From 98d9ae51fc4e1a6967b52e7708f6ddc66c684276 Mon Sep 17 00:00:00 2001 From: m-holger Date: Fri, 27 Jan 2023 18:58:50 +0000 Subject: Integrate JSONParser::decode_string into getToken --- libqpdf/JSON.cc | 117 +++++++++++++++----------------------------------------- 1 file changed, 30 insertions(+), 87 deletions(-) (limited to 'libqpdf') diff --git a/libqpdf/JSON.cc b/libqpdf/JSON.cc index f92d3ef8..b057bfdd 100644 --- a/libqpdf/JSON.cc +++ b/libqpdf/JSON.cc @@ -616,12 +616,9 @@ namespace void getToken(); void handleToken(); void numberError(); - static std::string - decode_string(std::string const& json, qpdf_offset_t offset); static void handle_u_code( - char const* s, + unsigned long codepoint, qpdf_offset_t offset, - qpdf_offset_t i, unsigned long& high_surrogate, qpdf_offset_t& high_offset, std::string& result); @@ -680,6 +677,7 @@ namespace size_t bytes; char const* p; qpdf_offset_t u_count; + unsigned long u_value{0}; qpdf_offset_t offset; bool done; std::string token; @@ -693,22 +691,15 @@ namespace void JSONParser::handle_u_code( - char const* s, + unsigned long codepoint, qpdf_offset_t offset, - qpdf_offset_t i, unsigned long& high_surrogate, qpdf_offset_t& high_offset, std::string& result) { - std::string hex = QUtil::hex_decode(std::string(s + i + 1, s + i + 5)); - unsigned char high = static_cast(hex.at(0)); - unsigned char low = static_cast(hex.at(1)); - unsigned long codepoint = high; - codepoint <<= 8; - codepoint += low; if ((codepoint & 0xFC00) == 0xD800) { // high surrogate - qpdf_offset_t new_high_offset = offset + i; + qpdf_offset_t new_high_offset = offset; if (high_offset) { QTC::TC("libtests", "JSON 16 high high"); throw std::runtime_error( @@ -721,10 +712,10 @@ JSONParser::handle_u_code( high_surrogate = codepoint; } else if ((codepoint & 0xFC00) == 0xDC00) { // low surrogate - if (offset + i != (high_offset + 6)) { + if (offset != (high_offset + 6)) { QTC::TC("libtests", "JSON 16 low not after high"); throw std::runtime_error( - "JSON: offset " + std::to_string(offset + i) + + "JSON: offset " + std::to_string(offset) + ": UTF-16 low surrogate found not immediately after high" " surrogate"); } @@ -737,74 +728,6 @@ JSONParser::handle_u_code( } } -std::string -JSONParser::decode_string(std::string const& str, qpdf_offset_t offset) -{ - // The string has already been validated when this private method - // is called, so errors are logic errors instead of runtime - // errors. - size_t len = str.length(); - char const* s = str.c_str(); - - // Keep track of UTF-16 surrogate pairs. - unsigned long high_surrogate = 0; - qpdf_offset_t high_offset = 0; - std::string result; - qpdf_offset_t olen = toO(len); - for (qpdf_offset_t i = 0; i < olen; ++i) { - if (s[i] == '\\') { - if (i + 1 >= olen) { - throw std::logic_error("JSON parse: nothing after \\"); - } - char ch = s[++i]; - switch (ch) { - case '\\': - case '\"': - case '/': - // \/ is allowed in json input, but so is /, so we - // don't map / to \/ in output. - result.append(1, ch); - break; - case 'b': - result.append(1, '\b'); - break; - case 'f': - result.append(1, '\f'); - break; - case 'n': - result.append(1, '\n'); - break; - case 'r': - result.append(1, '\r'); - break; - case 't': - result.append(1, '\t'); - break; - case 'u': - if (i + 4 >= olen) { - throw std::logic_error( - "JSON parse: not enough characters after \\u"); - } - handle_u_code( - s, offset, i, high_surrogate, high_offset, result); - i += 4; - break; - default: - break; - } - } else { - result.append(1, s[i]); - } - } - if (high_offset) { - QTC::TC("libtests", "JSON 16 dangling high"); - throw std::runtime_error( - "JSON: offset " + std::to_string(high_offset) + - ": UTF-16 high surrogate not followed by low surrogate"); - } - return result; -} - void JSONParser::numberError() { @@ -850,6 +773,11 @@ JSONParser::getToken() enum { append, ignore, reread } action = append; bool ready = false; token.clear(); + + // Keep track of UTF-16 surrogate pairs. + unsigned long high_surrogate = 0; + qpdf_offset_t high_offset = 0; + while (!done) { if (p == (buf + bytes)) { p = buf; @@ -1046,7 +974,13 @@ JSONParser::getToken() case ls_string: if (*p == '"') { - token = decode_string(token, token_start); + if (high_offset) { + QTC::TC("libtests", "JSON 16 dangling high"); + throw std::runtime_error( + "JSON: offset " + std::to_string(high_offset) + + ": UTF-16 high surrogate not followed by low " + "surrogate"); + } action = ignore; ready = true; } else if (*p == '\\') { @@ -1060,7 +994,6 @@ JSONParser::getToken() lex_state = ls_string; switch (*p) { case '\\': - token += "\\\\"; case '\"': case '/': // \/ is allowed in json input, but so is /, so we @@ -1083,9 +1016,9 @@ JSONParser::getToken() token += '\t'; break; case 'u': - token += "\\u"; lex_state = ls_u4; u_count = 0; + u_value = 0; break; default: QTC::TC("libtests", "JSON parse backslash bad character"); @@ -1097,13 +1030,23 @@ JSONParser::getToken() break; case ls_u4: - if (!QUtil::is_hex_digit(*p)) { + using ui = unsigned int; + action = ignore; + if ('0' <= *p && *p <= '9') { + u_value = 16 * u_value + (ui(*p) - ui('0')); + } else if ('a' <= *p && *p <= 'f') { + u_value = 16 * u_value + (10 + ui(*p) - ui('a')); + } else if ('A' <= *p && *p <= 'F') { + u_value = 16 * u_value + (10 + ui(*p) - ui('A')); + } else { QTC::TC("libtests", "JSON parse bad hex after u"); throw std::runtime_error( "JSON: offset " + std::to_string(offset - u_count - 1) + ": \\u must be followed by four hex digits"); } if (++u_count == 4) { + handle_u_code( + u_value, offset - 5, high_surrogate, high_offset, token); lex_state = ls_string; } break; -- cgit v1.2.3-54-g00ecf