581 lines
16 KiB
C
581 lines
16 KiB
C
// Part of JoeyLib, Copyright (c) 2026 Scott Duensing, under the MIT License.
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// See LICENSE.md for license information.
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// SPDX-License-Identifier: MIT
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//
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// toolXml.c - a small XML reader for the JoeyLib host tools (toolXml.h).
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#include <stdarg.h>
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#include <stdbool.h>
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#include <stdint.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "toolBuf.h"
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#include "toolFile.h"
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#include "toolXml.h"
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#define UTF8_BOM "\xEF\xBB\xBF"
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#define UTF8_BOM_BYTES 3u
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#define ASCII_END 0x80u
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#define UTF8_2_MAX 0x7FFu
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#define UTF8_3_MAX 0xFFFFu
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#define UNICODE_MAX 0x10FFFFu
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#define UTF8_CONT 0x80u
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#define UTF8_CONT_MASK 0x3Fu
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#define UTF8_LEAD_2 0xC0u
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#define UTF8_LEAD_3 0xE0u
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#define UTF8_LEAD_4 0xF0u
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#define UTF8_SHIFT 6u
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#define DECIMAL 10u
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#define HEX 16u
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#define HEX_LETTER 10u
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// The longest entity or character reference looked for, its & to its ;.
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#define ENTITY_MAX 16u
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typedef struct ParserT {
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const char *text;
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size_t len;
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size_t pos;
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char *err;
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bool failed;
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} ParserT;
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static void attrAdd(ToolXmlT *node, char *name, char *value);
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static void childAdd(ToolXmlT *node, ToolXmlT *child);
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static ToolXmlT *element(ParserT *p);
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static bool entity(ParserT *p, ToolBufT *out);
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static void error(ParserT *p, const char *fmt, ...) __attribute__((format(printf, 2, 3)));
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static bool isNameChar(char c);
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static bool isNameStart(char c);
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static bool isSpace(char c);
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static bool lookingAt(const ParserT *p, const char *s);
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static bool misc(ParserT *p);
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static char *name(ParserT *p);
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static bool skipPast(ParserT *p, const char *end);
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static void skipSpace(ParserT *p);
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static char *takeString(ToolBufT *buf);
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static void utf8Put(ToolBufT *out, uint32_t code);
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static void attrAdd(ToolXmlT *node, char *attrName, char *value) {
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ToolXmlAttrT *attrs;
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attrs = (ToolXmlAttrT *)realloc(node->attrs, (node->attrCount + 1u) * sizeof(ToolXmlAttrT));
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if (attrs == NULL) {
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toolFail("out of memory");
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}
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node->attrs = attrs;
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node->attrs[node->attrCount].name = attrName;
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node->attrs[node->attrCount].value = value;
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node->attrCount++;
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}
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static void childAdd(ToolXmlT *node, ToolXmlT *child) {
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ToolXmlT **children;
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children = (ToolXmlT **)realloc(node->children, (node->childCount + 1u) * sizeof(ToolXmlT *));
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if (children == NULL) {
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toolFail("out of memory");
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}
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node->children = children;
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node->children[node->childCount] = child;
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node->childCount++;
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}
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// An element from its '<' to the end of its end tag, or NULL on an error.
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static ToolXmlT *element(ParserT *p) {
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ToolXmlT *node;
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ToolXmlT *child;
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ToolBufT value;
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ToolBufT text;
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ToolBufT tail;
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char *attrName;
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char *endName;
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char quote;
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char c;
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bool sawChild;
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p->pos++;
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node = (ToolXmlT *)calloc(1u, sizeof(ToolXmlT));
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if (node == NULL) {
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toolFail("out of memory");
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}
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node->name = name(p);
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if (node->name == NULL) {
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free(node);
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return NULL;
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}
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// Attributes, to the end of the start tag.
