1 files changed, 139 insertions, 0 deletions
diff --git a/prism/internal/char.h b/prism/internal/char.h
new file mode 100644
index 0000000000..9a58fba8c5
--- /dev/null
+++ b/prism/internal/char.h
@@ -0,0 +1,139 @@
+#ifndef PRISM_INTERNAL_CHAR_H
+#define PRISM_INTERNAL_CHAR_H
+
+#include "prism/compiler/force_inline.h"
+
+#include "prism/arena.h"
+#include "prism/line_offset_list.h"
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+
+/* Bit flag for whitespace characters in pm_byte_table. */
+#define PRISM_CHAR_BIT_WHITESPACE (1 << 0)
+
+/* Bit flag for inline whitespace characters in pm_byte_table. */
+#define PRISM_CHAR_BIT_INLINE_WHITESPACE (1 << 1)
+
+/*
+ * A lookup table for classifying bytes. Each entry is a bitfield of
+ * PRISM_CHAR_BIT_* flags. Defined in char.c.
+ */
+extern const uint8_t pm_byte_table[256];
+
+/* Returns true if the given character is a whitespace character. */
+static PRISM_FORCE_INLINE bool
+pm_char_is_whitespace(const uint8_t b) {
+    return (pm_byte_table[b] & PRISM_CHAR_BIT_WHITESPACE) != 0;
+}
+
+/* Returns true if the given character is an inline whitespace character. */
+static PRISM_FORCE_INLINE bool
+pm_char_is_inline_whitespace(const uint8_t b) {
+    return (pm_byte_table[b] & PRISM_CHAR_BIT_INLINE_WHITESPACE) != 0;
+}
+
+/*
+ * Returns the number of characters at the start of the string that are inline
+ * whitespace (space/tab). Scans the byte table directly for use in hot paths.
+ */
+static PRISM_FORCE_INLINE size_t
+pm_strspn_inline_whitespace(const uint8_t *string, ptrdiff_t length) {
+    if (length <= 0) return 0;
+    size_t size = 0;
+    size_t maximum = (size_t) length;
+    while (size < maximum && (pm_byte_table[string[size]] & PRISM_CHAR_BIT_INLINE_WHITESPACE)) size++;
+    return size;
+}
+
+/*
+ * Returns the number of characters at the start of the string that are
+ * whitespace. Disallows searching past the given maximum number of characters.
+ */
+size_t pm_strspn_whitespace(const uint8_t *string, ptrdiff_t length);
+
+/*
+ * Returns the number of characters at the start of the string that are
+ * whitespace while also tracking the location of each newline. Disallows
+ * searching past the given maximum number of characters.
+ */
+size_t pm_strspn_whitespace_newlines(const uint8_t *string, ptrdiff_t length, pm_arena_t *arena, pm_line_offset_list_t *line_offsets, uint32_t start_offset);
+
+/*
+ * Returns the number of characters at the start of the string that are decimal
+ * digits. Disallows searching past the given maximum number of characters.
+ */
+size_t pm_strspn_decimal_digit(const uint8_t *string, ptrdiff_t length);
+
+/*
+ * Returns the number of characters at the start of the string that are
+ * hexadecimal digits. Disallows searching past the given maximum number of
+ * characters.
+ */
+size_t pm_strspn_hexadecimal_digit(const uint8_t *string, ptrdiff_t length);
+
+/*
+ * Returns the number of characters at the start of the string that are octal
+ * digits or underscores. Disallows searching past the given maximum number of
+ * characters.
+ *
+ * If multiple underscores are found in a row or if an underscore is
+ * found at the end of the number, then the invalid pointer is set to the index
+ * of the first invalid underscore.
+ */
+size_t pm_strspn_octal_number(const uint8_t *string, ptrdiff_t length, const uint8_t **invalid);
+
+/*
+ * Returns the number of characters at the start of the string that are decimal
+ * digits or underscores. Disallows searching past the given maximum number of
+ * characters.
+ *
+ * If multiple underscores are found in a row or if an underscore is
+ * found at the end of the number, then the invalid pointer is set to the index
+ * of the first invalid underscore.
+ */
+size_t pm_strspn_decimal_number(const uint8_t *string, ptrdiff_t length, const uint8_t **invalid);
+
+/*
+ * Returns the number of characters at the start of the string that are
+ * hexadecimal digits or underscores. Disallows searching past the given maximum
+ * number of characters.
+ *
+ * If multiple underscores are found in a row or if an underscore is
+ * found at the end of the number, then the invalid pointer is set to the index
+ * of the first invalid underscore.
+ */
+size_t pm_strspn_hexadecimal_number(const uint8_t *string, ptrdiff_t length, const uint8_t **invalid);
+
+/*
+ * Returns the number of characters at the start of the string that are regexp
+ * options. Disallows searching past the given maximum number of characters.
+ */
+size_t pm_strspn_regexp_option(const uint8_t *string, ptrdiff_t length);
+
+/*
+ * Returns the number of characters at the start of the string that are binary
+ * digits or underscores. Disallows searching past the given maximum number of
+ * characters.
+ *
+ * If multiple underscores are found in a row or if an underscore is
+ * found at the end of the number, then the invalid pointer is set to the index
+ * of the first invalid underscore.
+ */
+size_t pm_strspn_binary_number(const uint8_t *string, ptrdiff_t length, const uint8_t **invalid);
+
+
+/* Returns true if the given character is a binary digit. */
+bool pm_char_is_binary_digit(const uint8_t b);
+
+/* Returns true if the given character is an octal digit. */
+bool pm_char_is_octal_digit(const uint8_t b);
+
+/* Returns true if the given character is a decimal digit. */
+bool pm_char_is_decimal_digit(const uint8_t b);
+
+/* Returns true if the given character is a hexadecimal digit. */
+bool pm_char_is_hexadecimal_digit(const uint8_t b);
+
+#endif