) {
c = track_remover_tokenizer_get_char(self);
if(!is_number(c))
break;
++self->offset;
}
if(string_to_num_unchecked(self->str + number_start, self->offset - number_start, &self->range.start) != 0)
return TR_TOK_INVALID;
self->range.end = self->range.start;
if(c != '-')
return TR_TOK_RANGE;
++self->offset;
c = track_remover_tokenizer_get_char(self);
if(!is_number(c))
return TR_TOK_INVALID;
number_start = self->offset;
++self->offset;
for(;;) {
c = track_remover_tokenizer_get_char(self);
if(!is_number(c))
break;
++self->offset;
}
if(string_to_num_unchecked(self->str + number_start, self->offset - number_start, &self->range.end) != 0)
return TR_TOK_INVALID;
return TR_TOK_RANGE;
} else if(c == '\0') {
return TR_TOK_END_OF_FILE;
} else {
return TR_TOK_INVALID;
}
}
int track_remove_parser_parse(const char *str, size_t size, Buffer /*Range*/ *ranges) {
int num_ranges = 0;
TrackRemoveTokenizer tokenizer;
track_remover_tokenizer_init(&tokenizer, str, size);
for(;;) {
TrackRemoveToken token = track_remover_tokenizer_next(&tokenizer);
if(token == TR_TOK_RANGE) {
if(tokenizer.range.start > tokenizer.range.end) {
fprintf(stderr, "Invalid number range. The start range can't be past the end range\n");
return 1;
}
buffer_append(ranges, &tokenizer.range, sizeof(tokenizer.range));
++num_ranges;
} else if(token == TR_TOK_END_OF_FILE) {
break;
} else {
fprintf(stderr, "Invalid input. Expected numbers and/or number ranges\n");
return 1;
}
}
if(num_ranges == 0) {
fprintf(stderr, "Invalid input. Expected numbers and/or number ranges\n");
return 1;
}
return 0;
}
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