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for (;;) {
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skipSpace(p);
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if (lookingAt(p, "/>")) {
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p->pos += 2u;
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node->text = takeString(NULL);
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return node;
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}
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if (lookingAt(p, ">")) {
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p->pos++;
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break;
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}
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attrName = name(p);
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if (attrName == NULL) {
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toolXmlFree(node);
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return NULL;
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}
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if (toolXmlAttr(node, attrName) != NULL) {
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error(p, "duplicate attribute '%s'", attrName);
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free(attrName);
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toolXmlFree(node);
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return NULL;
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}
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skipSpace(p);
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if (!lookingAt(p, "=")) {
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error(p, "no '=' after attribute '%s'", attrName);
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free(attrName);
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toolXmlFree(node);
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return NULL;
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}
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p->pos++;
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skipSpace(p);
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if (p->pos >= p->len || (p->text[p->pos] != '"' && p->text[p->pos] != '\'')) {
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error(p, "attribute '%s' is not quoted", attrName);
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free(attrName);
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toolXmlFree(node);
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return NULL;
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}
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quote = p->text[p->pos++];
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memset(&value, 0, sizeof(value));
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while (p->pos < p->len && p->text[p->pos] != quote) {
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c = p->text[p->pos];
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if (c == '<') {
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error(p, "'<' in attribute '%s'", attrName);
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} else if (c == '&') {
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entity(p, &value);
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continue;
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} else if (c == '\r' && p->pos + 1u < p->len && p->text[p->pos + 1u] == '\n') {
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p->pos++;
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continue;
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} else {
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// Attribute-value normalisation: a literal tab or line end
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// is a space.
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toolBufByte(&value, (c == '\t' || c == '\n' || c == '\r') ? ' ' : (uint8_t)c);
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}
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p->pos++;
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}
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if (p->failed || p->pos >= p->len) {
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if (!p->failed) {
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error(p, "unclosed attribute '%s'", attrName);
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}
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toolBufFree(&value);
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free(attrName);
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toolXmlFree(node);
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return NULL;
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}
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p->pos++;
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attrAdd(node, attrName, takeString(&value));
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}
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// Content, to the end tag: the text before the first child is kept.
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memset(&text, 0, sizeof(text));
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memset(&tail, 0, sizeof(tail));
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sawChild = false;
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for (;;) {
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if (p->pos >= p->len) {
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error(p, "no end tag for <%s>", node->name);
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break;
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}
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if (lookingAt(p, "</")) {
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p->pos += 2u;
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endName = name(p);
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if (endName == NULL) {
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break;
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}
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skipSpace(p);
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if (strcmp(endName, node->name) != 0 || !lookingAt(p, ">")) {
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error(p, "mismatched tag: </%s> closes <%s>", endName, node->name);
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free(endName);
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break;
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}
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free(endName);
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p->pos++;
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node->text = takeString(&text);
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toolBufFree(&tail);
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return node;
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}
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if (lookingAt(p, "<![CDATA[")) {
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p->pos += strlen("<![CDATA[");
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while (p->pos < p->len && !lookingAt(p, "]]>")) {
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if (!sawChild) {
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toolBufByte(&text, (uint8_t)p->text[p->pos]);
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}
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p->pos++;
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}
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if (!skipPast(p, "]]>")) {
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break;
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}
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continue;
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}
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if (lookingAt(p, "<!--") || lookingAt(p, "<?")) {
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if (!misc(p)) {
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break;
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}
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continue;
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}
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if (lookingAt(p, "<")) {
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child = element(p);
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if (child == NULL) {
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break;
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}
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childAdd(node, child);
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sawChild = true;
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continue;
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}
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c = p->text[p->pos];
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if (c == '&') {
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// After the first child the text is a tail, not kept, but its
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// entities must still be good ones.
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entity(p, sawChild ? &tail : &text);
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tail.len = 0u;
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if (p->failed) {
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break;
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}
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continue;
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}
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if (!sawChild) {
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if (c == '\r') {
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toolBufByte(&text, '\n');
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if (p->pos + 1u < p->len && p->text[p->pos + 1u] == '\n') {
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p->pos++;
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}
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} else {
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toolBufByte(&text, (uint8_t)c);
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}
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}
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p->pos++;
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}
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toolBufFree(&text);
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toolBufFree(&tail);
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toolXmlFree(node);
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return NULL;
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}
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// An entity or character reference at p->pos, decoded into out; false (and
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// an error) when it is not one.
