From 3757fe80b30801119bda41ab0445e915271129fc Mon Sep 17 00:00:00 2001
From: dec05eba <dec05eba@protonmail.com>
Date: Wed, 26 May 2021 03:39:06 +0200
Subject: Allow use of multiple ranges when using cleanup command

---
 src/track_remove_parser.c | 133 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 133 insertions(+)
 create mode 100644 src/track_remove_parser.c

(limited to 'src/track_remove_parser.c')

diff --git a/src/track_remove_parser.c b/src/track_remove_parser.c
new file mode 100644
index 0000000..61c2375
--- /dev/null
+++ b/src/track_remove_parser.c
@@ -0,0 +1,133 @@
+#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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