381 lines
12 KiB
C
381 lines
12 KiB
C
#include <stdio.h>
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#include "./lexer.h"
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#include "./subtree.h"
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#include "./length.h"
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#include "./unicode.h"
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#define LOG(message, character) \
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if (self->logger.log) { \
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snprintf( \
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self->debug_buffer, \
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TREE_SITTER_SERIALIZATION_BUFFER_SIZE, \
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32 <= character && character < 127 ? \
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message " character:'%c'" : \
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message " character:%d", \
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character \
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); \
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self->logger.log( \
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self->logger.payload, \
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TSLogTypeLex, \
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self->debug_buffer \
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); \
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}
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static const int32_t BYTE_ORDER_MARK = 0xFEFF;
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static const TSRange DEFAULT_RANGE = {
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.start_point = {
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.row = 0,
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.column = 0,
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},
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.end_point = {
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.row = UINT32_MAX,
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.column = UINT32_MAX,
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},
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.start_byte = 0,
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.end_byte = UINT32_MAX
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};
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// Check if the lexer has reached EOF. This state is stored
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// by setting the lexer's `current_included_range_index` such that
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// it has consumed all of its available ranges.
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static bool ts_lexer__eof(const TSLexer *_self) {
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Lexer *self = (Lexer *)_self;
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return self->current_included_range_index == self->included_range_count;
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}
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// Clear the currently stored chunk of source code, because the lexer's
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// position has changed.
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static void ts_lexer__clear_chunk(Lexer *self) {
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self->chunk = NULL;
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self->chunk_size = 0;
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self->chunk_start = 0;
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}
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// Call the lexer's input callback to obtain a new chunk of source code
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// for the current position.
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static void ts_lexer__get_chunk(Lexer *self) {
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self->chunk_start = self->current_position.bytes;
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self->chunk = self->input.read(
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self->input.payload,
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self->current_position.bytes,
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self->current_position.extent,
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&self->chunk_size
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);
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if (!self->chunk_size) {
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self->current_included_range_index = self->included_range_count;
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self->chunk = NULL;
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}
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}
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// Decode the next unicode character in the current chunk of source code.
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// This assumes that the lexer has already retrieved a chunk of source
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// code that spans the current position.
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static void ts_lexer__get_lookahead(Lexer *self) {
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uint32_t position_in_chunk = self->current_position.bytes - self->chunk_start;
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const uint8_t *chunk = (const uint8_t *)self->chunk + position_in_chunk;
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uint32_t size = self->chunk_size - position_in_chunk;
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if (size == 0) {
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self->lookahead_size = 1;
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self->data.lookahead = '\0';
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return;
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}
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UnicodeDecodeFunction decode = self->input.encoding == TSInputEncodingUTF8
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? ts_decode_utf8
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: ts_decode_utf16;
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self->lookahead_size = decode(chunk, size, &self->data.lookahead);
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// If this chunk ended in the middle of a multi-byte character,
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// try again with a fresh chunk.
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if (self->data.lookahead == TS_DECODE_ERROR && size < 4) {
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ts_lexer__get_chunk(self);
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chunk = (const uint8_t *)self->chunk;
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size = self->chunk_size;
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self->lookahead_size = decode(chunk, size, &self->data.lookahead);
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}
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if (self->data.lookahead == TS_DECODE_ERROR) {
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self->lookahead_size = 1;
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}
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}
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// Advance to the next character in the source code, retrieving a new
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// chunk of source code if needed.
