53 lines
1.1 KiB
C
53 lines
1.1 KiB
C
#include "parser_internal.h"
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typedef struct {
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size_t len;
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const HParser **p_array;
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} HSequence;
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static HParseResult* parse_choice(void *env, HParseState *state) {
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HSequence *s = (HSequence*)env;
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HInputStream backup = state->input_stream;
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for (size_t i=0; i<s->len; ++i) {
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if (i != 0)
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state->input_stream = backup;
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HParseResult *tmp = h_do_parse(s->p_array[i], state);
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if (NULL != tmp)
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return tmp;
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}
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// nothing succeeded, so fail
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return NULL;
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}
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static const HParserVtable choice_vt = {
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.parse = parse_choice,
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};
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const HParser* h_choice(const HParser* p, ...) {
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va_list ap;
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size_t len = 0;
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HSequence *s = g_new(HSequence, 1);
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const HParser *arg;
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va_start(ap, p);
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do {
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len++;
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arg = va_arg(ap, const HParser *);
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} while (arg);
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va_end(ap);
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s->p_array = g_new(const HParser *, len);
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va_start(ap, p);
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s->p_array[0] = p;
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for (size_t i = 1; i < len; i++) {
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s->p_array[i] = va_arg(ap, const HParser *);
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} while (arg);
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va_end(ap);
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s->len = len;
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HParser *ret = g_new(HParser, 1);
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ret->vtable = &choice_vt; ret->env = (void*)s;
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return ret;
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}
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