111 lines
3.3 KiB
C
111 lines
3.3 KiB
C
// Example parser: Base64, syntax only.
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//
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// Demonstrates how to construct a Hammer parser that recognizes valid Base64
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// sequences.
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//
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// Note that no semantic evaluation of the sequence is performed, i.e. the
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// byte sequence being represented is not returned, or determined. See
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// base64_sem1.c and base64_sem2.c for examples how to attach appropriate
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// semantic actions to the grammar.
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#include <inttypes.h>
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#include "../src/hammer.h"
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#define DEBUG
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const HParser* document = NULL;
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void init_parser(void)
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{
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// CORE
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const HParser *digit = h_ch_range(0x30, 0x39);
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const HParser *alpha = h_choice(h_ch_range(0x41, 0x5a), h_ch_range(0x61, 0x7a), NULL);
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// AUX.
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const HParser *plus = h_ch('+');
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const HParser *slash = h_ch('/');
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const HParser *equals = h_ch('=');
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const HParser *bsfdig = h_choice(alpha, digit, plus, slash, NULL);
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const HParser *bsfdig_4bit = h_choice(
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h_ch('A'), h_ch('E'), h_ch('I'), h_ch('M'), h_ch('Q'), h_ch('U'),
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h_ch('Y'), h_ch('c'), h_ch('g'), h_ch('k'), h_ch('o'), h_ch('s'),
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h_ch('w'), h_ch('0'), h_ch('4'), h_ch('8'), NULL);
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const HParser *bsfdig_2bit = h_choice(h_ch('A'), h_ch('Q'), h_ch('g'), h_ch('w'), NULL);
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const HParser *base64_quad = h_sequence(bsfdig, bsfdig, bsfdig, bsfdig, NULL);
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const HParser *base64_quads = h_many(base64_quad);
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const HParser *base64_2 = h_sequence(bsfdig, bsfdig, bsfdig_4bit, equals, h_end_p(), NULL);
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const HParser *base64_1 = h_sequence(bsfdig, bsfdig_2bit, equals, equals, h_end_p(), NULL);
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const HParser *base64_ending = h_choice(h_end_p(), base64_2, base64_1, NULL);
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const HParser *base64 = h_sequence(base64_quads, base64_ending, NULL);
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// why does this parse "A=="?!
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// why does this parse "aaA=" but not "aA=="?!
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document = base64;
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}
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#include <string.h>
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#include <assert.h>
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#define TRUE (1)
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#define FALSE (0)
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void assert_parse(int expected, char *data) {
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const HParseResult *result;
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size_t datasize = strlen(data);
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result = h_parse(document, (void*)data, datasize);
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if((result != NULL) != expected) {
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fprintf(stderr, "Test failed: %s\n", data);
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}
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#ifdef DEBUG
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else {
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fprintf(stderr, "Test succeeded: %s\n", data);
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fprintf(stderr, "parsed=%lld bytes\n", result->bit_length/8);
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h_pprint(stdout, result->ast, 0, 0);
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}
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#endif
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}
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void test() {
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assert_parse(TRUE, "");
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assert_parse(TRUE, "YQ==");
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assert_parse(TRUE, "YXU=");
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assert_parse(TRUE, "YXVy");
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assert_parse(TRUE, "QVVSIFNBUkFG");
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assert_parse(TRUE, "QVVSIEhFUlUgU0FSQUY=");
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assert_parse(FALSE, "A");
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assert_parse(FALSE, "A=");
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assert_parse(FALSE, "A==");
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assert_parse(FALSE, "AAA==");
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assert_parse(FALSE, "aa==");
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}
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#include <stdio.h>
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int main(int argc, char **argv)
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{
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uint8_t input[102400];
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size_t inputsize;
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const HParseResult *result;
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init_parser();
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test();
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inputsize = fread(input, 1, sizeof(input), stdin);
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fprintf(stderr, "inputsize=%zu\ninput=", inputsize);
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fwrite(input, 1, inputsize, stderr);
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result = h_parse(document, input, inputsize);
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if(result) {
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fprintf(stderr, "parsed=%" PRId64 " bytes\n", result->bit_length/8);
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h_pprint(stdout, result->ast, 0, 0);
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return 0;
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} else {
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return 1;
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}
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}
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