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static void ts_lexer__advance(TSLexer *_self, bool skip) {
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Lexer *self = (Lexer *)_self;
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if (!self->chunk) return;
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if (skip) {
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LOG("skip", self->data.lookahead);
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} else {
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LOG("consume", self->data.lookahead);
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}
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if (self->lookahead_size) {
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self->current_position.bytes += self->lookahead_size;
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if (self->data.lookahead == '\n') {
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self->current_position.extent.row++;
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self->current_position.extent.column = 0;
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} else {
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self->current_position.extent.column += self->lookahead_size;
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}
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}
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const TSRange *current_range = NULL;
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if (self->current_included_range_index < self->included_range_count) {
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current_range = &self->included_ranges[self->current_included_range_index];
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if (self->current_position.bytes == current_range->end_byte) {
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self->current_included_range_index++;
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if (self->current_included_range_index < self->included_range_count) {
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current_range++;
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self->current_position = (Length) {
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current_range->start_byte,
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current_range->start_point,
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};
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} else {
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current_range = NULL;
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}
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}
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}
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if (skip) self->token_start_position = self->current_position;
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if (current_range) {
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if (self->current_position.bytes >= self->chunk_start + self->chunk_size) {
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ts_lexer__get_chunk(self);
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}
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ts_lexer__get_lookahead(self);
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} else {
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ts_lexer__clear_chunk(self);
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self->data.lookahead = '\0';
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self->lookahead_size = 1;
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}
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}
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// Mark that a token match has completed. This can be called multiple
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// times if a longer match is found later.
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static void ts_lexer__mark_end(TSLexer *_self) {
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Lexer *self = (Lexer *)_self;
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if (!ts_lexer__eof(&self->data)) {
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// If the lexer is right at the beginning of included range,
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// then the token should be considered to end at the *end* of the
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// previous included range, rather than here.
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TSRange *current_included_range = &self->included_ranges[
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self->current_included_range_index
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];
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if (
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self->current_included_range_index > 0 &&
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self->current_position.bytes == current_included_range->start_byte
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) {
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TSRange *previous_included_range = current_included_range - 1;
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self->token_end_position = (Length) {
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previous_included_range->end_byte,
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previous_included_range->end_point,
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};
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return;
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}
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}
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self->token_end_position = self->current_position;
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}
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static uint32_t ts_lexer__get_column(TSLexer *_self) {
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Lexer *self = (Lexer *)_self;
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uint32_t goal_byte = self->current_position.bytes;
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self->current_position.bytes -= self->current_position.extent.column;
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self->current_position.extent.column = 0;
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if (self->current_position.bytes < self->chunk_start) {
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ts_lexer__get_chunk(self);
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}
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uint32_t result = 0;
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while (self->current_position.bytes < goal_byte) {
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ts_lexer__advance(&self->data, false);
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result++;
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}
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return result;
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}
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// Is the lexer at a boundary between two disjoint included ranges of
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// source code? This is exposed as an API because some languages' external
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// scanners need to perform custom actions at these bounaries.
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static bool ts_lexer__is_at_included_range_start(const TSLexer *_self) {
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const Lexer *self = (const Lexer *)_self;
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if (self->current_included_range_index < self->included_range_count) {
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TSRange *current_range = &self->included_ranges[self->current_included_range_index];
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return self->current_position.bytes == current_range->start_byte;
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} else {
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return false;
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}
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}
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void ts_lexer_init(Lexer *self) {
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*self = (Lexer) {
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.data = {
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// The lexer's methods are stored as struct fields so that generated
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// parsers can call them without needing to be linked against this
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// library.
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.advance = ts_lexer__advance,
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.mark_end = ts_lexer__mark_end,
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.get_column = ts_lexer__get_column,
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.is_at_included_range_start = ts_lexer__is_at_included_range_start,
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.eof = ts_lexer__eof,
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.lookahead = 0,
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.result_symbol = 0,
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},
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.chunk = NULL,
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.chunk_size = 0,
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.chunk_start = 0,
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.current_position = {0, {0, 0}},
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.logger = {
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.payload = NULL,
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.log = NULL
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},
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.included_ranges = NULL,
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.included_range_count = 0,
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.current_included_range_index = 0,
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};
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ts_lexer_set_included_ranges(self, NULL, 0);
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}
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void ts_lexer_delete(Lexer *self) {
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ts_free(self->included_ranges);
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}
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static void ts_lexer_goto(Lexer *self, Length position) {
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self->current_position = position;
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bool found_included_range = false;
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// Move to the first valid position at or after the given position.
