Basic expressions with order precedence is now supported. ie. (----3 + ((1+2*3)/--2 + --5 *(8/4))) is 16.
Signed-off-by: Troy Kisky troy.kisky@boundarydevices.com --- tools/parse_helper.c | 172 +++++++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 162 insertions(+), 10 deletions(-)
diff --git a/tools/parse_helper.c b/tools/parse_helper.c index 0a5c5f6..50be832 100644 --- a/tools/parse_helper.c +++ b/tools/parse_helper.c @@ -97,20 +97,172 @@ int ph_skip_comma(struct parse_helper *ph) } }
+static const char precedence[] = { + /* ( + - * / & ^ | ) */ + 0, 2, 2, 1, 1, 3, 4, 5, 6 +}; +static const char unary_operations[] = "(+-"; +static const char binary_operations[] = " +-*/&^|)"; + +static uint32_t do_func(uint32_t val1, uint32_t val2, int op) +{ + switch (op) { + case 1: + return val1 + val2; + case 2: + return val1 - val2; + case 3: + return val1 * val2; + case 4: + return val1 / val2; + case 5: + return val1 & val2; + case 6: + return val1 ^ val2; + case 7: + return val1 | val2; + } + fprintf(stderr, "Error: in func %s: val1=%d val2=%d op = %d\n", + __func__, val1, val2, op); + exit(EXIT_FAILURE); +} + +static int find_op(char c, const char *p) +{ + int i; + for (i = 0; ; i++) { + if (c == p[i]) + return i; + if (!p[i]) + break; + } + return -1; +} + +#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0])) + int ph_get_value(struct parse_helper *ph, uint32_t *pval) { char *endptr; - uint32_t value; + int op_i = 0; + int val_i = 0; + unsigned char op[16]; + uint32_t val[16]; + int unary = 1; + char *p;
- if (ph_skip_separators(ph)) - return -1; - errno = 0; - value = strtoul(ph->p, &endptr, 16); - if (errno || (ph->p == endptr)) - return -1; - *pval = value; - ph->p = endptr; - return 0; + p = ph->p; + for (;;) { + char c; + int i, j; + const char *ops = unary ? unary_operations : binary_operations; + + if (unary) { + ph->p = p; + if (ph_skip_separators(ph)) + return -1; + p = ph->p; + c = *p; + } else { + for (;;) { + c = *p; + if ((c != ' ') && (c != '\t')) + break; + p++; + } + } + i = find_op(c, ops); + debug("%d,%c,%d:%s\n", i, c, unary, p); + if ((i < 0) && unary) { + if (val_i >= ARRAY_SIZE(val)) + return -1; + errno = 0; + val[val_i++] = strtoul(p, &endptr, 16); + if (errno || (p == endptr)) { + ph->p = p; + return -1; + } + p = endptr; + unary = 0; + debug("val[%d]=%x,%d,%d\n", val_i - 1, val[val_i - 1], + op_i, val_i); +do_unary: + while (op_i) { + j = op[op_i - 1]; + if (!(j & 0x80)) + break; + op_i--; + val[val_i - 1] = do_func(0, + val[val_i - 1], j & 0x7f); + debug("un:%d,%x,%d,%d\n", val[val_i - 1], j, + op_i, val_i); + } + continue; + } + if (i < 0) { + c = 0; + i = 8; + } else { + p++; + } + if (c == '(') { + if (op_i >= ARRAY_SIZE(op)) + return -1; + op[op_i++] = i; + debug("op[%d]=%x,%d,%d\n", op_i - 1, op[op_i - 1], + op_i, val_i); + unary = 1; + continue; + } + for (;;) { + if (!op_i || unary) + break; + j = op[op_i - 1]; + if (j == 0) { + if (c == ')') { + op_i--; + goto do_unary; + } + break; + } + if ((j & 0x80)) { + op_i--; + val[val_i - 1] = do_func(0, + val[val_i - 1], j & 0x7f); + debug("unary:%d,%x\n", val[val_i - 1], j); + continue; + } + if (precedence[i] < precedence[j]) + break; + if (val_i < 2) + return -1; + op_i--; + val[val_i - 2] = do_func(val[val_i - 2], + val[val_i - 1], j); + val_i--; + debug("binary:%d,%x,%d,%d\n", val[val_i - 1], j, + op_i, val_i); + } + if (c == ')') { + fprintf(stderr, "Error: unmatched parenthesis\n"); + return -1; + } + if (i == 8) { + if ((op_i != 0) || (val_i != 1)) { + fprintf(stderr, "Error: syntax %d %d\n", + op_i, val_i); + return -1; + } + ph->p = p; + *pval = val[0]; + return 0; + } + if (op_i >= ARRAY_SIZE(op)) + return -1; + op[op_i++] = i | (unary << 7); + debug("op[%d]=%x,%d,%d\n", op_i - 1, op[op_i - 1], op_i, val_i); + unary = 1; + } }
/*