[U-Boot] [PATCH V4 11/11] parse_helper: add expression evaluation

Liu Hui-R64343
2012-11-28T10:49:42Z

>-----Original Message-----
>From: Troy Kisky [mailto:troy.kisky at boundarydevices.com]
>Sent: Wednesday, November 28, 2012 9:32 AM
>To: sbabic at denx.de
>Cc: dirk.behme at googlemail.com; u-boot at lists.denx.de; Liu Hui-R64343;
>festevam at gmail.com; Troy Kisky
>Subject: [PATCH V4 11/11] parse_helper: add expression evaluation
>
>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>

Acked-by: Jason Liu <r64343@freescale.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;
>+ }
> }
>
> /*
>--
>1.7.9.5
>