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for (unsigned i = 0; i < self->included_range_count; i++) {
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TSRange *included_range = &self->included_ranges[i];
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if (included_range->end_byte > position.bytes) {
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if (included_range->start_byte > position.bytes) {
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self->current_position = (Length) {
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.bytes = included_range->start_byte,
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.extent = included_range->start_point,
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};
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}
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self->current_included_range_index = i;
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found_included_range = true;
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break;
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}
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}
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if (found_included_range) {
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// If the current position is outside of the current chunk of text,
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// then clear out the current chunk of text.
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if (self->chunk && (
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position.bytes < self->chunk_start ||
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position.bytes >= self->chunk_start + self->chunk_size
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)) {
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ts_lexer__clear_chunk(self);
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}
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self->lookahead_size = 0;
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self->data.lookahead = '\0';
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}
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// If the given position is beyond any of included ranges, move to the EOF
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// state - past the end of the included ranges.
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else {
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self->current_included_range_index = self->included_range_count;
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TSRange *last_included_range = &self->included_ranges[self->included_range_count - 1];
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self->current_position = (Length) {
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.bytes = last_included_range->end_byte,
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.extent = last_included_range->end_point,
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};
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ts_lexer__clear_chunk(self);
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self->lookahead_size = 1;
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self->data.lookahead = '\0';
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}
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}
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void ts_lexer_set_input(Lexer *self, TSInput input) {
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self->input = input;
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ts_lexer__clear_chunk(self);
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ts_lexer_goto(self, self->current_position);
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}
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// Move the lexer to the given position. This doesn't do any work
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// if the parser is already at the given position.
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void ts_lexer_reset(Lexer *self, Length position) {
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if (position.bytes != self->current_position.bytes) {
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ts_lexer_goto(self, position);
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}
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}
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void ts_lexer_start(Lexer *self) {
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self->token_start_position = self->current_position;
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self->token_end_position = LENGTH_UNDEFINED;
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self->data.result_symbol = 0;
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if (!ts_lexer__eof(&self->data)) {
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if (!self->chunk_size) ts_lexer__get_chunk(self);
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if (!self->lookahead_size) ts_lexer__get_lookahead(self);
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if (
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self->current_position.bytes == 0 &&
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self->data.lookahead == BYTE_ORDER_MARK
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) ts_lexer__advance(&self->data, true);
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}
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}
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void ts_lexer_finish(Lexer *self, uint32_t *lookahead_end_byte) {
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if (length_is_undefined(self->token_end_position)) {
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ts_lexer__mark_end(&self->data);
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}
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uint32_t current_lookahead_end_byte = self->current_position.bytes + 1;
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// In order to determine that a byte sequence is invalid UTF8 or UTF16,
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// the character decoding algorithm may have looked at the following byte.
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// Therefore, the next byte *after* the current (invalid) character
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// affects the interpretation of the current character.
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if (self->data.lookahead == TS_DECODE_ERROR) {
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current_lookahead_end_byte++;
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}
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if (current_lookahead_end_byte > *lookahead_end_byte) {
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*lookahead_end_byte = current_lookahead_end_byte;
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}
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}
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void ts_lexer_advance_to_end(Lexer *self) {
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while (self->chunk) {
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ts_lexer__advance(&self->data, false);
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}
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}
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void ts_lexer_mark_end(Lexer *self) {
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ts_lexer__mark_end(&self->data);
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}
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void ts_lexer_set_included_ranges(
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Lexer *self,
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const TSRange *ranges,
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uint32_t count
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) {
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if (count == 0 || !ranges) {
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ranges = &DEFAULT_RANGE;
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count = 1;
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}
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size_t size = count * sizeof(TSRange);
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self->included_ranges = ts_realloc(self->included_ranges, size);
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memcpy(self->included_ranges, ranges, size);
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self->included_range_count = count;
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ts_lexer_goto(self, self->current_position);
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}
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TSRange *ts_lexer_included_ranges(const Lexer *self, uint32_t *count) {
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*count = self->included_range_count;
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return self->included_ranges;
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}
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#undef LOG
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