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static bool entity(ParserT *p, ToolBufT *out) {
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static const char *const names[] = { "lt", "gt", "amp", "quot", "apos" };
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static const char values[] = { '<', '>', '&', '"', '\'' };
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size_t end;
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size_t i;
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size_t n;
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uint32_t code;
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uint32_t base;
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uint32_t digit;
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char c;
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for (end = p->pos + 1u; end < p->len && p->text[end] != ';' && end - p->pos < ENTITY_MAX; end++) {
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}
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if (end >= p->len || p->text[end] != ';') {
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error(p, "bad entity");
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return false;
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}
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n = end - p->pos - 1u;
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if (n >= 2u && p->text[p->pos + 1u] == '#') {
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i = p->pos + 2u;
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base = DECIMAL;
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if (p->text[i] == 'x') {
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base = HEX;
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i++;
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}
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code = 0u;
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if (i == end) {
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error(p, "bad character reference");
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return false;
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}
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for (; i < end; i++) {
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c = p->text[i];
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if (c >= '0' && c <= '9') {
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digit = (uint32_t)(c - '0');
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} else if (base == HEX && c >= 'a' && c <= 'f') {
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digit = (uint32_t)(c - 'a') + HEX_LETTER;
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} else if (base == HEX && c >= 'A' && c <= 'F') {
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digit = (uint32_t)(c - 'A') + HEX_LETTER;
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} else {
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error(p, "bad character reference");
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return false;
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}
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code = code * base + digit;
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if (code > UNICODE_MAX) {
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error(p, "bad character reference");
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return false;
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}
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}
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if (code == 0u) {
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error(p, "bad character reference");
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return false;
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}
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utf8Put(out, code);
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p->pos = end + 1u;
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return true;
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}
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for (i = 0; i < sizeof(values); i++) {
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if (strlen(names[i]) == n && strncmp(p->text + p->pos + 1u, names[i], n) == 0) {
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toolBufByte(out, (uint8_t)values[i]);
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p->pos = end + 1u;
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return true;
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}
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}
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error(p, "undefined entity");
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return false;
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}
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// The error, with the line it is on, unless one is already recorded.
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static void error(ParserT *p, const char *fmt, ...) {
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va_list args;
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size_t i;
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size_t line;
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int n;
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if (p->failed) {
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return;
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}
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p->failed = true;
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line = 1u;
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for (i = 0; i < p->pos && i < p->len; i++) {
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if (p->text[i] == '\n') {
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line++;
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}
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}
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n = snprintf(p->err, TOOL_XML_ERROR_BYTES, "line %zu: ", line);
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if (n < 0 || (size_t)n >= TOOL_XML_ERROR_BYTES) {
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return;
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}
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va_start(args, fmt);
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vsnprintf(p->err + n, TOOL_XML_ERROR_BYTES - (size_t)n, fmt, args);
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va_end(args);
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}
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static bool isNameChar(char c) {
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return isNameStart(c) || (c >= '0' && c <= '9') || c == '-' || c == '.';
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}
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// A name starts with a letter, '_', ':', or any non-ASCII character.
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static bool isNameStart(char c) {
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return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || c == '_' || c == ':' || (unsigned char)c >= ASCII_END;
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}
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static bool isSpace(char c) {
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return c == ' ' || c == '\t' || c == '\n' || c == '\r';
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}
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static bool lookingAt(const ParserT *p, const char *s) {
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size_t n;
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n = strlen(s);
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return p->pos + n <= p->len && memcmp(p->text + p->pos, s, n) == 0;
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}
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// Whitespace, a comment, a processing instruction, or a DOCTYPE skipped:
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// true when there was one.
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static bool misc(ParserT *p) {
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size_t start;
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if (p->failed) {
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return false;
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}
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start = p->pos;
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skipSpace(p);
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if (lookingAt(p, "<!--")) {
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return skipPast(p, "-->");
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}
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if (lookingAt(p, "<?")) {
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return skipPast(p, "?>");
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}
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if (lookingAt(p, "<!DOCTYPE")) {
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return skipPast(p, ">");
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}
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return p->pos != start;
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}
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// A name at p->pos, malloc'd; NULL (and an error) when there is none.
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static char *name(ParserT *p) {
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size_t start;
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char *out;
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start = p->pos;
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if (p->pos >= p->len || !isNameStart(p->text[p->pos])) {
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error(p, "not well-formed (a name was expected)");
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return NULL;
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}
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while (p->pos < p->len && isNameChar(p->text[p->pos])) {
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p->pos++;
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}
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out = (char *)malloc(p->pos - start + 1u);
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if (out == NULL) {
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toolFail("out of memory");
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}
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memcpy(out, p->text + start, p->pos - start);
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out[p->pos - start] = '\0';
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return out;
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}
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// Past the next end (inclusive); false (and an error) when it never comes.
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static bool skipPast(ParserT *p, const char *end) {
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size_t n;
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n = strlen(end);
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while (p->pos + n <= p->len) {
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if (memcmp(p->text + p->pos, end, n) == 0) {
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p->pos += n;
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return true;
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}
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p->pos++;
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}
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error(p, "unclosed token (no '%s')", end);
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return false;
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}
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static void skipSpace(ParserT *p) {
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while (p->pos < p->len && isSpace(p->text[p->pos])) {
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p->pos++;
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}
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}
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// A buffer's bytes as a malloc'd C string (an empty one for NULL or an
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// empty buffer); the buffer is handed over.
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static char *takeString(ToolBufT *buf) {
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char *out;
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if (buf == NULL || buf->len == 0u) {
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if (buf != NULL) {
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toolBufFree(buf);
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}
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out = (char *)calloc(1u, 1u);
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if (out == NULL) {
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toolFail("out of memory");
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}
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return out;
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}
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toolBufByte(buf, '\0');
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out = (char *)buf->data;
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buf->data = NULL;
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buf->len = 0u;
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buf->cap = 0u;
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return out;
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}
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const char *toolXmlAttr(const ToolXmlT *node, const char *attrName) {
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size_t i;
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for (i = 0; i < node->attrCount; i++) {
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if (strcmp(node->attrs[i].name, attrName) == 0) {
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return node->attrs[i].value;
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}
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}
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return NULL;
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}
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const ToolXmlT *toolXmlChild(const ToolXmlT *node, const char *childName) {
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size_t i;
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for (i = 0; i < node->childCount; i++) {
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if (strcmp(node->children[i]->name, childName) == 0) {
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return node->children[i];
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}
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}
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return NULL;
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}
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void toolXmlFree(ToolXmlT *node) {
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size_t i;
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if (node == NULL) {
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return;
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}
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for (i = 0; i < node->attrCount; i++) {
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free(node->attrs[i].name);
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free(node->attrs[i].value);
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}
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for (i = 0; i < node->childCount; i++) {
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toolXmlFree(node->children[i]);
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}
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free(node->attrs);
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free(node->children);
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free(node->name);
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free(node->text);
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free(node);
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}
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ToolXmlT *toolXmlParse(const char *text, size_t len, char err[TOOL_XML_ERROR_BYTES]) {
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ParserT p;
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ToolXmlT *root;
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p.text = text;
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p.len = len;
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p.pos = 0u;
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p.err = err;
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p.failed = false;
|
|
err[0] = '\0';
|
|
if (lookingAt(&p, UTF8_BOM)) {
|
|
p.pos += UTF8_BOM_BYTES;
|
|
}
|
|
while (misc(&p)) {
|
|
}
|
|
if (p.failed) {
|
|
return NULL;
|
|
}
|
|
if (p.pos >= p.len || p.text[p.pos] != '<') {
|
|
error(&p, "no element found");
|
|
return NULL;
|
|
}
|
|
root = element(&p);
|
|
if (root == NULL) {
|
|
return NULL;
|
|
}
|
|
while (misc(&p)) {
|
|
}
|
|
if (!p.failed && p.pos < p.len) {
|
|
error(&p, "junk after document element");
|
|
}
|
|
if (p.failed) {
|
|
toolXmlFree(root);
|
|
return NULL;
|
|
}
|
|
return root;
|
|
}
|
|
|
|
|
|
// A code point as UTF-8.
|
|
static void utf8Put(ToolBufT *out, uint32_t code) {
|
|
if (code < ASCII_END) {
|
|
toolBufByte(out, code);
|
|
} else if (code <= UTF8_2_MAX) {
|
|
toolBufByte(out, UTF8_LEAD_2 | (code >> UTF8_SHIFT));
|
|
toolBufByte(out, UTF8_CONT | (code & UTF8_CONT_MASK));
|
|
} else if (code <= UTF8_3_MAX) {
|
|
toolBufByte(out, UTF8_LEAD_3 | (code >> (2u * UTF8_SHIFT)));
|
|
toolBufByte(out, UTF8_CONT | ((code >> UTF8_SHIFT) & UTF8_CONT_MASK));
|
|
toolBufByte(out, UTF8_CONT | (code & UTF8_CONT_MASK));
|
|
} else {
|
|
toolBufByte(out, UTF8_LEAD_4 | (code >> (3u * UTF8_SHIFT)));
|
|
toolBufByte(out, UTF8_CONT | ((code >> (2u * UTF8_SHIFT)) & UTF8_CONT_MASK));
|
|
toolBufByte(out, UTF8_CONT | ((code >> UTF8_SHIFT) & UTF8_CONT_MASK));
|
|
toolBufByte(out, UTF8_CONT | (code & UTF8_CONT_MASK));
|
|
}
|
|
}
|